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Sample records for amorphous-metals high-performance corrosion-resistant

  1. High-Performance Corrosion-Resistant Materials: Iron-Based Amorphous-Metal Thermal-Spray Coatings

    International Nuclear Information System (INIS)

    Farmer, J C; Haslam, J J; Wong, F; Ji, X; Day, S D; Branagan, D J; Marshall, M C; Meacham, B E; Buffa, E J; Blue, C A; Rivard, J K; Beardsley, M B; Weaver, D T; Aprigliano, L F; Kohler, L; Bayles, R; Lemieux, E J; Wolejsza, T M; Martin, F J; Yang, N; Lucadamo, G; Perepezko, J H; Hildal, K; Kaufman, L; Heuer, A H; Ernst, F; Michal, G M; Kahn, H; Lavernia, E J

    2004-01-01

    The multi-institutional High Performance Corrosion Resistant Materials (HPCRM) Team is cosponsored by the Defense Advanced Projects Agency (DARPA) Defense Science Office (DSO) and the Department of Energy (DOE) Office of Civilian Radioactive Waste Management (OCRWM), and has developed new corrosion-resistant, iron-based amorphous metals that can be applied as coatings with advanced thermal spray technology. Two compositions have corrosion resistance superior to wrought nickel-based Alloy C-22 (UNS No. N06022) in very aggressive environments, including concentrated calcium-chloride brines at elevated temperature. Corrosion costs the Department of Defense billions of dollars every year, with an immense quantity of material in various structures undergoing corrosion. For example, in addition to fluid and seawater piping, ballast tanks, and propulsions systems, approximately 345 million square feet of structure aboard naval ships and crafts require costly corrosion control measures. The use of advanced corrosion-resistant materials to prevent the continuous degradation of this massive surface area would be extremely beneficial. The Fe-based corrosion-resistant, amorphous-metal coatings under development may prove of importance for applications on ships. Such coatings could be used as an ''integral drip shield'' on spent fuel containers, as well as protective coatings that could be applied over welds, thereby preventing exposure to environments that might cause stress corrosion cracking. In the future, such new high-performance iron-based materials could be substituted for more-expensive nickel-based alloys, thereby enabling a reduction in the $58-billion life cycle cost for the long-term storage of the Nation's spent nuclear fuel by tens of percent

  2. A High-Performance Corrosion-Resistant Iron-Based Amorphous Metal - The Effects of Composition, Structure and Environment on Corrosion Resistance

    International Nuclear Information System (INIS)

    Farmer, J.; Haslam, J.; Day, D.; Lian, T.; Saw, C.; Hailey, P.; Choi, J.S.; Rebak, R.; Yang, N.; Bayles, R.; Aprigliano, L.; Payer, J.; Perepezko, J.; Hildal, K.; Lavernia, E.; Ajdelsztajn, L.; Branagan, D.; Beardsley, B.

    2007-01-01

    The passive film stability of several Fe-based amorphous metal formulations have been found to be comparable to that of high-performance Ni-based alloys, and superior to that of stainless steels, based on electrochemical measurements of the passive film breakdown potential and general corrosion rates. Chromium (Cr), molybdenum (Mo) and tungsten (W) provide corrosion resistance; boron (B) enables glass formation; and rare earths such as yttrium (Y) lower critical cooling rate (CCR). The high boron content of this particular amorphous metal also makes it an effective neutron absorber, and suitable for criticality control applications, as discussed in companion publications. Corrosion data for SAM2X5 (Fe 49.7 Cr 17.7 Mn 1.9 Mo 7.4 W 1.6 B 15.2 C 3.8 Si 2.4 ) is discussed here. (authors)

  3. FY05 HPCRM Annual Report: High-Performance Corrosion-Resistant Iron-Based Amorphous Metal Coatings

    Energy Technology Data Exchange (ETDEWEB)

    Farmer, J; Choi, J; Haslam, J; Day, S; Yang, N; Headley, T; Lucadamo, G; Yio, J; Chames, J; Gardea, A; Clift, M; Blue, G; Peters, W; Rivard, J; Harper, D; Swank, D; Bayles, R; Lemieux, E; Brown, R; Wolejsza, T; Aprigliano, L; Branagan, D; Marshall, M; Meacham, B; Aprigliano, L; Branagan, D; Marshall, M; Meacham, B; Lavernia, E; Schoenung, J; Ajdelsztajn, L; Dannenberg, J; Graeve, O; Lewandowski, J; Perepezko, J; Hildal, K; Kaufman, L; Boudreau, J

    2007-09-20

    New corrosion-resistant, iron-based amorphous metals have been identified from published data or developed through combinatorial synthesis, and tested to determine their relative corrosion resistance. Many of these materials can be applied as coatings with advanced thermal spray technology. Two compositions have corrosion resistance superior to wrought nickel-based Alloy C-22 (UNS No. N06022) in some very aggressive environments, including concentrated calcium-chloride brines at elevated temperature. Two Fe-based amorphous metal formulations have been found that appear to have corrosion resistance comparable to, or better than that of Ni-based Alloy C-22, based on breakdown potential and corrosion rate. Both Cr and Mo provide corrosion resistance, B enables glass formation, and Y lowers critical cooling rate (CCR). SAM1651 has yttrium added, and has a nominal critical cooling rate of only 80 Kelvin per second, while SAM2X7 (similar to SAM2X5) has no yttrium, and a relatively high critical cooling rate of 610 Kelvin per second. Both amorphous metal formulations have strengths and weaknesses. SAM1651 (yttrium added) has a low critical cooling rate (CCR), which enables it to be rendered as a completely amorphous thermal spray coating. Unfortunately, it is relatively difficult to atomize, with powders being irregular in shape. This causes the powder to be difficult to pneumatically convey during thermal spray deposition. Gas atomized SAM1651 powder has required cryogenic milling to eliminate irregularities that make flow difficult. SAM2X5 (no yttrium) has a high critical cooling rate, which has caused problems associated with devitrification. SAM2X5 can be gas atomized to produce spherical powders of SAM2X5, which enable more facile thermal spray deposition. The reference material, nickel-based Alloy C-22, is an outstanding corrosion-resistant engineering material. Even so, crevice corrosion has been observed with C-22 in hot sodium chloride environments without buffer

  4. FY05 HPCRM Annual Report: High-Performance Corrosion-Resistant Iron-Based Amorphous Metal Coatings

    International Nuclear Information System (INIS)

    Farmer, J; Choi, J; Haslam, J; Day, S; Yang, N; Headley, T; Lucadamo, G; Yio, J; Chames, J; Gardea, A; Clift, M; Blue, G; Peters, W; Rivard, J; Harper, D; Swank, D; Bayles, R; Lemieux, E; Brown, R; Wolejsza, T; Aprigliano, L; Branagan, D; Marshall, M; Meacham, B; Aprigliano, L; Branagan, D; Marshall, M; Meacham, B; Lavernia, E; Schoenung, J; Ajdelsztajn, L; Dannenberg, J; Graeve, O; Lewandowski, J; Perepezko, J; Hildal, K; Kaufman, L; Boudreau, J

    2007-01-01

    New corrosion-resistant, iron-based amorphous metals have been identified from published data or developed through combinatorial synthesis, and tested to determine their relative corrosion resistance. Many of these materials can be applied as coatings with advanced thermal spray technology. Two compositions have corrosion resistance superior to wrought nickel-based Alloy C-22 (UNS No. N06022) in some very aggressive environments, including concentrated calcium-chloride brines at elevated temperature. Two Fe-based amorphous metal formulations have been found that appear to have corrosion resistance comparable to, or better than that of Ni-based Alloy C-22, based on breakdown potential and corrosion rate. Both Cr and Mo provide corrosion resistance, B enables glass formation, and Y lowers critical cooling rate (CCR). SAM1651 has yttrium added, and has a nominal critical cooling rate of only 80 Kelvin per second, while SAM2X7 (similar to SAM2X5) has no yttrium, and a relatively high critical cooling rate of 610 Kelvin per second. Both amorphous metal formulations have strengths and weaknesses. SAM1651 (yttrium added) has a low critical cooling rate (CCR), which enables it to be rendered as a completely amorphous thermal spray coating. Unfortunately, it is relatively difficult to atomize, with powders being irregular in shape. This causes the powder to be difficult to pneumatically convey during thermal spray deposition. Gas atomized SAM1651 powder has required cryogenic milling to eliminate irregularities that make flow difficult. SAM2X5 (no yttrium) has a high critical cooling rate, which has caused problems associated with devitrification. SAM2X5 can be gas atomized to produce spherical powders of SAM2X5, which enable more facile thermal spray deposition. The reference material, nickel-based Alloy C-22, is an outstanding corrosion-resistant engineering material. Even so, crevice corrosion has been observed with C-22 in hot sodium chloride environments without buffer

  5. Applications in the Nuclear Industry for Corrosion-Resistant Amorphous-Metal Thermal-Spray Coatings

    International Nuclear Information System (INIS)

    Farmer, J; Choi, J

    2007-01-01

    Amorphous metal and ceramic thermal spray coatings have been developed that can be used to enhance the corrosion resistance of containers for the transportation, aging and disposal of spent nuclear fuel and high-level radioactive wastes. Fe-based amorphous metal formulations with chromium, molybdenum and tungsten have shown the corrosion resistance believed to be necessary for such applications. Rare earth additions enable very low critical cooling rates to be achieved. The boron content of these materials, and their stability at high neutron doses, enable them to serve as high efficiency neutron absorbers for criticality control. Ceramic coatings may provide even greater corrosion resistance for container applications, though the boron-containing amorphous metals are still favored for criticality control applications. These amorphous metal and ceramic materials have been produced as gas atomized powders and applied as near full density, non-porous coatings with the high-velocity oxy-fuel process. This paper summarizes the performance of these coatings as corrosion-resistant barriers, and as neutron absorbers. Relevant corrosion models are also discussed, as well as a cost model to quantify the economic benefits possible with these new materials

  6. Corrosion-resistant amorphous metallic films of Mo49Cr33B18 alloy

    Science.gov (United States)

    Ramesham, R.; Distefano, S.; Fitzgerald, D.; Thakoor, A. P.; Khanna, S. K.

    1987-01-01

    Corrosion-resistant amorphous metallic alloy films of Mo49Cr33B18 with a crystallization temperature of 590 C were deposited onto glass and quartz substrates by magnetron sputter-quench technique. The amorphous nature of the films was confirmed by their diffuse X-ray diffraction patterns. The deposited films are densely packed (zone T) and exhibit low stress and good adhesion to the substrate. Corrosion current of as-deposited coating of MoCrB amorphous metallic alloy is approximately three orders of magnitude less than the corrosion current of 304 stainless steel in 1N H2SO4 solution.

  7. High-Performance Corrosion-Resistant Materials: Iron-Based Amorphous-Metal Thermal-Spray Coatings: SAM HPCRM Program ? FY04 Annual Report ? Rev. 0 - DARPA DSO & DOE OCRWM Co-Sponsored Advanced Materials Program

    Energy Technology Data Exchange (ETDEWEB)

    Farmer, J; Haslam, J; Wong, F; Ji, S; Day, S; Branagan, D; Marshall, M; Meacham, B; Buffa, E; Blue, C; Rivard, J; Beardsley, M; Buffa, E; Blue, C; Rivard, J; Beardsley, M; Weaver, D; Aprigliano, L; Kohler, L; Bayles, R; Lemieux, E; Wolejsza, T; Martin, F; Yang, N; Lucadamo, G; Perepezko, J; Hildal, K; Kaufman, L; Heuer, A; Ernst, F; Michal, G; Kahn, H; Lavernia, E

    2007-09-19

    The multi-institutional High Performance Corrosion Resistant Materials (HPCRM) Team is cosponsored by the Defense Advanced Projects Agency (DARPA) Defense Science Office (DSO) and the Department of Energy (DOE) Office of Civilian Radioactive Waste Management (OCRWM), and has developed new corrosion-resistant, iron-based amorphous metals that can be applied as coatings with advanced thermal spray technology. Two compositions have corrosion resistance superior to wrought nickel-based Alloy C-22 (UNS No. N06022) in very aggressive environments, including concentrated calcium-chloride brines at elevated temperature. Corrosion costs the Department of Defense billions of dollars every year, with an immense quantity of material in various structures undergoing corrosion. For example, in addition to fluid and seawater piping, ballast tanks, and propulsions systems, approximately 345 million square feet of structure aboard naval ships and crafts require costly corrosion control measures. The use of advanced corrosion-resistant materials to prevent the continuous degradation of this massive surface area would be extremely beneficial. The Fe-based corrosion-resistant, amorphous-metal coatings under development may prove of importance for applications on ships. Such coatings could be used as an 'integral drip shield' on spent fuel containers, as well as protective coatings that could be applied over welds, thereby preventing exposure to environments that might cause stress corrosion cracking. In the future, such new high-performance iron-based materials could be substituted for more-expensive nickel-based alloys, thereby enabling a reduction in the $58-billion life cycle cost for the long-term storage of the Nation's spent nuclear fuel by tens of percent.

  8. High-Performance Corrosion-Resistant Materials: Iron-Based Amorphous-Metal Thermal-Spray Coatings: SAM HPCRM Program ? FY04 Annual Report ? Rev. 0 - DARPA DSO and DOE OCRWM Co-Sponsored Advanced Materials Program

    International Nuclear Information System (INIS)

    Farmer, J; Haslam, J; Wong, F; Ji, S; Day, S; Branagan, D; Marshall, M; Meacham, B; Buffa, E; Blue, C; Rivard, J; Beardsley, M; Buffa, E; Blue, C; Rivard, J; Beardsley, M; Weaver, D; Aprigliano, L; Kohler, L; Bayles, R; Lemieux, E; Wolejsza, T; Martin, F; Yang, N; Lucadamo, G; Perepezko, J; Hildal, K; Kaufman, L; Heuer, A; Ernst, F; Michal, G; Kahn, H; Lavernia, E

    2007-01-01

    The multi-institutional High Performance Corrosion Resistant Materials (HPCRM) Team is cosponsored by the Defense Advanced Projects Agency (DARPA) Defense Science Office (DSO) and the Department of Energy (DOE) Office of Civilian Radioactive Waste Management (OCRWM), and has developed new corrosion-resistant, iron-based amorphous metals that can be applied as coatings with advanced thermal spray technology. Two compositions have corrosion resistance superior to wrought nickel-based Alloy C-22 (UNS No. N06022) in very aggressive environments, including concentrated calcium-chloride brines at elevated temperature. Corrosion costs the Department of Defense billions of dollars every year, with an immense quantity of material in various structures undergoing corrosion. For example, in addition to fluid and seawater piping, ballast tanks, and propulsions systems, approximately 345 million square feet of structure aboard naval ships and crafts require costly corrosion control measures. The use of advanced corrosion-resistant materials to prevent the continuous degradation of this massive surface area would be extremely beneficial. The Fe-based corrosion-resistant, amorphous-metal coatings under development may prove of importance for applications on ships. Such coatings could be used as an 'integral drip shield' on spent fuel containers, as well as protective coatings that could be applied over welds, thereby preventing exposure to environments that might cause stress corrosion cracking. In the future, such new high-performance iron-based materials could be substituted for more-expensive nickel-based alloys, thereby enabling a reduction in the $58-billion life cycle cost for the long-term storage of the Nation's spent nuclear fuel by tens of percent

  9. FY05 HPCRM Annual Report: High-Performance Corrosion-Resistant Iron-Based Amorphous Metal Coatings Evaluation of Corrosion Resistance FY05 HPCRM Annual Report No. Rev. 1DOE-DARPA Co-Sponsored Advanced Materials Program

    International Nuclear Information System (INIS)

    Farmer, J C; Haslam, J J; Day, S D

    2007-01-01

    New corrosion-resistant, iron-based amorphous metals have been identified from published data or developed through combinatorial synthesis, and tested to determine their relative corrosion resistance. Many of these materials can be applied as coatings with advanced thermal spray technology. Two compositions have corrosion resistance superior to wrought nickel-based Alloy C-22 (UNS No. N06022) in some very aggressive environments, including concentrated calcium-chloride brines at elevated temperature. Two Fe-based amorphous metal formulations have been found that appear to have corrosion resistance comparable to, or better than that of Ni-based Alloy C-22, based on breakdown potential and corrosion rate. Both Cr and Mo provide corrosion resistance, B enables glass formation, and Y lowers critical cooling rate (CCR). SAM1651 has yttrium added, and has a nominal critical cooling rate of only 80 Kelvin per second, while SAM2X7 (similar to SAM2X5) has no yttrium, and a relatively high critical cooling rate of 610 Kelvin per second. Both amorphous metal formulations have strengths and weaknesses. SAM1651 (yttrium added) has a low critical cooling rate (CCR), which enables it to be rendered as a completely amorphous thermal spray coating. Unfortunately, it is relatively difficult to atomize, with powders being irregular in shape. This causes the powder to be difficult to pneumatically convey during thermal spray deposition. Gas atomized SAM1651 powder has required cryogenic milling to eliminate irregularities that make flow difficult. SAM2X5 (no yttrium) has a high critical cooling rate, which has caused problems associated with devitrification. SAM2X5 can be gas atomized to produce spherical powders of SAM2X5, which enable more facile thermal spray deposition. The reference material, nickel-based Alloy C-22, is an outstanding corrosion-resistant engineering material. Even so, crevice corrosion has been observed with C-22 in hot sodium chloride environments without buffer

  10. DOE-DARPA High-Performance Corrosion-Resistant Materials (HPCRM), Annual HPCRM Team Meeting & Technical Review

    Energy Technology Data Exchange (ETDEWEB)

    Farmer, J; Brown, B; Bayles, B; Lemieux, T; Choi, J; Ajdelsztajn, L; Dannenberg, J; Lavernia, E; Schoenung, J; Branagan, D; Blue, C; Peter, B; Beardsley, B; Graeve, O; Aprigliano, L; Yang, N; Perepezko, J; Hildal, K; Kaufman, L; Lewandowski, J; Perepezko, J; Hildal, K; Kaufman, L; Lewandowski, J; Boudreau, J

    2007-09-21

    The overall goal is to develop high-performance corrosion-resistant iron-based amorphous-metal coatings for prolonged trouble-free use in very aggressive environments: seawater & hot geothermal brines. The specific technical objectives are: (1) Synthesize Fe-based amorphous-metal coating with corrosion resistance comparable/superior to Ni-based Alloy C-22; (2) Establish processing parameter windows for applying and controlling coating attributes (porosity, density, bonding); (3) Assess possible cost savings through substitution of Fe-based material for more expensive Ni-based Alloy C-22; (4) Demonstrate practical fabrication processes; (5) Produce quality materials and data with complete traceability for nuclear applications; and (6) Develop, validate and calibrate computational models to enable life prediction and process design.

  11. Corrosion resistance of high-performance materials titanium, tantalum, zirconium

    CERN Document Server

    2012-01-01

    Corrosion resistance is the property of a material to resist corrosion attack in a particular aggressive environment. Although titanium, tantalum and zirconium are not noble metals, they are the best choice whenever high corrosion resistance is required. The exceptionally good corrosion resistance of these high–performance metals and their alloys results from the formation of a very stable, dense, highly adherent, and self–healing protective oxide film on the metal surface. This naturally occurring oxide layer prevents chemical attack of the underlying metal surface. This behavior also means, however, that high corrosion resistance can be expected only under neutral or oxidizing conditions. Under reducing conditions, a lower resistance must be reckoned with. Only very few inorganic and organic substances are able to attack titanium, tantalum or zirconium at ambient temperature. As the extraordinary corrosion resistance is coupled with an excellent formability and weldability these materials are very valua...

  12. Corrosion resistant amorphous metals and methods of forming corrosion resistant amorphous metals

    Science.gov (United States)

    Farmer, Joseph C [Tracy, CA; Wong, Frank M. G. [Livermore, CA; Haslam, Jeffery J [Livermore, CA; Yang, Nancy [Lafayette, CA; Lavernia, Enrique J [Davis, CA; Blue, Craig A [Knoxville, TN; Graeve, Olivia A [Reno, NV; Bayles, Robert [Annandale, VA; Perepezko, John H [Madison, WI; Kaufman, Larry [Brookline, MA; Schoenung, Julie [Davis, CA; Ajdelsztajn, Leo [Walnut Creek, CA

    2009-11-17

    A system for coating a surface comprises providing a source of amorphous metal, providing ceramic particles, and applying the amorphous metal and the ceramic particles to the surface by a spray. The coating comprises a composite material made of amorphous metal that contains one or more of the following elements in the specified range of composition: yttrium (.gtoreq.1 atomic %), chromium (14 to 18 atomic %), molybdenum (.gtoreq.7 atomic %), tungsten (.gtoreq.1 atomic %), boron (.ltoreq.5 atomic %), or carbon (.gtoreq.4 atomic %).

  13. Amorphous Metallic Alloys: Pathways for Enhanced Wear and Corrosion Resistance

    Science.gov (United States)

    Aditya, Ayyagari; Felix Wu, H.; Arora, Harpreet; Mukherjee, Sundeep

    2017-11-01

    Amorphous metallic alloys are widely used in bulk form and as coatings for their desirable corrosion and wear behavior. Nevertheless, the effects of heat treatment and thermal cycling on these surface properties are not well understood. In this study, the corrosion and wear behavior of two Zr-based bulk metallic glasses were evaluated in as-cast and thermally relaxed states. Significant improvement in wear rate, friction coefficient, and corrosion penetration rate was seen for both alloys after thermal relaxation. A fully amorphous structure was retained with thermal relaxation below the glass transition. There was an increase in surface hardness and elastic modulus for both alloys after relaxation. The improvement in surface properties was explained based on annihilation of free volume.

  14. Study on applicability of highly corrosion-resistant amorphous coating techniques to components of reprocessing plant

    International Nuclear Information System (INIS)

    Ebata, Makoto; Okuyama, Gen; Chiba, Shigeru; Matsunaga, Tsunebumi

    1991-01-01

    In view of the growing need for prolongation of lives of reprocessing plant installations, we recently investigated the applicability of highly corrosion-resistant amorphous coating techniques to such plant components as to be subjected to a badly corrosive environment created by high temperatures, boiling nitric acid (HNO 3 ), etc. As the result, giving a preference to the Ta-based amorphous alloys exhibiting high corrosion-resistance in HNO 3 solutions, we made specimens of stainless steel plates coated with the above amorphous alloys through the sputtering process thereof. To our satisfaction, these specimens successfully passed various HNO 3 corrosion tests as described later on. Ta-based amorphous films give cathodic protection to 310 Nb stainless steel plates, and that with extremely low corrosion rates of themselves as protecting agents. For these reasons, we are confident that there will be no practical problems at all, in case we adopt stainless steel plates partially coated with such amorphous alloys for use in a nitric-acid environment. In this paper, we explain the comparative tests for various amorphous alloys with different compositions, referring also to the thus-selected Ta-based amorphous alloy along with several kinds of corrosion tests specially arranged for the same alloy. (author)

  15. Corrosion resistance of Fe-based amorphous alloys

    International Nuclear Information System (INIS)

    Botta, W.J.; Berger, J.E.; Kiminami, C.S.; Roche, V.; Nogueira, R.P.; Bolfarini, C.

    2014-01-01

    Highlights: ► We report corrosion properties of Fe-based amorphous alloys in different media. ► The Cr-containing alloys had corrosion resistance close to that of Pt in all media. ► The wide range of electrochemical stability is relevant in many industrial domains. -- Abstract: Fe-based amorphous alloys can be designed to present an attractive combination of properties with high corrosion resistance and high mechanical strength. Such properties are clearly adequate for their technological use as coatings, for example, in steel pipes. In this work, we studied the corrosion properties of amorphous ribbons of the following Fe-based compositions: Fe 66 B 30 Nb 4 , [(Fe 0.6 Co 0.4 ) 0.75 B 0.2 Si 0.05 ] 96 Nb 4 , [(Fe 0.7 Co 0.3 ) 0.75 B 0.2 Si 0.05 ] 96 Nb 4 , Fe 56 Cr 23 Ni 5.7 B 16 , Fe 53 Cr 22 Ni 5.6 B 19 and Fe 50 Cr 22 Ni 5.4 B 23 . The ribbons were obtained by rapid solidification using the melt-spinning process, and were characterized by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and optical (OM) and scanning electron microscopy (SEM). The corrosion properties were evaluated by corrosion potential survey and potentiodynamic polarization. The Cr containing alloys, that is the FeCrNiB type of alloys, showed the best corrosion resistance properties with the formation of a stable passive film that ensured a very large passivation plateau

  16. Corrosion resistance of amorphous NiCrZr and NiCrMoZr alloys

    International Nuclear Information System (INIS)

    Naka, M.; Miyake, M.; Okamoto, I.

    1987-01-01

    One of the authors has reported that the corrosion resistance of chromium containing amorphous alloys is extremely improved by alloying phosphorus among metalloids. Two factors operate for the improvement of corrosion resistance of the amorphous alloys. First, phosphorus serves for the rapid formation of protective passive film. Second, the compositional and structural homogeneity in amorphous state also account for the formation of protective film. The latter factor has been clearly seen in the high corrosion resistance of CoCrMoZr and CoCrWZr alloys without metalloids. In order to clarify the separately two factors in the corrosion resistance of amorphous alloys, the corrosion resistance of amorphous alloys without metalloids has to be further investigated. This paper also deals with the corrosion resistance and electrochemical behavior of NiCrZr and NiCrMoZr alloys in 1N HCl, and compare them with the corrosion behavior of the crystalline alloys containing the same composition as that of the amorphous alloys

  17. Corrosion resistant metallic glasses for biosensing applications

    Science.gov (United States)

    Sagasti, Ariane; Lopes, Ana Catarina; Lasheras, Andoni; Palomares, Verónica; Carrizo, Javier; Gutierrez, Jon; Barandiaran, J. Manuel

    2018-04-01

    We report the fabrication by melt spinning, the magnetic and magnetoelastic characterization and corrosion behaviour study (by potentiodynamic methods) of an Fe-based, Fe-Ni-Cr-Si-B metallic glass to be used as resonant platform for biological and chemical detection purposes. The same study has been performed in Fe-Co-Si-B (with excellent magnetoelastic properties) and Fe-Ni-B (with good corrosion properties due to the substitution of Co by Ni) composition amorphous alloys. The well-known, commercial metallic glass with high corrosion resistance Metglas 2826MB®(Fe40Ni38Mo4B18), widely used for such biological and chemical detection purposes, has been also fully characterized and used as reference. For our Fe-Ni-Cr-Si-B alloy, we have measured values of magnetization (1.22 T), magnetostriction (11.5 ppm) and ΔE effect (6.8 %) values, as well as corrosion potential (-0.25 V), current density (2.54 A/m2), and polarization resistance (56.22 Ω.cm2) that make this composition very promising for the desired biosensing applications. The obtained parameters from our exhaustive characterization are compared with the values obtained for the other different composition metallic glasses and discussed in terms of Ni and Cr content.

  18. Corrosion resistant metallic glasses for biosensing applications

    Directory of Open Access Journals (Sweden)

    Ariane Sagasti

    2018-04-01

    Full Text Available We report the fabrication by melt spinning, the magnetic and magnetoelastic characterization and corrosion behaviour study (by potentiodynamic methods of an Fe-based, Fe-Ni-Cr-Si-B metallic glass to be used as resonant platform for biological and chemical detection purposes. The same study has been performed in Fe-Co-Si-B (with excellent magnetoelastic properties and Fe-Ni-B (with good corrosion properties due to the substitution of Co by Ni composition amorphous alloys. The well-known, commercial metallic glass with high corrosion resistance Metglas 2826MB®(Fe40Ni38Mo4B18, widely used for such biological and chemical detection purposes, has been also fully characterized and used as reference. For our Fe-Ni-Cr-Si-B alloy, we have measured values of magnetization (1.22 T, magnetostriction (11.5 ppm and ΔE effect (6.8 % values, as well as corrosion potential (-0.25 V, current density (2.54 A/m2, and polarization resistance (56.22 Ω.cm2 that make this composition very promising for the desired biosensing applications. The obtained parameters from our exhaustive characterization are compared with the values obtained for the other different composition metallic glasses and discussed in terms of Ni and Cr content.

  19. Applications in the Nuclear Industry for Thermal Spray Amorphous Metal and Ceramic Coatings

    Science.gov (United States)

    Blink, J.; Farmer, J.; Choi, J.; Saw, C.

    2009-06-01

    Amorphous metal and ceramic thermal spray coatings have been developed with excellent corrosion resistance and neutron absorption. These coatings, with further development, could be cost-effective options to enhance the corrosion resistance of drip shields and waste packages, and limit nuclear criticality in canisters for the transportation, aging, and disposal of spent nuclear fuel. Iron-based amorphous metal formulations with chromium, molybdenum, and tungsten have shown the corrosion resistance believed to be necessary for such applications. Rare earth additions enable very low critical cooling rates to be achieved. The boron content of these materials and their stability at high neutron doses enable them to serve as high efficiency neutron absorbers for criticality control. Ceramic coatings may provide even greater corrosion resistance for waste package and drip shield applications, although the boron-containing amorphous metals are still favored for criticality control applications. These amorphous metal and ceramic materials have been produced as gas-atomized powders and applied as near full density, nonporous coatings with the high-velocity oxy-fuel process. This article summarizes the performance of these coatings as corrosion-resistant barriers and as neutron absorbers. This article also presents a simple cost model to quantify the economic benefits possible with these new materials.

  20. Corrosion-resistant metal surfaces

    Science.gov (United States)

    Sugama, Toshifumi [Wading River, NY

    2009-03-24

    The present invention relates to metal surfaces having thereon an ultrathin (e.g., less than ten nanometer thickness) corrosion-resistant film, thereby rendering the metal surfaces corrosion-resistant. The corrosion-resistant film includes an at least partially crosslinked amido-functionalized silanol component in combination with rare-earth metal oxide nanoparticles. The invention also relates to methods for producing such corrosion-resistant films.

  1. Corrosion resistance and biocompatibility of titanium surface coated with amorphous tantalum pentoxide

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Ying-Sui [Department of Oral Biology, National Yang-Ming University, Taipei, Taiwan (China); Chang, Jean-Heng [Dental Department, Cheng Hsin General Hospital, Taipei, Taiwan (China); Huang, Her-Hsiung, E-mail: hhhuang@ym.edu.tw [Department of Dentistry, National Yang-Ming University, Taipei, Taiwan (China); Department of Dentistry, Taipei City Hospital, Taipei, Taiwan (China); Department of Stomatology, Taipei Veterans General Hospital, Taipei, Taiwan (China)

    2013-01-01

    Tantalum pentoxide (Ta{sub 2}O{sub 5}) possesses good corrosion resistance and biocompatibility. This study aimed to improve the corrosion resistance and biocompatibility of titanium (Ti) by coating it with an amorphous Ta{sub 2}O{sub 5} surface layer. An amorphous Ta{sub 2}O{sub 5} layer was prepared on the Ti surface using a simple hydrolysis–condensation process at room temperature. The surface characteristics of the test specimens were analyzed using X-ray photoelectron spectroscopy, glancing angle X-ray diffraction, field emission scanning electron microscopy, and contact angle measurements. The corrosion resistance of the test specimens was evaluated from the potentiodynamic polarization curves and ion release measurements in simulated blood plasma (SBP). The biocompatibility of the test specimens was evaluated in terms of the protein (albumin) adsorption, cell adhesion, and cell growth of human bone marrow mesenchymal stem cells (hBMSCs). The amorphous Ta{sub 2}O{sub 5} layer with a porous micro-/nano-scale topography, which was deposited on the Ti surface using a simple hydrolysis–condensation process, increased the corrosion resistance (i.e., increased the corrosion potential and decreased the anodic current and ion release) of the Ti in the SBP and improved the surface wettability, albumin adsorption, and cell adhesion. We conclude that the presence of an amorphous Ta{sub 2}O{sub 5} layer on the Ti surface increased the corrosion resistance and biocompatibility of Ti. - Highlights: ► Amorphous Ta{sub 2}O{sub 5} layer was coated on Ti using simple hydrolysis–condensation process. ► Ta{sub 2}O{sub 5} surface layer showed a micro-/nano-scale porous topography. ► Ta{sub 2}O{sub 5} layer enhanced wettability and corrosion resistance of Ti. ► Ta{sub 2}O{sub 5} layer enhanced protein adsorption, cell adhesion, and cell proliferation of Ti.

  2. Corrosion-resistant amorphous alloy ribbons for electromagnetic filtration of iron rusts from water

    International Nuclear Information System (INIS)

    Kawashima, Asahi; Asami, Katsuhiko; Sato, Takeaki; Hashimoto, Koji

    1985-01-01

    An attempt was made to use corrosion-resistant amorphous Fe-9Cr-13P-7C alloy ribbons as an electromagnetic filter material for trapping various iron rusts suspended in water at 40 0 C. The ferrimagnetic Fe 3 O 4 rust was trapped with the 100 % efficiency and paramagnetic rusts such as α-Fe 2 O 3 , α-FeOOH and amorphous ferric oxyhydroxide were trapped with certain efficiencies at the magnetic field strength of 0.5-10 kOe. The regeneration of the filter by back-washing was easy. The trapping capacity of electromagnetic filter was proportional to the edge length of the filter material where the high magnetic field strength existed. Therefore, melt-spun thin and narrow amorphous alloy ribbons having the high corrosion resistance have the potential utility as electromagnetic filter material. (author)

  3. Improvement of bio-corrosion resistance for Ti42Zr40Si15Ta3 metallic glasses in simulated body fluid by annealing within supercooled liquid region.

    Science.gov (United States)

    Huang, C H; Lai, J J; Wei, T Y; Chen, Y H; Wang, X; Kuan, S Y; Huang, J C

    2015-01-01

    The effects of the nanocrystalline phases on the bio-corrosion behavior of highly bio-friendly Ti42Zr40Si15Ta3 metallic glasses in simulated body fluid were investigated, and the findings are compared with our previous observations from the Zr53Cu30Ni9Al8 metallic glasses. The Ti42Zr40Si15Ta3 metallic glasses were annealed at temperatures above the glass transition temperature, Tg, with different time periods to result in different degrees of α-Ti nano-phases in the amorphous matrix. The nanocrystallized Ti42Zr40Si15Ta3 metallic glasses containing corrosion resistant α-Ti phases exhibited more promising bio-corrosion resistance, due to the superior pitting resistance. This is distinctly different from the previous case of the Zr53Cu30Ni9Al8 metallic glasses with the reactive Zr2Cu phases inducing serious galvanic corrosion and lower bio-corrosion resistance. Thus, whether the fully amorphous or partially crystallized metallic glass would exhibit better bio-corrosion resistance, the answer would depend on the crystallized phase nature. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Influence of structural relaxation and partial devitrification on the corrosion resistance of Fe78B13Si9 amorphous alloy

    International Nuclear Information System (INIS)

    Souza, C.A.C.; Politi, F.S.; Kiminami, C.S.

    1998-01-01

    Amorphous alloys obtained by rapid solidification from the melt exhibit a similar structure to those observed in the liquid state, i.e., without long range ordering, in such a way that the constituents of the alloy usually are randomly and homogeneously distributed. Amorphous alloys, depending on their composition, may exhibit interesting characteristics such as very soft magnetic properties and improved resistance to corrosion. The high corrosion resistance of these alloys is attributed mainly to a higher rate of dissolution of passivating elements in the amorphous state. In addition, amorphous alloys are chemically homogeneous and free of defects such as grain boundaries, precipitates and segregation, which are favorable sites for corrosion. The corrosion resistance of amorphous alloys also depends on their thermal history. Several authors have reported that structural changes, such as structural relaxation and devitrification caused by annealing, change significantly the corrosion properties of these alloys. The purpose of this paper is to study corrosion resistance of the amorphous FeBSi alloy and the effects of structural changes such as structural relaxation and partial crystallization caused by annealing

  5. Corrosion Performance of Inconel 625 in High Sulphate Content

    Science.gov (United States)

    Ismail, Azzura

    2016-05-01

    Inconel 625 (UNS N06625) is a type of nickel-chromium-molybdenum alloy with excellent corrosion resistance in a wide range of corrosive media, being especially resistant to pitting and crevice corrosion. However, in aggressive environment, Inconel 625 will suffer corrosion attack like other metals. This research compared the corrosion performance of Inconel 625 when exposed to higher sulphate content compared to real seawater. The results reveal that Inconel 625 is excellent in resist the corrosion attack in seawater. However, at increasing temperature, the corrosion resistance of this metal decrease. The performance is same in seawater with high sulphate content at increasing temperature. It can be concluded that sulphate promote perforation on Inconel 625 and become aggressive agents that accelerate the corrosion attack.

  6. Applications in the Nuclear Industry for Thermal Spray Amorphous Metal and Ceramic Coatings

    OpenAIRE

    Blink, J.; Farmer, J.; Choi, J.; Saw, C.

    2009-01-01

    Amorphous metal and ceramic thermal spray coatings have been developed with excellent corrosion resistance and neutron absorption. These coatings, with further development, could be cost-effective options to enhance the corrosion resistance of drip shields and waste packages, and limit nuclear criticality in canisters for the transportation, aging, and disposal of spent nuclear fuel. Iron-based amorphous metal formulations with chromium, molybdenum, and tungsten have shown the corrosion resis...

  7. Influence of the microstructure on the corrosion behavior of magnetron sputter-quenched amorphous metallic alloys

    Science.gov (United States)

    Thakoor, A. P.; Khanna, S. K.; Williams, R. M.; Landel, R. F.

    1983-01-01

    The microstructure and corrosion behavior of magnetron sputter deposited amorphous metallic films of (Mo6ORu40)82B18 under varying sputtering atmospheres have been investigated. The microstructural details and topology of the films have been studied by scanning electron microscopy and correlated with the deposition conditions. By reducing the pressure of pure argon gas, the characteristic features of rough surface and columnar growth full of vertical voids can be converted into a mirror-smooth finish with very dense deposits. Films deposited in the presence of O2 or N2 exhibit columnar structure with vertical voids. Film deposited in pure argon at low pressure show remarkably high corrosion resistance due to the formation of a uniform passive surface layer. The influence of the microstructure and surface texture on the corrosion behavior is discussed.

  8. Localized corrosion of high performance metal alloys in an acid/salt environment

    Science.gov (United States)

    Macdowell, L. G.; Ontiveros, C.

    1991-01-01

    Various vacuum jacketed cryogenic supply lines at the Space Shuttle launch site at Kennedy Space Center use convoluted flexible expansion joints. The atmosphere at the launch site has a very high salt content, and during a launch, fuel combustion products include hydrochloric acid. This extremely corrosive environment has caused pitting corrosion failure in the thin walled 304L stainless steel flex hoses. A search was done to find a more corrosion resistant replacement material. The study focussed on 19 metal alloys. Tests which were performed include electrochemical corrosion testing, accelerated corrosion testing in a salt fog chamber, and long term exposure at a beach corrosion testing site. Based on the results of these tests, several nickel based alloys were found to have very high resistance to this corrosive environment. Also, there was excellent agreement between the electrochemical tests and the actual beach exposure tests. This suggests that electrochemical testing may be useful for narrowing the field of potential candidate alloys before subjecting samples to long term beach exposure.

  9. Corrosion behavior in high-temperature pressurized water of Zircaloy-4 joints brazed with Zr-Cu-based amorphous filler alloys

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jung Gu, E-mail: jglee88@ulsan.ac.kr [School of Materials Science and Engineering, University of Ulsan, Ulsan 44610 (Korea, Republic of); Lee, Gyoung-Ja; Park, Jin-Ju [Nuclear Materials Development Division, Korea Atomic Energy Research Institute (KAERI), Yuseong, Daejeon 34057 (Korea, Republic of); Lee, Min-Ku, E-mail: leeminku@kaeri.re.kr [Nuclear Materials Development Division, Korea Atomic Energy Research Institute (KAERI), Yuseong, Daejeon 34057 (Korea, Republic of)

    2017-05-15

    The compositional effects of ternary Zr-Cu-X (X: Al, Fe) amorphous filler alloys on galvanic corrosion susceptibility in high-temperature pressurized water were investigated for Zircaloy-4 brazed joints. Through an Al-induced microgalvanic reaction that deteriorated the overall nobility of the joint, application of the Zr-Cu-Al filler alloy caused galvanic coupling to develop readily between the Al-bearing joint and the Al-free base metal, finally leading to massive localized corrosion of the joint. Contrastingly, joints prepared with a Zr-Cu-Fe filler alloy showed excellent corrosion resistance comparable to that of the Zircaloy-4 base metal, since the Cu and Fe elements forming fine intermetallic particles with Zr did not influence the electrochemical stability of the resultant joints. The present results demonstrate that Fe is a more suitable alloying element than Al for brazing filler alloys subjected to high-temperature corrosive environments. - Highlights: •Corrosion of Zircaloy-4 joints brazed with Zr-Cu-X filler alloys was investigated. •Alloyed Al deteriorated the overall nobility of joints by microgalvanic reaction. •Compositional gradient of Al in joints was the driving force for galvanic corrosion. •Cu and Fe did not influence the electrochemical stability of joints. •Zr-Cu-Fe filler alloy yielded excellent high-temperature corrosion resistance.

  10. Corrosion behavior in high-temperature pressurized water of Zircaloy-4 joints brazed with Zr-Cu-based amorphous filler alloys

    International Nuclear Information System (INIS)

    Lee, Jung Gu; Lee, Gyoung-Ja; Park, Jin-Ju; Lee, Min-Ku

    2017-01-01

    The compositional effects of ternary Zr-Cu-X (X: Al, Fe) amorphous filler alloys on galvanic corrosion susceptibility in high-temperature pressurized water were investigated for Zircaloy-4 brazed joints. Through an Al-induced microgalvanic reaction that deteriorated the overall nobility of the joint, application of the Zr-Cu-Al filler alloy caused galvanic coupling to develop readily between the Al-bearing joint and the Al-free base metal, finally leading to massive localized corrosion of the joint. Contrastingly, joints prepared with a Zr-Cu-Fe filler alloy showed excellent corrosion resistance comparable to that of the Zircaloy-4 base metal, since the Cu and Fe elements forming fine intermetallic particles with Zr did not influence the electrochemical stability of the resultant joints. The present results demonstrate that Fe is a more suitable alloying element than Al for brazing filler alloys subjected to high-temperature corrosive environments. - Highlights: •Corrosion of Zircaloy-4 joints brazed with Zr-Cu-X filler alloys was investigated. •Alloyed Al deteriorated the overall nobility of joints by microgalvanic reaction. •Compositional gradient of Al in joints was the driving force for galvanic corrosion. •Cu and Fe did not influence the electrochemical stability of joints. •Zr-Cu-Fe filler alloy yielded excellent high-temperature corrosion resistance.

  11. Corrosion behavior of amorphous and crystalline Cu50Ti50 and Cu50Zr50 alloys

    International Nuclear Information System (INIS)

    Naka, M.; Hoshimoto, K.; Masumoto, T.

    1978-01-01

    Corrosion rates and anodic polarization curves of amorphous and crystalline Cu 50 Ti 50 and Cu 50 Zr 50 alloys have been examined in various acidic, neutral and alkaline solutions. The amorphous alloys are very stable in acidic and alkaline solutions, but unstable in agressive chloride solutions. The corrosion resistance of these amorphous alloys is higher than that of the crystallized alloys. The high corrosion resistance of amorphous alloys is attributable to the high chemical homogeneity of amorphous alloys without localized crystalline defects such as precipitates, segregates, grain boundaries, etc. Metalloid elements play an important role in the corrosion behavior of amorphous alloys; the addition of phosphorus to amorphous Cu-Ti alloy greatly increases the corrosion resistance, even in 1N HCl. (Auth.)

  12. Corrosion behavior in high-temperature pressurized water of Zircaloy-4 joints brazed with Zr-Cu-based amorphous filler alloys

    Science.gov (United States)

    Lee, Jung Gu; Lee, Gyoung-Ja; Park, Jin-Ju; Lee, Min-Ku

    2017-05-01

    The compositional effects of ternary Zr-Cu-X (X: Al, Fe) amorphous filler alloys on galvanic corrosion susceptibility in high-temperature pressurized water were investigated for Zircaloy-4 brazed joints. Through an Al-induced microgalvanic reaction that deteriorated the overall nobility of the joint, application of the Zr-Cu-Al filler alloy caused galvanic coupling to develop readily between the Al-bearing joint and the Al-free base metal, finally leading to massive localized corrosion of the joint. Contrastingly, joints prepared with a Zr-Cu-Fe filler alloy showed excellent corrosion resistance comparable to that of the Zircaloy-4 base metal, since the Cu and Fe elements forming fine intermetallic particles with Zr did not influence the electrochemical stability of the resultant joints. The present results demonstrate that Fe is a more suitable alloying element than Al for brazing filler alloys subjected to high-temperature corrosive environments.

  13. Corrosion resistance of amorphous and crystalline Pd40Ni40P20 alloys in aqueous solutions

    DEFF Research Database (Denmark)

    Wu, Y.F.; Chiang, Wen-Chi; Chu, J.

    2006-01-01

    The corrosion behaviors of amorphous and crystalline Pd40Ni40P20 alloys in various aqueous solutions are reported in this paper. The corrosion resistance of crystalline (annealed) Pd40Ni40P20 is better than that of amorphous Pd40Ni40P20 in various corrosive solutions, due to crystalline Pd40Ni40P20...... and mainly consists of inert Pd5P2, NI3P, Ni2Pd2P and noble Pd phases. These inert and noble properties result in a higher corrosion resistance in crystalline Pd40Ni40P20....

  14. Production and properties of light-metal base amorphous alloys

    International Nuclear Information System (INIS)

    Inoue, Akihisa; Masumoto, Tsuyoshi

    1993-01-01

    Light-metal base alloys with high specific strength and good corrosion resistance were produced through amorphization of Al and Mg-based alloys. The amorphous phase is formed in rapidly solidified Al-TM-Ln and Mg-TM-Ln (TM=transition metal, Ln=lanthanide metal) alloys. The highest tensile strength (σ f ) reaches 1,330 MPa for the Al base and 830 MPa for the Mg base. Furthermore, the Mg-based alloys have a large glass-forming capacity which enables to produce an amorphous phase by a metallic mold casting method. The extrusion of the Al-based amorphous powders at temperatures above crystallization temperature caused the formation of high strength materials with finely mixed structure consisting of dispersed intermetallic compounds in an Al matrix. The highest values of σ f and fatigue limit are as high as 940 and 313 MPa, respectively, at room temperature and 520 and 165 MPa at 473 K. The extruded Al-Ni-Mm alloy has already been used as machine parts and subsequent further development as practical materials is expected by taking these advantages

  15. Tribological properties, corrosion resistance and biocompatibility of magnetron sputtered titanium-amorphous carbon coatings

    Science.gov (United States)

    Dhandapani, Vishnu Shankar; Subbiah, Ramesh; Thangavel, Elangovan; Arumugam, Madhankumar; Park, Kwideok; Gasem, Zuhair M.; Veeraragavan, Veeravazhuthi; Kim, Dae-Eun

    2016-05-01

    Amorphous carbon incorporated with titanium (a-C:Ti) was coated on 316L stainless steel (SS) by magnetron sputtering technique to attain superior tribological properties, corrosion resistance and biocompatibility. The morphology, topography and functional groups of the nanostructured a-C:Ti coatings in various concentrations were analyzed using atomic force microscopy (AFM), Raman, X-Ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). Raman and XPS analyses confirmed the increase in sp2 bonds with increasing titanium content in the a-C matrix. TEM analysis confirmed the composite nature of the coating and the presence of nanostructured TiC for Ti content of 2.33 at.%. This coating showed superior tribological properties compared to the other a-C:Ti coatings. Furthermore, electrochemical corrosion studies were performed against stimulated body fluid medium in which all the a-C:Ti coatings showed improved corrosion resistance than the pure a-C coating. Preosteoblasts proliferation and viability on the specimens were tested and the results showed that a-C:Ti coatings with relatively high Ti (3.77 at.%) content had better biocompatibility. Based on the results of this work, highly durable coatings with good biocompatibility could be achieved by incorporation of optimum amount of Ti in a-C coatings deposited on SS by magnetron sputtering technique.

  16. Tribological properties, corrosion resistance and biocompatibility of magnetron sputtered titanium-amorphous carbon coatings

    International Nuclear Information System (INIS)

    Dhandapani, Vishnu Shankar; Subbiah, Ramesh; Thangavel, Elangovan; Arumugam, Madhankumar; Park, Kwideok; Gasem, Zuhair M.; Veeraragavan, Veeravazhuthi; Kim, Dae-Eun

    2016-01-01

    Highlights: • a-C:Ti nanocomposite coatings were prepared on 316L stainless steel by using R.F. magnetron sputtering method. • Properties of the nanocomposite coatings were analyzed with respect to titanium content. • Corrosion resistance, biocompatibility and hydrophobicity of nanocomposite coating were enhanced with increasing titanium content. • Coating with 2.33 at.% titanium showed superior tribological properties compared to other coatings. - Abstract: Amorphous carbon incorporated with titanium (a-C:Ti) was coated on 316L stainless steel (SS) by magnetron sputtering technique to attain superior tribological properties, corrosion resistance and biocompatibility. The morphology, topography and functional groups of the nanostructured a-C:Ti coatings in various concentrations were analyzed using atomic force microscopy (AFM), Raman, X-Ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). Raman and XPS analyses confirmed the increase in sp"2 bonds with increasing titanium content in the a-C matrix. TEM analysis confirmed the composite nature of the coating and the presence of nanostructured TiC for Ti content of 2.33 at.%. This coating showed superior tribological properties compared to the other a-C:Ti coatings. Furthermore, electrochemical corrosion studies were performed against stimulated body fluid medium in which all the a-C:Ti coatings showed improved corrosion resistance than the pure a-C coating. Preosteoblasts proliferation and viability on the specimens were tested and the results showed that a-C:Ti coatings with relatively high Ti (3.77 at.%) content had better biocompatibility. Based on the results of this work, highly durable coatings with good biocompatibility could be achieved by incorporation of optimum amount of Ti in a-C coatings deposited on SS by magnetron sputtering technique.

  17. FY 2000 report on the survey on energy conservation technology of large plant using ultra high corrosion resistant materials; 2000 nendo chokotaishokusei zairyo wo mochiita ogata plant no sho energy gijutsu ni kansuru chosa hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-03-01

    For the purpose of achieving remarkable energy conservation/resource conservation in large plants, the paper carried out an investigational survey of effects obtained in case of applying amorphous super metal which is the newest corrosion resistant material. Amorphous alloys as an ultra high corrosion resistant material are a peculiar material which shows the extremely excellent corrosion resistance even in much strong acid by containing passivated elements with the needed concentration. The corrosion resistant amorphous alloy applied to large plants need the thickness and diameter of more than several millimeters as a bulk material. The subjects are scaling-up of bulk materials and stabilization of characteristics. Even under the tough dew point corrosion environment of the waste power plant, etc., heat recovery from exhaust gas is made possible by heat exchanger applied with ultra high corrosion resistant materials. Effects of the annual heat recovery from the nationwide refuse incinerators and coal thermal power plants are estimated to be approximately 5.2 million kL toe, that is, to be equal to energy conservation of 6 x a million kW class power plant. (NEDO)

  18. Effect of manufacturing process sequence on the corrosion resistance characteristics of coated metallic bipolar plates

    Science.gov (United States)

    Dur, Ender; Cora, Ömer Necati; Koç, Muammer

    2014-01-01

    Metallic bipolar plate (BPP) with high corrosion and low contact resistance, durability, strength, low cost, volume, and weight requirements is one of the critical parts of the PEMFC. This study is dedicated to understand the effect of the process sequence (manufacturing then coating vs. coating then manufacturing) on the corrosion resistance of coated metallic bipolar plates. To this goal, three different PVD coatings (titanium nitride (TiN), chromium nitride (CrN), zirconium nitride (ZrN)), with three thicknesses, (0.1, 0.5, 1 μm) were applied on BPPs made of 316L stainless steel alloy before and after two types of manufacturing (i.e., stamping or hydroforming). Corrosion test results indicated that ZrN coating exhibited the best corrosion protection while the performance of TiN coating was the lowest among the tested coatings and thicknesses. For most of the cases tested, in which coating was applied before manufacturing, occurrence of corrosion was found to be more profound than the case where coating was applied after manufacturing. Increasing the coating thickness was found to improve the corrosion resistance. It was also revealed that hydroformed BPPs performed slightly better than stamped BPPs in terms of the corrosion behavior.

  19. Co-sputtered amorphous Nb–Ta, Nb–Zr and Ta–Zr coatings for corrosion protection of cyclotron targets for [{sup 18}F] production

    Energy Technology Data Exchange (ETDEWEB)

    Skliarova, Hanna, E-mail: Hanna.Skliarova@lnl.infn.it [National Institute of Nuclear Physics, Legnaro National Laboratories, Viale dell’Università, 2, 35020 Legnaro, Padua (Italy); University of Ferrara, Ferrara (Italy); Azzolini, Oscar, E-mail: Oscar.Azzolini@lnl.infn.it [National Institute of Nuclear Physics, Legnaro National Laboratories, Viale dell’Università, 2, 35020 Legnaro, Padua (Italy); Johnson, Richard R., E-mail: richard.johnson@teambest.com [BEST Cyclotron Systems Inc., 8765 Ash Street Unit 7, Vancouver, BC V6P 6T3 (Canada); Palmieri, Vincenzo, E-mail: Vincenzo.Palmieri@lnl.infn.it [National Institute of Nuclear Physics, Legnaro National Laboratories, Viale dell’Università, 2, 35020 Legnaro, Padua (Italy); University of Padua, Padua (Italy)

    2015-08-05

    Highlights: • Nb–Ta, Nb–Zr and Ta–Zr alloy films were deposited by co-sputtering. • Co-sputtered Nb–Zr and Nb–Ta alloy coatings had crystalline microstructures. • Diffusion barrier efficiency of Nb–Zr and Nb–Ta decreased with the increase of Nb %. • Co-sputtered Ta–Zr films with 30–73 at.% Ta were amorphous. • Sputtered amorphous Ta–Zr films showed superior diffusion barrier efficiency. - Abstract: Protective corrosion resistant coatings serve for decreasing the amount of ionic contaminants from Havar® entrance foils of the targets for [{sup 18}F] production. The corrosion damage of coated entrance foils is caused mainly by the diffusion of highly reactive products of water radiolysis through the protective film toward Havar® substrate. Since amorphous metal alloys (metallic glasses) are well-known to perform a high corrosion resistance, the glass forming ability, microstructure and diffusion barrier efficiency of binary alloys containing chemically inert Nb, Ta, Zr were investigated. Nb–Ta, Nb–Zr and Ta–Zr films of different alloy composition and ∼1.5 μm thickness were co-deposited by magnetron sputtering. Diffusion barrier efficiency tests used reactive aluminum underlayer and protons of acid solution and gallium atoms at elevated temperature as diffusing particles. Though co-sputtered Nb–Ta and Nb–Zr alloy films of different contents were crystalline, Ta–Zr alloy was found to form dense amorphous microstructures in a range of composition with 30–73% atomic Ta. The diffusion barrier efficiency of Nb–Zr and Nb–Ta alloy coatings decreased with increase of Nb content. The diffusion barrier efficiency of sputtered Ta–Zr alloy coatings increased with the transition from nanocrystalline columnar microstructure to amorphous for coatings with 30–73 at.% Ta.

  20. Effect of composition on corrosion resistance of high-alloy austenitic stainless steel weld metals

    International Nuclear Information System (INIS)

    Marshall, P.I.; Gooch, T.G.

    1993-01-01

    The corrosion resistance of stainless steel weld metal in the ranges of 17 to 28% chromium (Cr), 6 to 60% nickel (Ni), 0 to 9% molybdenum (Mo), and 0.0 to 0.37% nitrogen (N) was examined. Critical pitting temperatures were determined in ferric chloride (FeCl 3 ). Passive film breakdown potentials were assessed from potentiodynamic scans in 3% sodium chloride (NaCl) at 50 C. Potentiodynamic and potentiostatic tests were carried out in 30% sulfuric acid (H 2 SO 4 ) ar 25 C, which was representative of chloride-free acid media of low redox potential. Metallographic examination and microanalysis were conducted on the test welds. Because of segregation of alloying elements, weld metal pitting resistance always was lower than that of matching composition base steel. The difference increased with higher Cr, Mo, and N contents. Segregation also reduced resistance to general corrosion in H 2 SO 4 , but the effect relative to the base steel was less marked than with chloride pitting. Segregation of Cr, Mo, and N in fully austenitic deposits decreased as the Ni' eq- Cr' eq ratio increased. Over the compositional range studied, weld metal pitting resistance was dependent mainly on Mo content and segregation. N had less effect than in wrought alloys. Both Mo and N enhanced weld metal corrosion resistance in H 2 SO 4

  1. Eelectrochemical properties and corrosion resistance of carbon-ion-implanted magnesium

    International Nuclear Information System (INIS)

    Xu, Ruizhen; Yang, Xiongbo; Li, Penghui; Suen, Kai Wong; Wu, Guosong; Chu, Paul K.

    2014-01-01

    Highlights: • Carbon, as a biocompatible benign element, was implanted into Mg. • A protective amorphous carbon layer was formed after implantation. • Treated sample exhibits good corrosion resistance in two solutions. - Abstract: The corrosion resistance of magnesium-based biomaterials is critical to clinical applications. In this work, carbon as a biocompatible and benign nonmetallic element with high chemical inertness is implanted into pure magnesium to improve the corrosion behavior. X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HR-TEM), and Raman scattering reveal the formation of an amorphous carbon layer after ion implantation. Electrochemical studies demonstrate remarkable improvement in the corrosion resistance of magnesium in simulated body fluids (SBF) and Dulbecco’s Modified Eagle Medium (DMEM)

  2. Effect of applied potential on passivation and erosion–corrosion of a Fe-based amorphous metallic coating under slurry impingement

    International Nuclear Information System (INIS)

    Zheng, Z.B.; Zheng, Y.G.; Sun, W.H.; Wang, J.Q.

    2014-01-01

    Highlights: • The passive current density of coating increases with the increasing potential. • Preferential dissolution of high-valence oxides happens at high applied potential. • More chlorides exist in the passive film at high film formation potential. • Critical flow velocity under impingement is related to resistance of passive film. - Abstract: The passive behaviour and erosion–corrosion behaviour of a HVOF sprayed Fe-based amorphous metallic coating have been investigated in 3.5 wt.% NaCl solution by using potentiostatic polarisation, X-ray photoelectron spectroscopy and Mott–Schottky analysis. The fact that passive current density increased with rising potential might result from the preferential dissolution of high-valence oxides and the existence of more chlorides at a higher potential. The critical flow velocity decreased with rising potential because of the lower resistance of passive film at a higher potential. The reason why passive current density changed under jet impingement was discussed by a simple formula

  3. HIGHWAY INFRASTRUCTURE FOCUS AREA NEXT-GENERATION INFRASTRUCTURE MATERIALS VOLUME I - TECHNICAL PROPOSAL & MANAGEMENTENHANCEMENT OF TRANSPORTATION INFRASTRUCTURE WITH IRON-BASED AMORPHOUS-METAL AND CERAMIC COATINGS

    Energy Technology Data Exchange (ETDEWEB)

    Farmer, J C

    2007-12-04

    The infrastructure for transportation in the United States allows for a high level of mobility and freight activity for the current population of 300 million residents, and several million business establishments. According to a Department of Transportation study, more than 230 million motor vehicles, ships, airplanes, and railroads cars were used on 6.4 million kilometers (4 million miles) of highways, railroads, airports, and waterways in 1998. Pipelines and storage tanks were considered to be part of this deteriorating infrastructure. The annual direct cost of corrosion in the infrastructure category was estimated to be approximately $22.6 billion in 1998. There were 583,000 bridges in the United States in 1998. Of this total, 200,000 bridges were steel, 235,000 were conventional reinforced concrete, 108,000 bridges were constructed using pre-stressed concrete, and the balance was made using other materials of construction. Approximately 15 percent of the bridges accounted for at this point in time were structurally deficient, primarily due to corrosion of steel and steel reinforcement. Iron-based amorphous metals, including SAM2X5 (Fe{sub 49.7}Cr{sub 17.7}Mn{sub 1.9}Mo{sub 7.4}W{sub 1.6}B{sub 15.2}C{sub 3.8}Si{sub 2.4}) and SAM1651 (Fe{sub 48}Mo{sub 14}Cr{sub 15}Y{sub 2}C{sub 15}B{sub 6}) have been developed, and have very good corrosion resistance. These materials have been prepared as a melt-spun ribbons, as well as gas atomized powders and thermal-spray coatings. During electrochemical testing in several environments, including seawater at 90 C, the passive film stabilities of these materials were found to be comparable to that of more expensive high-performance alloys, based on electrochemical measurements of the passive film breakdown potential and general corrosion rates. These materials also performed very well in standard salt fog tests. Chromium (Cr), molybdenum (Mo) and tungsten (W) provided corrosion resistance, and boron (B) enabled glass formation

  4. HIGH TEMPERATURE CORROSION RESISTANCE OF METALLIC MATERIALS IN HARSH CONDITIONS

    OpenAIRE

    Novello, Frederic; Dedry, Olivier; De Noose, Vincent; Lecomte-Beckers, Jacqueline

    2014-01-01

    Highly efficient energy recovery from renewable sources and from waste incineration causes new problems of corrosion at high temperature. A similar situation exists for new recycling processes and new energy storage units. These corrosions are generally considered to be caused by ashes or molten salts, the composition of which differs considerably from one plant to another. Therefore, for the assessment of corrosion-resistance of advanced materials, it is essential to precisely evaluate the c...

  5. Corrosion resistance of metals and alloys in molten alkalies

    International Nuclear Information System (INIS)

    Zarubitskij, O.G.; Dmitruk, B.F.; Minets, L.A.

    1979-01-01

    Literature data on the corrosion of non-ferrous and noble metals, iron and steels in the molten alkalis and mixtures of their base are presented. It is shown that zirconium, niobium and tantalum are characterized by high corrosion stability in the molten NaOH. Additions of NaOH and KOH to the alkali chloride melts result in a 1000 time decrease of zirconium corrosion rate at 850 deg. The data testify to the characteristic passivating properties of OH - ions; Mo and W do not possess an ability to selfpassivation in hydroxide melts. Corrosion resistance of carbon and chromium-nickel steels in hydroxide melts depends considerably on the temperature, electrolyte composition and atmosphere over them. At the temperatures up to 600 deg C chromium-nickel steel is corrosion resistant in the molten alkali only in the inert atmosphere. Corrosion rate of chromium-nickel alloy is the lower the less chromium and the more nickel it contains. For the small installations the 4Kh18N25S2 and Kh23N28M3D3T steels can be recommended

  6. Development of a highly weldable and corrosion resistant nickel-chromium filler metal

    International Nuclear Information System (INIS)

    Young, G.A.; Capobianco, T.E.; Etien, R.A.; Mullen, J.V.; Leveillee, S.; Sander, P.C.

    2007-01-01

    This paper reports on a long term research effort to develop an improved filler metal for gas-tungsten- arc welding of Alloy 690. The goal of this work was to maintain the corrosion resistance of wrought Alloy 690 while eliminating ductility dip cracking (DDC) or other as welded defects in prototypical welds. Results from weld mockups, weldability testing, microstructural and microchemical characterization, and computational modeling show that ductility dip cracking is a form of precipitation-induced-cracking and can be mitigated via alloying to control the type and extent of carbide formation. Additionally, these tests illustrate that in commercially available filler metals, alloying additions intended to provide DDC resistance (Nb, B, and Zr) are not effective and, in many cases, cause solidification cracking in addition to DDC. Based on these welding results, three candidate alloys of 24 wt.%, 27 wt.%, and 30 wt.% chromium were further evaluated for their mechanical properties, phase stability, and resistance to environmentally assisted cracking (EAC). Results to date show weldability mechanical properties, and phase stability comparable to EN82, but significantly improved resistance to EAC. These findings are used to define an alloy designated EN52i, that offers a desirable combination of weldability and corrosion resistance. (author)

  7. Development of a highly weldable and corrosion resistant nickel-chromium filler metal

    Energy Technology Data Exchange (ETDEWEB)

    Young, G.A.; Capobianco, T.E.; Etien, R.A.; Mullen, J.V.; Leveillee, S.; Sander, P.C. [Lockheed Martin Corp., Schenectady, New York (United States)

    2007-07-01

    This paper reports on a long term research effort to develop an improved filler metal for gas-tungsten- arc welding of Alloy 690. The goal of this work was to maintain the corrosion resistance of wrought Alloy 690 while eliminating ductility dip cracking (DDC) or other as welded defects in prototypical welds. Results from weld mockups, weldability testing, microstructural and microchemical characterization, and computational modeling show that ductility dip cracking is a form of precipitation-induced-cracking and can be mitigated via alloying to control the type and extent of carbide formation. Additionally, these tests illustrate that in commercially available filler metals, alloying additions intended to provide DDC resistance (Nb, B, and Zr) are not effective and, in many cases, cause solidification cracking in addition to DDC. Based on these welding results, three candidate alloys of 24 wt.%, 27 wt.%, and 30 wt.% chromium were further evaluated for their mechanical properties, phase stability, and resistance to environmentally assisted cracking (EAC). Results to date show weldability mechanical properties, and phase stability comparable to EN82, but significantly improved resistance to EAC. These findings are used to define an alloy designated EN52i, that offers a desirable combination of weldability and corrosion resistance. (author)

  8. Wear Resistant Amorphous and Nanocomposite Coatings

    Energy Technology Data Exchange (ETDEWEB)

    Racek, O

    2008-03-26

    Glass forming materials (critical cooling rate <10{sup 4}K.s{sup -1}) are promising for their high corrosion and wear resistance. During rapid cooling, the materials form an amorphous structure that transforms to nanocrystalline during a process of devitrification. High hardness (HV 1690) can be achieved through a controlled crystallization. Thermal spray process has been used to apply coatings, which preserves the amorphous/nanocomposite structure due to a high cooling rate of the feedstock particles during the impact on a substrate. Wear properties have been studied with respect to process conditions and feedstock material properties. Application specific properties such as sliding wear resistance have been correlated with laboratory tests based on instrumented indentation and scratch tests.

  9. Corrosion of metallic materials by uranium hexafluoride at high temperatures (1963)

    International Nuclear Information System (INIS)

    Langlois, G.

    1963-01-01

    The corrosion of the following metals or alloys by UF 6 : nickel, monel, Inconel, gold, platinum, stainless steel, is studied in the temperature range from 300 to 1000 deg. C. The test method, designed to avoid heating the apparatus containing the corrosive fluid to a high temperature, consists in using threadlike samples heated by the Joule effect, the rest of the apparatus being maintained close to room temperature. This technique makes it possible also to determine continuously the penetration of the corrosion by measuring the electrical resistance of the sample with a double Thomson bridge. A series of rapid comparison tests shows that stainless steel, precious metals and Inconel are attacked far too rapidly to be used above 500 deg. C; only monel and especially nickel appear capable of resisting at high temperatures. The detailed examination of the behaviour of nickel shows that the metallic fluoride is volatilized and that this influences the corrosion rate. It shows also the existence of a temperature zone situated between 550 and 700 deg. C in which occurs A strong intergranular corrosion the cause of which appears to be the presence of impurities in the metal. (author) [fr

  10. Iron-based amorphous alloys and methods of synthesizing iron-based amorphous alloys

    Science.gov (United States)

    Saw, Cheng Kiong; Bauer, William A.; Choi, Jor-Shan; Day, Dan; Farmer, Joseph C.

    2016-05-03

    A method according to one embodiment includes combining an amorphous iron-based alloy and at least one metal selected from a group consisting of molybdenum, chromium, tungsten, boron, gadolinium, nickel phosphorous, yttrium, and alloys thereof to form a mixture, wherein the at least one metal is present in the mixture from about 5 atomic percent (at %) to about 55 at %; and ball milling the mixture at least until an amorphous alloy of the iron-based alloy and the at least one metal is formed. Several amorphous iron-based metal alloys are also presented, including corrosion-resistant amorphous iron-based metal alloys and radiation-shielding amorphous iron-based metal alloys.

  11. Corrosion resistance characteristics of stamped and hydroformed proton exchange membrane fuel cell metallic bipolar plates

    Energy Technology Data Exchange (ETDEWEB)

    Dundar, F. [NSF I/UCRC Center for Precision Forming (CPF), Virginia Commonwealth University, Richmond, VA (United States); Department of Materials Science and Engineering, Gebze Institute of Technology (Turkey); Dur, Ender; Koc, M. [NSF I/UCRC Center for Precision Forming (CPF), Virginia Commonwealth University, Richmond, VA (United States); Mahabunphachai, S. [NSF I/UCRC Center for Precision Forming (CPF), Virginia Commonwealth University, Richmond, VA (United States); National Metal and Materials Technology Center (MTEC), Pathumthani (Thailand)

    2010-06-01

    Metallic bipolar plates have several advantages over bipolar plates made from graphite and composites due to their high conductivity, low material and production costs. Moreover, thin bipolar plates are possible with metallic alloys, and hence low fuel cell stack volume and mass are. Among existing fabrication methods for metallic bipolar plates, stamping and hydroforming are seen as prominent approaches for mass production scales. In this study, the effects of important process parameters of these manufacturing processes on the corrosion resistance of metallic bipolar plates made of SS304 were investigated. Specifically, the effects of punch speed, pressure rate, stamping force and hydroforming pressure were studied as they were considered to inevitably affect the bipolar plate micro-channel dimensions, surface topography, and hence the corrosion resistance. Corrosion resistance under real fuel cell conditions was examined using both potentiodynamic and potentiostatic experiments. The majority of the results exhibited a reduction in the corrosion resistance for both stamped and hydroformed plates when compared with non-deformed blank plates of SS304. In addition, it was observed that there exist an optimal process window for punch speed in stamping and the pressure rate in hydroforming to achieve improved corrosion resistance at a faster production rate. (author)

  12. Study on Co-free amorphous material cladding using a laser beam to improve the resistance of primary system parts in NPPs to wear/erosion-corrosion

    International Nuclear Information System (INIS)

    Kim, J. S.; Woo, S. S.; Seo, J. H.

    2001-01-01

    A study on Co-free amorphous material, ARMACOR M, cladding using a laser beam has been performed to improve resistance of the primary system main parts on nuclear power plants to wear/erosion-corrosion. The wear/erosion-corrosion properties of ARMACRO M cladded speciemens were characterized in air at room temperature and 300 .deg. C and in air at room temperature, and compared to those of other hardfacing materials, such as Stellite 6, NOREM 02, Deloro 50, TIG-welde or laer cladded. According to the results, ARMACOR M laser-cladded specimen showed to have the highest resistance to wear/erosion-corrosion

  13. THE EFFECT OF HIGH OVERVOLTAGES AT ELECTROCRYSTALLIZATION ON THE CORROSION RESISTANCE OF THE FILMS CO-P

    Directory of Open Access Journals (Sweden)

    V. O. Zabludovskyi

    2009-03-01

    Full Text Available Electrochemical and gravimetric methods are used in order to research the influence of high overvoltages during electroplating on corrosive and electrochemical behavior of amorphous Co-P films, which were made using deposition from water solution of an electrolyte. It is obtained that alloys, which were plated using higher overvoltages on cathode, are more corrosion-resistant.

  14. A computation model for the corrosion resistance of nanocrystalline zirconium metal

    International Nuclear Information System (INIS)

    Zhang Xiyan; Shi Minghua; Liu Nianfu; Wei Yiming; Li Cong; Qiu Shaoyu; Zhang Qiang; Zhang Pengcheng

    2007-01-01

    In this paper a computation model of corrosion rate-grain size of nanocrystalline and ultra-fine zirconium has been presented. The model is based on the Wagner's theory and the electron theory of solids. The conductivity, electronic mean free path and grain size of metal were considered. By this model, the corrosion rate of zirconium metal under different temperature was computed. The results show that the corrosion weight gain and rate constant of nanocrystalline zirconium is lower than that of zirconium with coarse grain size. And the corrosion rate constant and weight gain of nanocrystalline zirconium metal decrease with the decrease of grain size. So the refinement of grain size can remarkably improve the corrosion resistance of zirconium metal. (authors)

  15. Corrosion-Resistant High-Entropy Alloys: A Review

    Directory of Open Access Journals (Sweden)

    Yunzhu Shi

    2017-02-01

    Full Text Available Corrosion destroys more than three percent of the world’s gross domestic product. Therefore, the design of highly corrosion-resistant materials is urgently needed. By breaking the classical alloy-design philosophy, high-entropy alloys (HEAs possess unique microstructures, which are solid solutions with random arrangements of multiple elements. The particular locally-disordered chemical environment is expected to lead to unique corrosion-resistant properties. In this review, the studies of the corrosion-resistant HEAs during the last decade are summarized. The corrosion-resistant properties of HEAs in various aqueous environments and the corrosion behavior of HEA coatings are presented. The effects of environments, alloying elements, and processing methods on the corrosion resistance are analyzed in detail. Furthermore, the possible directions of future work regarding the corrosion behavior of HEAs are suggested.

  16. Compositions of corrosion-resistant Fe-based amorphous metals suitable for producing thermal spray coatings

    Science.gov (United States)

    Farmer, Joseph C; Wong, Frank M.G.; Haslam, Jeffery J; Ji, Xiaoyan; Day, Sumner D; Blue, Craig A; Rivard, John D.K.; Aprigliano, Louis F; Kohler, Leslie K; Bayles, Robert; Lemieux, Edward J; Yang, Nancy; Perepezko, John H; Kaufman, Larry; Heuer, Arthur; Lavernia, Enrique J

    2013-09-03

    A method of coating a surface comprising providing a source of amorphous metal that contains manganese (1 to 3 atomic %), yttrium (0.1 to 10 atomic %), and silicon (0.3 to 3.1 atomic %) in the range of composition given in parentheses; and that contains the following elements in the specified range of composition given in parentheses: chromium (15 to 20 atomic %), molybdenum (2 to 15 atomic %), tungsten (1 to 3 atomic %), boron (5 to 16 atomic %), carbon (3 to 16 atomic %), and the balance iron; and applying said amorphous metal to the surface by a spray.

  17. Corrosion resistance of high performance stainless steels in cooling water and other refinery environments

    International Nuclear Information System (INIS)

    Kovach, C.W.; Redmerski, L.S.

    1984-01-01

    The recent successful introduction of high performance stainless steels as tubing for seawater cooled electric utility condensers suggests that these alloys can also provide useful service in refinery heat exchanger applications. Since many of these applications involve higher temperature exposure than steam condensers, a study was conducted to evaluate crevice corrsion resistance over a range of cooling water temperature and chloride concentrations, and also to evaluate general corrosion resistance in some strong chemical and refinery environments. These stainless steels display excellent crevice corrosion resistance as well as good resistance to a variety of chemical environments that may be encountered in refinery, petrochemical and chemical plant service

  18. Metal Matrix Composite Coatings of Cupronickel Embedded with Nanoplatelets for Improved Corrosion Resistant Properties

    Directory of Open Access Journals (Sweden)

    Casey R. Thurber

    2018-01-01

    Full Text Available The deterioration of metals under the influence of corrosion is a costly problem faced by many industries. Therefore, particle-reinforced composite coatings are being developed in different technological fields with high demands for corrosion resistance. This work studies the effects of nanoplatelet reinforcement on the durability, corrosion resistance, and mechanical properties of copper-nickel coatings. A 90 : 10 Cu-Ni alloy was coelectrodeposited with nanoplatelets of montmorillonite (Mt embedded into the metallic matrix from electrolytic baths containing 0.05, 0.10, and 0.15% Mt. X-ray diffraction of the coatings indicated no disruption of the crystal structure with addition of the nanoplatelets into the alloy. The mechanical properties of the coatings improved with a 17% increase in hardness and an 85% increase in shear adhesion strength with nanoplatelet incorporation. The measured polarization resistance increased from 11.77 kΩ·cm2 for pure Cu-Ni to 33.28 kΩ·cm2 for the Cu-Ni-0.15% Mt coating after soaking in a simulated seawater environment for 30 days. The incorporation of montmorillonite also stabilized the corrosion potential during the immersion study and increased resistance to corrosion.

  19. Corrosion resistance and characterization of metallic coatings deposited by thermal spray on carbon steel

    International Nuclear Information System (INIS)

    Sá Brito, V.R.S.; Bastos, I.N.; Costa, H.R.M.

    2012-01-01

    Highlights: ► Five combinations of metallic coatings and intermediate bonds were deposited on carbon steels. ► High strength was reached in adhesion tests. ► Epoxy sealing of coatings improves corrosion resistance. -- Abstract: Carbon steels are not resistant to corrosion and several methods are used in surface engineering to protect them from aggressive environments such as marine. The main objective of this work is the evaluation of mechanical and metallurgical properties of five metallic coatings produced by thermal spray on carbon steel. Five chemical compositions were tested in order to give a large panel of possibility. Coatings were characterized by several methods to result in a screening of their performance. At first, the assessment of microstructural morphology by optical microscopy (OM) and by scanning electron microscopy (SEM) was made. OM and SEM results showed uniformity of deposited layer, low amount of oxides and porosity. The physical properties of coatings were also evaluated by microhardness measurement, adhesion and porosity quantification. The corrosion resistance was analyzed in salt spray and electrochemical polarization tests. In the polarization test, as well as in the salt spray, all sealed conditions presented low corrosion. A new intermediate 78.3Ni20Cr1.4Si0.3Fe alloy was studied in order to reduce pores and microcracks that are frequently found in ordinary 95Ni5Al alloy. Based on the performed characterizations, the findings suggested that the FeCrCo deposition, with an epoxy sealing, is suitable to be used as an efficient coating of carbon steel in aggressive marine environments.

  20. High-temperature corrosion of metals in the salt and metallic melts containing rare earths

    Science.gov (United States)

    Karpov, V. V.; Abramov, A. V.; Zhilyakov, A. Yu.; Belikov, S. V.; Volkovich, V. A.; Polovov, I. B.; Rebrin, O. I.

    2016-09-01

    A complex of independent methods was employed to study the corrosion resistance of molybdenum, zirconium, tantalum and tungsten in chloride, chloride-fluoride and fluoride-oxide melts based on LiCl, CaCl2, NaCl- KCl, LiF, and containing rare earths. Tests were conducted for 30 h at 750-1050 °C. The metals showed excellent corrosion resistance in fused chlorides (the corrosion rates were below 0.0005 g/(m2 h). Despite the presence of chemically active fluoride ions in the chloride-fluoride melts, the metals studied also showed very low corrosion rates, except molybdenum, for which the rate of corrosion was 0,8 g/(m2 h). The corrosion resistance of tantalum was considerably reduced in the fluoride-oxide melts; the corrosion rate was over 1 g/(m2 h) corresponding to the 8-th grade of stability and placing tantalum to the group of "low stability" materials.

  1. Effect of chromium and phosphorus on the physical properties of iron and titanium-based amorphous metallic alloy films

    Science.gov (United States)

    Distefano, S.; Rameshan, R.; Fitzgerald, D. J.

    1991-01-01

    Amorphous iron and titanium-based alloys containing various amounts of chromium, phosphorus, and boron exhibit high corrosion resistance. Some physical properties of Fe and Ti-based metallic alloy films deposited on a glass substrate by a dc-magnetron sputtering technique are reported. The films were characterized using differential scanning calorimetry, stress analysis, SEM, XRD, SIMS, electron microprobe, and potentiodynamic polarization techniques.

  2. Electrochemical and corrosion behaviour of ion and laser-beam modified metal surfaces

    International Nuclear Information System (INIS)

    Bonora, P.L.

    1989-01-01

    Ion implantation may improve the resistance of metals to wear and corrosion both: by the formation of stable or metastable chemical compounds localized in a thin external layer; or by the so-called 'radiation damage' which is mainly active in lowering the potential gradients between different grains and between grain and grain boundaries as an effect of subdivision into substructures, up to a quasi-amorphous inert surface. The changes in the corrosion fatigue behaviour of iron as well as in its catalytic properties as a consequence of ion implantation are considered. The electrochemical behaviour of laser irradiated and ion mixed metals in terms of changed corrosion rate, corrosion morphology, passivability or breakdown of passivity is also explained. 27 refs.; 12 figs.; 5 tabs

  3. Corrosion performance of several metals in plutonium nitrate solution

    International Nuclear Information System (INIS)

    Takeda, Seiichiro; Nagai, Takayuki; Yasu, Shozo; Koizumi, Tsutomu

    1995-01-01

    Corrosion behavior of several metals exposed in plutonium nitrate solution was studied. Plutonium nitrate solution with the plutonium concentration ranging from 0.01 to 300 g/l was used as a corrosive medium. Specimens tested were type 304 ULC (304 ULC) stainless steel, type 310 Nb (310 Nb) stainless steel, titanium (Ti), titanium-5% tantalum alloy (Ti-5Ta), and zirconium (Zr). Corrosion behavior of these metals in plutonium nitrate solution was evaluated through examining electrochemical characteristics and corrosion rates obtained by weight loss measurement. From the results of the corrosion tests, it was found that the corrosion rate of stainless steels i.e. 304 ULC and 310 Nb, increases by the presence of plutonium in nitric acid solution. The corrosion potential of the stainless steels shifted linearly towards the noble direction as the concentration of plutonium increases. It is thought that the shifts in corrosion potential of the stainless steels to the noble direction results an increase in anodic current and, hence, corrosion rate. Valve metals, i.e. Ti, Ti-5Ta and Zr, showed good corrosion resistance over the whole range of plutonium concentration examined here. (author)

  4. Effects of Rare Earth Metal addition on the cavitation erosion-corrosion resistance of super duplex stainless steels

    Science.gov (United States)

    Shim, Sung-Ik; Park, Yong-Soo; Kim, Soon-Tae; Song, Chi-Bok

    2002-05-01

    Austenitic stainless steels such as AISI 316L have been used in equipment in which fluid flows at high speeds which can induce cavitation erosion on metallic surfaces due to the collapse of cavities, where the collapse is caused by the sudden change of local pressure within the liquid. Usually AISI 316L is susceptible to cavitation erosion. This research focuses on developing a better material to replace the AISI 316L used in equipment with high speed fluid flow, such as impellers. The effects of Rare Earth Metal (REM) additions on the cavitation erosion-corrosion resistance of duplex stainless steels were studied using metallographic examination, the potentiodynamic anodic polarization test, the tensile test, the X-ray diffraction test and the ultrasonic cavitation erosion test. The experimental alloys were found to have superior mechanical properties due to interstitial solid solution strengthening, by adding high nitrogen (0.4%), as well as by the refinement of phases and grains induced by fine REM oxides and oxy-sulfides. Corrosion resistance decreases in a gentle gradient as the REM content increases. However, REM containing alloys show superior corrosion resistance compared with that of other commercial alloys (SAF 2507, AISI 316L). Owing to their excellent mechanical properties and corrosion resistance, the alloys containing REM have high cavitation erosion-corrosion resistance.

  5. An evaluation of corrosion resistant alloys by field corrosion test in Japanese refuse incineration plants

    International Nuclear Information System (INIS)

    Kawahara, Yuuzou; Nakamura, Masanori; Shibuya, Eiichi; Yukawa, Kenichi

    1995-01-01

    As the first step for development of the corrosion resistant superheater tube materials of 500 C, 100 ata used in high efficient waste-to-energy plants, field corrosion tests of six conventional alloys were carried out at metal temperatures of 450 C and 550 C for 700 and 3,000 hours in four typical Japanese waste incineration plants. The test results indicate that austenitic alloys containing approximately 80 wt% [Cr+Ni] show excellent corrosion resistance. When the corrosive environment is severe, intergranular corrosion of 40∼200 microm depth occurs in stainless steel and high alloyed materials. It is confirmed quantitatively that corrosion behavior is influenced by environmental corrosion factors such as Cl concentration and thickness of deposits on tube surface, metal temperature, and flue gas temperature. The excellent corrosion resistance of high [Cr+Ni+Mo] alloys such as Alloy 625 is explained by the stability of its protective oxide, such that the time dependence of corrosion nearly obeys the parabolic rate law

  6. High temperature corrosion of metals

    International Nuclear Information System (INIS)

    Quadakkers, W.J.; Schuster, H.; Ennis, P.J.

    1988-08-01

    This paper covers three main topics: 1. high temperature oxidation of metals and alloys, 2. corrosion in sulfur containing environments and 3. structural changes caused by corrosion. The following 21 subjects are discussed: Influence of implanted yttrium and lanthanum on the oxidation behaviour of beta-NiA1; influence of reactive elements on the adherence and protective properties of alumina scales; problems related to the application of very fine markers in studying the mechanism of thin scale formation; oxidation behaviour of chromia forming Co-Cr-Al alloys with or without reactive element additions; growth and properties of chromia-scales on high-temperature alloys; quantification of the depletion zone in high temperature alloys after oxidation in process gas; effects of HC1 and of N2 in the oxidation of Fe-20Cr; investigation under nuclear safety aspects of Zircaloy-4 oxidation kinetics at high temperatures in air; on the sulfide corrosion of metallic materials; high temperature sulfide corrosion of Mn, Nb and Nb-Si alloys; corrosion behaviour or NiCrAl-based alloys in air and air-SO2 gas mixtures; sulfidation of cobalt at high temperatures; preoxidation for sulfidation protection; fireside corrosion and application of additives in electric utility boilers; transport properties of scales with complex defect structures; observations of whiskers and pyramids during high temperature corrosion of iron in SO2; corrosion and creep of alloy 800H under simulated coal gasification conditions; microstructural changes of HK 40 cast alloy caused by exploitation in tubes in steam reformer installation; microstructural changes during exposure in corrosive environments and their effect on mechanical properties; coatings against carburization; mathematical modeling of carbon diffusion and carbide precipitation in Ni-Cr-based alloys. (MM)

  7. Research report of FY 1997 on the industrial science and technology development. Technology development of super-metal (technology development of nano-amorphous structural control materials); 1997 nendo sangyo kagaku gijutsu kenkyu kaihatsu Shin Energy Sangyo Gijutsu Sogo Kaihatsu Kiko itaku seika hokokusho. Super metal no gijutsu kaihatsu (nano-amorphous kozo seigyo zairyo no gijutsu kaihatsu)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    Research and development of the innovative metals have been conducted, by which the weight reduction of members can be done by drastically improving the strength compared with conventional metals. For the high-rate cluster deposition and super plastic forming technologies, research and development of aluminum-based light-weight materials have been conducted, which provides excellent strength, toughness, and super plastic formability at room temperature. For the high-density energy utilization and control technology (amorphous-A), super-metals have been investigated as high dew point and corrosion resistance materials used for waste incinerators operated under the very severe conditions. These are expected to be applied to the apparatuses and equipment due to their excellent properties. For the controlled cooling technology (amorphous-B), super-metals with excellent soft magnetic characteristics and degree of shape freedom have been investigated for high performance and high efficiency devices including electric/electronic/communication devices, power transmission devices, and various industrial devices and parts. These are expected to contribute to the creation of new markets and the improvement of international competitive force. 123 refs., 160 figs., 33 tabs.

  8. Scratch, wear and corrosion resistant organic inorganic hybrid materials for metals protection and barrier

    International Nuclear Information System (INIS)

    Barletta, M.; Gisario, A.; Puopolo, M.; Vesco, S.

    2015-01-01

    Highlights: • Polysiloxane coatings as protective barriers to delay erosion/corrosion of Fe 430 B metal substrates. • Methyl groups feature a very small steric hindrance and confer ductility to the Si–O–Si backbone. • Phenyl groups feature a larger steric hindrance, but they ensure stability and high chemical inertness. • Remarkable adhesion to the substrate, good scratch resistance and high wear endurance. • Innovative ways to design of long lasting protective barriers against corrosion and aggressive chemicals. - Abstract: Polysiloxanes are widely used as protective barriers to delay erosion/corrosion and increase chemical inertness of metal substrates. In the present work, a high molecular weight methyl phenyl polysiloxane resin was designed to manufacture a protective coating for Fe 430 B structural steel. Methyl groups feature very small steric hindrance and confer ductility to the Si–O–Si backbone of the organic inorganic hybrid resin, thus allowing the achievement of high thickness. Phenyl groups feature larger steric hindrance, but they ensure stability and high chemical inertness. Visual appearance and morphology of the coatings were studied by field emission scanning electron microscopy and contact gauge surface profilometry. Micro-mechanical response of the coatings was analyzed by instrumented progressive load scratch, while wear resistance by dry sliding linear reciprocating tribological tests. Lastly, chemical inertness and corrosion endurance of the coatings were evaluated by linear sweep voltammetry and chronoamperometry in aggressive acid environment. The resulting resins yielded protective materials, which feature remarkable adhesion to the substrate, good scratch resistance and high wear endurance, thus laying the foundations to manufacture long lasting protective barriers against corrosion and, more in general, against aggressive chemicals

  9. Corrosion Monitoring of Flexible Metallic Substrates for Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Trystan Watson

    2013-01-01

    Full Text Available Two techniques for monitoring corrosion within a dye-sensitized solar cell (DSC system are presented, which enable continuous, high sensitivity, in situ measurement of electrolyte breakdown associated with DSCs fabricated on metals. The first method uses UV/Vis reflectance spectrophotometry in conjunction with encapsulation cells, which incorporate a 25 μm thick electrolyte layer, to provide highly resolved triiodide absorption data. The second method uses digital image capture to extract colour intensity data. Whilst the two methods provide very similar kinetic data on corrosion, the photographic method has the advantage that it can be used to image multiple samples in large arrays for rapid screening and is also relatively low cost. This work shows that the triiodide electrolyte attacks most metals that might be used for structural applications. Even a corrosion resistant metal, such as aluminium, can be induced to corrode through surface abrasion. This result should be set in the context with the finding reported here that certain nitrogen containing heterocyclics used in the electrolyte to enhance performance also act as corrosion inhibitors with significant stabilization for metals such as iron. These new techniques will be important tools to help develop corrosion resistant metal surfaces and corrosion inhibiting electrolytes for use in industrial scale devices.

  10. Leading research on super metal. 3. Amorphous and nanostructured metallic materials; Super metal no sendo kenkyu. 3. Kogata buzai

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    Very fine structure control technique for amorphous and nanostructured metallic materials was reviewed to exceed the marginal performance of small metallic member materials. In Japan, high strength alloys and anticorrosion alloys are currently developed as an amorphous structure control technique, and ultra fine powder production and nano-compaction molding are studied for nanostructured materials. Fabrication of amorphous alloy wire materials and metal glass in USA are also introduced. Fabrication of metallic nanocrystals deposited within gas phase in Germany are attracting attention. The strength and abrasion resistance are remarkably enhanced by making nanostructured crystals and dispersing them. It may be most suitable to utilize amorphous and nanostructured metallic materials for earth-friendly materials having anticorrosion, and catalyst and biomaterial affinities, and also for magnetic materials. It is important for controlling micro-structures to clarify the formation mechanism of structures. For their processing techniques, the diversity and possibility are suggested, as to the condensation and solidification of gaseous and liquid phase metals, the molding and processing of very fine solid phase alloys, and the manufacturing members by heat treatment. 324 refs., 109 figs., 21 tabs.

  11. Corrosion behavior and pitting susceptibility of in-situ Ti-based metallic glass matrix composites in 3.5 wt.% NaCl solutions

    Science.gov (United States)

    Xu, K. K.; Lan, A. D.; Yang, H. J.; Han, P. D.; Qiao, J. W.

    2017-11-01

    The Ti62Zr12V13Cu4Be9, Ti58Zr16V10Cu4Be12, Ti46Zr20V12Cu5Be17, and Ti40Zr24V12Cu5Be19 metallic glass matrix composites (MGMCs) were prepared by copper mould casting. The corrosion resistance and the pitting susceptibility of Ti-based MGMCs were tested on their cross-sectional areas in 3.5 wt.% NaCl solutions by potentiodynamic polarization measurements. The composites with lower Ti contents (Ti40Zr24V12Cu5Be19 and Ti46Zr20V12Cu5Be17) exhibit a low resistance to the chloride induced pitting and local corrosion. The preferential dissolution of amorphous matrix is explained by the high chemical reactivity of beryllium element compared to that of stable dendrites and by the detected lower Ti and V contents. However, fairly good passivity was found in the composite with higher Ti contents (Ti62Zr12V13Cu4Be9). XPS measurements revealed that protective Ti-enriched oxide film was formed on the composite surface, additionally, lower content of beryllium element in amorphous matrix hinder the selective corrosion of amorphous matrix. The assessment of experimental observation leads to a proposed corrosion mechanism involving selective dissolution of amorphous matrix and chloride induced pitting process.

  12. Krypton-85 storage in sputter-deposited amorphous metals

    International Nuclear Information System (INIS)

    Tingey, G.L.; McClanahan, E.D.; Lytle, J.M.; Gordon, N.R.; Knoll, R.W.

    1982-06-01

    After comparing options for storing radioactive krypton gas, the United States Department of Energy selected ion implantation of the gas into a sputter-deposited metal matrix as the reference process. This technique is being developed with pilot-scale testing and further characterization of the deposited product. The process involves implanting krypton atoms into a growing deposit during the sputtering process. An amorphous metal deposit of nominal composition Ni 0 81 La 0 09 Kr 0 10 has been selected for further studies because of the high krypton loading, high sputtering yield, relatively low cost of the metallic components, resistance to corrosion, and stability of the product. The krypton release from this amorphous metal is described as an activated diffusion process which increases linearly with the square root of time. Studies of krypton release rate as a function of temperature were completed and an activation energy for the diffusion of 70 kcal/mole obtained. From these data, we estimated that the krypton release during the first ten years would be 0.5% for a maximum temperature of 350 0 C. The actual release of the krypton during storage was projected to be lower by a factor of 10 7 with the maximum temperature only 220 0 C. Thermal analysis studies show two energy releases occurring with krypton-containing alloys: one associated with recrystallization of the amorphous alloy and a second associated with krypton release. The total energy release between 100 and 800 0 C was less than 50 cal/g. Estimates are given for the cost of operation of the ion implantation process for solidification of the krypton-85 from a 2000-tonne heavy metal/year reprocessing plant. The present value costs, in 1981 dollars including capital and operating costs and assuming a 30-year life, are about $26M for the lifetime of the plant. Annual energy consumption of the process was estimated to be 3.9 M kWh/year

  13. Investigations of metal contacts to amorphous evaporated Ge films and amorphous sputtered Si films

    International Nuclear Information System (INIS)

    Hafiz, M.; Mgbenu, E.; Tove, P.A.; Norde, H.; Petersson, S.

    1976-02-01

    Amorphous Ge or Si films have been used as ohmic contacts to high-resistivity n-silicon radiation detectors. One interesting property of this contact is that it does not inject minority carriers even when the depletion region extends up to the contact thus generating an extracting field there. The function of this contact is not yet fully explored. One part problem is the role of the metal films used as external contacts to the amorphous film. In this report the function of different contacting metals, such as Au, Al, Cr are investigated by measuring the I-V-characteristics of sandwich structures with two metals on both sides of the amorphous evaporated (Ge) and sputtered (Si) film (of typical thickness 1000 A). It was found that while the symmetric structures Au-αGe-Au and Cr-αGe-Cr were low-resistive (leading to resistivity values of approximately 10 5 Ωcm for the αGe film), Al-αGe-Al structures showed much higher resistance and were also polarity dependent. The former feature was found also for unsymmetric structures, i.e. Cr-αGe-Au, Cr-αGe-Al. (Auth.)

  14. Corrosion of metal bipolar plates for PEM fuel cells: A review

    Energy Technology Data Exchange (ETDEWEB)

    Antunes, Renato A. [Engenharia de Materiais, Universidade Federal do ABC (UFABC), 09210-170 Santo Andre, SP (Brazil); Oliveira, Mara Cristina L.; Ett, Gerhard; Ett, Volkmar [Electrocell Ind. Com. Equip. Elet. LTDA, Centro de Inovacao, Empreendedorismo e Tecnologia (CIETEC), 05508-000 Sao Paulo, SP (Brazil)

    2010-04-15

    PEM fuel cells are of prime interest in transportation applications due to their relatively high efficiency and low pollutant emissions. Bipolar plates are the key components of these devices as they account for significant fractions of their weight and cost. Metallic materials have advantages over graphite-based ones because of their higher mechanical strength and better electrical conductivity. However, corrosion resistance is a major concern that remains to be solved as metals may develop oxide layers that increase electrical resistivity, thus lowering the fuel cell efficiency. This paper aims to present the main results found in recent literature about the corrosion performance of metallic bipolar plates. (author)

  15. Corrosion resistant cemented carbide

    International Nuclear Information System (INIS)

    Hong, J.

    1990-01-01

    This paper describes a corrosion resistant cemented carbide composite. It comprises: a granular tungsten carbide phase, a semi-continuous solid solution carbide phase extending closely adjacent at least a portion of the grains of tungsten carbide for enhancing corrosion resistance, and a substantially continuous metal binder phase. The cemented carbide composite consisting essentially of an effective amount of an anti-corrosion additive, from about 4 to about 16 percent by weight metal binder phase, and with the remaining portion being from about 84 to about 96 percent by weight metal carbide wherein the metal carbide consists essentially of from about 4 to about 30 percent by weight of a transition metal carbide or mixtures thereof selected from Group IVB and of the Periodic Table of Elements and from about 70 to about 96 percent tungsten carbide. The metal binder phase consists essentially of nickel and from about 10 to about 25 percent by weight chromium, the effective amount of an anti-corrosion additive being selected from the group consisting essentially of copper, silver, tine and combinations thereof

  16. Corrosion resistant composite materials

    International Nuclear Information System (INIS)

    Ul'yanin, E.A.

    1986-01-01

    Foundations for corrosion-resistant composite materials design are considered with account of components compatibility. Fibrous and lamellar composites with metal matrix, dispersion-hardened steels and alloys, refractory metal carbides-, borides-, nitrides-, silicides-based composites are described. Cermet compositions and fields of their application, such as protective coatings for operation in agressive media at high temperatures, are presented

  17. Corrosion resistance of chromium-nickel steel containing rare earths

    International Nuclear Information System (INIS)

    Asatiani, G.N.; Mandzhgaladze, S.N.; Tavadze, L.F.; Chuvatina, S.N.; Saginadze, D.I.

    1983-01-01

    Effect of additional out-of-furnace treatment with complex alloy (foundry alloy) calcite-silicon-magnesium-rare earth metal on corrosion resistance of the 03Kh18N20M3D3C3B steel has been studied. It is shown that introduction of low additions of rare earths improves its corrosion resistance improves its corrosion resistance in agressive media (in 70% - sulfuric acid) in the range of transition from active to passive state. Effect of additional introduction of rare earth metals is not considerable, if potential of steel corrosion is in the range of stable passive state (32% - sulfuric acid). Additional out-of-furnace treatment with complex foundry alloy, containing rare earth metals, provides a possibility to use a steel with a lower content of Cr, Ni, Mo, than in conventional acid-resistant steels in highly agressive media

  18. Amorphous filler metal foils for brazing zirconium grid plates

    International Nuclear Information System (INIS)

    Plyushchev, A.N.; Kalin, B.A.; Fedotov, V.T.; Sevryukov, O.N.; Mamedova, T.T.; Shestakov, E.F.; Timoshin, S.N.

    2001-01-01

    A new amorphous ribbon filler metal of Zr-5.5 Fe-2.5 Be-1.0 Nb-8.0 Cu-2.0 Sn-0.4 Cr (mass %) with the temperature of melting onset of 745-750 deg C is designed to braze spacer grids of zirconium base alloys. The brazing conditions (780-790 deg C, 40-45 s) are determined which provide minimal standing at temperatures above 700 deg C (∼ 1.5 min) for spacer grids. Mechanical tests show that tensile strength of brazed joints is 55-59 kgf what is twice that of analogous welded joints. In addition, the brazed joints exhibit high corrosion resistance when testing in a distilled steam-water mixture at a temperature of 350 deg C and 16.5 MPa pressure for 10000 h [ru

  19. Advanced Corrosion-Resistant Zr Alloys for High Burnup and Generation IV Application

    International Nuclear Information System (INIS)

    Jeong, Y. H.; Park, S. Y.; Lee, M. H.; Choi, B. K.; Baek, J. H.; Park, J. Y.; Kim, J. H.; Kim, H. G.; Jung, Y. H.; Bang, B. G.

    2006-08-01

    The systematic study was performed to develop the advanced corrosion-resistant Zr alloys for high burnup and Gen IV application. The corrosion behavior was significantly changed with the alloy composition and the corrosion environment. In general, the model alloys with a higher alloying elements showed a higher corrosion resistance. Among the model alloys tested in this study, Zr-10Cr-0.2Fe showed the best corrosion resistance regardless of the corrosion condition. The oxide on the higher corrosion-resistant alloy such as Zr-1.0Cr-0.2Fe consisted of mainly columnar grains, and it have a higher tetragonal phase stability. In comparison with other alloys being considered for the SCWR, the Zr alloys showed a lower corrosion rate than ferritic-martensitic steels. The results of this study imply that, at least from a corrosion standpoint, Zr alloys deserve consideration as potential cladding or structural materials in supercritical water cooled reactors

  20. FY 1999 report on the results of the development of technology of super metal. Development of nano/amorphous structure control materials; 1999 nendo super metal no gijutsu kaihatsu seika hokokusho. Nano amorphous kozo seigyo gijutsu no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    For the purpose of reducing the amount of energy consumption of transportation equipment such as automobiles, the development is made of innovative metal materials enabling the weight reduction of members relatively on the basis of simple chemical components and by making more substantial improvement of characteristics such as strength and toughness than in the existing metals. For it, the following R and D are conducted in which nano crystal structure and non-equilibrium phase structure such as amorphous are controlled to the limits: 1) particle micro-dispersion technology; 2) high speed super plastic formation technology; 3) high density energy utilization control technology; 4) control cooling technology. In 1), study was made of alloy components and effects of the creation process which are needed for achievement of the nano level of crystal grain. In 2), conditions of vapor deposition and production in high speed particle deposition method are optimally selected, and amorphous and nano crystal structures can easily be produced. In 3), high corrosion-resistant amorphous alloy bulk materials with 5mm thickness and 10mm diameter were successfully trially manufactured. In 4), a bulk amorphous specimen with 10mm outer diameter, 6mm inner diameter and 1mm thickness which was fabricated in the forging method indicated favorable magnetic properties. A method to make a specimen which is more stable is being studied. (NEDO)

  1. Corrosion resistance and cytocompatibility of biodegradable surgical magnesium alloy coated with hydrogenated amorphous silicon.

    Science.gov (United States)

    Xin, Yunchang; Jiang, Jiang; Huo, Kaifu; Tang, Guoyi; Tian, Xiubo; Chu, Paul K

    2009-06-01

    The fast degradation rates in the physiological environment constitute the main limitation for the applications of surgical magnesium alloys as biodegradable hard-tissue implants. In this work, a stable and dense hydrogenated amorphous silicon coating (a-Si:H) with desirable bioactivity is deposited on AZ91 magnesium alloy using magnetron sputtering deposition. Raman spectroscopy and Fourier transform infrared spectroscopy reveal that the coating is mainly composed of hydrogenated amorphous silicon. The hardness of the coated alloy is enhanced significantly and the coating is quite hydrophilic as well. Potentiodynamic polarization results show that the corrosion resistance of the coated alloy is enhanced dramatically. In addition, the deterioration process of the coating in simulated body fluids is systematically investigated by open circuit potential evolution and electrochemical impedance spectroscopy. The cytocompatibility of the coated Mg is evaluated for the first time using hFOB1.19 cells and favorable biocompatibility is observed. 2008 Wiley Periodicals, Inc.

  2. Microstructure and pitting corrosion of shielded metal arc welded high nitrogen stainless steel

    Directory of Open Access Journals (Sweden)

    Raffi Mohammed

    2015-09-01

    Full Text Available The present work is aimed at studying the microstructure and pitting corrosion behaviour of shielded metal arc welded high nitrogen steel made of Cromang-N electrode. Basis for selecting this electrode is to increase the solubility of nitrogen in weld metal due to high chromium and manganese content. Microscopic studies were carried out using optical microscopy (OM and field emission scanning electron microscopy (FESEM. Energy back scattered diffraction (EBSD method was used to determine the phase analysis, grain size and orientation image mapping. Potentio-dynamic polarization testing was carried out to study the pitting corrosion resistance in aerated 3.5% NaCl environment using a GillAC electrochemical system. The investigation results showed that the selected Cr–Mn–N type electrode resulted in a maximum reduction in delta-ferrite and improvement in pitting corrosion resistance of the weld zone was attributed to the coarse austenite grains owing to the reduction in active sites of the austenite/delta ferrite interface and the decrease in galvanic interaction between austenite and delta-ferrite.

  3. Investigations on the corrosion resistance of metallic bipolar plates (BPP) in proton exchange membrane fuel cells (PEMFC) - understanding the effects of material, coating and manufacturing

    Science.gov (United States)

    Dur, Ender

    Polymer Electrolyte Membrane Fuel Cell (PEMFC) systems are promising technology for contributing to meet the deficiency of world`s clean and sustainable energy requirements in the near future. Metallic bipolar plate (BPP) as one of the most significant components of PEMFC device accounts for the largest part of the fuel cell`s stack. Corrosion for metallic bipolar plates is a critical issue, which influences the performance and durability of PEMFC. Corrosion causes adverse impacts on the PEMFC`s performance jeopardizing commercialization. This research is aimed at determining the corrosion resistance of metallic BPPs, particularly stainless steels, used in PEMFC from different aspects. Material selection, coating selection, manufacturing process development and cost considerations need to be addressed in terms of the corrosion behavior to justify the use of stainless steels as a BPP material in PEMFC and to make them commercially feasible in industrial applications. In this study, Ti, Ni, SS304, SS316L, and SS 430 blanks, and BPPs comprised of SS304 and SS316L were examined in terms of the corrosion behavior. SS316L plates were coated to investigate the effect of coatings on the corrosion resistance performance. Stamping and hydroforming as manufacturing processes, and three different coatings (TiN, CrN, ZrN) applied via the Physical Vapor Deposition (PVD) method in three different thicknesses were selected to observe the effects of manufacturing processes, coating types and coating thicknesses on the corrosion resistance of BPP, respectively. Uncoated-coated blank and formed BPP were subjected to two different corrosion tests: potentiostatic and potentiodynamic. Some of the substantial results: 1- Manufacturing processes have an adverse impact on the corrosion resistance. 2- Hydroformed plates have slightly higher corrosion resistance than stamped samples. 3- BPPs with higher channel size showed better corrosion resistance. 4- Since none of the uncoated samples

  4. Investigation of corrosion resistance of alloys with high mechanical characteristics in some environments of food industry

    International Nuclear Information System (INIS)

    Tremoureux, Yves

    1978-01-01

    This research thesis aimed at improving knowledge in the field of stress-free corrosion of alloys with high mechanical characteristics in aqueous environments, at highlighting some necessary aspects of their behaviour during cleaning or disinfection, and at selecting alloys which possess a good stress-free corrosion resistance in view of a later investigation of their stress corrosion resistance. After a presentation of the metallurgical characteristics of high mechanical strength alloys and the report of a bibliographical study on corrosion resistance of these alloys, the author presents and discusses the results obtained in the study of a possible migration of metallic ions in a milk product which is submitted to a centrifugation, and of the corrosion resistance of selected alloys with respect to the different media they will be in contact with during ultra-centrifugation. The following alloys have been used in this research: Marval 18, Marphynox, Marval X12, 17-4PH steel, Inconel 718 [fr

  5. High corrosion-resistant fuel spacers

    International Nuclear Information System (INIS)

    Yoshida, Toshimi; Takase, Iwao; Ikeda, Shinzo; Masaoka, Isao; Nakajima, Junjiro.

    1986-01-01

    Purpose: To enable manufacturing BWR fuel spacers by prior-art production process, using a zirconium-base alloy having very excellent corrosion resistance. Method: A highly improved nodular-resistant, corrosion-resistant zirconium alloy is devised by adding a slight amount of niobium, titanium and vanadium to zircaloy, of which fuel spacers are produced. That is, there can be obtained an alloy having much more excellent nodular resistance than conventional zircaloy, and free from a large change in plasticity, workability, and weldability, by adding to zirconium about 1.5 % of tin, about 0.15 % of iron, about 0.05 % of chromium, about 0.05 % of nickel, and 0.05 to 0.5 % of at least one or two kinds of niobium, titanium and vanadium. Using this zirconium-base alloy can manufacture fuel spacers by the same manufacturing process, thus improving economy and reliability. (Kamimura, M.)

  6. Corrosion and surface modification on biocompatible metals: A review.

    Science.gov (United States)

    Asri, R I M; Harun, W S W; Samykano, M; Lah, N A C; Ghani, S A C; Tarlochan, F; Raza, M R

    2017-08-01

    Corrosion prevention in biomaterials has become crucial particularly to overcome inflammation and allergic reactions caused by the biomaterials' implants towards the human body. When these metal implants contacted with fluidic environments such as bloodstream and tissue of the body, most of them became mutually highly antagonistic and subsequently promotes corrosion. Biocompatible implants are typically made up of metallic, ceramic, composite and polymers. The present paper specifically focuses on biocompatible metals which favorably used as implants such as 316L stainless steel, cobalt-chromium-molybdenum, pure titanium and titanium-based alloys. This article also takes a close look at the effect of corrosion towards the implant and human body and the mechanism to improve it. Due to this corrosion delinquent, several surface modification techniques have been used to improve the corrosion behavior of biocompatible metals such as deposition of the coating, development of passivation oxide layer and ion beam surface modification. Apart from that, surface texturing methods such as plasma spraying, chemical etching, blasting, electropolishing, and laser treatment which used to improve corrosion behavior are also discussed in detail. Introduction of surface modifications to biocompatible metals is considered as a "best solution" so far to enhanced corrosion resistance performance; besides achieving superior biocompatibility and promoting osseointegration of biocompatible metals and alloys. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Ion implantation and amorphous metals

    International Nuclear Information System (INIS)

    Hohmuth, K.; Rauschenbach, B.

    1981-01-01

    This review deals with ion implantation of metals in the high concentration range for preparing amorphous layers (>= 10 at%, implantation doses > 10 16 ions/cm 2 ). Different models are described concerning formation of amorphous phases of metals by ion implantation and experimental results are given. The study of amorphous phases has been carried out by the aid of Rutherford backscattering combined with the channeling technique and using transmission electron microscopy. The structure of amorphous metals prepared by ion implantation has been discussed. It was concluded that amorphous metal-metalloid compounds can be described by a dense-random-packing structure with a great portion of metal atoms. Ion implantation has been compared with other techniques for preparing amorphous metals and the adventages have been outlined

  8. Amorphous metal composites

    International Nuclear Information System (INIS)

    Byrne, M.A.; Lupinski, J.H.

    1984-01-01

    This patent discloses an improved amorphous metal composite and process of making the composite. The amorphous metal composite comprises amorphous metal (e.g. iron) and a low molecular weight thermosetting polymer binder. The process comprises placing an amorphous metal in particulate form and a thermosetting polymer binder powder into a container, mixing these materials, and applying heat and pressure to convert the mixture into an amorphous metal composite

  9. Corrosion considerations of high-nickel alloys and titanium alloys for high-level radioactive waste disposal containers

    International Nuclear Information System (INIS)

    Gdowski, G.E.; McCright, R.D.

    1991-07-01

    Corrosion resistant materials are being considered for the metallic barrier of the Yucca Mountain Project's high-level radioactive waste disposal containers. High nickel alloys and titanium alloys have good corrosion resistance properties and are considered good candidates for the metallic barrier. The localized corrosion phenomena, pitting and crevice corrosion, are considered as potentially limiting for the barrier lifetime. An understanding of the mechanisms of localized corrosion of how various parameters affect it will be necessary for adequate performance assessments of candidate container materials. Examples of some of the concerns involving candidate container materials. Examples of some of the concerns of involving localized corrosion are discussed. The effects of various parameters, such as temperature and concentration of halide species, on localized corrosion are given. In addition concerns about aging of the protective oxide layer in the expected service temperature range (50 to 250 degrees C) are presented. Also some mechanistic considerations of localized corrosion are given. 31 refs., 1 tab

  10. Bulk metallic glasses and high entropy alloys for reprocessing applications

    International Nuclear Information System (INIS)

    Kamachi Mudali, U.; Jayaraj, J.

    2016-01-01

    Recent breakthroughs in materials engineering have generated complex alloys that retain a glassy state in bulk form (bulk metallic glasses or BMGs) via ingot casting. High corrosion resistance is expected for BMGs (amorphous) as they are free from defects associated with the crystalline state such as grain boundaries, dislocations and stacking faults. Compared with conventional alloys containing one or two principal elements, the recently developed HEAs are usually composed of five or more elements with equimolar or near equimolar elemental fractions, which forms single solid solution phase. These HEAs exhibit excellent microstructural stability with better mechanical, wear and corrosion resistance properties as they are essentially single phase. Reprocessing of spent fuel from the fast breeder reactor involves the use of high concentration of (11.5 M) nitric acid under boiling conditions for the dissolution of the fuel. Conventional AISI type 304LSS and nitric acid grade 304L stainless steel would undergo inter-granular corrosion under these conditions and cannot be used for the fabrication of dissolver vessel. Currently titanium is used and zirconium alloys are proposed for future dissolver applications. Thus searching for newer materials with higher corrosion resistance suggests metallic glasses and HEAs for critical components of the dissolver application. Several Zr-based glassy alloys with different microstructural states and Ni-Nb based glassy alloys and TiZrHfNbTa HEA were cast and characterized for microstructure and corrosion resistance in nitric acid medium. From these studies, factors such as the corrosive environment (nitric acid, chloride and fluoride), and the presence of passivating elements in the alloy were emphasized for better corrosion resistance of BMGs and HEA. Attempts were also made to prepare coatings of Zr-and Ni-based glassy alloys on 304LSS by laser based deposition technique and their corrosion properties were evaluated. (author)

  11. Atmospheric corrosion of metals in tropics and subtropic. 2. Corrosion resistance of different metals and alloys

    International Nuclear Information System (INIS)

    Strekalov, P.V.

    1993-01-01

    Data from 169 sources concerning corrosion of different metals, alloys and means of protection, obtained for a 30-year period (up to 1987) in different continent including Europe (Bulgaria, Spain, Italy, France, USSR); America (USA, Panama, Cuba, Venezuela, Brasil, Argentine); Africa (Nigeria, SAR); Australia, New Zeland, Papua-Newguinea, Philippines, are systemized. Actual results of full-scal atmospheric testings of iron, zinc, copper, cadmium, aluminium, tin, lead, carbon, low-alloys. Stainless steels, cast irons, halvanic coatings, copper, aluminium, nickel, titanium, magnesium alloys are presented. Data on the fracture rate can be used for creating the data base in banks on atmospheric resistance of metal materials

  12. Method for Evaluating the Corrosion Resistance of Aluminum Metallization of Integrated Circuits under Multifactorial Influence

    Science.gov (United States)

    Kolomiets, V. I.

    2018-03-01

    The influence of complex influence of climatic factors (temperature, humidity) and electric mode (supply voltage) on the corrosion resistance of metallization of integrated circuits has been considered. The regression dependence of the average time of trouble-free operation t on the mentioned factors has been established in the form of a modified Arrhenius equation that is adequate in a wide range of factor values and is suitable for selecting accelerated test modes. A technique for evaluating the corrosion resistance of aluminum metallization of depressurized CMOS integrated circuits has been proposed.

  13. Liquid metal corrosion considerations in alloy development

    International Nuclear Information System (INIS)

    Tortorelli, P.F.; DeVan, J.H.

    1984-01-01

    Liquid metal corrosion can be an important consideration in developing alloys for fusion and fast breeder reactors and other applications. Because of the many different forms of liquid metal corrosion (dissolution, alloying, carbon transfer, etc.), alloy optimization based on corrosion resistance depends on a number of factors such as the application temperatures, the particular liquid metal, and the level and nature of impurities in the liquid and solid metals. The present paper reviews the various forms of corrosion by lithium, lead, and sodium and indicates how such corrosion reactions can influence the alloy development process

  14. Corrosion-resistant coating development

    Energy Technology Data Exchange (ETDEWEB)

    Stinton, D.P.; Kupp, D.M.; Martin, R.L. [Oak Ridge National Lab., TN (United States)

    1997-12-01

    SiC-based heat exchangers have been identified as the prime candidate material for use as heat exchangers in advanced combined cycle power plants. Unfortunately, hot corrosion of the SiC-based materials created by alkali metal salts present in the combustion gases dictates the need for corrosion-resistant coatings. The well-documented corrosion resistance of CS-50 combined with its low (and tailorable) coefficient of thermal expansion and low modulus makes CS-50 an ideal candidate for this application. Coatings produced by gelcasting and traditional particulate processing have been evaluated.

  15. Thermal Aging Effect on Corrosion Resistance in Fusion Boundary of A533 Gr. B and Alloy 152

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Kyoung Joon; Yoo, Seung Chang; Kim, Taeho; Ham, Junhyuk; Kim, Ji Hyun [UNIST, Ulsan (Korea, Republic of)

    2016-10-15

    Dissimilar metal weldment (DMW) is frequently used for joining low-alloy steel pressure vessel nozzles and steam generator nozzles to nickel-based wrought alloy or austenitic stainless steel components in high energy systems. This feature also significantly hinders C diffusion from the ferrite base metal to the weld metal. Until now, stress corrosion cracking has not occurred in DMWs where a High-Cr weld metal (such as Alloy 152 or Alloy 690), which is Ni-base weld metal including relative high Cr, is used as the weld metal in the weld between the nickel-based alloy and low-alloy steel. To understand the microstructure and corrosion evolution on fusion boundary between low-alloy steel and Ni-base weld metal, microstructural analysis and polarization test were performed with A533 Gr. B/Alloy 152/Alloy 690. Remarkable changes were observed in corrosion resistance and hardness at fusion boundary between low-alloy steel and Ni-base weld metal. The precipitate, which has different potential with peripheral region, can cause galvanic corrosion or pitting corrosion and is the one of hardening methods by disturbing movement of the dislocation. At initial step of heat treatment, the number of precipitates was increased. In fusion boundary between A533 Gr. B and Alloy 152, the corrosion resistance was decreased, and the hardness was increased. Next, at further step, the number of precipitates.

  16. Corrosion resistant alloy uses in the power industry

    International Nuclear Information System (INIS)

    Nickerson, J.L.; Hall, F.A.; Asphahani, A.I.

    1989-01-01

    Nickel-base alloys have been used as cost-effective measures in a variety of severely corrosive situations in pollution control units for coal-fired power plants. Cost effectiveness and practical answers to corrosion problems are illustrated (specifically the wallpaper concept/metallic lining technique). Numerous cases of successful use of HASTELLOY alloys in Flue Gas Desulfurization (FGD) systems and hazardous waste treatment incineration scrubber systems are listed. In this paper developments in nickel-base alloys and their use in FGD and other segments of the power industry are discussed. In the Ni-Cr-Mo-W alloy family, the C-22 alloy has the best resistance to localized corrosion in halide environments (chloride/fluoride-containing solutions). This alloy is also used effectively as a universal filler metal to weld less-resistant alloys were weld corrosion may be a problem. Field performance of this alloy in the power industry is described

  17. Corrosion Resistance and Pitting Behaviour of Low-Carbon High-Mn Steels in Chloride Solution

    Directory of Open Access Journals (Sweden)

    Grajcar A.

    2016-06-01

    Full Text Available Corrosion resistance of the X4MnSiAlNbTi27-4-2 and X6MnSiAlNbTi26-3-3 type austenitic steels, after hot deformation as well as after cold rolling, were evaluated in 3.5% NaCl solution using potentiodynamic polarization tests. A type of nonmetallic inclusions and their pitting corrosion behaviour were investigated. Additionally, the effect of cold deformation on the corrosion resistance of high-Mn steels was studied. The SEM micrographs revealed that corrosion damage formed in both investigated steels is characterized by various shapes and an irregular distribution at the metallic matrix, independently on the steel state (thermomechanically treated or cold worked. Corrosion pits are generated both in grain interiors, grain boundaries and along the deformation bands. Moreover, corrosion damage is stronger in cold deformed steels in comparison to the thermomechanically treated specimens. EDS analysis revealed that corrosion pits preferentially nucleated on MnS and AlN inclusions or complex oxysulphides. The morphology of corrosion damage in 3.5% NaCl supports the data registered in potentiodynamic tests.

  18. Corrosion behavior of Al-Fe-sputtering-coated steel, high chromium steels, refractory metals and ceramics in high temperature Pb-Bi

    International Nuclear Information System (INIS)

    Abu Khalid, Rivai; Minoru, Takahashi

    2007-01-01

    Corrosion tests of Al-Fe-coated steel, high chromium steels, refractory metals and ceramics were carried out in high temperature Pb-Bi at 700 C degrees. Oxygen concentrations in this experiment were 6.8*10 -7 wt.% for Al-Fe-coated steels and 5*10 -6 wt.% for high chromium steels, refractory metals and ceramics. All specimens were immersed in molten Pb-Bi in a corrosion test pot for 1.000 hours. Coating was done with using the unbalanced magnetron sputtering (UBMS) technique to protect the steel from corrosion. Sputtering targets were Al and SUS-304. Al-Fe alloy was coated on STBA26 samples. The Al-Fe alloy-coated layer could be a good protection layer on the surface of steel. The whole of the Al-Fe-coated layer still remained on the base surface of specimen. No penetration of Pb-Bi into this layer and the matrix of the specimen. For high chromium steels i.e. SUS430 and Recloy10, the oxide layer formed in the early time could not prevent the penetration of Pb-Bi into the base of the steels. Refractory metals of tungsten (W) and molybdenum (Mo) had high corrosion resistance with no penetration of Pb-Bi into their matrix. Penetration of Pb-Bi into the matrix of niobium (Nb) was observed. Ceramic materials were SiC and Ti 3 SiC 2 . The ceramic materials of SiC and Ti 3 SiC 2 had high corrosion resistance with no penetration of Pb-Bi into their matrix. (authors)

  19. The role of nitrogen in improving pitting corrosion resistance of high-alloy austenitic and duplex stainless steel welds

    International Nuclear Information System (INIS)

    Vilpas, M.; Haenninen, H.

    1999-01-01

    The effects of nitrogen alloyed shielding gas on weld nitrogen content and pitting corrosion resistance of super austenitic (6%Mo) and super duplex stainless steels have been studied with special emphasis on microsegregation behaviour of Cr, Mo and N. The measurements performed with the 6%Mo steel indicate that all these elements segregate interdendritically in the fully austenitic weld metal. With nitrogen addition to the shielding gas the enrichment of nitrogen to the interdendritic regions is more pronounced than to the dendrite cores due to which the pitting corrosion resistance of the dendrite cores increases only marginally. In the super duplex steel welds nitrogen enriches in austenite increasing its pitting corrosion resistance more effectively. In these welds the pitting corrosion resistance of the ferrite phase remains lower. (orig.)

  20. Characterization and properties of shock and corrosion resistant of titanium based coatings

    International Nuclear Information System (INIS)

    Motoiu, P.; Rosso, M.

    2001-01-01

    Thermal spraying technologies are an effective way to ensure surface protection against destructive effects of wear, corrosion and oxidizing phenomena. These technologies can be applied in majority of industrial sectors in order to improve properties of new parts or for reconditioning worn out parts technology. Ideally, it would be comfortable to have a material able to resist to all type of wear, but the work condition intricacy combined with economic reason have lead to the development of a big number of powder materials that are used in thermal spraying technologies. The titanium powders are suitable for coating layers which have a good behavior in 'metal on metal friction', toughness, shock and corrosion resistance. In particular, titanium layers obtained by plasma spraying are used in different aerospace and non aerospace applications due to the combination of low density, very good mechanical properties and high corrosion resistance. The accomplishment of new titanium thermal layers is effectively used in order to increase the lifetime of different engine parts securing the thermal protection in use, resistance to high corrosion and oxidizing phenomena. This paper deals about the mechanical properties of Ti based coatings applied by plasma spray process on steel substrates, the obtained results show the possibility to apply titanium coatings where special and high performance materials are needed. (author)

  1. Corrosion resistance of Fe-Al alloy-coated steel under bending stress in high temperature lead-bismuth eutectic

    International Nuclear Information System (INIS)

    Yamaki, Eriko; Takahashi, Minoru

    2009-01-01

    Formation of thin Fe-Al alloy layers on the surface of cladding and structural materials is effective to protect a base material from corrosion in high temperature LBE. However, it is concerned that these protective layers may be damaged under various stress conditions. This study on Fe-Al alloy coatings deposited by unbalanced magnetron sputtering (UBMS) is focused to evaluate corrosion resistance and integrity of the Fe-Al coating layers with thickness of 0.5 mm under bending stress in high temperature LBE. High chromium steel specimens (HCM12A, Recloy10) with Fe-Al alloy coating were exposed to LBE pool with low oxygen concentration (up to 5.2x10 -8 wt%) at 550 and 650degC under 45kg-loading for 240 and 500 h. No LBE corrosion was observed in the base metal and coating layer after the tests at 550degC for 550 h. The coating layers could be barrier for corrosion resistance from LBE at 550degC, although the coating scales are cracked by the load. At 650degC, because the base metal was contoccured directly with LBE through cracks across the coating layer. Penetration of LBE to base metal and dissolution of beset metal into LBE occurred. Fe-Al coating layer was not corroded by LBE. (author)

  2. Effect of crystallization on corrosion behavior of Fe40Ni38B18Mo4 amorphous alloy in 3.5% sodium chloride solution

    DEFF Research Database (Denmark)

    Wu, Y.F.; Chiang, Wen-Chi; Wu, J.K.

    2008-01-01

    After the crystallization of F40Ni38B18Mo4 amorphous alloy by vacuum annealing, the corrosion resistance of its crystalline state shows inferior to its amorphous state due to the local cell action between Ni phase and (Fe, Ni, Mo)(23)B-6 phase in matrix.......After the crystallization of F40Ni38B18Mo4 amorphous alloy by vacuum annealing, the corrosion resistance of its crystalline state shows inferior to its amorphous state due to the local cell action between Ni phase and (Fe, Ni, Mo)(23)B-6 phase in matrix....

  3. Enhanced Corrosion Resistance and Interfacial Conductivity of TiC x/a-C Nanolayered Coatings via Synergy of Substrate Bias Voltage for Bipolar Plates Applications in PEMFCs.

    Science.gov (United States)

    Yi, Peiyun; Zhang, Weixin; Bi, Feifei; Peng, Linfa; Lai, Xinmin

    2018-06-06

    Proton-exchange membrane fuel cells are one kind of renewable and clean energy conversion device, whose metallic bipolar plates are one of the key components. However, high interfacial contact resistance and poor corrosion resistance are still great challenges for the commercialization of metallic bipolar plates. In this study, we demonstrated a novel strategy for depositing TiC x /amorphous carbon (a-C) nanolayered coatings by synergy of 60 and 300 V bias voltage to enhance corrosion resistance and interfacial conductivity. The synergistic effects of bias voltage on the composition, microstructure, surface roughness, electrochemical corrosion behaviors, and interfacial conductivity of TiC x /a-C coatings were explored. The results revealed that the columnar structures in the inner layer were suppressed and the surface became rougher with the 300 V a-C layer outside. The composition analysis indicated that the sp 2 content increased with an increase of 300 V sputtering time. Due to the synergy strategy of bias voltage, lower corrosion current densities were achieved both in potentiostatic polarization (1.6 V vs standard hydrogen electrode) and potentiodynamic polarization. With the increase of 300 V sputtering time, the interfacial conductivity was improved. The enhanced corrosion resistance and interfacial conductivity of the TiC x /a-C coatings would provide new opportunities for commercial bipolar plates.

  4. Corrosion resistance of metal materials for HLW canister

    International Nuclear Information System (INIS)

    Furuya, Takashi; Muraoka, Susumu; Tashiro, Shingo

    1982-02-01

    In order to verify the materials as an important artificial barrier for canister of vitrified high-level waste from spent fuel reprocessing, data and reports were researched on corrosion resistance of the materials under conditions from glass form production to final disposal. Then, in this report, investigated subjects, improvement methods and future subjects are reviewed. It has become clear that there would be no problem on the inside and outside corrosion of the canister during glass production, but long term corrosion and radiation effect tests and the vitrification methods would be subjects in future on interim storage and final disposal conditions. (author)

  5. The effect of carbon content on mechanical properties, failure and corrosion resistance of deposited chromium metal

    Directory of Open Access Journals (Sweden)

    Леонід Кімович Лещинськiй

    2017-06-01

    Full Text Available It has been shown that if choosing a metal composition for surfacing rolls and rollers of continuous casting machines, both the carbon impact on the mechanical and functional properties and the critical values of the chromium concentration, which determine the corrosion resistance of the metal with regard to electrochemical corrosion theory, should be considered as well. The paper studied the effect of chromium and carbon steel the X5-X12 type on the structure, technological strength, mechanical properties, fracturing resistance and corrosion resistance of the weld metal. The composition of chromium tool steels (deposited metal (X5-used for the rolls of hot rolling mills and (X12-used for continuous casting machines rollers correspond to these values. The impact of carbon on the properties of the deposited metal containing chromium was considered by comparing the data for both types of the deposited metal. It was found that for both types of the deposited metal (X5 and X12, the limiting value of the carbon content, providing an optimal combination of strength, ductility, failure resistance is the same. If the carbon content is more than the limiting value – (0,25% the technological strength and failure resistance of the deposited metal significantly reduce. With increasing carbon content from 0,18 to 0,25% the martensite structure has a mixed morphology – lath and plate. The strength and toughness of the deposited metal grow. Of particular interest is simultaneous increase in the specific work of failure resulted from crack inhibition at the boundary with far less solid and more ductile ferrite. As for the 5% chromium metal, the X12 type composition with 0,25% C, is borderline. With a further increase in the carbon content of the metal both ductility and failure resistance sharply decrease and with 0,40% C the growth rate of fatigue crack increases by almost 1,5 times

  6. Corrosion resistance of metallic materials for use in nuclear fuel reprocessing

    International Nuclear Information System (INIS)

    Legry, J.P.; Pelras, M.; Turluer, G.

    1989-01-01

    This paper reviews the corrosion resistance properties required from metallic materials to be used in the various developments of the PUREX process for nuclear fuel reprocessing. Stainless steels, zirconium or titanium base alloys are considered for the various plant components, where nitric acid is the main electrolyte with differing acid and nitrate concentrations, temperature and oxidizing species. (author)

  7. Effect of substrate temperature on corrosion performance of nitrogen doped amorphous carbon thin films in NaCl solution

    Energy Technology Data Exchange (ETDEWEB)

    Khun, N.W. [School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Liu, E., E-mail: MEJLiu@ntu.edu.s [School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore)

    2009-07-01

    Nitrogen doped amorphous carbon (a-C:N) thin films were deposited on p-Si substrates by DC magnetron sputtering at varying substrate temperature from room temperature (RT) to 300 {sup o}C. The bonding structure, surface morphology and adhesion strength of the a-C:N films were investigated by using X-ray photoelectron spectroscopy (XPS), micro-Raman spectroscopy, atomic force microscopy (AFM) and micro-scratch testing. The corrosion behavior of the a-C:N films was evaluated by potentiodynamic polarization test in a 0.6 M NaCl solution. The results indicated that the corrosion resistance of the films depended on the sp{sup 3}-bonded cross-link structure that was significantly affected by the substrate temperature.

  8. Effect of substrate temperature on corrosion performance of nitrogen doped amorphous carbon thin films in NaCl solution

    International Nuclear Information System (INIS)

    Khun, N.W.; Liu, E.

    2009-01-01

    Nitrogen doped amorphous carbon (a-C:N) thin films were deposited on p-Si substrates by DC magnetron sputtering at varying substrate temperature from room temperature (RT) to 300 o C. The bonding structure, surface morphology and adhesion strength of the a-C:N films were investigated by using X-ray photoelectron spectroscopy (XPS), micro-Raman spectroscopy, atomic force microscopy (AFM) and micro-scratch testing. The corrosion behavior of the a-C:N films was evaluated by potentiodynamic polarization test in a 0.6 M NaCl solution. The results indicated that the corrosion resistance of the films depended on the sp 3 -bonded cross-link structure that was significantly affected by the substrate temperature.

  9. Effects of rare earth metals addition on the resistance to pitting corrosion of super duplex stainless steel - Part 1

    International Nuclear Information System (INIS)

    Kim, Soon-Tae; Jeon, Soon-Hyeok; Lee, In-Sung; Park, Yong-Soo

    2010-01-01

    To elucidate the effects of rare earth metals addition on the resistance to pitting corrosion of super duplex stainless steel, a metallographic examination, potentiodynamic and potentiostatic polarization tests, a SEM-EDS and a SAM analysis of inclusion, austenite phase and ferrite phase were conducted. The addition of rare earth metals to the base alloy led to the formation of (Mn, Cr, Si, Al, Ce) oxides and (Mn, Cr, Si, Ce) oxides, which improved the resistance to pitting corrosion and caused a decrease in the preferential interface areas for the initiation of the pitting corrosion.

  10. Thermally oxidized titania nanotubes enhance the corrosion resistance of Ti6Al4V.

    Science.gov (United States)

    Grotberg, John; Hamlekhan, Azhang; Butt, Arman; Patel, Sweetu; Royhman, Dmitry; Shokuhfar, Tolou; Sukotjo, Cortino; Takoudis, Christos; Mathew, Mathew T

    2016-02-01

    The negative impact of in vivo corrosion of metallic biomedical implants remains a complex problem in the medical field. We aimed to determine the effects of electrochemical anodization (60V, 2h) and thermal oxidation (600°C) on the corrosive behavior of Ti-6Al-4V, with serum proteins, at physiological temperature. Anodization produced a mixture of anatase and amorphous TiO2 nanopores and nanotubes, while the annealing process yielded an anatase/rutile mixture of TiO2 nanopores and nanotubes. The surface area was analyzed by the Brunauer-Emmett-Teller method and was estimated to be 3 orders of magnitude higher than that of polished control samples. Corrosion resistance was evaluated on the parameters of open circuit potential, corrosion potential, corrosion current density, passivation current density, polarization resistance and equivalent circuit modeling. Samples both anodized and thermally oxidized exhibited shifts of open circuit potential and corrosion potential in the noble direction, indicating a more stable nanoporous/nanotube layer, as well as lower corrosion current densities and passivation current densities than the smooth control. They also showed increased polarization resistance and diffusion limited charge transfer within the bulk oxide layer. The treatment groups studied can be ordered from greatest corrosion resistance to least as Anodized+Thermally Oxidized > Anodized > Smooth > Thermally Oxidized for the conditions investigated. This study concludes that anodized surface has a potential to prevent long term implant failure due to corrosion in a complex in-vivo environment. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. New class of materials - amorphous metals. Properties and applications

    Energy Technology Data Exchange (ETDEWEB)

    Vuchkov, L. [Institute of Electrochemistry and Energy Systems, Bulgarian Academy of Scinces, Sofia (Bulgaria)

    2008-07-01

    This work presents the result of a cycle of scientific investigations and testing of physicomechanical, physicochemical and electromagnetic shielding properties of both electrochemically and metallurgically produced thin amorphous and crystalline films of Fe, Co, Ni and their alloys and Cr. Key words: microhardness, tensile strength, corrosion resistance, shielding.

  12. Exceptionally high cavitation erosion and corrosion resistance of a high entropy alloy.

    Science.gov (United States)

    Nair, R B; Arora, H S; Mukherjee, Sundeep; Singh, S; Singh, H; Grewal, H S

    2018-03-01

    Cavitation erosion and corrosion of structural materials are serious concerns for marine and offshore industries. Durability and performance of marine components are severely impaired due to degradation from erosion and corrosion. Utilization of advanced structural materials can play a vital role in limiting such degradation. High entropy alloys (HEAs) are a relatively new class of advanced structural materials with exceptional properties. In the present work, we report on the cavitation erosion behavior of Al 0.1 CoCrFeNi HEA in two different media: distilled water with and without 3.5wt% NaCl. For comparison, conventionally used stainless steel SS316L was also evaluated in identical test conditions. Despite lower hardness and yield strength, the HEA showed significantly longer incubation period and lower erosion-corrosion rate (nearly 1/4th) compared to SS316L steel. Enhanced erosion resistance of HEA was attributed to its high work-hardening behavior and stable passivation film on the surface. The Al 0.1 CoCrFeNi HEA showed lower corrosion current density, high pitting resistance and protection potential compared to SS316L steel. Further, HEA showed no evidence of intergranular corrosion likely due to the absence of secondary precipitates. Although, the degradation mechanisms (formation of pits and fatigue cracks) were similar for both the materials, the damage severity was found to be much higher for SS316L steel compared to HEA. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Improving corrosion resistance of post-tensioned substructures emphasizing high performance grouts

    Science.gov (United States)

    Schokker, Andrea Jeanne

    The use of post-tensioning in bridges can provide durability and structural benefits to the system while expediting the construction process. When post-tensioning is combined with precast elements, traffic interference can be greatly reduced through rapid construction. Post-tensioned concrete substructure elements such as bridge piers, hammerhead bents, and straddle bents have become more prevalent in recent years. Chloride induced corrosion of steel in concrete is one of the most costly forms of corrosion each year. Coastal substructure elements are exposed to seawater by immersion or spray, and inland bridges may also be at risk due to the application of deicing salts. Corrosion protection of the post-tensioning system is vital to the integrity of the structure because loss of post-tensioning can result in catastrophic failure. Documentation for durability design of the grout, ducts, and anchorage systems is very limited. The objective of this research is to evaluate the effectiveness of corrosion protection measures for post-tensioned concrete substructures by designing and testing specimens representative of typical substructure elements using state-of-the-art practices in aggressive chloride exposure environments. This was accomplished through exposure testing of twenty-seven large-scale beam specimens and ten large-scale column specimens. High performance grout for post-tensioning tendon injection was also developed through a series of fresh property tests, accelerated exposure tests, and a large-scale pumping test to simulate field conditions. A high performance fly ash grout was developed for applications with small vertical rises, and a high performance anti-bleed grout was developed for applications involving large vertical rises such as tall bridge piers. Long-term exposure testing of the beam and column specimens is ongoing, but preliminary findings indicate increased corrosion protection with increasing levels of post-tensioning, although traditional

  14. Electrochemical corrosion testing of metal waste forms

    International Nuclear Information System (INIS)

    Abraham, D. P.; Peterson, J. J.; Katyal, H. K.; Keiser, D. D.; Hilton, B. A.

    1999-01-01

    Electrochemical corrosion tests have been conducted on simulated stainless steel-zirconium (SS-Zr) metal waste form (MWF) samples. The uniform aqueous corrosion behavior of the samples in various test solutions was measured by the polarization resistance technique. The data show that the MWF corrosion rates are very low in groundwaters representative of the proposed Yucca Mountain repository. Galvanic corrosion measurements were also conducted on MWF samples that were coupled to an alloy that has been proposed for the inner lining of the high-level nuclear waste container. The experiments show that the steady-state galvanic corrosion currents are small. Galvanic corrosion will, hence, not be an important mechanism of radionuclide release from the MWF alloys

  15. Identifying the optimal HVOF spray parameters to attain minimum porosity and maximum hardness in iron based amorphous metallic coatings

    Directory of Open Access Journals (Sweden)

    S. Vignesh

    2017-04-01

    Full Text Available Flow based Erosion – corrosion problems are very common in fluid handling equipments such as propellers, impellers, pumps in warships, submarine. Though there are many coating materials available to combat erosion–corrosion damage in the above components, iron based amorphous coatings are considered to be more effective to combat erosion–corrosion problems. High velocity oxy-fuel (HVOF spray process is considered to be a better process to coat the iron based amorphous powders. In this investigation, iron based amorphous metallic coating was developed on 316 stainless steel substrate using HVOF spray technique. Empirical relationships were developed to predict the porosity and micro hardness of iron based amorphous coating incorporating HVOF spray parameters such as oxygen flow rate, fuel flow rate, powder feed rate, carrier gas flow rate, and spray distance. Response surface methodology (RSM was used to identify the optimal HVOF spray parameters to attain coating with minimum porosity and maximum hardness.

  16. Electrochemical evaluation of corrosion and tribocorrosion behaviour of amorphous and nanocrystalline cobalt–tungsten electrodeposited coatings

    Energy Technology Data Exchange (ETDEWEB)

    Fathollahzade, N.; Raeissi, K., E-mail: k_raeissi@cc.iut.ac.ir

    2014-11-14

    Amorphous and nanocrystalline Co–W coatings were electrodeposited on copper substrates from a citrate–ammonia bath. The coatings showed nodular surface morphologies, but a microcrack network was detected in the amorphous coating. However, a better corrosion resistance was achieved for the amorphous coating. During sliding under open circuit potential (OCP) condition, the potential of amorphous coating gradually became more active probably due to the widening of wear scar, and thus expansion of active area. The amorphous coatings showed a higher volume loss at OCP probably due to its lower microhardness. In anodic sliding, a sharp increase in current density was observed due to mass transport and depassivation effects. In all sliding conditions, the proportion of mass transport was higher than wear accelerated corrosion, which implied that the dissolution reaction of the coatings was mainly a mass-transport controlled process. The results also showed that the effect of sliding on degradation is more intense for the nanocrystalline coating. For both coatings, the formation of the superficial microcracks in the vicinity of wear scars indicating on a surface fatigue wear mechanism. - Highlights: • Mass-transport effect had higher proportion in tribocorrosion of Co–W coatings. • The major electrochemical-wear degradation was for the nanocrystalline coating. • The higher proportion of wear accelerated corrosion was for the amorphous coating. • Superficial microcracks were formed near scars due to the coatings brittleness.

  17. A study on corrosion resistance of dissimilar welds between Monel 400 and 316L austenitic stainless steel

    Science.gov (United States)

    Mani, Cherish; Karthikeyan, R.; Vincent, S.

    2018-04-01

    An attempt has been made to study the corrosion resistance of bi-metal weld joints of Monel 400 tube to stainless steel 316 tube by GTAW process. The present research paper contributes to the ongoing research work on the use of Monel400 and 316L austenitic stainless steel in industrial environments. Potentiodynamic method is used to investigate the corrosion behavior of Monel 400 and 316L austenitic stainless steel welded joints. The analysis has been performed on the base metal, heat affected zone and weld zone after post weld heat treatment. Optical microscopy was also performed to correlate the results. The heat affected zone of Monel 400 alloy seems to have the lowest corrosion resistance whereas 316L stainless steel base metal has the highest corrosion resistance.

  18. Corrosion processes of physical vapor deposition-coated metallic implants.

    Science.gov (United States)

    Antunes, Renato Altobelli; de Oliveira, Mara Cristina Lopes

    2009-01-01

    Protecting metallic implants from the harsh environment of physiological fluids is essential to guaranteeing successful long-term use in a patient's body. Chemical degradation may lead to the failure of an implant device in two different ways. First, metal ions may cause inflammatory reactions in the tissues surrounding the implant and, in extreme cases, these reactions may inflict acute pain on the patient and lead to loosening of the device. Therefore, increasing wear strength is beneficial to the performance of the metallic implant. Second, localized corrosion processes contribute to the nucleation of fatigue cracks, and corrosion fatigue is the main reason for the mechanical failure of metallic implants. Common biomedical alloys such as stainless steel, cobalt-chrome alloys, and titanium alloys are prone to at least one of these problems. Vapor-deposited hard coatings act directly to improve corrosion, wear, and fatigue resistances of metallic materials. The effectiveness of the corrosion protection is strongly related to the structure of the physical vapor deposition layer. The aim of this paper is to present a comprehensive review of the correlation between the structure of physical vapor deposition layers and the corrosion properties of metallic implants.

  19. Corrosion of metallic materials by uranium hexafluoride at high temperatures (1963); Corrosion de materiaux metalliques par l'hexafluorure d'uranium a haute temperature (1963)

    Energy Technology Data Exchange (ETDEWEB)

    Langlois, G [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1963-07-01

    The corrosion of the following metals or alloys by UF{sub 6}: nickel, monel, Inconel, gold, platinum, stainless steel, is studied in the temperature range from 300 to 1000 deg. C. The test method, designed to avoid heating the apparatus containing the corrosive fluid to a high temperature, consists in using threadlike samples heated by the Joule effect, the rest of the apparatus being maintained close to room temperature. This technique makes it possible also to determine continuously the penetration of the corrosion by measuring the electrical resistance of the sample with a double Thomson bridge. A series of rapid comparison tests shows that stainless steel, precious metals and Inconel are attacked far too rapidly to be used above 500 deg. C; only monel and especially nickel appear capable of resisting at high temperatures. The detailed examination of the behaviour of nickel shows that the metallic fluoride is volatilized and that this influences the corrosion rate. It shows also the existence of a temperature zone situated between 550 and 700 deg. C in which occurs A strong intergranular corrosion the cause of which appears to be the presence of impurities in the metal. (author) [French] La corrosion par l'UF{sub 6} des metaux ou alliages suivants: lickel, monel, inconel, or, platine, acier inoxydable, est etudiee dans le un domaine de temperature compris entre 300 et 1000 deg. C. La methode d'essai, destinee a eviter le chauffage de l'enceinte contenant le fluide corrosif a temperature elevee, consiste a utiliser des eprouvettes filiformes, echauffees par effet Joule, le reste de l'appareillage etant maintenu a une temperature proche de l'ambiance. Cette technique permet en outre de determiner en continu la penetration de la corrosion, par mesure de la resistance electrique de l'eprouvette, au moyen d'un pont double de Thomson. Une serie d'essais comparatifs, assez sommaires, montre que l'acier inoxydable, les metaux precieux et l'inconel sont attaques beaucoup

  20. Amorphous metal based nanoelectromechanical switch

    KAUST Repository

    Mayet, Abdulilah M.; Smith, Casey; Hussain, Muhammad Mustafa

    2013-01-01

    Nanoelectromechanical (NEM) switch is an interesting ultra-low power option which can operate in the harsh environment and can be a complementary element in complex digital circuitry. Although significant advancement is happening in this field, report on ultra-low voltage (pull-in) switch which offers high switching speed and area efficiency is yet to be made. One key challenge to achieve such characteristics is to fabricate nano-scale switches with amorphous metal so the shape and dimensional integrity are maintained to achieve the desired performance. Therefore, we report a tungsten alloy based amorphous metal with fabrication process development of laterally actuated dual gated NEM switches with 100 nm width and 200 nm air-gap to result in <5 volts of actuation voltage (Vpull-in). © 2013 IEEE.

  1. Amorphous metal based nanoelectromechanical switch

    KAUST Repository

    Mayet, Abdulilah M.

    2013-04-01

    Nanoelectromechanical (NEM) switch is an interesting ultra-low power option which can operate in the harsh environment and can be a complementary element in complex digital circuitry. Although significant advancement is happening in this field, report on ultra-low voltage (pull-in) switch which offers high switching speed and area efficiency is yet to be made. One key challenge to achieve such characteristics is to fabricate nano-scale switches with amorphous metal so the shape and dimensional integrity are maintained to achieve the desired performance. Therefore, we report a tungsten alloy based amorphous metal with fabrication process development of laterally actuated dual gated NEM switches with 100 nm width and 200 nm air-gap to result in <5 volts of actuation voltage (Vpull-in). © 2013 IEEE.

  2. Corrosion and wear resistant metallic layers produced by electrochemical methods

    DEFF Research Database (Denmark)

    Christoffersen, Lasse; Maahn, Ernst Emanuel

    1999-01-01

    Corrosion and wear-corrosion properties of novel nickel alloy coatings with promising production characteristics have been compared with conventional bulk materials and hard platings. Corrosion properties in neutral and acidic environments have been investigated with electrochemical methods....... Determination of polarisation resistance during 100 hours followed by stepwise anodic polarisation seems to be a promising technique to obtain steady state data on slowly corroding coatings with transient kinetics. A slurry test enables determination of simultaneous corrosion and abrasive wear. Comparison...... of AISI 316, hard chromium and hardened Ni-P shows that there is no universal correlation between surface hardness and wear-corrosion loss. The possible relation between questionable passivity of Ni-P coatings and their high wear-corrosion loss rate compared to hard chromium is discussed....

  3. Corrosion resistance of cast irons and titanium alloys as reference engineered metal barriers for use in basalt geologic storage: a literature assessment

    International Nuclear Information System (INIS)

    Charlot, L.A.; Westerman, R.E.

    1981-07-01

    A survey and assessment of the literature on the corrosion resistance of cast irons and low-alloy titanium are presented. Selected engineering properties of cast iron and titanium are briefly described; however, the corrosion resistance of cast iron and titanium in aqueous solutions or in soils and their use in a basalt repository are emphasized. In evaluating the potential use of cast iron and titanium as structural barrier materials for long-lived nuclear waste packages, it is assumed that titanium has the general corrosion resistance to be used in relatively thin cross sections whereas the cost and availability of cast iron allows its use even in very thick cross sections. Based on this assumption, the survey showed that: The uniform corrosion of low-alloy titanium in a basalt environment is expected to be extremely low. A linear extrapolation of general corrosion rates with an added corrosion allowance suggests that a 3.2- to 6.4-mm-thick wall may have a life of 1000 yr. Pitting and crevice corrosion are not likely corrosion modes in basalt ground waters. It is also unlikely that stress corrosion cracking (SCC) will occur in the commercially pure (CP) titanium alloy or in palladiumor molybdenum-alloyed titanium materials. Low-alloy cast irons may be used as barrier metals if the environment surrounding the metal keeps the alloy in the passive range. The solubility of the corrosion product and the semipermeable nature of the oxide film allow significant uniform corrosion over long time periods. A linear extrapolation of high-temperature corrosion rates on carbon steels and corrosion rates of cast irons in soils gives an estimated metal penetration of 51 to 64 mm after 1000 yr. A corrosion allowance of 3 to 5 times that suggests that an acceptable cast iron wall may be from 178 to 305 mm thick. Although they cannot be fully assessed, pitting and crevice corrosion should not affect cast iron due to the ground-water chemistry of basalt

  4. Chromium-modified a-C films with advanced structural, mechanical and corrosive-resistant characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Ming, Miao Yi [International Chinese-Belarusian scientific laboratory on vacuum-plasma technology, Nanjing University of Science and Technology, Nanjing 210094 (China); Francisk Skorina Gomel State University, Gomel 246019 (Belarus); Jiang, Xiaohong, E-mail: jxh0668@sina.com [International Chinese-Belarusian scientific laboratory on vacuum-plasma technology, Nanjing University of Science and Technology, Nanjing 210094 (China); Francisk Skorina Gomel State University, Gomel 246019 (Belarus); Piliptsou, D.G., E-mail: pdg_@mail.ru [International Chinese-Belarusian scientific laboratory on vacuum-plasma technology, Nanjing University of Science and Technology, Nanjing 210094 (China); Francisk Skorina Gomel State University, Gomel 246019 (Belarus); Zhuang, Yuzhao; Rogachev, A.V.; Rudenkov, A.S. [International Chinese-Belarusian scientific laboratory on vacuum-plasma technology, Nanjing University of Science and Technology, Nanjing 210094 (China); Francisk Skorina Gomel State University, Gomel 246019 (Belarus); Balmakou, A. [Faculty of Material Science and Technology, Slovak University of Technology, Trnava 91724 (Slovakia)

    2016-08-30

    Highlights: • Influence of the chromium interlayer on the structure and mechanical properties of a-C:Cr films. • Residual stress and wear of a-C:Cr and Cr/a-C varies due to their phase and surface morphology. • Chromium-modified a-C films with advanced structural, mechanical and corrosive-resistant characteristics. - Abstract: To improve structural, mechanical and chemical properties of diamond-like carbon films, we developed amorphous carbon chromium-modified composite films fabricated by means of cathode magnetic filtered arc deposition. The properties were analyzed by Raman spectroscopy, X-ray photoelectron spectroscopy and atomic force microscopy for the purpose of the structure characterization, elemental analysis and topology examination. Moreover, we also assessed residual stress, the coefficient of friction, hardness, the elastic modulus and corrosion parameters through X-ray double-crystal surface profilometry, tribo-testing, nanoindenter-testing, as well as contact angle measurements and potentiodynamic polarization analysis. As a result of a comparative analysis, we revealed a substantial improvement in the characteristics of developed composite films in comparison with amorphous carbon films. For example, Cr-modification is resulted, in greater integrated performance, toughness and corrosion resistance; the residual stress was reduced substantially.

  5. Properties, microstructure and resistance to metal corrosion from pure runoff of supermartensitic stainless steel

    International Nuclear Information System (INIS)

    Zappa, S; Burgueno, A; Svoboda, H. G; Ramini de Rissone, M; Surian, E. S

    2008-01-01

    Supermartensitic stainless steels (AISM) are characterized by their very low carbon content, providing good tenacity and weldability. They also contain Ni as a stabilizing agent of the austenite and Mo to improve corrosion resistance. The weldability of these materials is fundamentally important for their applications, mainly in the gas and oil industries. The presence of CO 2 , H 2 S, water with a high solids content and condensed water in the production of hydrocarbons together with the large amounts of Cl in these aqueous phases make localized corrosion one of the mechanisms for the degradation of these steels while in service. The protective gases used in the semiautomatic welding process with heavy or tubular wires (GMAW, FCAW) affect the chemical composition of the deposits, particularly the contents of C, O and N, generating variations in their properties. The mechanical properties of these steels are usually optimized after a post-welding heat treatment (PWHT), which may also significantly affect the corrosion resistance of the welding deposits. This work studied the influence of the welding procedure (protective gas and PWHT) on corrosion resistance from pitting of the unalloyed AISM metal. Two test pieces of unalloyed metal were welded according to ANSI/AWS A5.22-95 with a GMAW process using a 1.2 mm diameter tubular wire with metal filling that deposits a supermartensitic stainless steel. The effect of the gas protection was evaluated, welding one of the test pieces with Ar- 5%He and the other with Ar-18%CO 2 . The effect of the PWHT was analyzed, for which samples were extracted from each welded test piece, which were thermally treated at 650 o C for 15 minutes, producing as-welded (AW) samples and with PWHT. The chemical composition for both welding conditions was determined. Microstructural characterization was carried out for the four conditions , using optic and scanning electron microscopy and X-ray diffraction, and the Vickers microhardness was

  6. Metallic materials corrosion problems in molten salt reactors

    International Nuclear Information System (INIS)

    Chauvin, G.; Dixmier, J.; Jarny, P.

    1977-01-01

    The USA forecastings concerning the molten salt reactors are reviewed (mixtures of fluorides containing the fuel, operating between 560 and 700 0 C). Corrosion problems are important in these reactors. The effects of certain characteristic factors on corrosion are analyzed: humidity and metallic impurities in the salts, temperature gradients, speed of circulation of salts, tellurium from fission products, coupling. In the molten fluorides and experimental conditions, the materials with high Ni content are particularly corrosion resistant alloys (hastelloy N). The corrosion of this material is about 2.6 mg.cm -2 at 700 0 C [fr

  7. Improvement of corrosion resistance in NaOH solution and glass forming ability of as-cast Mg-based bulk metallic glasses by microalloying

    Directory of Open Access Journals (Sweden)

    Peng Hao

    2011-02-01

    Full Text Available The influences of the addition of Ag on the glass forming ability (GFA and corrosion behavior were investigated in the Mg-Ni-based alloy system by X-ray diffraction (XRD and electrochemical polarization in 0.1 mol/L NaOH solution. Results shows that the GFA of the Mg-Ni-based BMGs can be improved dramatically by the addition of an appropriate amount of Ag; and the addition element Ag can improve the corrosion resistance of Mg-Ni-based bulk metallic glass. The large difference in atomic size and large negative mixing enthalpy in alloy system can contribute to the high GFA. The addition element Ag improves the forming speed and the stability of the passive film, which is helpful to decrease the passivation current density and to improve the corrosion resistance of Mg-Ni-based bulk metallic glass.

  8. Studies on microstructure, mechanical and corrosion properties of high nitrogen stainless steel shielded metal arc welds

    Science.gov (United States)

    Mohammed, Raffi; Madhusudhan Reddy, G.; Srinivasa Rao, K.

    2018-03-01

    The present work is aimed at studying the microstructure, mechanical and corrosion properties of high nitrogen stainless steel shielded metal arc (SMA) welds made with Cromang-N electrode. Basis for selecting this electrode is to increase the solubility of nitrogen in weld metal due to high chromium and manganese content. Microstructures of the welds were characterized using optical microscopy (OM), field emission scanning electron microscopy (FESEM) and electron back scattered diffraction (EBSD) mainly to determine the morphology, phase analysis, grain size and orientation image mapping. Hardness, tensile and ductility bend tests were carried out to determine mechanical properties. Potentio-dynamic polarization testing was carried out to study the pitting corrosion resistance using a GillAC basic electrochemical system. Constant load type testing was carried out to study stress corrosion cracking (SCC) behaviour of welds. The investigation results shown that the selected Cr–Mn–N type electrode resulted in favourable microstructure and completely solidified as single phase coarse austenite. Mechanical properties of SMA welds are found to be inferior when compared to that of base metal and is due to coarse and dendritic structure.

  9. Corrosion of metallic materials. Dry corrosion, aqueous corrosion and corrosion by liquid metal, methods of protection

    International Nuclear Information System (INIS)

    Helie, Max

    2015-01-01

    This book is based on a course on materials given in an engineering school. The author first gives an overview of metallurgy issues: metallic materials (pure metals, metallic alloys), defects of crystal lattices (point defects, linear defects or dislocations), equilibrium diagrams, steels and cast, thermal processing of steels, stainless steels, aluminium and its alloys, copper and its alloys. The second part addresses the properties and characterization of surfaces and interfaces: singularity of a metal surface, surface energy of a metal, energy of grain boundaries, adsorption at a material surface, metal-electrolyte interface, surface oxide-electrolyte interface, techniques of surface analysis. The third chapter addresses the electrochemical aspects of corrosion: description of the corrosion phenomenon, free enthalpy of a compound and free enthalpy of a reaction, case of dry corrosion (thermodynamic aspect, Ellingham diagram, oxidation mechanisms, experimental study, macroscopic modelling), case of aqueous corrosion (electrochemical thermodynamics and kinetics, experimental determination of corrosion rate). The fourth part addresses the different forms of aqueous corrosion: generalized corrosion (atmospheric corrosion, mechanisms and tests), localized corrosion (galvanic, pitting, cracking, intergranular, erosion and cavitation), particular cases of stress cracking (stress corrosion, fatigue-corrosion, embrittlement by hydrogen), and bi-corrosion (of non alloyed steels, of stainless steels, and of aluminium and copper alloys). The sixth chapter addresses the struggle and the protection against aqueous corrosion: methods of prevention, scope of use of main alloys, geometry-based protection of pieces, use of corrosion inhibitors, use of organic or metallic coatings, electrochemical protection. The last chapter proposes an overview of corrosion types in industrial practices: in the automotive industry, in the oil industry, in the aircraft industry, and in the

  10. Metal (Ag/Ti)-Containing Hydrogenated Amorphous Carbon Nanocomposite Films with Enhanced Nanoscratch Resistance: Hybrid PECVD/PVD System and Microstructural Characteristics.

    Science.gov (United States)

    Constantinou, Marios; Nikolaou, Petros; Koutsokeras, Loukas; Avgeropoulos, Apostolos; Moschovas, Dimitrios; Varotsis, Constantinos; Patsalas, Panos; Kelires, Pantelis; Constantinides, Georgios

    2018-03-30

    This study aimed to develop hydrogenated amorphous carbon thin films with embedded metallic nanoparticles (a-C:H:Me) of controlled size and concentration. Towards this end, a novel hybrid deposition system is presented that uses a combination of Plasma Enhanced Chemical Vapor Deposition (PECVD) and Physical Vapor Deposition (PVD) technologies. The a-C:H matrix was deposited through the acceleration of carbon ions generated through a radio-frequency (RF) plasma source by cracking methane, whereas metallic nanoparticles were generated and deposited using terminated gas condensation (TGC) technology. The resulting material was a hydrogenated amorphous carbon film with controlled physical properties and evenly dispersed metallic nanoparticles (here Ag or Ti). The physical, chemical, morphological and mechanical characteristics of the films were investigated through X-ray reflectivity (XRR), Raman spectroscopy, Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), Transmission Electron Microscopy (TEM) and nanoscratch testing. The resulting amorphous carbon metal nanocomposite films (a-C:H:Ag and a-C:H:Ti) exhibited enhanced nanoscratch resistance (up to +50%) and low values of friction coefficient (<0.05), properties desirable for protective coatings and/or solid lubricant applications. The ability to form nanocomposite structures with tunable coating performance by potentially controlling the carbon bonding, hydrogen content, and the type/size/percent of metallic nanoparticles opens new avenues for a broad range of applications in which mechanical, physical, biological and/or combinatorial properties are required.

  11. High Velocity Oxidation and Hot Corrosion Resistance of Some ODS Alloys

    Science.gov (United States)

    Lowell, C. E.; Deadmore, D. L.

    1977-01-01

    Several oxide dispersion strengthened (ODS) alloys were tested for cyclic, high velocity, oxidation, and hot corrosion resistance. These results were compared to the resistance of an advanced, NiCrAl coated superalloy. An ODS FeCrAl were identified as having sufficient oxidation and hot corrosion resistance to allow potential use in an aircraft gas turbine without coating.

  12. Comparative corrosion resistance of selected metals and nonmetals

    International Nuclear Information System (INIS)

    Anon.

    1977-01-01

    The relative corrosion resistance to 140 corrosive media is tabulated for the following substances: stainless steels 302, 303, 304, 305, 316, 410, 416, and 430, brass, silicon bronze, copper alloy 110, monel alloy 400, aluminum, and nylon (type 6/6)

  13. Effect of yttrium chromite doping on its resistance to high-temperature salt and gas corrosions

    International Nuclear Information System (INIS)

    Oryshich, I.V.; Poryadchenko, N.E.; Rakitskij, A.N.; Bega, N.D.

    1996-01-01

    Effect of yttrium chromite doping with 2-4 group metal oxides on the corrosion resistance in the air at 1300 C during 5 hours and in sodium chloride and sulfate melts at 900 C during 20 hours is investigated. A notable increase of corrosion resistance is achieved under complex doping with zirconium and magnesium oxides in a quantity, close to solubility in yttrium oxide and solubility by aluminium oxide. Doping with calcium and strontium oxides in the quantities, dose to solubility in yttrium oxide does not produce any notable effect, and at higher concentrations it reduces the corrosion resistance in media indicated. Refs. 8, refs. 2, tabs. 1

  14. Corrosion of metallic materials by uranium hexafluoride at high temperatures (1963); Corrosion de materiaux metalliques par l'hexafluorure d'uranium a haute temperature (1963)

    Energy Technology Data Exchange (ETDEWEB)

    Langlois, G. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1963-07-01

    The corrosion of the following metals or alloys by UF{sub 6}: nickel, monel, Inconel, gold, platinum, stainless steel, is studied in the temperature range from 300 to 1000 deg. C. The test method, designed to avoid heating the apparatus containing the corrosive fluid to a high temperature, consists in using threadlike samples heated by the Joule effect, the rest of the apparatus being maintained close to room temperature. This technique makes it possible also to determine continuously the penetration of the corrosion by measuring the electrical resistance of the sample with a double Thomson bridge. A series of rapid comparison tests shows that stainless steel, precious metals and Inconel are attacked far too rapidly to be used above 500 deg. C; only monel and especially nickel appear capable of resisting at high temperatures. The detailed examination of the behaviour of nickel shows that the metallic fluoride is volatilized and that this influences the corrosion rate. It shows also the existence of a temperature zone situated between 550 and 700 deg. C in which occurs A strong intergranular corrosion the cause of which appears to be the presence of impurities in the metal. (author) [French] La corrosion par l'UF{sub 6} des metaux ou alliages suivants: lickel, monel, inconel, or, platine, acier inoxydable, est etudiee dans le un domaine de temperature compris entre 300 et 1000 deg. C. La methode d'essai, destinee a eviter le chauffage de l'enceinte contenant le fluide corrosif a temperature elevee, consiste a utiliser des eprouvettes filiformes, echauffees par effet Joule, le reste de l'appareillage etant maintenu a une temperature proche de l'ambiance. Cette technique permet en outre de determiner en continu la penetration de la corrosion, par mesure de la resistance electrique de l'eprouvette, au moyen d'un pont double de Thomson. Une serie d'essais comparatifs, assez sommaires, montre que l'acier inoxydable, les metaux

  15. Influence of the pressure of Fe fundamental amorphous metallic fusions to magnet description

    International Nuclear Information System (INIS)

    Panakhov, T.M; Ahmadov, V.I; Musayev, Z.S

    2011-01-01

    Full tex: Obtaining, exploration and application of amorphous fusions on the basis of iron group magnet metals including amorphous phase non-magnetic additions as silisium and boric playing the role of stabilizer of the amorphous phase is widely used last years. Scientific and technical interest to these objects is connected with their physical property - high mechanical, electric, uncial agreement of corrosion and magnet characteristics. Amorphous alloy Fe58Ni20Si9B13 was selected as the object of research. To set the built-in hysteresis characteristics of magnetic fusion mesh, then the maximum magnetic induction (saturation induction) was appointed to the BS and the residual induction Br. The average distance between the borders as a result of pressure and magnetic characteristics of nano parosities in comparison of the relative change that is to say they are close to each other, with the magnetic characteristics of amorphous fusions nano parosity characteristics indicate that the corellation is between magnetic characteristics and nano parosity characteristics.

  16. Corrosion performance of some titanium-based hard coatings

    International Nuclear Information System (INIS)

    Matthes, B.; Broszeit, E.; Aromaa, J.; Ronkainen, H.; Hannula, S.P.; Leyland, A.; Matthews, A.

    1991-01-01

    Tools and machine parts which could benefit from wear-resistant titanium-based hard films are often subject to corrosive environments. Physically vapour-deposited coatings frequently exhibit porosity and even small defects, which can cause rapid local corrosion of the substrate material; there is therefore a requirement for dense and chemically inert coatings. This paper presents corrosion data for titanium-based hard coatings such as TiN, (Ti, Al)N, Ti(B, N) and TiB 2 and also for multilayered structures where additional aluminium-based insulating surface layers (AlN and Al 2 O 3 ) were deposited. The corrosion resistance and porosity of the films were analysed by electrochemical techniques. The degree of metallic bonding can play a significant role in influencing the corrosion resistance of refractory transition-metal-based ceramic coatings. Here we demonstrate that, under potentiodynamic corrosion test conditions, resistance to corrosive attack was relatively poor for TiB 2 , better for (Ti, Al)N and Ti(B, N) and best for TiN. It is also shown that applying the additional protective aluminium-based insulating surface layers on the coating can further improve corrosion resistance. (orig.)

  17. Corrosion resistance of aluminum-magnesium alloys in glacial acetic acid

    International Nuclear Information System (INIS)

    Zaitseva, L.V.; Romaniv, V.I.

    1984-01-01

    Vessels for the storage and conveyance of glacial acetic acid are produced from ADO and AD1 aluminum, which are distinguished by corrosion resistance, weldability and workability in the hot and cold conditions but have low tensile strength. Aluminum-magnesium alloys are stronger materials close in corrosion resistance to technical purity aluminum. An investigation was made of the basic alloying components on the corrosion resistance of these alloys in glacial acetic acid. Both the base metal and the weld joints were tested. With an increase in temperature the corrosion rate of all of the tested materials increases by tens of times. The metals with higher magnesium content show more pitting damage. The relationship of the corrosion resistance of the alloys to magnesium content is confirmed by the similar intensity of failure of the joint metal of all of the investigated alloys and by electrochemical investigations. The data shows that AMg3 alloy is close to technically pure ADO aluminum. However, the susceptibility of even this material to local corrosion eliminates the possibility of the use of aluminum-magnesium alloys as reliable constructional materials in glacial acetic acid

  18. Biotribocorrosion-an appraisal of the time dependence of wear and corrosion interactions: I. The role of corrosion

    International Nuclear Information System (INIS)

    Yan, Y; Neville, A; Dowson, D

    2006-01-01

    With the increasing interest in metal-on-metal (MoM) joint implants, studies have been focused on their wear and corrosion behaviour. Integrated electrochemical tests have been conducted and are reported in this paper. The corrosion, wear and wear-corrosion behaviour for three materials (high carbon CoCrMo, low carbon CoCrMo and UNS S31603) have been discussed. Corrosion effects on the overall performance for the three materials are analysed. Two distinct regimes have been found for the three materials: (a) the running-in regime and (b) the steady state regime, in line with other research. Even in the steady state regime, 20%-30% of the material degradation can be attributed to corrosion-related damage. High carbon CoCrMo showed excellent corrosion, wear and corrosion-wear resistance and therefore it delivered the best overall performance in terms of a lower wear rate, a lower friction coefficient and a higher resistance to corrosion

  19. Corrosion resistance testing of high-boron-content stainless steels

    International Nuclear Information System (INIS)

    Petrman, I.; Safek, V.

    1994-01-01

    Boron steels, i.e. stainless steels with boron contents of 0.2 to 2.25 wt.%, are employed in nuclear engineering for the manufacture of baskets or wells in which radioactive fissile materials are stored, mostly spent nuclear fuel elements. The resistance of such steels to intergranular corrosion and uniform corrosion was examined in the Strauss solution and in boric acid; the dependence of the corrosion rate of the steels on their chemical composition was investigated, and their resistance was compared with that of AISI 304 type steel. Corrosion resistance tests in actual conditions of ''wet'' compact storage (demineralized water or a weak boric acid solution) gave evidence that boron steels undergo nearly no uniform corrosion and, as electrochemical measurements indicated, match standard corrosion-resistant steels. Corrosion resistance was confirmed to decrease slightly with increasing boron content and to increase somewhat with increasing molybdenum content. (Z.S.). 3 tabs., 4 figs., 7 refs

  20. Amorphous Al–Mn coating on NdFeB magnets: Electrodeposition from AlCl3–EMIC–MnCl2 ionic liquid and its corrosion behavior

    International Nuclear Information System (INIS)

    Chen Jing; Xu Bajin; Ling Guoping

    2012-01-01

    Amorphous Al–Mn coating was electrodeposited on NdFeB magnets from AlCl 3 –EMIC–MnCl 2 ionic liquid with the pretreatment of anodic electrolytic etching in AlCl 3 –EMIC ionic liquid at room temperature. The microstructure, composition and phase constituents of the coatings were investigated by scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDS), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The corrosion resistance of the coatings was tested by means of potentiodynamic polarization and immersion test in 3.5 wt. % NaCl solution. The results show that anodic electrolytic etching in AlCl 3 –EMIC ionic liquid is a satisfactory pretreatment to remove the surface oxide film and favor the adhesion of the Al–Mn alloy coating to the NdFeB substrate. The amorphous Al–Mn alloy coating provides sacrificial anodic protection for NdFeB. It exhibited good corrosion resistance and significantly reduced the corrosion current density of NdFeB by three orders of magnitude at potentiodynamic polarization. - Highlights: ► Amorphous Al–Mn alloy coating was electrodeposited on NdFeB magnet from ionic liquid. ► To remove the surface oxides of NdFeB, anodic etching pretreatment is used. ► The deposited Al–Mn alloy coating shows high adhesion to the NdFeB substrate. ► Corrosion tests show that amorphous Al–Mn alloy coating is anodic coating for NdFeB magnet.

  1. Galvanic corrosion evaluation of high activity nuclear waste container metals components

    International Nuclear Information System (INIS)

    Semino, C.J.

    1990-04-01

    The final disposal container for vitrified high-level waste is assumed to have three metallic layers: a stainless steel inner layer, and external one of a metal to be selected and a thick lead layer (10 cm) in the middle. As design limit, the container shall act as an engineering barrier, granting the isolation of the radionuclides for approximately 1000 years. Preliminary titanium-lead galvanic couple tests showed that titanium behaved always as a cathode in the galvanic couple, promoting the galvanic corrosion of lead. This corrosion study focused on the behaviour of lead-AISI 304 stainless steel and lead-carbon steel (SAE 1010 and 1020) galvanic couples with different area relationships, temperature and media composition. High purity lead (99,999%) and commercial lead (99,9%) were used for galvanic couples tests. Tests were performed at 75, 50, 45 and 40 deg. C. Test solution was either synthetic groundwater, a suspension of 10% bentonite in groundwater, or synthetic sea water. The synthetic sea water was used at 100, 50 and 25% concentration by dilution with distilled water. Tests with lead-304 stainless steel galvanic couples showed that lead always behaves as an anode, corroding preferentially. Very low lead corrosion rates were found in lead-carbon steel galvanic couple in 10% bentonite suspension in synthetic groundwater test at 75 deg. C. An increase of carbon content in steel has very little influence on steel corrosion rate. Commercial lead has a higher corrosion rate and presented a more pronounced attack than high purity lead. Its corrosion rate is at least twice when lead-carbon steel area relationship increases from 1:10 to 1:40. There are higher steel corrosion rates in sea water than in groundwater. Lead behaves as a cathode to the end of the test. 8 refs, 85 figs, 10 tabs

  2. Improvement of corrosion resistance of transparent conductive multilayer coating consisting of silver layers and transparent metal oxide layers

    International Nuclear Information System (INIS)

    Koike, Katsuhiko; Yamazaki, Fumiharu; Okamura, Tomoyuki; Fukuda, Shin

    2007-01-01

    An optical filter for plasma display panel (PDP) requires an electromagnetic shield with very high ability. The authors investigated a transparent conductive multilayer coating consisting of silver (Ag) layers and transparent metal oxide layers. The durability of the multilayer sputter coating, including the silver layer, is very sensitive to the surrounding atmosphere. For example, after an exposure test they found discolored points on the multilayer sputter coatings, possibly caused by migration of silver atoms in the silver layers. In their investigation, they modified the top surface of the multilayer sputter coatings with transition metals to improve the corrosion resistance of the multilayer coating. Specifically, they deposited transition metals 0.5-2 nm thick on the top surface of the multilayer coatings by sputtering. They chose indium tin oxide (ITO) as the transparent metal oxide. They applied the multilayer sputter coatings of seven layers to a polyethylene terephthalate (PET) film substrate. A cross-sectional structure of the film with the multilayer coatings is PET film/ITO/Ag/ITO/Ag/ITO/Ag/ITO. They evaluated the corrosion resistance of the films by a salt-water immersion test. In the test, they immersed the film with multilayer coatings into salt water, and then evaluated the appearance, transmittance, and electrical resistance of the multilayer coatings. They investigated several transition metals as the modifying material, and found that titanium and tantalum drastically improved the resistance of the multilayer coatings to the salt-water exposure without a significant decline in transmittance. They also investigated the relation between elapsed time after deposition of the modifying materials and resistance to the salt water. Furthermore, they investigated the effects of a heat treatment and an oxide plasma treatment on resistance to the salt water

  3. Highly corrosion resistant zirconium based alloy for reactor structural material

    International Nuclear Information System (INIS)

    Ito, Yoichi.

    1996-01-01

    The alloy of the present invention is a zirconium based alloy comprising tin (Sn), chromium (Cr), nickel (Ni) and iron (Fe) in zirconium (Zr). The amount of silicon (Si) as an impurity is not more than 60ppm. It is preferred that Sn is from 0.9 to 1.5wt%, that of Cr is from 0.05 to 0.15wt%, and (Fe + Ni) is from 0.17 to 0.5wt%. If not less than 0.12wt% of Fe is added, resistance against nodular corrosion is improved. The upper limit of Fe is preferably 0.40wt% from a view point of uniform suppression for the corrosion. The nodular corrosion can be suppressed by reducing the amount of Si-rich deposition product in the zirconium based alloy. Accordingly, a highly corrosion resistant zirconium based alloy improved for the corrosion resistance of zircaloy-2 and usable for a fuel cladding tube of a BWR type reactor can be obtained. (I.N.)

  4. Improvement of localised corrosion resistance of AISI 2205 Duplex Stainless Steel joints made by gas metal arc welding under electromagnetic interaction of low intensity

    Science.gov (United States)

    García-Rentería, M. A.; López-Morelos, V. H.; García-Hernández, R.; Dzib-Pérez, L.; García-Ochoa, E. M.; González-Sánchez, J.

    2014-12-01

    The resistance to localised corrosion of AISI 2205 duplex stainless steel plates joined by Gas Metal Arc Welding (GMAW) under the effect of electromagnetic interaction of low intensity (EMILI) was evaluated with sensitive electrochemical methods. Welds were made using two shielding gas mixtures: 98% Ar + 2% O2 (M1) and 97% Ar + 3% N2 (M2). Plates were welded under EMILI using the M1 gas with constant welding parameters. The modified microstructural evolution in the high temperature heat affected zone and at the fusion zone induced by application of EMILI during welding is associated with the increase of resistance to localised corrosion of the welded joints. Joints made by GMAW using the shielding gas M2 without the application of magnetic field presented high resistance to general corrosion but high susceptibility to undergo localised attack.

  5. Ternary graphene/amorphous carbon/nickel nanocomposite film for outstanding superhydrophobicity

    Science.gov (United States)

    Zhu, Xiaobo; Zhou, Shengguo; Yan, Qingqing

    2018-04-01

    A novel superhydrophobic ternary graphene/amorphous carbon/nickel (G-Ni/a-C:H) carbon-based film was fabricated by a green approach of high-voltage electrochemical deposition without using aqueous solution, which was systematically investigated including the structure and relating applications on self-cleaning and corrosion resistance. Graphene and nickel nano-particle inserts were effective to tailor the feature of nanocrystallite/amorphous microstructure as well as micro-nanoscale hierarchical rose-petal-like surface for G-Ni/a-C:H carbon-based film. Surprisingly, this deposit could present outstanding superhydrophobicity with the contact angle of 158.98 deg and sliding angle of 2.75 deg without any further surface modification meanwhile it could possess fairly well adhesion. Furthermore, the superhydrophobic G-Ni/a-C:H carbon-based film could exhibit excellent corrosion resistance and self-cleaning performances compared to no graphene incorporated deposit. The procedure of fabricating deposit might be simple, scalable, and environmental friendly, indicating a promising prospect for industrial applications in the field of anti-fouling, anti-corrosion and drag resistance.

  6. Development of rapidly quenched nickel-based non-boron filler metals for brazing corrosion resistant steels

    Science.gov (United States)

    Ivannikov, A.; Kalin, B.; Suchkov, A.; Penyaz, M.; Yurlova, M.

    2016-04-01

    Corrosion-resistant steels are stably applied in modern rocket and nuclear technology. Creating of permanent joints of these steels is a difficult task that can be solved by means of welding or brazing. Recently, the use rapidly quenched boron-containing filler metals is perspective. However, the use of such alloys leads to the formation of brittle borides in brazing zone, which degrades the corrosion resistance and mechanical properties of the compounds. Therefore, the development of non-boron alloys for brazing stainless steels is important task. The study of binary systems Ni-Be and Ni-Si revealed the perspective of replacing boron in Ni-based filler metals by beryllium, so there was the objective of studying of phase equilibrium in the system Ni-Be-Si. The alloys of the Ni-Si-Be with different contents of Si and Be are considered in this paper. The presence of two low-melting components is revealed during of their studying by methods of metallography analysis and DTA. Microhardness is measured and X-ray diffraction analysis is conducted for a number of alloys of Ni-Si-Be. The compositions are developed on the basis of these data. Rapidly quenched brazing alloys can be prepared from these compositions, and they are suitable for high temperature brazing of steels.

  7. Influence of in situ synthesized TiC on thermal stability and corrosion behavior of Zr60Cu10Al15Ni15 amorphous composites

    International Nuclear Information System (INIS)

    Geng, Jiwei; Teng, Xinying; Zhou, Guorong; Leng, Jinfeng; Zhao, Degang

    2014-01-01

    In situ synthesized TiC particles were prepared by a thermal explosion method. Adding “in situ synthesized” TiC into Zr 60 Cu 10 Al 15 Ni 15 glass matrix to obtain amorphous matrix composites was achieved. The corrosion behavior of Zr 60 Cu 10 Al 15 Ni 15 amorphous composites was evaluated using potentiodynamic polarization measurements in 3.5 wt% NaCl solution at room temperature. The results show that the microhardness and thermal stability are improved apparently, while the TiC (≤0.6 wt%) does not significantly affect the supercooled liquid behavior. Moreover, the corrosion resistance is improved apparently because the nanocrystals accelerate the diffusion of passive elements for faster formation of the protective passive film at nanocrystals/amorphous interfaces. However, when the TiC content is more than 0.6 wt%, both glass forming ability and corrosion resistance are reduced significantly

  8. Fatigue and corrosion of a Pd-based bulk metallic glass in various environments

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, L.Y. [East Los Angeles College, Monterey Park, CA 91754 (United States); Roberts, S.N. [Keck Laboratory of Materials Science, California Institute of Technology, Pasadena, CA 91125 (United States); Baca, N. [Department of Chemistry and Biochemistry, California State University Northridge, Northridge, CA 91330 (United States); Wiest, A. [Naval Surface Warfare Center, Norco, CA (United States); Garrett, S.J. [Department of Chemistry and Biochemistry, California State University Northridge, Northridge, CA 91330 (United States); Conner, R.D., E-mail: rdconner@csun.edu [Department of Manufacturing Systems Engineering and Management, California State University Northridge, 18111 Nordhoff St., Mail Code 8295, Northridge, CA 91330 (United States)

    2013-10-15

    Bulk metallic glasses (BMGs) possess attractive properties for biomedical applications, including high strength, hardness and corrosion resistance, and low elastic modulus. In this study, we conduct rotating beam fatigue tests on Pd{sub 43}Ni{sub 10}Cu{sub 27}P{sub 20} bulk metallic glass in air and Eagle's medium (EM) and measure the corrosive resistance of the alloy by submersion in acidic and basic electrolytes. Fatigue results are compared to those of commonly used biometals in EM. Rotating beam fatigue tests conducted in air and in Eagle's medium show no deterioration in fatigue properties in this potentially corrosive environment out to 10{sup 7} cycles. A specimen size effect is revealed when comparing fatigue results to those of a similar alloy of larger minimum dimensions. Corrosion tests show that the alloy is not affected by highly basic (NaOH) or saline (NaCl) solutions, nor in EM, and is affected by chlorinated acidic solutions (HCl) to a lesser extent than other commonly used biometals. Corrosion in HCl initiates with selective leaching of late transition metals, followed by dissolution of Pd. - Highlights: • Fatigue limit of 600 MPa with no deterioration when exposed to Eagle's medium. • Fatigue shows sample size effect. • Pd-based BMG is unaffected by saline or strong basic solutions. • Pd-based BMG is substantially more resistant to chlorinated acids than CoCrMo, 316 L Stainless, or Ti6Al4V alloys. • Corrosion shows selective leaching of late transition metals, followed by Pd and P.

  9. Metal (Ag/Ti-Containing Hydrogenated Amorphous Carbon Nanocomposite Films with Enhanced Nanoscratch Resistance: Hybrid PECVD/PVD System and Microstructural Characteristics

    Directory of Open Access Journals (Sweden)

    Marios Constantinou

    2018-03-01

    Full Text Available This study aimed to develop hydrogenated amorphous carbon thin films with embedded metallic nanoparticles (a–C:H:Me of controlled size and concentration. Towards this end, a novel hybrid deposition system is presented that uses a combination of Plasma Enhanced Chemical Vapor Deposition (PECVD and Physical Vapor Deposition (PVD technologies. The a–C:H matrix was deposited through the acceleration of carbon ions generated through a radio-frequency (RF plasma source by cracking methane, whereas metallic nanoparticles were generated and deposited using terminated gas condensation (TGC technology. The resulting material was a hydrogenated amorphous carbon film with controlled physical properties and evenly dispersed metallic nanoparticles (here Ag or Ti. The physical, chemical, morphological and mechanical characteristics of the films were investigated through X-ray reflectivity (XRR, Raman spectroscopy, Scanning Electron Microscopy (SEM, Atomic Force Microscopy (AFM, Transmission Electron Microscopy (TEM and nanoscratch testing. The resulting amorphous carbon metal nanocomposite films (a–C:H:Ag and a–C:H:Ti exhibited enhanced nanoscratch resistance (up to +50% and low values of friction coefficient (<0.05, properties desirable for protective coatings and/or solid lubricant applications. The ability to form nanocomposite structures with tunable coating performance by potentially controlling the carbon bonding, hydrogen content, and the type/size/percent of metallic nanoparticles opens new avenues for a broad range of applications in which mechanical, physical, biological and/or combinatorial properties are required.

  10. Physics of amorphous metals

    CERN Document Server

    Kovalenko, Nikolai P; Krey, Uwe

    2008-01-01

    The discovery of bulk metallic glasses has led to a large increase in the industrial importance of amorphous metals, and this is expected to continue. This book is the first to describe the theoretical physics of amorphous metals, including the important theoretical development of the last 20 years.The renowned authors stress the universal aspects in their description of the phonon or magnon low-energy excitations in the amorphous metals, e.g. concerning the remarkable consequences of the properties of these excitations for the thermodynamics at low and intermediate temperatures. Tunneling

  11. Superconducting and normal properties of metallic amorphous systems

    International Nuclear Information System (INIS)

    Esquinazi, P.D.

    1983-02-01

    The superconducting and transport properties (superconducing critical temperature, superconducting critical currents, electric resistivity and thermal conductivity) of the amorphous alloys La 70 Cu 30 and Zr 70 Cu 30 prepared by melt spinning have been investigated. The modification of these properties when, the initial amorphous metals relax to other metastable state under thermal treatment at below crystallization temperatures, have also been studied. (M.E.L.) [es

  12. Electrochemical and Friction Characteristics of Metallic Glass Composites at the Microstructural Length-scales.

    Science.gov (United States)

    Ayyagari, Aditya; Hasannaeimi, Vahid; Arora, Harpreet; Mukherjee, Sundeep

    2018-01-17

    Metallic glass composites represent a unique alloy design strategy comprising of in situ crystalline dendrites in an amorphous matrix to achieve damage tolerance unseen in conventional structural materials. They are promising for a range of advanced applications including spacecraft gears, high-performance sporting goods and bio-implants, all of which demand high surface degradation resistance. Here, we evaluated the phase-specific electrochemical and friction characteristics of a Zr-based metallic glass composite, Zr 56.2 Ti 13.8 Nb 5.0 Cu 6.9 Ni 5.6 Be 12.5 , which comprised roughly of 40% by volume crystalline dendrites in an amorphous matrix. The amorphous matrix showed higher hardness and friction coefficient compared to the crystalline dendrites. But sliding reciprocating tests for the composite revealed inter-phase delamination rather than preferred wearing of one phase. Pitting during potentiodynamic polarization in NaCl solution was prevalent at the inter-phase boundary, confirming that galvanic coupling was the predominant corrosion mechanism. Scanning vibration electrode technique demonstrated that the amorphous matrix corroded much faster than the crystalline dendrites due to its unfavorable chemistry. Relative work function values measured using scanning kelvin probe showed the amorphous matrix to be more electropositive, which explain its preferred corrosion over the crystalline dendrites as well as its characteristic friction behavior. This study paves the way for careful partitioning of elements between the two phases in a metallic glass composite to tune its surface degradation behavior for a range of advanced applications.

  13. Investigation on corrosion and wear behaviors of nanoparticles reinforced Ni-based composite alloying layer

    International Nuclear Information System (INIS)

    Xu Jiang; Tao Jie; Jiang Shuyun; Xu Zhong

    2008-01-01

    In order to investigate the role of amorphous SiO 2 particles in corrosion and wear resistance of Ni-based metal matrix composite alloying layer, the amorphous nano-SiO 2 particles reinforced Ni-based composite alloying layer has been prepared by double glow plasma alloying on AISI 316L stainless steel surface, where Ni/amorphous nano-SiO 2 was firstly predeposited by brush plating. The composition and microstructure of the nano-SiO 2 particles reinforced Ni-based composite alloying layer were analyzed by using SEM, TEM and XRD. The results indicated that the composite alloying layer consisted of γ-phase and amorphous nano-SiO 2 particles, and under alloying temperature (1000 deg. C) condition, the nano-SiO 2 particles were uniformly distributed in the alloying layer and still kept the amorphous structure. The corrosion resistance of composite alloying layer was investigated by an electrochemical method in 3.5%NaCl solution. Compared with single alloying layer, the amorphous nano-SiO 2 particles slightly decreased the corrosion resistance of the Ni-Cr-Mo-Cu alloying layer. X-ray photoelectron spectroscopy (XPS) revealed that the passive films formed on the composite alloying consisted of Cr 2 O 3 , MoO 3 , SiO 2 and metallic Ni and Mo. The dry wear test results showed that the composite alloying layer had excellent friction-reduced property, and the wear weight loss of composite alloying layer was less than 60% of that of Ni-Cr-Mo-Cu alloying layer

  14. Investigation of the resistance of several new metallic reinforcing bars to chloride-induced corrosion in concrete.

    Science.gov (United States)

    2003-01-01

    The Virginia Department of Transportation recently initiated a search for metallic reinforcing bars that are not only more durable and corrosion resistant than the epoxy-coated bars currently used, but also economical. In the last few years, several ...

  15. Studies of Corrosion Resistant Materials Being Considered for High-Level Nuclear Waste Containment in Yucca Mountain Relevant Environments

    International Nuclear Information System (INIS)

    McCright, R.D.; Ilevbare, G.; Estill, J.; Rebak, R.

    2001-01-01

    Containment of spent nuclear fuel and vitrified forms of high level nuclear waste require use of materials that are highly corrosion resistant to all of the anticipated environmental scenarios that can occur in a geological repository. Ni-Cr-Mo Alloy 22 (UNS N60622) is proposed for the corrosion resistant outer barrier of a two-layer waste package container at the potential repository site at Yucca Mountain. A range of water compositions that may contact the outer barrier is under consideration, and a testing program is underway to characterize the forms of corrosion and to quantify the corrosion rates. Results from the testing support models for long term prediction of the performance of the container. Results obtained to date indicate a very low general corrosion rate for Alloy 22 and very high resistance to all forms of localized and environmentally assisted cracking in environments tested to date

  16. Effect of Chromium on Corrosion Behavior of P110 Steels in CO2-H2S Environment with High Pressure and High Temperature

    Directory of Open Access Journals (Sweden)

    Jianbo Sun

    2016-03-01

    Full Text Available The novel Cr-containing low alloy steels have exhibited good corrosion resistance in CO2 environment, mainly owing to the formation of Cr-enriched corrosion film. In order to evaluate whether it is applicable to the CO2 and H2S coexistence conditions, the corrosion behavior of low-chromium steels in CO2-H2S environment with high pressure and high temperature was investigated using weight loss measurement and surface characterization. The results showed that P110 steel suffered localized corrosion and both 3Cr-P110 and 5Cr-P110 steels exhibited general corrosion. However, the corrosion rate of 5Cr-P110 was the highest among them. The corrosion process of the steels was simultaneously governed by CO2 and H2S. The outer scales on the three steels mainly consisted of FeS1−x crystals, whereas the inner scales on Cr-containing steels comprised of amorphous FeS1−x, Cr(OH3 and FeCO3, in contrast with the amorphous FeS1−x and FeCO3 mixture film of P110 steel. The more chromium the steel contains, the more chromium compounds the corrosion products contain. The addition of chromium in steels increases the uniformity of the Cr-enriched corrosion scales, eliminates the localized corrosion, but cannot decrease the general corrosion rates. The formation of FeS1−x may interfere with Cr-enriched corrosion scales and lowering the corrosion performance of 3Cr-P110 and 5Cr-P110 steels.

  17. Effect of Chromium on Corrosion Behavior of P110 Steels in CO2-H2S Environment with High Pressure and High Temperature

    Science.gov (United States)

    Sun, Jianbo; Sun, Chong; Lin, Xueqiang; Cheng, Xiangkun; Liu, Huifeng

    2016-01-01

    The novel Cr-containing low alloy steels have exhibited good corrosion resistance in CO2 environment, mainly owing to the formation of Cr-enriched corrosion film. In order to evaluate whether it is applicable to the CO2 and H2S coexistence conditions, the corrosion behavior of low-chromium steels in CO2-H2S environment with high pressure and high temperature was investigated using weight loss measurement and surface characterization. The results showed that P110 steel suffered localized corrosion and both 3Cr-P110 and 5Cr-P110 steels exhibited general corrosion. However, the corrosion rate of 5Cr-P110 was the highest among them. The corrosion process of the steels was simultaneously governed by CO2 and H2S. The outer scales on the three steels mainly consisted of FeS1−x crystals, whereas the inner scales on Cr-containing steels comprised of amorphous FeS1−x, Cr(OH)3 and FeCO3, in contrast with the amorphous FeS1−x and FeCO3 mixture film of P110 steel. The more chromium the steel contains, the more chromium compounds the corrosion products contain. The addition of chromium in steels increases the uniformity of the Cr-enriched corrosion scales, eliminates the localized corrosion, but cannot decrease the general corrosion rates. The formation of FeS1−x may interfere with Cr-enriched corrosion scales and lowering the corrosion performance of 3Cr-P110 and 5Cr-P110 steels. PMID:28773328

  18. Corrosion behaviour of construction materials for high temperature water electrolysers

    Energy Technology Data Exchange (ETDEWEB)

    Nikiforov, A.; Petruchina, I.; Christensen, E.; Bjerrum, N.J.; Tomas-Garcya, A.L. [Technical Univ. of Denmark, Lyngby (Denmark). Dept. of Chemistry, Materials Science Group

    2010-07-01

    This presentation reported on a study in which the feasibility of using different corrosion resistant stainless steels as a possible metallic bipolar plate and construction material was evaluated in terms of corrosion resistance under conditions corresponding to the conditions in high temperature proton exchange membrane (PEM) water electrolysers (HTPEMWE). PEM water electrolysis technology has been touted as an effective alternative to more conventional alkaline water electrolysis. Although the energy efficiency of this technology can be increased considerably at temperatures above 100 degrees C, this increases the demands to all the used materials with respect to corrosion stability and thermal stability. In this study, Ni-based alloys as well as titanium and tantalum samples were exposed to anodic polarization in 85 per cent phosphoric acid electrolyte solution. Tests were performed at 80 and 120 degrees C to determine the dependence of corrosion speed and working temperature. Platinum and gold plates were also tested for a comparative evaluation. Steady-state voltammetry was used along with scanning electron microscopy and energy-dispersive X-ray spectroscopy. Titanium showed the poorest corrosion resistance, while Ni-based alloys showed the highest corrosion resistance, with Inconel R 625 being the most promising alloy for the bipolar plate of an HTPEMWE. 3 refs., 1 tab., 2 figs.

  19. Improvement of localised corrosion resistance of AISI 2205 Duplex Stainless Steel joints made by gas metal arc welding under electromagnetic interaction of low intensity

    Energy Technology Data Exchange (ETDEWEB)

    García-Rentería, M.A., E-mail: crazyfim@gmail.com [Instituto de Investigación en Metalurgia y Materiales, Universidad Michoacana de San Nicolás de Hidalgo, A.P. 888, CP 58000, Morelia, Michoacán (Mexico); López-Morelos, V.H., E-mail: vhlopez@umich.mx [Instituto de Investigación en Metalurgia y Materiales, Universidad Michoacana de San Nicolás de Hidalgo, A.P. 888, CP 58000, Morelia, Michoacán (Mexico); García-Hernández, R., E-mail: rgarcia@umich.mx [Instituto de Investigación en Metalurgia y Materiales, Universidad Michoacana de San Nicolás de Hidalgo, A.P. 888, CP 58000, Morelia, Michoacán (Mexico); Dzib-Pérez, L., E-mail: luirdzib@uacam.mx [Centre for Corrosion Research, Autonomous University of Campeche, Av. Agustín Melgar s/n, Col. Buenavista, CP 24039, Campeche, Cam (Mexico); García-Ochoa, E.M., E-mail: emgarcia@uacam.mx [Centre for Corrosion Research, Autonomous University of Campeche, Av. Agustín Melgar s/n, Col. Buenavista, CP 24039, Campeche, Cam (Mexico); González-Sánchez, J., E-mail: jagonzal@uacam.mx [Centre for Corrosion Research, Autonomous University of Campeche, Av. Agustín Melgar s/n, Col. Buenavista, CP 24039, Campeche, Cam (Mexico)

    2014-12-01

    Highlights: • Electromagnetic interaction in welding improved localised corrosion resistance. • Electromagnetic interaction in welding enhanced γ/δ phase balance of DuplexSS. • Welding under Electromagnetic interaction repress formation and growth of detrimental phases. • Welds made with gas protection (2% O{sub 2} + 98% Ar) have better microstructural evolution during welding. - Abstract: The resistance to localised corrosion of AISI 2205 duplex stainless steel plates joined by Gas Metal Arc Welding (GMAW) under the effect of electromagnetic interaction of low intensity (EMILI) was evaluated with sensitive electrochemical methods. Welds were made using two shielding gas mixtures: 98% Ar + 2% O{sub 2} (M1) and 97% Ar + 3% N{sub 2} (M2). Plates were welded under EMILI using the M1 gas with constant welding parameters. The modified microstructural evolution in the high temperature heat affected zone and at the fusion zone induced by application of EMILI during welding is associated with the increase of resistance to localised corrosion of the welded joints. Joints made by GMAW using the shielding gas M2 without the application of magnetic field presented high resistance to general corrosion but high susceptibility to undergo localised attack.

  20. Deformation behavior, corrosion resistance, and cytotoxicity of Ni-free Zr-based bulk metallic glasses.

    Science.gov (United States)

    Liu, L; Qiu, C L; Chen, Q; Chan, K C; Zhang, S M

    2008-07-01

    Two Ni-free bulk metallic glasses (BMGs) of Zr(60)Nb(5)Cu(22.5)Pd(5)Al(7.5) and Zr(60)Nb(5)Cu(20)Fe(5)Al(10) were successfully prepared by arc-melting and copper mold casting. The thermal stability and crystallization were studied using differential scanning calorimetry. It demonstrates that the two BMGs exhibit very good glass forming ability with a wide supercooled liquid region. A multi-step process of crystallization with a preferential formation of quasicrystals occurred in both BMGs under continuous heating. The deformation behavior of the two BMGs was investigated using quasi-static compression testing. It reveals that the BMGs exhibit not only superior strength but also an extended plasticity. Corrosion behaviors of the BMGs were investigated in phosphate buffered solution by electrochemical polarization. The result shows that the two BMGs exhibit excellent corrosion resistance characterized by low corrosion current densities and wide passive regions. X-ray photoelectron spectroscopy analysis revealed that the passive film formed after anodic polarization was highly enriched in zirconium, niobium, and aluminum oxides. This is attributed to the excellent corrosion resistance. Additionally, the potential cytotoxicity of the two Ni-free BMGs was evaluated through cell culture for 1 week followed by 3-(4,5-Dimethylthiazol-2-yl-)-2,5-diphenyltetrazolium bromide assay and SEM observation. The results indicate that the two Ni-free BMGs exhibit as good biocompatibility as Ti-6Al-4V alloy, and thus show a promising potential for biomedical applications. (c) 2007 Wiley Periodicals, Inc.

  1. Stability of (Fe-Tm-B) amorphous alloys: relaxation and crystallization phenomena

    International Nuclear Information System (INIS)

    Zemcik, T.

    1994-01-01

    Fe-Tm-B base (TM = transition metal) amorphous alloys (metallic glasses) are thermodynamically metastable. This limits their use as otherwise favourable materials, e.g. magnetically soft, corrosion resistant and mechanically firm. By analogy of the mechanical strain-stress dependence, at a certain degree of thermal activation the amorphous structure reaches its limiting state where it changes its character and physical properties. Relaxation and early crystallization processes in amorphous alloys, starting already around 100 C, are reviewed involving subsequently stress relief, free volume shrinking, topological and chemical ordering, pre-crystallization phenomena up to partial (primary) crystallization. Two diametrically different examples are demonstrated from among the soft magnetic materials: relaxation and early crystallization processes in the Fe-Co-B metallic glasses and controlled crystallization of amorphous ribbons yielding rather modern nanocrystalline ''Finemet'' alloys where late relaxation and pre-crystallization phenomena overlap when forming extremely dispersive and fine-grained nanocrystals-in-amorphous-sauce structure. Moessbauer spectroscopy seems to be unique for magnetic and phase analysis of such complicated systems. (orig.)

  2. Corrosion Resistance Properties of Aluminum Coating Applied by Arc Thermal Metal Spray in SAE J2334 Solution with Exposure Periods

    Directory of Open Access Journals (Sweden)

    Han-Seung Lee

    2016-03-01

    Full Text Available Arc thermal metal spray coating provides excellent corrosion, erosion and wear resistance to steel substrates. This paper incorporates some results of aluminum coating applied by this method on plain carbon steel. Thereafter, coated panels were exposed to an environment known to form stable corrosion products with aluminum. The coated panels were immersed in Society of Automotive Engineers (SAE J2334 for different periods of time. This solution consists of an aqueous solution of NaCl, CaCl2 and NaHCO3. Various electrochemical techniques, i.e., corrosion potential-time, electrochemical impedance spectroscopy (EIS and the potentiodynamic were used to determine the performance of stimulants in improving the properties of the coating. EIS studies revealed the kinetics and mechanism of corrosion and potentiodynamic attributed the formation of a passive film, which stifles the penetration of aggressive ions towards the substrate. The corrosion products that formed on the coating surface, identified using Raman spectroscopy, were Dawsonite (NaAlCO3(OH2 and Al(OH3. These compounds of aluminum are very sparingly soluble in aqueous solution and protect the substrate from pitting and uniform corrosion. The morphology and composition of corrosion products determined by scanning electron microscopy and energy dispersive X-ray analyses indicated that the environment plays a decisive role in improving the corrosion resistance of aluminum coating.

  3. Resistance to Corrosion of Reinforcement of High Volume Fly Ash Concrete

    International Nuclear Information System (INIS)

    Kwon, S. O.; Bae, S. H.; Lee, H. J.; Lee, K. M.; Jung, S. H.

    2014-01-01

    Due to the increasing of interest about the eco-friendly concrete, it is increased to use concretes containing by-products of industry such as fly ash(FA), ground granulated blast furnace slag(GGBFS), silica fume(SF), and etc. Especially, these are well known for improving the resistances to reinforcement corrosion in concrete and decreasing chloride ion penetration. The purpose of this experimental research is to evaluate the resistance against corrosion of reinforcement of high volume fly ash(HVFA) concrete which is replaced with high volume fly ash for cement volume. For this purpose, the concrete test specimens were made for various strength level and replacement ratio of FA, and then the compressive strength and diffusion coefficient for chloride ion of them were measured for 28, 91, and 182 days, respectively. Also, corrosion monitoring by half cell potential method was carried out for the made lollypop concrete test specimens to detect the time of corrosion initiation for reinforcement in concrete. As a result, it was observed from the test results that the compressive strength of HVFA concrete was decreased with increasing replacement ratio of FA but long-term resistances against reinforcement corrosion and chloride ion penetration of that were increased

  4. Corrosion of metal materials embedded in concrete

    International Nuclear Information System (INIS)

    Duffo, G.S.; Farina, S.B.; Schulz, F.M.

    2010-01-01

    Carbon steel is the material most frequently used to strengthen reinforced concrete structures; however, stainless steel and galvanized steel reinforcements are also used in construction concretes; and they are not often used in Latin America. Meanwhile, there are other metals that are embedded in the concrete forming part of the openings (aluminum) or in tubing systems (copper and lead). The use of concrete as a cementing material is also useful for immobilizing wastes, such as for example those generated by the nuclear industry. There is a great deal of research and development on the corrosion of steel reinforcements, but the same is not true for the behavior of other metals embedded in concrete and that also undergo corrosive processes. This work aims to study the corrosion of different metals: copper, lead, aluminum, zinc, stainless steel and carbon steel; embedded in concrete with and without the presence of aggressive species for the metal materials. Test pieces were made of mortar containing rods of different materials for testing, and with chlorides added in concentrations of 0; 0.3 % and 1% (mass of chloride per mass of cement). The test pieces were exposed to different conditions; laboratory environment with a relative humidity (RH) of 45%, a controlled atmosphere with 98% RH and submerged in a solution of 3.5% NaCl. The susceptibility to corrosion of the different metals was evaluated using techniques to monitor the corrosion potential, the resistivity of the mortar and the polarization resistance (PR). The rods were weighed before being placed inside the test pieces to later determine the loss of weight generated by the corrosion process. Polarization curves for the metals were also traced in a simulated pore solution (SPS) and in SPS with added chloride. The results obtained to date show that, of all the metals analyzed, aluminum is the most susceptible to corrosion, and that the test specimens with 0% and 1% of chloride exposed to the laboratory

  5. Study of the corrosion fatigue resistance of steel grades for automotive suspension springs

    Energy Technology Data Exchange (ETDEWEB)

    Mougin, J. [Ascometal CREAS, BP70045, F-57301 Hagondange Cedex (France); Mostacchi, A. [Ascometal Developpement, BP17, F-38570 Le Cheylas (France); Hersart, Y. [Allevard Rejna Autosuspensions CRDT, 201 Rue de Sin-le-Noble, BP629, F-59506 Douai Cedex (France)

    2004-07-01

    In order to reduce the total weight of vehicles for ecological and economical reasons, the car makers use down-sizing for several components of the cars. Concerning helical suspension springs, the size of the bar diameter and the number of spring coils are decreased, leading to an increase of the stress level applied on the spring. In this respect, steels with high mechanical properties are required, to achieve a good fatigue resistance of the springs. The corrosion resistance is also important for this application. Indeed, during service, the protective coating applied on the springs can be scratched by gravels, and bare underlying metal can be put in contact with the atmosphere, including humidity, drops of rain but also de-icing salts. Generally speaking, an increase of mechanical properties decreases the corrosion fatigue resistance of the steels. In this respect, a compromise needs to be found, that is why the study of corrosion fatigue resistance is very important. In order to study the corrosion fatigue resistance of spring steels, an original device and test procedure have been set up. Torsional fatigue on specimens is used to simulate the stress applied on each spring coil. The stress levels are chosen to be representative of the actual inservice loads. The specimens are shot-peened and coated in a same way as the actual springs. Scratching of the painting is performed, giving rise to small areas of bare metal. Three types of tests are performed: fatigue in air (taken as the reference level), fatigue on specimens which have been corroded previously (test similar to the spring-makers practice) and coupled corrosion fatigue. The mechanisms involved in corrosion fatigue have been studied. For all the specimens, crack initiated on corrosion pits. For the specimens corroded prior fatigue testing, the corrosion pits can be quite severe. In this case, these pits act as a surface defect which increases locally the stress concentration and accelerates the crack

  6. Corrosion behaviour of metallic and non-metallic materials in various media in the Anhydrite and Gypsum Mine Felsenau/AG

    International Nuclear Information System (INIS)

    Laske, D.; Wiedemann, K.H.

    1983-10-01

    The final underground disposal of radioactive wastes necessitates container materials with a good long-term resistance against corrosion from both external agents and the solidification matrix inside. For low- and medium-level active waste, repositories in anhydrite sites, among others, are under consideration. Sheet and plate samples from 14 metallic and 8 non-metallic materials have been tested for 5 years in a tunnel in the Anhydrite and Gypsum Mine Felsenau/AG for their corrosion resistance in the tunnel atmosphere, anhydrite powder, gypsum powder, gypsum, and cement. From the metallic materials tested, only chromium-nickel steel is corrosion resistant to all the media present. Zinc plated and tin plated iron sheet as well as aluminium and aluminium alloys are corrosion resistant only in the atmosphere of the tunnel, and lead plated iron sheet is resistant also in cement. Aluminium is dissolved in cement. Uncovered iron sheet undergoes severe corrosion. The non-metallic coatings tested (lacquer, stove lacquer, or synthetic resins) partially flake off already after one year's testing and are therefore not appropriate for iron sheet corrosion protection. No influence of the different media has been observed after 5 years on the 8 plastic materials tested (6 without, and 2 with glass fiber reinforcement). (author)

  7. Evaluation of High Temperature Corrosion Resistance of Finned Tubes Made of Austenitic Steel And Nickel Alloys

    Directory of Open Access Journals (Sweden)

    Turowska A.

    2016-06-01

    Full Text Available The purpose of the paper was to evaluate the resistance to high temperature corrosion of laser welded joints of finned tubes made of austenitic steel (304,304H and nickel alloys (Inconel 600, Inconel 625. The scope of the paper covered the performance of corrosion resistance tests in the atmosphere of simulated exhaust gases of the following chemical composition: 0.2% HCl, 0.08% SO2, 9.0% O2 and N2 in the temperature of 800°C for 1000 hours. One found out that both tubes made of austenitic steel and those made of nickel alloy displayed good resistance to corrosion and could be applied in the energy industry.

  8. Long-term corrosion studies

    International Nuclear Information System (INIS)

    Gdowski, G.

    1998-01-01

    The scope of this activity is to assess the long-term corrosion properties of metallic materials under consideration for fabricating waste package containers. Three classes of metals are to be assessed: corrosion resistant, intermediate corrosion resistant, and corrosion allowance. Corrosion properties to be evaluated are general, pitting and crevice corrosion, stress-corrosion cracking, and galvanic corrosion. The performance of these materials will be investigated under conditions that are considered relevant to the potential emplacement site. Testing in four aqueous solutions, and vapor phases above them, and at two temperatures are planned for this activity. (The environmental conditions, test metals, and matrix are described in detail in Section 3.0.) The purpose and objective of this activity is to obtain the kinetic and mechanistic information on degradation of metallic alloys currently being considered for waste package containers. This information will be used to provide assistance to (1) waste package design (metal barrier selection) (E-20-90 to E-20-92), (2) waste package performance assessment activities (SIP-PA-2), (3) model development (E-20-75 to E-20-89). and (4) repository license application

  9. Surface composition, microstructure and corrosion resistance of AZ31 magnesium alloy irradiated by high-intensity pulsed ion beam

    International Nuclear Information System (INIS)

    Li, P.; Lei, M.K.; Zhu, X.P.

    2011-01-01

    High-intensity pulsed ion beam (HIPIB) irradiation of AZ31 magnesium alloy is performed and electrochemical corrosion experiment of irradiated samples is carried out by using potentiodynamic polarization technology in order to explore the effect of HIPIB irradiation on corrosion resistance of magnesium alloy. The surface composition, cross-sectional morphology and microstructure are characterized by using electron probe microanalyzer, optical microscope and transmission electron microscope, respectively. The results indicated that HIPIB irradiation leads to a significant improvement in corrosion resistance of magnesium alloy, in terms of the considerable increase in both corrosion potential and pitting breakdown potential. The microstructural refinement and surface purification induced by HIPIB irradiation are responsible for the improved corrosion resistance. - Research Highlights: → A modified layer about 30 μm thick is obtained by HIPIB irradiation. → Selective ablation of element/impurity phase having lower melting point is observed. → More importantly, microstructural refinement occurred on the irradiated surface. → The modified layer exhibited a significantly improved corrosion resistance. → Improved corrosion resistance is ascribed to the combined effect induced by HIPIB.

  10. Amorphous Al-Mn coating on NdFeB magnets: Electrodeposition from AlCl{sub 3}-EMIC-MnCl{sub 2} ionic liquid and its corrosion behavior

    Energy Technology Data Exchange (ETDEWEB)

    Chen Jing; Xu Bajin [Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Ling Guoping, E-mail: linggp@zju.edu.cn [Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China)

    2012-06-15

    Amorphous Al-Mn coating was electrodeposited on NdFeB magnets from AlCl{sub 3}-EMIC-MnCl{sub 2} ionic liquid with the pretreatment of anodic electrolytic etching in AlCl{sub 3}-EMIC ionic liquid at room temperature. The microstructure, composition and phase constituents of the coatings were investigated by scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDS), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The corrosion resistance of the coatings was tested by means of potentiodynamic polarization and immersion test in 3.5 wt. % NaCl solution. The results show that anodic electrolytic etching in AlCl{sub 3}-EMIC ionic liquid is a satisfactory pretreatment to remove the surface oxide film and favor the adhesion of the Al-Mn alloy coating to the NdFeB substrate. The amorphous Al-Mn alloy coating provides sacrificial anodic protection for NdFeB. It exhibited good corrosion resistance and significantly reduced the corrosion current density of NdFeB by three orders of magnitude at potentiodynamic polarization. - Highlights: Black-Right-Pointing-Pointer Amorphous Al-Mn alloy coating was electrodeposited on NdFeB magnet from ionic liquid. Black-Right-Pointing-Pointer To remove the surface oxides of NdFeB, anodic etching pretreatment is used. Black-Right-Pointing-Pointer The deposited Al-Mn alloy coating shows high adhesion to the NdFeB substrate. Black-Right-Pointing-Pointer Corrosion tests show that amorphous Al-Mn alloy coating is anodic coating for NdFeB magnet.

  11. Highly featured amorphous silicon nanorod arrays for high-performance lithium-ion batteries

    International Nuclear Information System (INIS)

    Soleimani-Amiri, Samaneh; Safiabadi Tali, Seied Ali; Azimi, Soheil; Sanaee, Zeinab; Mohajerzadeh, Shamsoddin

    2014-01-01

    High aspect-ratio vertical structures of amorphous silicon have been realized using hydrogen-assisted low-density plasma reactive ion etching. Amorphous silicon layers with the thicknesses ranging from 0.5 to 10 μm were deposited using radio frequency plasma enhanced chemical vapor deposition technique. Standard photolithography and nanosphere colloidal lithography were employed to realize ultra-small features of the amorphous silicon. The performance of the patterned amorphous silicon structures as a lithium-ion battery electrode was investigated using galvanostatic charge-discharge tests. The patterned structures showed a superior Li-ion battery performance compared to planar amorphous silicon. Such structures are suitable for high current Li-ion battery applications such as electric vehicles

  12. Highly featured amorphous silicon nanorod arrays for high-performance lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Soleimani-Amiri, Samaneh; Safiabadi Tali, Seied Ali; Azimi, Soheil; Sanaee, Zeinab; Mohajerzadeh, Shamsoddin, E-mail: mohajer@ut.ac.ir [Thin Film and Nanoelectronics Lab, Nanoelectronics Center of Excellence, School of Electrical and Computer Engineering, University of Tehran, Tehran 143957131 (Iran, Islamic Republic of)

    2014-11-10

    High aspect-ratio vertical structures of amorphous silicon have been realized using hydrogen-assisted low-density plasma reactive ion etching. Amorphous silicon layers with the thicknesses ranging from 0.5 to 10 μm were deposited using radio frequency plasma enhanced chemical vapor deposition technique. Standard photolithography and nanosphere colloidal lithography were employed to realize ultra-small features of the amorphous silicon. The performance of the patterned amorphous silicon structures as a lithium-ion battery electrode was investigated using galvanostatic charge-discharge tests. The patterned structures showed a superior Li-ion battery performance compared to planar amorphous silicon. Such structures are suitable for high current Li-ion battery applications such as electric vehicles.

  13. The resistance of titanium to pitting, microbially induced corrosion and corrosion in unsaturated conditions

    Energy Technology Data Exchange (ETDEWEB)

    Shoesmith, D W; Ikeda, B M

    1997-04-01

    Titanium and its alloys (Grades-2, -12, -16) are candidate materials for Canadian nuclear waste containers on the basis of their apparent immunity to many localized corrosion processes. This simplifies markedly the effort needed to justify the use of these materials and to develop models to predict the lifetimes of containers. Here we review the pitting, microbially influenced corrosion (MIC), and corrosion under unsaturated conditions, of titanium. For all these processes, the properties of the passive oxide film are paramount in determining the metal`s resistance to corrosion. A review of these oxide properties is included and the conditions to which the metal must be exposed if localized corrosion is to occur are defined. Since these conditions cannot be achieved under Canadian waste vault conditions, it can be concluded that pitting and MIC will not occur and that corrosion under unsaturated conditions is extremely unlikely. (author) 114 refs., 1 tab., 18 figs.

  14. Effects of Alloying Elements (Cr, Mn) on Corrosion Properties of Carbon Steel in Synthetic Seawater

    International Nuclear Information System (INIS)

    Hyun, Youngmin; Kim, Heesan

    2016-01-01

    Effects of alloying elements, manganese and chromium, on corrosion resistance of carbon steel were examined using weight loss test and electrochemical tests (polarization test and electrochemical impedance spectroscopy (EIS)) in synthetic seawater at 60 ℃. The results from the weight loss test showed that chromium effectively improved corrosion resistance of carbon steel during the entire immersion time, but manganese improved corrosion resistance after the lowered corrosion resistance at the beginnings of immersion. Unlike the weight loss test, the electrochemical tests showed that the corrosion resistance did not increase with immersion time, in all the specimens. This disagreement is explained by the presence of rust involved in electrochemical reaction during electrochemical tests. The analysis of rust with transmission electron microscopy (TEM)−energy dispersive spectroscopy (EDS) showed that the amorphous-like rust layer located at the metal/rust interface with enriched alloying element (Cr, Mn) prevents diffusion of corrosive species into a metal/rust interface effectively, which leads to increased corrosion resistance. The initial corrosion behaviour is also affected by the rust types. In other words, manganese accelerated the formation of spinel oxides, negatively affecting corrosion resistance. Meanwhile, chromium accelerated the formation of goethite but impeded the formation of spinel oxides, positively affecting the corrosion resistance. From the above results, the corrosion resistance of steel is closely related with a rust type.

  15. Effects of Alloying Elements (Cr, Mn) on Corrosion Properties of Carbon Steel in Synthetic Seawater

    Energy Technology Data Exchange (ETDEWEB)

    Hyun, Youngmin; Kim, Heesan [Hongik University, Sejong (Korea, Republic of)

    2016-02-15

    Effects of alloying elements, manganese and chromium, on corrosion resistance of carbon steel were examined using weight loss test and electrochemical tests (polarization test and electrochemical impedance spectroscopy (EIS)) in synthetic seawater at 60 ℃. The results from the weight loss test showed that chromium effectively improved corrosion resistance of carbon steel during the entire immersion time, but manganese improved corrosion resistance after the lowered corrosion resistance at the beginnings of immersion. Unlike the weight loss test, the electrochemical tests showed that the corrosion resistance did not increase with immersion time, in all the specimens. This disagreement is explained by the presence of rust involved in electrochemical reaction during electrochemical tests. The analysis of rust with transmission electron microscopy (TEM)−energy dispersive spectroscopy (EDS) showed that the amorphous-like rust layer located at the metal/rust interface with enriched alloying element (Cr, Mn) prevents diffusion of corrosive species into a metal/rust interface effectively, which leads to increased corrosion resistance. The initial corrosion behaviour is also affected by the rust types. In other words, manganese accelerated the formation of spinel oxides, negatively affecting corrosion resistance. Meanwhile, chromium accelerated the formation of goethite but impeded the formation of spinel oxides, positively affecting the corrosion resistance. From the above results, the corrosion resistance of steel is closely related with a rust type.

  16. Performance of single wire earth return transformers with amorphous alloy core in a rural electric energy distribution system

    Directory of Open Access Journals (Sweden)

    Benedito Antonio Luciano

    2012-10-01

    Full Text Available In this paper are presented some considerations about the performance of single wire earth return amorphous alloy core transformers in comparison with conventional silicon steel sheets cores transformers used in rural electric energy distribution network. It has been recognized that amorphous metal core transformers improve electrical power distribution efficiency by reducing transformer core losses. This reduction is due to some electromagnetic properties of the amorphous alloys such as: high magnetic permeability, high resistivity, and low coercivity. Experimental results obtained with some single-phase, 60 Hz, 5 kVA amorphous core transformers installed in a rural area electric distribution system in Northern Brazil have been confirming their superior performance in comparison to identical nominal rated transformers built with conventional silicon steel cores, particularly with regard to the excitation power and to the no-load losses.

  17. Canister materials proposed for final disposal of high level nuclear waste - a review with respect to corrosion resistance

    Energy Technology Data Exchange (ETDEWEB)

    Mattsson, E; Odoj, R; Merz, E [eds.

    1981-06-01

    Spent fuel from nuclear reactors has to be disposed of either after reprocessing or without such treatment. Due to toxic radiation the nuclear waste has to be isolated from the biosphere for 300-1000 years, or in extreme cases for more than 100,000 years. The nuclear waste will be enclosed in corrosion resistant canisters. These will be deposited in repositories in geological formations, such as granite, basalt, clay, bedded or domed salt, or the sediments beneath the deep ocean floor. There the canisters will be exposed to groundwater, brine or seawater at an elevated temperature. Species formed by radiolysis may affect the corrosivity of the agent. The corrosion resistance of candidate canister materials is evaluated by corrosion tests and by thermodynamic and mass transport calculations. Examination of ancient metal objects after long exposure in nature may give additional information. On the basis of the work carried out so far, the principal candidate canister materials are titanium materials, copper and high purity alumina.

  18. Corrosion study of the passive film of amorphous Fe-Cr-Ni-(Si, P, B alloys

    Directory of Open Access Journals (Sweden)

    López, M. F.

    1996-12-01

    Full Text Available Amorphous Fe62Cr10Ni8X20 (X = P, B, Si alloys in 0.01M HCl solution have been investigated by means of standard electrochemical measurements in order to evaluate their corrosion resistance. The study reveals that the best corrosion behaviour is given by the Si containing amorphous alloy. X-ray photoelectron spectroscopy (XPS and Auger electron spectroscopy (AJES have been employed to study the composition of the passive layers, formed on the surface of the different amorphous alloys. The results on Fe62Cr10Ni8X20 show that a protective passive film, mainly consisting of oxidized chromium, greatly enhances its corrosion resistance.

    La resistencia a la corrosión de las aleaciones amorfas Fe62Cr10Ni8X20 (X = P, B, Si inmersas en HCl 0,01M se evaluó usando técnicas electroquímicas. Las técnicas de espectroscopia de fotoemisión de rayos X y espectroscopia Auger se emplearon para estudiar la composición de las capas pasivas, formadas en aire sobre la superficie de las aleaciones amorfas. Del estudio realizado se concluye que el mejor comportamiento frente a la corrosión viene dado por la aleación amorfa que contiene como metaloide Si. Esto es debido a que la capa pasiva de dicha aleación está formada principalmente de óxido de cromo, lo cual confiere una alta resistencia a la corrosión.

  19. Performance of HVOF carbide coatings under erosion/corrosion

    International Nuclear Information System (INIS)

    Simard, S.; Arsenault, B.; Legoux, J.G.; Hawthorne, H.M.

    1999-01-01

    Cermet based materials are known to have an excellent performance under several wear conditions. High velocity oxy-fuel (HVOF) technology allows the deposition of such hard materials in the form of protective coatings onto different surfaces. Under slurry erosion, the performance of the coatings is influenced by the occurrence of corrosion reactions on the metallic matrix. Indeed, wet conditions promote the dissolution of metallic binder resulting in a potential synergic effect between the corrosion and wear mechanisms. The composition of the metallic matrix plays a key role on the stability of the coatings and their degradation rate. In this work, four coatings based on tungsten carbide embedded in different metallic binders were evaluated with regard to corrosion and wear. (author)

  20. Corrosion resistance of ERW (Electric Resistance Welded) seam welds as compared to metal base in API 5L steel pipes

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez Velasquez, Jorge L.; Godinez Salcedo, Jesus G.; Lopez Fajardo, Pedro [Instituto Politecnico Nacional (IPN), Mexico D.F. (Mexico). Escuela Superior de Ingenieria Quimica e Industrias Extractivas (ESIQIE). Dept. de Ingenieria Metalurgica

    2009-07-01

    The corrosion resistance of ERW seam welds and the base metal in API 5L X70 steel pipes was evaluated by Tafel tests. The procedure was according to ASTM G3 standard. The study was completed with metallographic and chemical characterization of the tested zones, that is, the welded zone and the base metal away of the weld. All tests were made on the internal surface of the pipe in order to assess the internal corrosion of an in-service pipeline made of the API 5L X70 steel. The test solution was acid brine prepared according to NACE Publications 1D182 and 1D196. The results showed that the ERW seam weld corrodes as much as three times faster than the base material. This behavior is attributed to a more heterogeneous microstructure with higher internal energy in the ERW seam weld zone, as compared to the base metal, which is basically a ferrite pearlite microstructure in a normalized condition. This result also indicates that pipeline segments made of ERW steel pipe where the seam weld is located near or at the bottom of the pipe are prone to a highly localized attack that may form channels of metal loss if there is water accumulation at the bottom of the pipeline. (author)

  1. The role of molybdenum in corrosion resistance of stainless steel

    International Nuclear Information System (INIS)

    Abdul Razak bin Daud

    1989-01-01

    The effect of Mo on corrosion properties of stainless steels in 1M MgCl 2 solution was studied using an electrochemical polarization method. Procedure for the preparation of electrochemically polarized samples for surface analysis is described. The samples surface were analyzed using X-ray Photoelectron Spectroscopy (XPS). The stainless steel which has high Mo content has a better resistance to corrosion in Cl containing media. Cr and Mo are enriched in the surface of Mo-bearing stainless steels which have undergone high anodic-metal dissolution. Mo may exist as MoO 2 which is responsible in slowing down the rate of corrosion attack. (author)

  2. Electrochemical characterization of Zr-based thin film metallic glass in hydrochloric aqueous solution

    International Nuclear Information System (INIS)

    Chuang, Ching-Yen; Liao, Yi-Chia; Lee, Jyh-Wei; Li, Chia-Lin; Chu, Jinn P.; Duh, Jenq-Gong

    2013-01-01

    Recently thin film metallic glass represents a class of promising engineering materials for structural applications. In this work, the Zr-based thin film metallic glass (TFMG) was fabricated on the Si and AISI 420 substrates using a Zr–Cu–Ni–Al alloy and pure Zr metal targets by a pulsed DC magnetron sputtering system. The chemical compositions, crystalline structures, microstructures and corrosion behavior in hydrochloric (HCl) aqueous solutions of Zr-based TFMGs were investigated. The results showed that the surface morphologies of Zr-based TFMG were very smooth. A compact and dense structure without columnar structure was observed. The amorphous structure of Zr-based TFMG was characterized by the X-ray diffractometer and transmission electron microscopy analyses. After the potentiodynamic polarization test, the better corrosion resistance was achieved for the Zr-based TFMG coated AISI 420 in 1 mM HCl aqueous solution. Based on the surface morphologies and chemical analysis results of the corroded surfaces, the pitting, crevice corrosion and filiform corrosion were found. The corrosion mechanisms of the Zr-based TFMG were discussed in this work. - Highlights: ► Zr-based thin film metallic glass with amorphous structure. ► Better corrosion resistance of Zr-based thin film metallic glass observed. ► Pitting, crevice and filiform corrosion reactions revealed. ► The Cu-rich corrosion products found in the pit. ► Nanowire and flaky corrosion products formed adjacent to the filiform corrosion path

  3. The applicability of alkaline-resistant glass fiber in cement mortar of road pavement: Corrosion mechanism and performance analysis

    Directory of Open Access Journals (Sweden)

    Qin Xiaochun

    2017-11-01

    Full Text Available The main technical requirements of road pavement concrete are high flexural strength and fatigue durability. Adding glass fiber into concrete could greatly increase flexural strength and wearing resistance of concrete. However, glass fiber has the great potential of corrosion during the cement hydration, which will directly affect the long-term performance and strength stability. In this paper, accelerated corrosion experiments have been done to find out the corrosion mechanism and property of alkali-resistant glass fiber in cement mortar. The applicability and practicability of alkaline-resistant glass fiber in road concrete have been illustrated in the analysis of flexural strength changing trend of cement mortar mixed with different proportions of activated additives to protect the corrosion of glass fiber by cement mortar. The results have shown that a 30% addition of fly ash or 10% addition of silica fume to cement matrix could effectively improve the corrosion resistance of alkali-resistant glass fiber. The optimal mixing amount of alkali-resistant glass fiber should be about 1.0 kg/m3 in consideration of ensuring the compressive strength of reinforced concrete in road pavement. The closest-packing method has been adopted in the mixture ratio design of alkali-resistant glass fiber reinforced concrete, not only to reduce the alkalinity of the cement matrix through large amount addition of activated additives but also to greatly enhance the flexural performance of concrete with the split pressure ratio improvement of 12.5–16.7%. The results suggested a prosperous application prospect for alkaline-resistant glass fiber reinforced concrete in road pavement.

  4. Manufacture and evaluation of integrated metal-oxide electrode prototype for corrosion monitoring in high temperature water

    International Nuclear Information System (INIS)

    Hashimoto, Yoshinori; Tani, Jun-ichi

    2014-01-01

    We have developed an integrated metal-oxide (M/O) electrode based on an yttria-stabilized-zirconia-(YSZ)-membrane M/O electrode, which was used as a reference electrode for corrosion monitoring in high temperature water. The YSZ-membrane M/O electrode can operate at high temperatures because of the conductivity of YSZ membrane tube. We cannot utilize it for long term monitoring at a wide range of temperatures. It also has a braze juncture between the YSZ membrane and metal tubes, which may corrode in high-temperature water. This corrosion should be prevented to improve the performance of the M/O electrode. An integrated M/O electrode was developed (i.e., integrated metal-oxide electrode, IMOE) to eliminate the braze juncture and increase the conductivity of YSZ. These issues should be overcome to improve the performance of M/O electrode. So we have developed two type of IMOE prototype with sputter - deposition or thermal oxidation. In this paper we will present and discuss the performance of our IMOEs in buffer solution at room temperature. (author)

  5. Effect of ion nitridation process on hardness and the corrosion resistance of biomaterials

    International Nuclear Information System (INIS)

    Wirjoadi; Lely Susita; Bambang Siswanto; Sudjatmoko

    2012-01-01

    Ion nitriding process has been performed on metal biomaterials to improve their mechanical properties of materials, particularly to increase hardness and corrosion resistance. This metallic biomaterials used for artificial bone or a prosthetic graft and used as devices of orthopedic biomaterials are usually of 316L SS metal-type and Ti-6Al-4V alloy. The purpose of this study is to research the development and utilization of ion nitridation method in order to get iron and titanium nitride thin films on the metallic biomaterials for artificial bone that has wear resistance and corrosion resistance is better. Microhardness of the samples was measured using a microhardness tester, optimum hardness of SS 316L samples are about 582 VHN, this was obtained at the nitriding temperature of 500 °C, the nitriding time of 3 hours and the nitrogen gas pressure of 1.6 mbar, while optimum hardness of Ti-6Al-4V alloy is 764 VHN, this was obtained at the nitriding temperature of 500 °C, the nitriding time of 4 hours and the nitrogen gas pressure of 1.6 mbar. The hardness value of SS 316L sample and Ti-6Al-4V alloy increase to 143% and 153%, if compared with standard samples. The optimum corrosion resistance at temperature of 350 °C for SS 316L and Ti-6Al-4V are 260,12 and 110,49 μA/cm 2 or corrosion rate are 29,866 and 15,189 mpy, respectively. (author)

  6. Corrosion resistance and microstructure characterization of rare-earth-transition metal-aluminum-magnesium alloys

    International Nuclear Information System (INIS)

    Banczek, E.P.; Zarpelon, L.M.C.; Faria, R.N.; Costa, I.

    2009-01-01

    This paper reports the results of investigation carried out to evaluate the corrosion resistance and microstructure of some cast alloys represented by the general formula: La 0.7-x Pr x Mg 0.3 Al 0.3 Mn 0.4 Co 0.5 Ni 3.8 (x = 0, 0.1, 0.3, 0.5, and 0.7). Scanning electron microscopy (SEM) and electrochemical methods, specifically, polarization curves and electrochemical impedance spectroscopy (EIS), have been employed in this study. The effects of Pr substitution on the composition of the various phases in the alloys and their corrosion resistance have been studied. The electrochemical results showed that the alloy without Pr and the one with total La substitution showed the highest corrosion resistance among the studied alloys. The corrosion resistance of the alloys decreased when Pr was present in the lowest concentrations (0.1 and 0.3), but for higher Pr concentrations (0.5 and 0.7), the corrosion resistance increased. Corrosion occurred preferentially in a Mg-rich phase.

  7. The corrosion resistance of Nitinol alloy in simulated physiological solutions

    International Nuclear Information System (INIS)

    Milošev, Ingrid; Kapun, Barbara

    2012-01-01

    The corrosion behaviour of Nitinol alloy containing nearly equi-atomic composition of nickel and titanium and its constituent metals (nickel and titanium) was investigated in simulated Hanks physiological solution (pH value 7.5) and pH modified simulated Hanks physiological solution (pH values 4.5 and 6.5) and by electrochemical method of anodic potentiodynamic polarization at 37 °C. In this chloride-rich medium the corrosion stability of Nitinol is limited by the susceptibility to localized corrosion and is in that sense more similar to nickel than to titanium. The corrosion stability of Nitinol is strongly dependent on the surface preparation—grinding, polishing or chemical etching. Whereas a ground surface is not resistant to localized corrosion, polished and chemically etched surfaces are resistant to this type of corrosion attack. The reasons for this behaviour were investigated through metallurgical, topographical and chemical properties of the surface as a function of surface preparation. For that purpose, scanning electron microscopy combined with chemical analysis, confocal microscopy and X-ray photoelectron spectroscopy were used. The surface roughness decreased in the following order: chemically etched > ground > polished surface. Besides differences in topography, distinct differences in the chemical composition of the outermost surface are observed. Ground, rough surfaces comprised mainly titanium oxides and small amounts of nickel metal. Chemically etched and, especially, polished surfaces are composed of a mixture of titanium, nickel and titanium oxides, as studied by angle resolved X-ray photoelectron spectroscopy. These results emphasize the importance of detailed investigation of the metal surface since small differences in surface preparation may induce large differences in corrosion stability of material when exposed to corrosive environments. - Highlights: ► The corrosion resistance of Nitinol is dependent on the surface preparation.

  8. Corrosion resistant coatings suitable for elevated temperature application

    Science.gov (United States)

    Chan, Kwai S [San Antonio, TX; Cheruvu, Narayana Sastry [San Antonio, TX; Liang, Wuwei [Austin, TX

    2012-07-31

    The present invention relates to corrosion resistance coatings suitable for elevated temperature applications, which employ compositions of iron (Fe), chromium (Cr), nickel (Ni) and/or aluminum (Al). The compositions may be configured to regulate the diffusion of metals between a coating and a substrate, which may then influence coating performance, via the formation of an inter-diffusion barrier layer. The inter-diffusion barrier layer may comprise a face-centered cubic phase.

  9. Mg amorphous alloys for biodegradable implants

    International Nuclear Information System (INIS)

    Danez, G.P.; Koga, G.Y.; Tonucci, S.; Bolfarini, C.; Kiminami, C.S.; Botta Filho, W.J.

    2010-01-01

    The use of implants made from amorphous alloys magnesium-based with additions of zinc and calcium are promising. Properties such as biocompatibility, low density, high mechanical strength, low modulus (as compared to alloys such as stainless steel and titanium), corrosion resistance and wear resistance make it attractive for use in implants. Moreover, the by-products of corrosion and wear are not toxic and may contribute to fixation. Aiming to understand the tendency of this amorphous ternary (Mg-Zn-Ca) and expand the information about this system, this work involved the use of the topological criterion of instability (λ) and the criterion of electronegativity (Δe) to the choice of compositions. The alloys were processed into wedge-shaped and analyzed structurally and in X-ray diffraction and scanning electron microscopy. (author)

  10. Assessing resistance of stabilized corrosion resistant steels to intergranular corrosion

    International Nuclear Information System (INIS)

    Karas, A.; Cihal, V. Jr.; Vanek, V.; Herzan, J.; Protiva, K.; Cihal, V.

    1987-01-01

    Resistance to intergranular corrosion was determined for four types of titanium-stabilized steels from the coefficients of stabilization efficiency according to the degree the chemical composition was known. The ATA SUPER steel showed the highest resistance parameter value. The resistance of this type of steel of a specific composition, showing a relatively low value of mean nitrogen content was compared with steel of an optimized chemical composition and with low-carbon niobium stabilized, molybdenum modified steels. The comparison showed guarantees of a sufficient resistance of the steel to intergranular corrosion. The method of assessing the resistance to intergranular corrosion using the calculation of the minimum content of Cr', i.e., the effective chromium content, and the maximum effective carbon content C' giving the resistance parameter k seems to be prospective for practical use in the production of corrosion resistant steels. (author). 1 tab., 5 figs., 15 refs

  11. Study of the corrosion of metallic coatings and alloys containing aluminum in a mixed atmosphere - sulphur, oxygen - at high temperatures

    International Nuclear Information System (INIS)

    Fellmann, Daniel

    1982-01-01

    The objective of this research thesis is the development of materials for a sulphur experimental loop allowing the thermodynamic properties of such an energy cycle to be checked. As solutions must comply with industrial methods, rare materials are excluded as they are too expensive or difficult to implement. Iron-based materials have been tested but could not have at the same time a good corrosion resistance and high temperature forming and mechanical toughness properties. Therefore, metallic coatings have been chosen, specifically alumina. After having reported a bibliographical study on corrosion by sulphur vapour and by oxygen and by sulphur-oxygen, the author presents the experimental materials and methods. Then, the author reports the study of mixed corrosion (by sulphur and oxygen together) of metallic alloys (ferritic and austeno-ferritic alloys, aluminium and titanium alloys), and of the corrosion of FeAlx coatings, of AlTix alloys [fr

  12. Enhancing Corrosion and Wear Resistance of AA6061 by Friction Stir Processing with Fe78Si₉B13 Glass Particles.

    Science.gov (United States)

    Guo, Lingyu; Liu, Yan; Shen, Kechang; Song, Chaoqun; Yang, Min; Kim, Kibuem; Wang, Weimin

    2015-08-07

    The AA6061-T6 aluminum alloy samples including annealed Fe 78 Si₉B 13 particles were prepared by friction stir processing (FSP) and investigated by various techniques. The Fe 78 Si₉B 13 -reinforced particles are uniformly dispersed in the aluminum alloy matrix. The XRD results indicated that the lattice parameter of α-Al increases and the preferred orientation factors F of (200) plane of α-Al reduces after friction stir processing. The coefficient of thermal expansion (CTE) for FSP samples increases at first with the temperature but then decreases as the temperature further increased, which can be explained by the dissolving of Mg and Si from β phase and Fe 78 Si₉B 13 particles. The corrosion and wear resistance of FSP samples have been improved compared with that of base metal, which can be attributed to the reduction of grain size and the CTE mismatch between the base metal and reinforced particles by FSP, and the lubrication effect of Fe 78 Si₉B 13 particles also plays a role in improving wear resistance. In particular, the FSP sample with reinforced particles in amorphous state exhibited superior corrosion and wear resistance due to the unique metastable structure.

  13. Microstructure and corrosion resistance of Ce–V conversion coating on AZ31 magnesium alloy

    International Nuclear Information System (INIS)

    Jiang, Xiao; Guo, Ruiguang; Jiang, Shuqin

    2015-01-01

    Highlights: • Through simple chemical conversion process, a Ce–V conversion coating is prepared on AZ31 magnesium alloy. The coating (∼2 μm thick) has a duplex structure and is composed of Mg, Al, Ce, V and O in the outer layer and Mg, Al, V, F and O in the inner layer. • The Ce–V conversion coating can increase the E corr by 157 mV and decrease the i corr by 80 times compared to AZ31 magnesium alloy substrate. Moreover, the performance of the Ce–V conversion coating excels the chromate conversion coating on AZ31 magnesium alloy. • The EIS results of Ce–V conversion coating indicate an increase of 10× in the corrosion resistance and a delay in the corrosion process kinetics compared to uncoated AZ31 magnesium alloy in 3.5 wt.% NaCl solution. • The ball cratering is a simple and effective technique of thickness measurement for chemical conversion coating. - Abstract: A Ce–V conversion coating was developed to improve the corrosion resistance of AZ31 magnesium alloy. Scanning electronic microscope (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectrometer (XPS), grazing incidence X-ray diffraction (GIXRD) and the ball cratering test were adopted to study the morphology, chemical composition, structure and thickness of the coating. The coating has duplex structure with network and its thickness is about 2 μm. The coating contains high contents of Ce and V, which exhibits amorphous structure. Potentiodynamic polarization shows the coating can increase the corrosion potential and reduce the corrosion current density of AZ31 magnesium alloy. Moreover, the electrochemical impedance spectra exhibit the coating significantly improves the corrosion resistance of AZ31 magnesium alloy. Results indicate that the Ce–V conversion coating can provide effective protection to AZ31 magnesium alloy

  14. Microstructure and corrosion resistance of Ce–V conversion coating on AZ31 magnesium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Xiao, E-mail: xiaoxiao217@126.com; Guo, Ruiguang; Jiang, Shuqin

    2015-06-30

    Highlights: • Through simple chemical conversion process, a Ce–V conversion coating is prepared on AZ31 magnesium alloy. The coating (∼2 μm thick) has a duplex structure and is composed of Mg, Al, Ce, V and O in the outer layer and Mg, Al, V, F and O in the inner layer. • The Ce–V conversion coating can increase the E{sub corr} by 157 mV and decrease the i{sub corr} by 80 times compared to AZ31 magnesium alloy substrate. Moreover, the performance of the Ce–V conversion coating excels the chromate conversion coating on AZ31 magnesium alloy. • The EIS results of Ce–V conversion coating indicate an increase of 10× in the corrosion resistance and a delay in the corrosion process kinetics compared to uncoated AZ31 magnesium alloy in 3.5 wt.% NaCl solution. • The ball cratering is a simple and effective technique of thickness measurement for chemical conversion coating. - Abstract: A Ce–V conversion coating was developed to improve the corrosion resistance of AZ31 magnesium alloy. Scanning electronic microscope (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectrometer (XPS), grazing incidence X-ray diffraction (GIXRD) and the ball cratering test were adopted to study the morphology, chemical composition, structure and thickness of the coating. The coating has duplex structure with network and its thickness is about 2 μm. The coating contains high contents of Ce and V, which exhibits amorphous structure. Potentiodynamic polarization shows the coating can increase the corrosion potential and reduce the corrosion current density of AZ31 magnesium alloy. Moreover, the electrochemical impedance spectra exhibit the coating significantly improves the corrosion resistance of AZ31 magnesium alloy. Results indicate that the Ce–V conversion coating can provide effective protection to AZ31 magnesium alloy.

  15. High Temperature Corrosion on Biodust Firing

    DEFF Research Database (Denmark)

    Okoro, Sunday Chukwudi

    The high content of alkali metals and chlorine in biomass gives rise to fouling/slagging and corrosion of heat exchange components, such as superheaters, in biomass fired power plants. Increasing the lifetime of these components, and in addition, preventing unwarranted plant shutdowns due...... to their failure, requires understanding of the complex corrosion mechanisms, as well as development of materials that are resistant to corrosion under biomass firing conditions, thereby motivating the current work. To understand the mechanisms of corrosion attack, comprehensive analysis of corrosion products...... by the combined use of complementary information from microscopy, energy dispersive X-ray spectroscopy and various X-ray diffraction characterization techniques. In light of the wide variation in operating conditions in biomass fired power plants, systematic and well-controlled, but realistic laboratory scale...

  16. Study on corrosion of metal materials in nitrate molten salts

    Science.gov (United States)

    Zhai, Wei; Yang, Bo; Li, Maodong; Li, Shiping; Xin, Mingliang; Zhang, Shuanghong; Huang, Guojia

    2017-01-01

    High temperature molten salts as a heat transfer heat storage medium has been more widely used in the field of concentrated solar thermal power generation. In the thermal heat storage system, metal material stability and performance at high temperatures are of one major limitation in increasing this operating temperature. In this paper, study on corrosion of 321H, 304, 316L, P91 metal materials in modified solar two molten salts. The corrosion kinetics of 304, 316L, 321H, P91 metal material in the modified solar two molten salts at 450°C, 500°C is also investigated. Under the same condition it was found that 304, 321H corroded at a rate of 40% less than P91. Spallation of corrosion products was observed on P91 steel, while no obvious observed on other kinds of stainless steel. Corrosion rates of 304, 321H, and 316L slowly increased with temperature. Oxidation mechanisms little varied with temperature. Corrosion products of metal materials observed at 450°C, 500°C were primarily Fe oxide and Fe, Cr oxide.

  17. Amorphization of metals by ion implantation and ion beam mixing

    International Nuclear Information System (INIS)

    Rauschenbach, B.; Heera, V.

    1988-01-01

    Amorphous metallic systems can be formed either by high-fluence ion implantation of glassforming species or by irradiation of layered metal systems with inert gas ions. Both techniques and experimental examples are presented. Empirical rules are discussed which predict whether a given system can be transformed into an amorphous phase. Influence of temperature, implantation dose and pre-existing crystalline metal composition on amorphization is considered. Examples are given of the implantation induced amorphous structure, recrystallization and formation of quasicrystalline structures. (author)

  18. Physical Metallurgy, Weldability, and in-Service Performance of Nickel-Chromium Filler Metals Used in Nuclear Power Systems

    Science.gov (United States)

    Young, George A.; Etien, Robert A.; Hackett, Micah J.; Tucker, Julie D.; Capobianco, Thomas E.

    Wrought Alloy 690 is well established for corrosion resistant nuclear applications but development continues to improve the weldability of a filler metal that retains the corrosion resistance and phase stability of the base metal. High alloy Ni-Cr filler metals are prone to several types of welding defects and new alloys are emerging for commercial use. This paper uses experimental and computational methods to illustrate key differences among welding consumables. Results show that solidification segregation is critical to understanding the weldability and environmentally-assisted cracking resistance of these alloys. Primary water stress corrosion cracking tests show a marked decrease in crack growth rates near 21 wt. % Cr at the grain boundary. While filler metals with 21-29 wt.% grain boundary Cr show similar PWSCC resistance, the higher alloyed grades are more prone to solidification cracking. Modeling and aging studies indicate that in some filler metals minor phase formation (e.g., Laves and σ) and long range order (LRO) must be assessed to ensure adequate weldability and inservice performance.

  19. Studies of corrosion in metallic container for storage of high level radioactive wastes

    International Nuclear Information System (INIS)

    Azkarate, I.; Madina, V.; Insausti, M.

    1999-01-01

    The metallic container is one of the most important barriers that, along with engineered and natural barriers, will isolate high level nuclear waste in saline and granite geological formations from the geosphere. However, general and localized corrosion modes such as stress corrosion cracking (SCC), pitting, crevice corrosion and hydrogen damage can be active under disposal conditions, so the corrosion behaviour of the metal container material must be carefully studied. Several metals and their alloys have been proposed for the fabrication of nuclear waste containers including carbon steels, stainless steels, titanium and titanium alloys and copper and copper-base alloys. Carbon steels and copper alloys are considered for the two rock formations, titanium is considered for salt environments and the stainless steel only in the case of a granite formation. (Author)

  20. Corrosion behavior of corrosion resistant alloys in stimulation acids

    Energy Technology Data Exchange (ETDEWEB)

    Cheldi, Tiziana [ENI E and P Division, 20097 San Donato Milanese Milano (Italy); Piccolo, Eugenio Lo; Scoppio, Lucrezia [Centro Sviluppo Materiali, via Castel Romano 100, 00128 Rome (Italy)

    2004-07-01

    In the oil and gas industry, selection of CRAs for downhole tubulars is generally based on resistance to corrosive species in the production environment containing CO{sub 2}, H{sub 2}S, chloride and in some case elemental sulphur. However, there are non-production environments to which these materials must also be resistant for either short term or prolonged duration; these environments include stimulation acids, brine and completion fluids. This paper reports the main results of a laboratory study performed to evaluate the corrosion and stress corrosion behaviour to the acidizing treatments of the most used CRAs for production tubing and casing. Laboratory tests were performed to simulate both 'active' and 'spent' acids operative phases, selecting various environmental conditions. The selected steel pipes were a low alloyed steel, martensitic, super-martensitic, duplex 22 Cr, superduplex 25 Cr and super-austenitic stainless steels (25 Cr 35 Ni). Results obtained in the 'active' acid environments over the temperature range of 100-140 deg. C, showed that the blend acids with HCl at high concentration and HCl + HF represented too much severe conditions, where preventing high general corrosion and heavy localised corrosion by inhibition package becomes very difficult, especially for duplex steel pipe, where, in some case, the specimens were completely dissolved into the solution. On the contrary, all steels pipes were successfully protected by inhibitor when organic acid solution (HCOOH + CH{sub 3}COOH) were used. Furthermore, different effectiveness on corrosion protection was showed by the tested inhibitors packages: e.g. in the 90% HCl at 12% + 10 CH{sub 3}COOH acid blend. In 'spent' acid environments, all steel pipes showed to be less susceptible to the localised and general corrosion attack. Moreover, no Sulphide Stress Corrosion Cracking (SSC) was observed. Only one super-austenitic stainless steel U-bend specimen showed

  1. The resistance of titanium to pitting, microbially induced corrosion and corrosion in unsaturated conditions

    International Nuclear Information System (INIS)

    Shoesmith, D.W.; Ikeda, B.M.

    1997-04-01

    Titanium and its alloys (Grades-2, -12, -16) are candidate materials for Canadian nuclear waste containers on the basis of their apparent immunity to many localized corrosion processes. This simplifies markedly the effort needed to justify the use of these materials and to develop models to predict the lifetimes of containers. Here we review the pitting, microbially influenced corrosion (MIC), and corrosion under unsaturated conditions, of titanium. For all these processes, the properties of the passive oxide film are paramount in determining the metal's resistance to corrosion. A review of these oxide properties is included and the conditions to which the metal must be exposed if localized corrosion is to occur are defined. Since these conditions cannot be achieved under Canadian waste vault conditions, it can be concluded that pitting and MIC will not occur and that corrosion under unsaturated conditions is extremely unlikely. (author)

  2. A study of the diffusion mechanisms in amorphous metallic alloys: diffusion and diffusion under high pressure in an amorphous NiZr alloy

    International Nuclear Information System (INIS)

    Grandjean, A.

    1996-01-01

    The aim of this work is a better understanding of the diffusion mechanism in amorphous metallic alloys. Then interdiffusion and hafnium diffusion in amorphous NiZr alloy have been studied. Samples used are made by sputtering co-deposition under vacuum and are well relaxed before the diffusion measurements. The time evolution of resistivity during annealing due to the decay of a composition modulated film has been measured and from this change in resistivity interdiffusion coefficients have been determined. Dependence of Hf diffusion on temperature and pressure has been studied using (SIMS). In this two cases, the diffusion process obeys an Arrhenius law and gives an activation energy of 1.33 eV for interdiffusion, and 0.76 eV for Hf diffusion. An effect of pressure on Hf diffusion has been found leading to an activation volume of 8.5 angstrom 3 . Thanks to these results, two approaches of the diffusion mechanisms in these systems have been proposed. The first comes from a comparison with the diffusion mechanisms in crystalline metals, that is to say by point defects. The second is an hypothesis of collective motions in these non crystalline alloys. (author)

  3. Study on the corrosion assessment of overpack welds-III (Joint research)

    International Nuclear Information System (INIS)

    Mitsui, Hiroyuki; Takahashi, Rieko; Otsuki, Akiyoshi; Asano, Hidekazu; Taniguchi, Naoki; Yui, Mikazu

    2006-12-01

    There is some possibility that the corrosion resistance of overpack welds is different from that of base metal due to the differences of material properties. In this study, corrosion behavior of welded joint for carbon steel was compared with base metal using the specimens taken from welded joint model fabricated by TIG, MAG and EBW respectively. The corrosion tests were performed for following four items. Passivation behavior and corrosion type. Propagation of general corrosion, pitting corrosion and crevice corrosion under aerobic condition. Stress corrosion cracking susceptibility. Propagation of general corrosion and hydrogen embrittlement under anaerobic condition. The results of these corrosion tests indicated that the corrosion resistance of welded metal by TIG and MAG was inferior to base metal for general corrosion, pitting corrosion and crevice corrosion. It was implied that the filler materials used for welding affected the corrosion resistance. No deterioration of corrosion resistance was observed in any corrosion modes for EBW, which does not need filler material. The susceptibility to stress corrosion cracking of welded metal and heat affected zone was lower than that of base metal. (author)

  4. FY 1998 annual report on the results of new industry creation type industrial science and technology research and development on the research and development of supermetals. Development of techniques for controlling structures of nano-amorphous materials; 1998 nendo super metal no gijutsu kaihatsu. Nano amorphous kozo seigyo zairyo no gijutsu kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    Described herein are the FY 1998 results of the development of techniques for controlling structures of nano-amorphous materials. For the development of techniques for finely dispersing fine particles, mechanical alloying (MA) and mechanical milling (MM) are investigated, to structure nano-crystals in common steel, for which hot isostatic pressing is evaluated as a consolidation process for the MA- and MM-prepared powders in the FY 1998. For researches on high-speed particle deposition and super plastic forming, an Al-Ni, Al-Fe and Al-Ti alloy are selected as the nano-structure materials to be prepared by evaporation, and various compositions of these systems are evaporated, in order to investigate their microstructures, mechanical properties and thermal stabilities. For researches on techniques for controlling phases with the aid of high-density energy, the R and D efforts are directed to exploration of composition of high resistance to corrosion by acid at dew point, preparation of non-equilibrium (e.g., amorphous) powders, and development of solidification and forming techniques, with the target of creation of an amorphous alloy showing corrosion resistance at least twice as high as that of the commercial corrosion-resistance material and formable into a bulk shape having a thickness of at least 1 mm. For researches on controlled cooling techniques, the basic data are collected. (NEDO)

  5. High temperature corrosion in straw-fired power plants: Influence of steam/metal temperature on corrosion rates for TP347H

    DEFF Research Database (Denmark)

    Montgomery, Melanie; Biede, O; Larsen, OH

    2002-01-01

    The corrosion in straw-fired boilers has been investigated at various straw-fired power plants in Denmark. Water/air-cooled probes, a test superheater and test sections removed from the actual superheater have been utilised to characterise corrosion and corrosion rates. This paper describes...... the corrosion rates measured for the TP347H type steel. The corrosion morphology at high temperature consists of grain boundary attack and selective attack of chromium. The corrosion rate increases with calculated metal temperature (based on steam temperature), however there is great variation within....... The difference in the results could be traced back to a lower flue gas temperature on one side of the boiler. Although metal temperature is the most important parameter with respect to corrosion rate, flue gas temperature also plays an important role. Efforts to quantify the effect of flue gas temperature...

  6. Effect of heat treatment conditions on stress corrosion cracking resistance of alloy X-750 in high temperature water

    International Nuclear Information System (INIS)

    Yonezawa, Toshio; Onimura, Kichiro; Sakamoto, Naruo; Sasaguri, Nobuya; Susukida, Hiroshi; Nakata, Hidenori.

    1984-01-01

    In order to improve the resistance of the Alloy X-750 in high temperature and high purity water, the authors investigated the influence of heat treatment condition on the stress corrosion cracking resistance of the alloy. This paper describes results of the stress corrosion cracking test and some discussion on the mechanism of the stress corrosion cracking of Alloy X-750 in deaerated high temperature water. The following results were obtained. (1) The stress corrosion cracking resistance of Alloy X-750 in deaerated high temperature water remarkably depended upon the heat treatment condition. The materials solution heat treated and aged within temperature ranges from 1065 to 1100 0 C and from 704 to 732 0 C, respectively, have a good resistance to the stress corrosion cracking in deaerated high temperature water. Especially, water cooling after the solution heat treatment gives an excellent resistance to the stress corrosion cracking in deaerated high temperature water. (2) Any correlations were not observed between the stress corrosion cracking susceptibility of Alloy X-750 in deaerated high temperature water and grain boundary chromium depleted zones, precipitate free zones and the grain boundary segregation of impurity elements and so on. It appears that there are good correlations between the stress corrosion cracking resistance of the alloy in the environment and the kinds, morphology and coherency of precipitates along the grain boundaries. (author)

  7. Corrosion Resistant Coatings for High Temperature Applications

    Energy Technology Data Exchange (ETDEWEB)

    Besman, T.M.; Cooley, K.M.; Haynes, J.A.; Lee, W.Y.; Vaubert, V.M.

    1998-12-01

    Efforts to increase efficiency of energy conversion devices have required their operation at ever higher temperatures. This will force the substitution of higher-temperature structural ceramics for lower temperature materials, largely metals. Yet, many of these ceramics will require protection from high temperature corrosion caused by combustion gases, atmospheric contaminants, or the operating medium. This paper discusses examples of the initial development of such coatings and materials for potential application in combustion, aluminum smelting, and other harsh environments.

  8. Corrosion resistance of Ni-50Cr HVOF coatings on 310S alloy substrates in a metal dusting atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Saaedi, J. [Centre for Advanced Coating Technologies, Department of Materials Science and Engineering, University of Toronto, 184 College Street, Toronto, Ontario M5S 3E4 (Canada); Department of Materials and Metallurgical Engineering, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of); Arabi, H.; Mirdamadi, S.; Ghorbani, H. [Department of Materials and Metallurgical Engineering, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of); Coyle, T.W. [Centre for Advanced Coating Technologies, Department of Materials Science and Engineering, University of Toronto, 184 College Street, Toronto, Ontario M5S 3E4 (Canada)

    2011-09-15

    Metal dusting attack has been examined after three 168 h cycles on two Ni-50Cr coatings with different microstructures deposited on 310S alloy substrates by the high velocity oxy-fuel (HVOF) thermal-spray process. Metal dusting in uncoated 310S alloy specimens was found to be still in the initiation stage after 504 h of exposure in the 50H{sub 2}:50CO gas environment at 620 C. Dense Ni-50Cr coatings offered suitable resistance to metal dusting. Metal dusting was observed in the 310S substrates adjacent to pores at the interface between the substrate and a porous Ni-50Cr coating. The porosity present in the as-deposited coatings was shown to introduce a large variability into coating performance. Carbon formed by decomposition of the gaseous species accumulated in the surface pores and resulted in the dislodgement of surface splats due to stresses generated by the volume changes. When the corrosive gas atmosphere was able to penetrate through the interconnected pores and reach the coating-substrate interface, the 310S substrate was carburized, metal dusting attack occurred, and the resulting formation of coke in the pores led to local failure of the coating. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. High temperature corrosion of thermally sprayed NiCr- and amorphous Fe-based coatings covered with a KCl-K{sub 2}SO{sub 4} salt

    Energy Technology Data Exchange (ETDEWEB)

    Varis, T.; Suhonen, T.; Tuurna, S.; Ruusuvuori, K.; Holmstroem, S.; Salonen, J. [VTT, Espoo (Finland); Bankiewicz, D.; Yrjas, P. [Aabo Akademi Univ., Turku (Finland)

    2010-07-01

    New process conditions due to the requirement of higher efficiency together with the use of high-chlorine and alkali containing fuels such as biomass and waste fuels for heat and electricity production will challenge the resistance and life of tube materials. In conventional materials the addition of alloying elements to increase the corrosion resistance in aggressive combustion conditions increases costs relatively rapidly. Thermally sprayed coating offer promising, effective, flexible and cost efficient solutions to fulfill the material needs for the future. Some heat exchanger design alteractions before global commercialization have to be overcome, though. High temperature corrosion in combustion plants can occur by a variety of mechanisms including passive scale degradation with subsequent rapid scaling, loss of adhesion and scale detachment, attack by melted or partly melted deposits via fluxing reactions and intergranular-/interlamellar corrosion. A generally accepted model of the ''active oxidation'' attributes the responsibility for inducing corrosion to chlorine. The active oxidation mechanism plays a key role in the thermally sprayed coatings due to their unique lamellar structure. In this study, the corrosion behaviour of NiCr (HVOF and Wire Arc), amorphous Fe-based, and Fe13Cr (Wire Arc) thermally sprayed coatings, were tested in the laboratory under simplified biomass combustion conditions. The tests were carried out by using a KCl-K{sub 2}SO{sub 4} salt mixture as a synthetic biomass ash, which was placed on the materials and then heat treated for one week (168h) at two different temperatures (550{sup 0}C and 600 C) and in two different gas atmospheres (air and air+30%H{sub 2}O). After the exposures, the metallographic cross sections of the coatings were studied with SEM/EDX analyzer. The results showed that the coatings behaved relatively well at the lower test temperature while critical corrosion through the lamella boundaries

  10. Nanocontainer-Enhanced Self-Healing for Corrosion-Resistant Ni Coating on Mg Alloy.

    Science.gov (United States)

    Xie, Zhi-Hui; Li, Dan; Skeete, Zakiya; Sharma, Anju; Zhong, Chuan-Jian

    2017-10-18

    The ability to manipulate the functionalization of Ni coating is of great importance in improving the corrosion resistance of magnesium (Mg) alloy for many industrial applications. In the present work, MCM-41 type mesoporous silica nanocontainers (MSNs) loaded with corrosion inhibitor (NaF) were synthesized and employed as smart reinforcements to enhance the integrity and corrosion inhibition of the Ni coating. The incorporation of the F-loaded MSNs (F@MSNs) to enhance the corrosion resistant capacity of a metallic coating is reported for the first time. The mesoporous structures of the as-prepared MSNs and F@MSNs were confirmed by transmission electron microscopy (TEM), small angle X-rays scattering (SAXS), and N 2 adsorption-desorption isotherms. The X-ray photoelectron spectroscopy (XPS) data demonstrated the successful immobilization of fluoride ion on the MSNs and formation of a magnesium fluoride (MgF 2 ) protective film at the corrosion sites of the Mg alloy upon soaking in a F@MSNs-containing NaCl solution. The results from potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) for both bare Mg alloy and Ni coatings with and without F@MSNs have revealed a clear decrease in corrosion rate in a corrosive solution for a long-time immersion due to the introduction of F@MSNs. These findings open new opportunities in the exploration of self-healing metallic coatings for highly enhanced anticorrosion protection of Mg alloy.

  11. Development of high-performance concrete having high resistance to chloride penetration

    International Nuclear Information System (INIS)

    Oh, Byung Hwan; Cha, Soo Won; Jang, Bong Seok; Jang, Seung Yup

    2002-01-01

    The resistance to chloride penetration is one of the simplest measures to determine the durability of concrete, e.g. resistance to freezing and thawing, corrosion of steel in concrete and other chemical attacks. Thus, high-performance concrete may be defined as the concrete having high resistance to chloride penetration as well as high strength. The purpose of this paper is to investigate the resistance to chloride penetration of different types of concrete and to develop high-performance concrete that has very high resistance to chloride penetration, and thus, can guarantee high durability. A large number of concrete specimens have been tested by the rapid chloride permeability test method as designated in AASHTO T 277 and ASTM C 1202. The major test variables include water-to-binder ratios, type of cement, type and amount of mineral admixtures (silica fume, fly ash and blast-furnace slag), maximum size of aggregates and air-entrainment. Test results show that concrete containing optimal amount of silica fume shows very high resistance to chloride penetration, and high-performance concrete developed in this study can be efficiently employed to enhance the durability of concrete structures in severe environments such as nuclear power plants, water-retaining structures and other offshore structures

  12. Neutron irradiation and high temperature effects on amorphous Fe-based nano-coatings on steel - A macroscopic assessment

    Science.gov (United States)

    Simos, N.; Zhong, Z.; Dooryhee, E.; Ghose, S.; Gill, S.; Camino, F.; Şavklıyıldız, İ.; Akdoğan, E. K.

    2017-06-01

    The study revealed that loss of ductility in an amorphous Fe-alloy coating on a steel substrate composite structure was essentially prevented from occurring, following radiation with modest neutron doses of ∼2 × 1018 n/cm2. At the higher neutron dose of ∼2 × 1019, macroscopic stress-strain analysis showed that the amorphous Fe-alloy nanostructured coating, while still amorphous, experienced radiation-induced embrittlement, no longer offering protection against ductility loss in the coating-substrate composite structure. Neutron irradiation in a corrosive environment revealed exemplary oxidation/corrosion resistance of the amorphous Fe-alloy coating, which is attributed to the formation of the Fe2B phase in the coating. To establish the impact of elevated temperatures on the amorphous-to-crystalline transition in the amorphous Fe-alloy, electron microscopy was carried out which confirmed the radiation-induced suppression of crystallization in the amorphous Fe-alloy nanostructured coating.

  13. A study on heat resistance of high temperature resistant coating

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Liping; Wang, Xueying; Zhang, Qibin; Qin, Yanlong; Lin, Zhu [Research Institute of Engineering Technology of CNPC, Tianjin (China)

    2005-04-15

    A high temperature resistant coating has been developed, which is mainly for heavy oil production pipes deserved the serious corrosion. The coating has excellent physical and mechanical performance and corrosion resistance at room and high temperature. In order to simulate the underground working condition of heavy oil pipes,the heat resistance of the high temperature resistant coating has been studied. The development and a study on the heat resistance of the DHT high temperature resistance coating have been introduced in this paper

  14. A study on heat resistance of high temperature resistant coating

    International Nuclear Information System (INIS)

    Zhang, Liping; Wang, Xueying; Zhang, Qibin; Qin, Yanlong; Lin, Zhu

    2005-01-01

    A high temperature resistant coating has been developed, which is mainly for heavy oil production pipes deserved the serious corrosion. The coating has excellent physical and mechanical performance and corrosion resistance at room and high temperature. In order to simulate the underground working condition of heavy oil pipes,the heat resistance of the high temperature resistant coating has been studied. The development and a study on the heat resistance of the DHT high temperature resistance coating have been introduced in this paper

  15. Long-term research in Japan: amorphous metals, metal oxide varistors, high-power semiconductors and superconducting generators

    Energy Technology Data Exchange (ETDEWEB)

    Hane, G.J.; Yorozu, M.; Sogabe, T.; Suzuki, S.

    1985-04-01

    The review revealed that significant activity is under way in the research of amorphous metals, but that little fundamental work is being pursued on metal oxide varistors and high-power semiconductors. Also, the investigation of long-term research program plans for superconducting generators reveals that activity is at a low level, pending the recommendations of a study currently being conducted through Japan's Central Electric Power Council.

  16. NATO Advanced Study Institute on Hydrogen in Disordered and Amorphous Solids

    CERN Document Server

    Bowman, Robert

    1986-01-01

    This is the second volume in the NATO ASI series dealing with the topic of hydrogen in solids. The first (V. B76, Metal Hydrides) appeared five years ago and focussed primarily on crystalline phases of hydrided metallic systems. In the intervening period, the amorphous solid state has become an area of intense research activity, encompassing both metallic and non-metallic, e.g. semiconducting, systems. At the same time the problem of storage of hydrogen, which motivated the first ASI, continues to be important. In the case of metallic systems, there were early indications that metallic glasses and disordered alloys may be more corrosion resistant, less susceptible to embrittlement by hydrogen and have a higher hydrogen mobility than ordered metals or intermetallics. All of these properties are desirable for hydrogen storage. Subsequent research has shown that thermodynamic instability is a severe problem in many amorphous metal hydrides. The present ASI has provided an appropriate forum to focus on these issu...

  17. Studies on Fusion Welding of High Nitrogen Stainless Steel: Microstructure, Mechanical and corrosion Behaviour

    Science.gov (United States)

    Mohammed, Raffi; Srinivasa Rao, K.; Madhusudhan Reddy, G.

    2018-03-01

    An attempt has been made in the present investigation to weld high nitrogen steel of 5mm thick plates using various process i.e., shielded metal arc welding (SMAW), gas tungsten arc welding (GTAW) and autogenous electron beam welding (EBW) process. Present work is aimed at studying the microstructural changes and its effects on mechanical properties and corrosion resistance. Microstructure is characterized by optical, scanning electron microscopy and electron back scattered diffraction technique. Vickers hardness, tensile properties, impact toughness and face bend ductility testing of the welds was carried out. Pitting corrosion resistance of welds was determined using potentio-dynamic polarization testing in 3.5%NaCl solution. Results of the present investigation established that SMA welds made using Cr-Mn-N electrode were observed to have a austenite dendritic grain structure in the weld metal and is having poor mechanical properties but good corrosion resistance. GTA welds made using 18Ni (MDN 250) filler wire were observed to have a reverted austenite in martensite matrix of the weld metal and formation of unmixed zone at the fusion boundary which resulted in better mechanical properties and poor corrosion resistance. Fine grains and uniform distribution of delta ferrite in the austenite matrix and narrow width of weld zone are observed in autogeneous electron beam welds. A good combination of mechanical properties and corrosion resistance was achieved for electron beam welds of high nitrogen steel when compared to SMA and GTA welds.

  18. Corrosion of high temperature resisting alloys exposed to heavy fuel ash; Corrosion de aleaciones resistentes a altas temperaturas expuestas a ceniza de combustoleo pesado

    Energy Technology Data Exchange (ETDEWEB)

    Wong Moreno, Adriana del Carmen

    1998-03-01

    The objective of the performed research was to study the degradation process by high temperature corrosion of alloys exposed to heavy fuel oil ashes through a comparative experimental evaluation of its performance that allowed to establish the mechanisms involved in the phenomenon. The experimentation carried out involved the determination of the resistance to the corrosion of 14 alloys of different type (low and medium alloy steels, ferritic and austenitic stainless steels, nickel base alloys and a FeCrAl alloy of type ODS) exposed to high temperatures (580 Celsius degrees - 900 Celsius degrees) in 15 ash deposits with different corrosive potential, which were collected in the high temperature zone of boilers of thermoelectric power stations. The later studies to the corrosion tests consisted of the analysis by sweeping electron microscopy supported by microanalysis of the corroded probes, with the purpose of determining the effect of Na, V and S on the corrosivity of the ash deposits and the effect of the main alloying elements on the corrosion resistance of the alloys. Such effects are widely documented to support the proposed mechanisms of degradation that are occurring. The global analysis of the generated results has allowed to propose a model to explain the global mechanism of corrosion of alloys exposed to the high temperatures of ash deposits. The proposed model, complements the processed one by Wilson, widely accepted for fused vanadates, as far as on one hand, it considers the effect of the sodium sulfate presence (in addition to the vanadium compounds) in the deposits, and on the other hand, it extends it to temperatures higher than the point of fusion of constituent vanadium compounds of the deposits. Both aspects involve considering the roll that the process of diffusion of species has on the degradation and the capacity of protection of the alloy. The research performed allowed to confirm what the Wilson model had established for deposits with high

  19. Salt Fog Testing Iron-Based Amorphous Alloys

    International Nuclear Information System (INIS)

    Rebak, Raul B.; Aprigliano, Louis F.; Day, S. Daniel; Farmer, Joseph C.

    2007-01-01

    Iron-based amorphous alloys are hard and highly corrosion resistant, which make them desirable for salt water and other applications. These alloys can be produced as powder and can be deposited as coatings on any surface that needs to be protected from the environment. It was of interest to examine the behavior of these amorphous alloys in the standard salt-fog testing ASTM B 117. Three different amorphous coating compositions were deposited on 316L SS coupons and exposed for many cycles of the salt fog test. Other common engineering alloys such as 1018 carbon steel, 316L SS and Hastelloy C-22 were also tested together with the amorphous coatings. Results show that amorphous coatings are resistant to rusting in salt fog. Partial devitrification may be responsible for isolated rust spots in one of the coatings. (authors)

  20. Production of amorphous metal layers using ion implantation and investigation of the related modification of some surface properties

    International Nuclear Information System (INIS)

    Hoang Dac Luc; Vu Hoang Lam.

    1993-01-01

    Amorphous layers were produced by implanting B + ions into Al at 50 keV. The modification of the electrochemical corrosion resistance and the mechanical strength of implanted specimen was investigated. (author). 2 refs, 1 tab, 2 figs

  1. Composite plasma electrolytic oxidation to improve the thermal radiation performance and corrosion resistance on an Al substrate

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Donghyun [Department of Materials Science and Engineering, Pusan National University, Busan 46241 (Korea, Republic of); Sung, Dahye [Department of Materials Science and Engineering, Pusan National University, Busan 46241 (Korea, Republic of); Korea Institute of Industrial Technology (KITECH), Busan 46742 (Korea, Republic of); Lee, Junghoon [Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, NJ 07030 (United States); Kim, Yonghwan [Korea Institute of Industrial Technology (KITECH), Busan 46742 (Korea, Republic of); Chung, Wonsub, E-mail: wschung1@pusan.ac.kr [Department of Materials Science and Engineering, Pusan National University, Busan 46241 (Korea, Republic of)

    2015-12-01

    Highlights: • Composite plasma electrolytic oxidation was performed using dispersed CuO particles in convectional PEO electrolyte. • Thermal radiation performance and corrosion resistance were examined by FT-IR spectroscopy and electrochemical methods, respectively. • Deposited copper oxide on the surface of the Al substrate was enhanced the corrosion resistance and the emissivity compared with the conventional PEO. - Abstract: A composite plasma electrolytic oxidation (PEO) was performed for enhancing the thermal radiation performance and corrosion resistance on an Al alloy by dispersing cupric oxide (CuO) particles in a conventional PEO electrolyte. Cu-based oxides (CuO and Cu{sub 2}O) formed by composite PEO increased the emissivity of the substrate to 0.892, and made the surface being dark color, similar to a black body, i.e., an ideal radiator. In addition, the corrosion resistance was analyzed using potentio-dynamic polarization and electrochemical impedance spectroscopy tests in 3.5 wt.% NaCl aqueous solution. An optimum condition of 10 ampere per square decimeter (ASD) current density and 30 min processing time produced appropriate surface morphologies and coating thicknesses, as well as dense Cu- and Al-based oxides that constituted the coating layers.

  2. The role of aluminum distribution on the local corrosion resistance of the microstructure in a sand-cast AM50 alloy

    International Nuclear Information System (INIS)

    Danaie, Mohsen; Asmussen, Robert Matthew; Jakupi, Pellumb; Shoesmith, David W.; Botton, Gianluigi A.

    2013-01-01

    Highlights: •Site-specific analytical electron microscopy was performed on corroded AM50. •Areas close to eutectic microstructure show less corrosion damage. •Eutectic Mg grains develop an Al-rich layer between the alloy and corrosion product. •We demonstrate, using low-loss EELS, that the Al-rich layer is metallic in character. •Primary α-Mg grains, with lower Al content, do not develop the Al-rich layer and corrode severely. -- Abstract: Site-specific analytical electron microscopy was performed on a corroded sand-cast AM50 alloy. Areas close to partially divorced eutectic were the regions with less corrosion damage. The corrosion product layer in these areas consisted of a columnar section of predominantly amorphous MgO. At the alloy interface, an aluminum-rich layer was identified. Electron energy-loss spectroscopy suggests this layer is metallic in character. The corrosion product film on the primary α-Mg grains possessed a bi-layer morphology: a thin columnar film and a thicker, porous sub-layer. The formation of the Al-rich layer depends on the Al content in solid solution at a specific location

  3. Relaxation processes during amorphous metal alloys heating

    International Nuclear Information System (INIS)

    Malinochka, E.Ya.; Durachenko, A.M.; Borisov, V.T.

    1982-01-01

    Behaviour of Te+15 at.%Ge and Fe+13 at.%P+7 at.%C amorphous metal alloys during heating has been studied using the method of differential scanning calorimetry (DSC) as the most convenient one for determination of the value of heat effects, activation energies, temperature ranges of relaxation processes. Thermal effects corresponding to high-temperature relaxation processes taking place during amorphous metal alloys (AMA) heating are detected. The change of ratio of relaxation peaks values on DSC curves as a result of AMA heat treatment can be explained by the presence of a number of levels of inner energy in amorphous system, separated with potential barriers, the heights of which correspond to certain activation energies of relaxation processes

  4. Enhanced thermoelectric performance of amorphous Nb based oxynitrides

    Science.gov (United States)

    Music, Denis; Geyer, Richard W.; Hans, Marcus

    2015-12-01

    Using density functional theory, amorphous Nb0.27Ru0.06O0.56N0.10 was designed to facilitate a combination of an enhanced Seebeck coefficient and low electrical resistivity. Based on a positive Cauchy pressure, ductile behavior is expected. To verify these predictions, the transport and mechanical properties of amorphous thin films were evaluated. Metallic electrical resistivity and the Seebeck coefficient of -94 μV K-1 are obtained, which is consistent with our predictions. As there is no crack formation, these samples can be perceived as ductile. We demonstrate that the power factor can be increased by an order of magnitude, while keeping the thermal fatigue low.

  5. Transition metal carbide nanocomposite and amorphous thin films

    OpenAIRE

    Tengstrand, Olof

    2014-01-01

    This thesis explores thin films of binary and ternary transition metal carbides, in the Nb-C, Ti-Si-C, Nb-Si-C, Zr-Si-C, and Nb-Ge-C systems. The electrical and mechanical properties of these systems are affected by their structure and here both nanocomposite and amorphous thin films are thus investigated. By appropriate choice of transition metal and composition the films can be designed to be multifunctional with a combination of properties, such as low electric resistivity, low contact res...

  6. Metallic glasses: viable tool materials for the production of surface microstructures in amorphous polymers by micro-hot-embossing

    International Nuclear Information System (INIS)

    Henann, David L; Srivastava, Vikas; Taylor, Hayden K; Hale, Melinda R; Hardt, David E; Anand, Lallit

    2009-01-01

    Metallic glasses possess unique mechanical properties which make them attractive materials for fabricating components for a variety of applications. For example, the commercial Zr-based metallic glasses possess high tensile strengths (≈2.0 GPa), good fracture toughnesses (≈10–50 MPa√m) and good wear and corrosion resistances. A particularly important characteristic of metallic glasses is their intrinsic homogeneity to the nanoscale because of the absence of grain boundaries. This characteristic, coupled with their unique mechanical properties, makes them ideal materials for fabricating micron-scale components, or high-aspect-ratio micro-patterned surfaces, which may in turn be used as dies for the hot-embossing of polymeric microfluidic devices. In this paper we consider a commercially available Zr-based metallic glass which has a glass transition temperature of T g ≈ 350 °C and describe the thermoplastic forming of a tool made from this material, which has the (negative) microchannel pattern for a simple microfluidic device. This tool was successfully used to produce the microchannel pattern by micro-hot-embossing of the amorphous polymers poly(methyl methacrylate) (T g ≈ 115 °C) and Zeonex-690R (T g ≈ 136 °C) above their glass transition temperatures. The metallic glass tool was found to be very robust, and it was used to produce hundreds of high-fidelity micron-scale embossed patterns without degradation or failure

  7. Specification for corrosion-resisting chromium and chromium-nickel steel covered welding electrodes

    International Nuclear Information System (INIS)

    Anon.

    1983-01-01

    This specification prescribes requirements for covered corrosion-resisting chromium and chromium-nickel steel electrodes. These electrodes normally are used for shielded metal arc welding, and include those alloy steels designated as corrosion or heat-resisting chromium-nickel steels in which chromium exceeds 4.0 percent and nickel does not exceed 50.0 percent

  8. Specification for corrosion-resisting chromium and chromium-nickel steel covered welding electrodes

    International Nuclear Information System (INIS)

    Anon.

    1981-01-01

    This specification prescribes requirements for covered corrosion-resisting chromium and chromium-nickel steel electrodes. These electrodes are normally used for shielded metal arc welding, and include those alloy steels designated as corrosion or heat-resisting chromium and chromium-nickel steels, in which chromium exceeds 4.0% and nickel does not exceed 50.0%

  9. Effect of heat treatment on the grooving corrosion resistance of ERW pipes

    International Nuclear Information System (INIS)

    Lee, Jong Kwon; Lee, Jae Young; Lim, Soo Hyun; Park, Ji Hwan; Seo, Bo Min; Kim, Seon Hwa

    2002-01-01

    The v-sharp grooving corrosion of ERW(electrical resistance welding) steel pipes limited their wide application in the industry in spite of their high productivity and efficiency. The grooving corrosion is caused mainly by the different microstructures between the matrix and weld that is formed during the rapid heating and cooling cycle in welding. By this localized corrosion reaction of pipes, it evolves economic problems such as the early damage of industrial facilities and pipe lines of apartment, and water pollution. Even though the diminishing of sulfur content is most effective to decrease the susceptibility of grooving corrosion, it requires costly process. In this study, improvement of grooving corrosion resistance was pursuited by post weld heat treatment in the temperature range between 650 .deg. C and 950 .deg. C. Also, the effect of heat input in the welding was investigated. By employing chromnoamperometry and potentiodynamic experiment, the corrosion rate and grooving corrosion index(α) were obtained. It was found that heat treatment could improve the grooving corrosion resistance. Among them, the heat treated at 900 .deg. C and 950 .deg. C had excellent grooving corrosion resistance. The index of heat treated specimen at 900 .deg. C and 950 .deg. C were 1.0, 1.2, respectively, which are almost immune to the grooving corrosion. Potential difference after the heat treatment, between base and weld metal was decreased considerably. While the as-received one measured 61∼71 mV, that of the 900 .deg. C heat treated steel pipe measured only 10mV. The results were explained and discussed

  10. Microstructure, microhardness and corrosion resistance of remelted TiG2 and Ti6Al4V by a high power diode laser

    International Nuclear Information System (INIS)

    Amaya-Vazquez, M.R.; Sánchez-Amaya, J.M.; Boukha, Z.; Botana, F.J.

    2012-01-01

    Highlights: ► Laser remelting of TiG2 and Ti6Al4V is performed with argon shielded diode laser. ► Microstructure, microhardness and corrosion of remelted samples are deeply analysed. ► Microstructural changes of laser remelted TiG2 lead to microhardness increase. ► Remelted Ti6Al4V presents microhardness increase and corrosion improvement. ► Martensite depth in remelted Ti6Al4V is linearly proportional to laser fluence. - Abstract: The high strength, low density and superior corrosion resistance allow titanium alloys to be widely employed in different industrial applications. The properties of these alloys can be modulated by different heat treatments, including laser processing. In the present paper, laser remelting treatments, performed with a high power diode laser, were applied to samples of two titanium alloys (TiG2 and Ti6Al4V). The influence of the applied laser fluence on microstructure, microhardness and corrosion resistance is investigated. Results show that laser remelting treatments with appropriate fluences provoke microstructural changes leading to microhardness increase and corrosion resistance improvement.

  11. Neutron irradiation and high temperature effects on amorphous Fe-based nano-coatings on steel – A macroscopic assessment

    International Nuclear Information System (INIS)

    Simos, N.; Zhong, Z.; Dooryhee, E.; Ghose, S.; Gill, S.

    2017-01-01

    Here, this study revealed that loss of ductility in an amorphous Fe-alloy coating on a steel substrate composite structure was essentially prevented from occurring, following radiation with modest neutron doses of ~2 x 10 18 n/cm 2 . At the higher neutron dose of ~2 x 10 19 , macroscopic stress-strain analysis showed that the amorphous Fe-alloy nanostructured coating, while still amorphous, experienced radiation-induced embrittlement, no longer offering protection against ductility loss in the coating-substrate composite structure. Neutron irradiation in a corrosive environment revealed exemplary oxidation/corrosion resistance of the amorphous Fe-alloy coating, which is attributed to the formation of the Fe 2 B phase in the coating. To establish the impact of elevated temperatures on the amorphous-to-crystalline transition in the amorphous Fe-alloy, electron microscopy was carried out which confirmed the radiation-induced suppression of crystallization in the amorphous Fe-alloy nanostructured coating.

  12. Mechanical and corrosion behaviors of developed copper-based metal matrix composites

    Science.gov (United States)

    Singh, Manvandra Kumar; Gautam, Rakesh Kumar; Prakash, Rajiv; Ji, Gopal

    2018-03-01

    This work investigates mechanical properties and corrosion resistances of cast copper-tungsten carbide (WC) metal matrix composites (MMCs). Copper matrix composites have been developed by stir casting technique. Different sizes of micro and nano particles of WC particles are utilized as reinforcement to prepare two copper-based composites, however, nano size of WC particles are prepared by high-energy ball milling. XRD (X-rays diffraction) characterize the materials for involvement of different phases. The mechanical behavior of composites has been studied by Vickers hardness test and compression test; while the corrosion behavior of developed composites is investigated by electrochemical impedance spectroscopy in 0.5 M H2SO4 solutions. The results show that hardness, compressive strength and corrosion resistance of copper matrix composites are very high in comparison to that of copper matrix, which attributed to the microstructural changes occurred during composite formation. SEM (Scanning electron microscopy) reveals the morphology of the corroded surfaces.

  13. Effects of laser polishing on surface microstructure and corrosion resistance of additive manufactured CoCr alloys

    Science.gov (United States)

    Wang, W. J.; Yung, K. C.; Choy, H. S.; Xiao, T. Y.; Cai, Z. X.

    2018-06-01

    Laser polishing of 3D printed metal components has drawn great interest in view of its potential applications in the dental implant industries. In this study, corrosion resistance, surface composition and crystalline structure of CoCr alloys were investigated. The corrosion resistance, micromorphology, composition, phase transformations and crystalline structures of samples were characterized using an electrochemical analyzer, scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and transmission electron microscope (TEM), respectively. The results indicate that high laser powers and low object distances within a certain range can facilitate the formation of complex oxide films, which exhibits high corrosion resistance. Further, object distances have a significant influence on cooling rates during the solidification of the melt pool in laser polishing, and fast cooling generates vast amounts of vacancies and defects, which result in the crystalline phase transformation from γ to ε. Consequently, the formed oxides play an important role in corrosion resistance on the outer layer, and inner layer with γ phase also helps keep the CoCr alloys in a stable structure with high resistant to corrosion. The two process parameters in laser polishing, laser power and object distances, are demonstrated as being important for controlling the surface microstructures and corrosion resistance of the additive manufactured CoCr alloy components.

  14. Electrical resistivity of amorphous Fesub(1-x) Bsub(x) alloys

    International Nuclear Information System (INIS)

    Paja, A.; Stobiecki, T.

    1984-07-01

    The concentration dependence of the electrical resistivity of amorphous Fesub(1-x) Bsub(x) alloys has been studied over a broad composition range. The measurements for RF sputtered films made in the liquid helium temperature have been analyzed in the framework of the diffraction model. The calculated results are in good agreement with the experimental data in the range of concentration 0.12< x <0.37 where samples are amorphous and have a metallic character. (author)

  15. Corrosion-resistant powder-metallurgy stainless steel powders and compacts therefrom

    International Nuclear Information System (INIS)

    Klar, E.; Ro, D.H.; Whitman, C.I.

    1980-01-01

    Disclosed is a process for improving the corrosion resistance of a stainless steel powder or compact thereof wherein the powder is produced by atomizing a melt of metals in an oxidizing environment whereby the resulting stainless steel powder is surface-enriched in silicon oxides. The process comprises adding an effective proportion of modifier metal to the melt prior to the atomization, the modifier metal selected from the group consisting of tin, aluminum, lead, zinc, magnesium, rare earth metals and like metals capable of enrichment about the surface of the resulting atomized stainless steel powder and effective under reductive sintering conditions in the depletion of the silicon oxides about the surface; and sintering the resulting atomized powder or a compact thereof under reducing conditions, the sintered powder or compact thereof being depleted in the silicon oxides and the corrosion resistance of the powder or compact thereof being improved thereby

  16. Ion implanting ferrous metals to improve corrosion resistance

    International Nuclear Information System (INIS)

    Dearnaley, G.; Goode, P.D.

    1981-01-01

    A process is described for the treatment of a surface of a ferrous article to improve its corrosion resistance, wherein the surface is subjected to ion bombardment at a temperature above one hundred degrees centigrade in an evacuated enclosure which contains a residual quantity of gaseous oxygen. (author)

  17. Structure adhesion and corrosion resistance study of tungsten bisulfide doped with titanium deposited by DC magnetron co-sputtering

    Energy Technology Data Exchange (ETDEWEB)

    De La Roche, J. [Laboratorio de Física del Plasma, Universidad Nacional de Colombia Sede Manizales, Km. 9 vía al aeropuerto, Campus La Nubia, Manizales (Colombia); González, J.M. [Laboratorio de Recubrimientos Duros y Aplicaciones Industriales – RDAI, Universidad del Valle, Calle 13 N° 100-00 Ciudadela Meléndez, Cali (Colombia); Restrepo-Parra, E., E-mail: erestrepop@unal.edu.co [Laboratorio de Física del Plasma, Universidad Nacional de Colombia Sede Manizales, Km. 9 vía al aeropuerto, Campus La Nubia, Manizales (Colombia); Sequeda, F. [Laboratorio de Recubrimientos Duros y Aplicaciones Industriales – RDAI, Universidad del Valle, Calle 13 N° 100-00 Ciudadela Meléndez, Cali (Colombia); Alleh, V.; Scharf, T.W. [The University of North Texas, Department of Materials Science and Engineering, Denton, TX 76203 (United States)

    2014-11-30

    Highlights: • Ti-doped WS{sub 2} films were grown via the magnetron co-sputtering technique. • At a high Ti percentage, the crystalline structure of WS{sub 2} coatings tends to be amorphous. • As the Ti percentage increases in WS{sub 2} coatings, nanocomposites tend to form. • Ti-doped WS{sub 2} films have elastic behavior compared with the plastic response of pure WS{sub 2} films. • A high Ti percentage increases the corrosion resistance of WS{sub 2} films. - Abstract: Titanium-doped tungsten bisulfide thin films (WS{sub 2}-Ti) were grown using a DC magnetron co-sputtering technique on AISI 304 stainless steel and silicon substrates. The films were produced by varying the Ti cathode power from 0 to 25 W. Using energy dispersive spectroscopy (EDS), the concentration of Ti in the WS{sub 2} was determined, and a maximum of 10% was obtained for the sample grown at 25 W. Moreover, the S/W ratio was calculated and determined to increase as a function of the Ti cathode power. According to transmission electron microscopy (TEM) results, at high titanium concentrations (greater than 6%), nanocomposite formation was observed, with nanocrystals of Ti embedded in an amorphous matrix of WS{sub 2}. Using the scratch test, the coatings’ adhesion was analyzed, and it was observed that as the Ti percentage was increased, the critical load (Lc) also increased. Furthermore, the failure type changed from plastic to elastic. Finally, the corrosion resistance was evaluated using the electrochemical impedance spectroscopy (EIS) technique, and it was observed that at high Ti concentrations, the corrosion resistance was improved, as Ti facilitates coating densification and generates a protective layer.

  18. Specification for corrosion-resisting chromium and chromium-nickel steel covered welding electrodes

    International Nuclear Information System (INIS)

    Anon.

    1981-01-01

    This specification prescribes requirements for covered corrosion-resisting chromium and chromium-nickel steel electrodes. These electrodes are normally used for shielded metal arc welding, and include those alloy steels designated as corrosion or heat-resisting chromium and chromium-nickel steels, in which chromium exceeds 4.0 percent and nickel does not exceed 50.0 percent

  19. Corrosion behavior of Nb-based and Mo-based super heat-resisting alloys in liquid Li

    International Nuclear Information System (INIS)

    Saito, J.; Kano, S.; Morinaga, M.

    1998-07-01

    Research on structural materials which will be utilized even in the severe environment of high-temperature liquid alkali metals has been promoted in order to develop the frontiers of materials techniques. The super-heat resisting alloys which are based on refractory metals, Nb and Mo, are aimed as promising materials used in such an environment. The corrosion resistance in liquid Li and the mechanical properties such as creep and tensile strengths at high temperatures are important for these structural materials. On the basis of many experiments and analyses of these properties at 1473 K, the material design of Nb-based and Mo-based alloys has been carried out successfully. In this report, all the previous experimental results of corrosion tests in liquid Li were summarized systematically for Nb-based and Mo-based alloys. The corrosion mechanism was proposed on the basis of a series of analyses, in particular, focussing on the deposition mechanism of corrosion products on the surface and also on the initiation and growth mechanism of cracks on the corroded surface of Nb-based alloys. The principal results are as follows. (1) For the deposition mechanism, a reaction took place first between dissolved metallic elements and nitrogen which existed as an impurity in liquid Li and then corrosion products (nitrides) precipitated on the metal surface. Subsequently, another reaction took place between dissolved metallic elements in liquid Li, and corrosion products (intermetallic compounds) precipitated on the metal surface. The composition of deposited corrosion products could be predicted on the basis of the deposition mechanism. (2) For the crack initiation mechanism, the chemical potential diagrams were utilized in order to understand the formation of Li-M-O ternary oxides which caused cracks to be formed on the corroded surface. Consequently, it was evident that not only the concentration of the dissolved oxygen in the alloy but also the concentration of Li which

  20. KTA 625 alloy tube with excellent corrosion resistance and heat resistance

    International Nuclear Information System (INIS)

    Fujiwara, Kazuo; Kadonaga, Toshiki; Kikuma, Seiji.

    1982-01-01

    The problems when seamless tubes are produced by using nickel base 625 alloy (61Ni-22Cr-9Mo-Cb) which is known as a corrosion resistant and heat resistant alloyF were examined, and the confirmation experiment was carried out on its corrosion resistance and heat resistance. Various difficulties have been experienced in the tube making owing to the characteristics due to the chemical composition, but they were able to be solved by the repeated experiments. As for the characteristics of the product, the corrosion resistance was excellent particularly in the environment containing high temperature, high concentration chloride, and also the heat resistance was excellent in the wide temperature range from normal temperature to 1000 deg C. From these facts, the wide fields of application are expected for these alloy tubes, including the evaporation and concentration equipment for radioactive wastes in atomic energy field. Expecting the increase of demand hereafter, Kobe Steel Ltd. examined the problems when seamless tubes are produced from the 625 alloy by Ugine Sejournet process. The aptitude for tube production such as the chemical composition, production process and the product characteristics, the corrosion resistance against chloride, hydrogen sulfide, polythionic and other acids,F the high temperature strength and oxidation resistance are reported. (Kako, I.)

  1. Alloy SCR-3 resistant to stress corrosion cracking

    International Nuclear Information System (INIS)

    Kowaka, Masamichi; Fujikawa, Hisao; Kobayashi, Taiki

    1977-01-01

    Austenitic stainless steel is used widely because the corrosion resistance, workability and weldability are excellent, but the main fault is the occurrence of stress corrosion cracking in the environment containing chlorides. Inconel 600, most resistant to stress corrosion cracking, is not necessarily safe under some severe condition. In the heat-affected zone of SUS 304 tubes for BWRs, the cases of stress corrosion cracking have occurred. The conventional testing method of stress corrosion cracking using boiling magnesium chloride solution has been problematical because it is widely different from actual environment. The effects of alloying elements on stress corrosion cracking are remarkably different according to the environment. These effects were investigated systematically in high temperature, high pressure water, and as the result, Alloy SCR-3 with excellent stress corrosion cracking resistance was found. The physical constants and the mechanical properties of the SCR-3 are shown. The states of stress corrosion cracking in high temperature, high pressure water containing chlorides and pure water, polythionic acid, sodium phosphate solution and caustic soda of the SCR-3, SUS 304, Inconel 600 and Incoloy 800 are compared and reported. (Kako, I.)

  2. PM alloy 625M for high strength corrosion resistant applications

    International Nuclear Information System (INIS)

    Rizzo, F.J.; Floreen, S.

    1997-06-01

    In applications where the combination of high strength and good corrosion resistance are required, there have been only a few alloys of choice. A new powder metallurgy alloy has been developed, PM 625M, a niobium modification of Alloy 625, as a material to fill this need. One area of particular interest is the nuclear power industry, where many problems have been encountered with bolts, springs, and guidepins. Mechanical properties and stress corrosion cracking data of PM 625M are presented in this paper

  3. Coal Ash Corrosion Resistant Materials Testing

    Energy Technology Data Exchange (ETDEWEB)

    D. K. McDonald; P. L. Daniel; D. J. DeVault

    2007-12-31

    In April 1999, three identical superheater test sections were installed into the Niles Unit No.1 for the purpose of testing and ranking the coal ash corrosion resistance of candidate superheater alloys. The Niles boiler burns high sulfur coal (3% to 3.5%) that has a moderate alkali content (0.2% sodium equivalents), thus the constituents necessary for coal ash corrosion are present in the ash. The test sections were controlled to operate with an average surface metal temperature from approximately 1060 F to 1210 F which was within the temperature range over which coal ash corrosion occurs. Thus, this combination of aggressive environment and high temperature was appropriate for testing the performance of candidate corrosion-resistant tube materials. Analyses of the deposit and scale confirmed that aggressive alkali sulfate constituents were present at the metal surface and active in tube metal wastage. The test sections were constructed so that the response of twelve different candidate tube and/or coating materials could be studied. The plan was to remove and evaluate one of the three test sections at time intervals of 1 year, 3 years, and 5 years. This would permit an assessment of performance of the candidate materials as a function of time. Test Section A was removed in November 2001 after about 24 months of service at the desired steam temperature set point, with about 15.5 months of exposure at full temperature. A progress report, issued in October 2002, was written to document the performance of the candidate alloys in that test section. The evaluation described the condition of each tube sample after exposure. It involved a determination of the rate of wall thickness loss for these samples. In cases where there was more than one sample of a candidate material in the test section, an assessment was made of the performance of the alloy as a function of temperature. Test Sections B and C were examined during the November 2001 outage, and it was decided that

  4. Enhancing Corrosion and Wear Resistance of AA6061 by Friction Stir Processing with Fe78Si9B13 Glass Particles

    Directory of Open Access Journals (Sweden)

    Lingyu Guo

    2015-08-01

    Full Text Available The AA6061-T6 aluminum alloy samples including annealed Fe78Si9B13 particles were prepared by friction stir processing (FSP and investigated by various techniques. The Fe78Si9B13-reinforced particles are uniformly dispersed in the aluminum alloy matrix. The XRD results indicated that the lattice parameter of α-Al increases and the preferred orientation factors F of (200 plane of α-Al reduces after friction stir processing. The coefficient of thermal expansion (CTE for FSP samples increases at first with the temperature but then decreases as the temperature further increased, which can be explained by the dissolving of Mg and Si from β phase and Fe78Si9B13 particles. The corrosion and wear resistance of FSP samples have been improved compared with that of base metal, which can be attributed to the reduction of grain size and the CTE mismatch between the base metal and reinforced particles by FSP, and the lubrication effect of Fe78Si9B13 particles also plays a role in improving wear resistance. In particular, the FSP sample with reinforced particles in amorphous state exhibited superior corrosion and wear resistance due to the unique metastable structure.

  5. Corrosion resistance and in vitro response of laser-deposited Ti-Nb-Zr-Ta alloys for orthopedic implant applications.

    Science.gov (United States)

    Samuel, Sonia; Nag, Soumya; Nasrazadani, Seifollah; Ukirde, Vaishali; El Bouanani, Mohamed; Mohandas, Arunesh; Nguyen, Kytai; Banerjee, Rajarshi

    2010-09-15

    While direct metal deposition of metallic powders, via laser deposition, to form near-net shape orthopedic implants is an upcoming and highly promising technology, the corrosion resistance and biocompatibility of such novel metallic biomaterials is relatively unknown and warrants careful investigation. This article presents the results of some initial studies on the corrosion resistance and in vitro response of laser-deposited Ti-Nb-Zr-Ta alloys. These new generation beta titanium alloys are promising due to their low elastic modulus as well as due the fact that they comprise of completely biocompatible alloying elements. The results indicate that the corrosion resistance of these laser-deposited alloys is comparable and in some cases even better than the currently used commercially-pure (CP) titanium (Grade 2) and Ti-6Al-4V ELI alloys. The in vitro studies indicate that the Ti-Nb-Zr-Ta alloys exhibit comparable cell proliferation but enhanced cell differentiation properties as compared with Ti-6Al-4V ELI. (c) 2010 Wiley Periodicals, Inc.

  6. Effect of Heat treatment on Hardness and Corrosion Resistance of Super Cast Iron

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Roun; Kim, Young Sik [Andong National University, Andong (Korea, Republic of)

    2014-07-15

    In fossil-fuel-fired power plants, a variety of pollutants are produced from the combustion of conventional fuels such as coal, oil and gas. Major component of such pollution are ash and corrosive chemicals, which also destroy pumps and piping; by causing erosion/corrosion, pitting, and wear. In order to over come such damage, materials with high hardness and high corrosion resistance are needed. In this work, we melted super-cast-iron with excellent corrosion resistance and high hardness. To elucidate the effect of heat treatment, microstructural analysis, hardness measurement, and corrosion tests were performed. Test results revealed that the super-cast-iron had several tens better corrosion resistance than 316 L stainless steel, and it also had a high surface hardness (> HRC45). High hardness, in spite of its low carbon content (0.74%C), could resulted from a hardening heat treatment to precipitate sufficient Cr{sub 7}C{sub 3} and Cr{sub 2}3C{sub 6}. Also, it was concluded that the excellent corrosion resistance of the super-cast-iron was due to the increase of the relative chromium content by minimizing the carbon content, and by the enhancement of passive film by the addition of Cr, Mo, Cu, and W.

  7. Improvement on corrosion resistance of NiTi orthopedic materials by carbon plasma immersion ion implantation

    International Nuclear Information System (INIS)

    Poon, Ray W.Y.; Ho, Joan P.Y.; Luk, Camille M.Y.; Liu Xuanyong; Chung, Jonathan C.Y.; Chu, Paul K.; Yeung, Kelvin W.K.; Lu, William W.; Cheung, Kenneth M.C.

    2006-01-01

    Nickel-titanium shape memory alloys (NiTi) have potential applications as orthopedic implants because of their unique super-elastic properties and shape memory effects. However, the problem of out-diffusion of harmful Ni ions from the alloys during prolonged use inside a human body must be overcome before they can be widely used in orthopedic implants. In this work, we enhance the corrosion resistance of NiTi using carbon plasma immersion ion implantation and deposition (PIII and D). Our corrosion and simulated body fluid tests indicate that either an ion-mixed amorphous carbon coating fabricated by PIII and D or direct carbon PIII can drastically improve the corrosion resistance and block the out-diffusion of Ni from the materials. Results of atomic force microscopy (AFM) indicate that both C 2 H 2 -PIII and D and C 2 H 2 -PIII do not roughen the original flat surface to an extent that can lead to degradation in corrosion resistance

  8. High temperature corrosion in gasifiers

    Directory of Open Access Journals (Sweden)

    Bakker Wate

    2004-01-01

    Full Text Available Several commercial scale coal gasification combined cycle power plants have been built and successfully operated during the last 5-10 years. Supporting research on materials of construction has been carried out for the last 20 years by EPRI and others. Emphasis was on metallic alloys for heat exchangers and other components in contact with hot corrosive gases at high temperatures. In this paper major high temperature corrosion mechanisms, materials performance in presently operating gasifiers and future research needs will be discussed.

  9. Enhanced thermoelectric performance of amorphous Nb based oxynitrides

    Energy Technology Data Exchange (ETDEWEB)

    Music, Denis, E-mail: music@mch.rwth-aachen.de; Geyer, Richard W.; Hans, Marcus

    2015-12-15

    Using density functional theory, amorphous Nb{sub 0.27}Ru{sub 0.06}O{sub 0.56}N{sub 0.10} was designed to facilitate a combination of an enhanced Seebeck coefficient and low electrical resistivity. Based on a positive Cauchy pressure, ductile behavior is expected. To verify these predictions, the transport and mechanical properties of amorphous thin films were evaluated. Metallic electrical resistivity and the Seebeck coefficient of −94 µV K{sup −1} are obtained, which is consistent with our predictions. As there is no crack formation, these samples can be perceived as ductile. We demonstrate that the power factor can be increased by an order of magnitude, while keeping the thermal fatigue low.

  10. Enhanced thermoelectric performance of amorphous Nb based oxynitrides

    International Nuclear Information System (INIS)

    Music, Denis; Geyer, Richard W.; Hans, Marcus

    2015-01-01

    Using density functional theory, amorphous Nb_0_._2_7Ru_0_._0_6O_0_._5_6N_0_._1_0 was designed to facilitate a combination of an enhanced Seebeck coefficient and low electrical resistivity. Based on a positive Cauchy pressure, ductile behavior is expected. To verify these predictions, the transport and mechanical properties of amorphous thin films were evaluated. Metallic electrical resistivity and the Seebeck coefficient of −94 µV K"−"1 are obtained, which is consistent with our predictions. As there is no crack formation, these samples can be perceived as ductile. We demonstrate that the power factor can be increased by an order of magnitude, while keeping the thermal fatigue low.

  11. Corrosion resistance of Cu-Al coatings produced by thermal spray

    Directory of Open Access Journals (Sweden)

    Laura Marcela Dimaté Castellanos

    2012-01-01

    Full Text Available Many components in the shipbuilding industry are made of copper-based alloys. These pieces tend to break due to corrosion generated by a marine environment; such components can be salvaged through surface engineering, through deposition of suitable coatings. This paper studied the influence of three surface preparation methods involving phosphor bronze substrates concerning the corrosion resistance of commercial coatings having Al-Cu +11% Fe chemical composition. The surface was prepared using three methods: sand blasting, shot blasting and metal polishing with an abrasive disk (with and without a base layer. The deposited coatings were micro-structurally characterised by x-ray diffraction (XRD, optical microscopy and scanning electron microscopy (SEM. Corrosion resistance was evaluated by electrochemical test electrochemical impedance spectroscopy (EIS. Surfaces prepared by sandblasting showed the best resistance to corrosion, so these systems could be a viable alternative for salvaging certain parts in the marine industry. The corrosion mechanisms for the coatings produced are discussed in this research.

  12. Effects of surface topography and vibrations on wetting: Superhydrophobicity, icephobicity and corrosion resistance

    Science.gov (United States)

    Ramachandran, Rahul

    lowered using a hydrophobic emulsion. The hydrophobic concrete samples were able to repel incoming water droplets as well as resist droplet pinning. Corrosion resistance is achieved in cast iron samples by rendering them superhydrophobic. The corrosion resistance of superhydrophobic surfaces with micro/nanotopography may be explained by the low effective contact area with the electrolyte. The experimental results matched the theoretical predictions based on surface roughness and wettability. The icephobicity of engineered cementitious composite samples is achieved by hydrophobization, by using coatings containing dielectric material (such as polyvinyl alcohol fibers), and by controlling the surface topography. Two aspects of the icephobicity of concrete, namely, the repulsion of incoming water droplets before freezing and the ice adhesion strength, are investigated experimentally. It is found that icephobic performance of concrete depends on these parameters --- the hydrophobic emulsion concentration, the polyvinyl alcohol fiber content, the water to cement ratio, and the sand to cement ratio. The potential for biomimetic icephobicity of thermogenic skunk cabbage plant is investigated, and it is found that the surface topography of its leaves can affect the heat transfer from the plant to the surrounding snow. The hierarchical microstructure of the leaf surface coupled with its high adhesion to water suggests the presence of an impregnated wetting state, which can minimize the heat loss. Thus functional materials and surfaces, such as hydrophobic and icephobic engineered cementitious composites and corrosion resistant metallic surfaces, can be produced by controlling the surface micro/nanotopography.

  13. Study of the Effect of Sulfide Ions on the Corrosion Resistance of Copper for Use in Containers for High Level radioactive waste

    International Nuclear Information System (INIS)

    Urbal Espinoza, Andrea Elizabeth

    2000-01-01

    The work 'Study of sulfide ion on Resisting Copper Corrosion' is part of the project 'Study of Copper Corrosion in Underground Water Solution in Reducer Conditions', which the Department of Nuclear Materials, Chilean Nuclear Energy Commission is carrying out. These activities are important because of this metal's potential applications for handling and controlling contaminating wastes that are a product of using nuclear energy in electric generation. Copper has important mechanical properties and is also resistant to disintegration in corrosive environments, which is an important condition for its use in manufacturing of high level radioactive waste containers. This work is based on a study of cyclic volta metric curves, anodic and cathodic polarization and potentiostatic measurements, with which the potential range, sweep speed system, electrochemical reactions involved and corrosion speed could be defined. The microstructural characterization of the films was done by Scanning Electron Microscopy (SEM), and the chemical composition and surface contamination of the film were studied by photoelectron spectroscopy induced by X- rays (XPS), and the crystalline structure by X- ray Diffraction (XRD). Some noticeable results, such as low potentials (less than .7 V, in cathode direction) and high concentrations of sulfur make the formation of copper sulfides (I) and (II) possible; unlike the potential over .6 V, in anodic direction, where copper oxides (I) and (II) are formed, but they are inhibited by high sulfur concentrations. The morphological study of the copper surface has shown that the film that forms is more abundant and granular at higher cathodic potentials, forming small pits on the surface. The effect of the presence of sulfur ions is minimal, and the metal's deterioration is inhibited by other ions in the groundwater. The corrosion rate is greater as the sulfur concentration rises, and a time period of 20,000 years can be predicted for the total corrosion of

  14. Investigation of the influence of pretreatment parameters on the surface characteristics of amorphous metal for use in power industry

    Science.gov (United States)

    Nieroda, Jolanta; Rybak, Andrzej; Kmita, Grzegorz; Sitarz, Maciej

    2018-05-01

    Metallic glasses are metallic materials, which exhibit an amorphous structure. These are mostly three or more component alloys, and some of them are magnetic metals. Materials of this kind are characterized by high electrical resistivity and at the same time exhibit very good magnetic properties (e.g. low-magnetization loss). The above mentioned properties are very useful in electrical engineering industry and this material is more and more popular as a substance for high-efficiency electrical devices production. This industry area is still evolving, and thus even higher efficiency of apparatus based on amorphous material is expected. A raw material must be carefully investigated and characterized before the main production process is started. Presented work contains results of complementary examination of amorphous metal Metglas 2605. Studies involve two ways to obtain clean and oxidized surface with high reactivity, namely degreasing followed by annealing process and plasma treatment. The amorphous metal parameters were examined by means of several techniques: surface free energy (SFE) measurements by sessile drop method, X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), and both ex situ and in situ Raman spectroscopy. Additionally, influence of plasma parameters on wetting properties were optimized in systematic way with Design of Experiments (DOE) method. A wide range of used methods allow to fully investigate the amorphous metal material during preliminary preparation of surface. Obtained results provide information about appropriate parameters that should be applied in order to obtain highly reactive surface with functional oxide layer on it.

  15. Control and optimization of baths for electrodeposition of Co-Mo-B amorphous alloys

    Directory of Open Access Journals (Sweden)

    S. Prasad

    2000-12-01

    Full Text Available Optimization and control of an electrodeposition process for depositing boron-containing amorphous metallic layer of cobalt-molybdenum alloy onto a cathode from an electrolytic bath having cobalt sulfate, sodium molybdate, boron phosphate, sodium citrate, 1-dodecylsulfate-Na, ammonium sulfate and ammonia or sulfuric acid for pH adjustments has been studied. Detailed studies on bath composition, pH, temperature, mechanical agitation and cathode current density have led to optimum conditions for obtaining satisfactory alloy deposits. These alloys were found to have interesting properties such as high hardness, corrosion resistance, wear resistance and also sufficient ductility. A voltammetric method for automatic monitoring and control of the process has been proposed.

  16. Stress corrosion of very high purity stainless steels in alkaline media

    International Nuclear Information System (INIS)

    Hechmat-Dehcordi, Ebrahim

    1981-01-01

    This research thesis reports the study of stress corrosion resistance of stainless steels in caustic environments. It notably concerns the electronuclear industrial sector, the production of soda by electrolysis, and the preparation of hydrogen as energy vector. After a presentation of the experimental conditions, the author highlights the influence of purity on stress corrosion cracking of 20Cr-25Ni-type austenitic alloys. The specific action of a high number of addition metallic and non-metallic elements has been studied. Stress corrosion tests have been also performed in autoclave on austeno-ferritic (21 to 25 pc Cr - 6 to 10 pc Ni) as well as ferritic (26 pc Cr) grades. The author reports the study of electrochemical properties of stainless steel in soda by means of potentiostatic techniques with an application of Pourbaix thermodynamic equilibrium diagrams, and the study of the chemical composition of passivation thin layers by Auger spectroscopy. He more particularly studies the influence of electrode potential and of some addition elements on the chemical characteristics of oxides developed at the surface of austenite. Then, the author tries to establish correlations between strain hardening microstructure of the various steels and their sensitivity to stress corrosion [fr

  17. Microstructure, microhardness and corrosion resistance of remelted TiG2 and Ti6Al4V by a high power diode laser

    Energy Technology Data Exchange (ETDEWEB)

    Amaya-Vazquez, M.R. [Laboratorio de Corrosion y Proteccion, Universidad de Cadiz, Departamento de Ciencia de los Materiales e Ingenieria Metalurgica y Quimica Inorganica, Avda. Republica Saharaui s/n, 11510 Puerto Real, Cadiz (Spain); Sanchez-Amaya, J.M., E-mail: josemaria.sanchez@uca.es [Titania, Ensayos y Proyectos Industriales S.L., Ctra Sanlucar A-2001 Km 7,5, Parque Tecnologico TecnoBahia-Edif. RETSE Nave 4, 11500 El Puerto de Santa Maria, Cadiz (Spain); Departamento de Fisica Aplicada, CASEM, Avda. Republica Saharaui s/n, 11510-Puerto Real, Cadiz (Spain); Boukha, Z.; Botana, F.J. [Laboratorio de Corrosion y Proteccion, Universidad de Cadiz, Departamento de Ciencia de los Materiales e Ingenieria Metalurgica y Quimica Inorganica, Avda. Republica Saharaui s/n, 11510 Puerto Real, Cadiz (Spain)

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer Laser remelting of TiG2 and Ti6Al4V is performed with argon shielded diode laser. Black-Right-Pointing-Pointer Microstructure, microhardness and corrosion of remelted samples are deeply analysed. Black-Right-Pointing-Pointer Microstructural changes of laser remelted TiG2 lead to microhardness increase. Black-Right-Pointing-Pointer Remelted Ti6Al4V presents microhardness increase and corrosion improvement. Black-Right-Pointing-Pointer Martensite depth in remelted Ti6Al4V is linearly proportional to laser fluence. - Abstract: The high strength, low density and superior corrosion resistance allow titanium alloys to be widely employed in different industrial applications. The properties of these alloys can be modulated by different heat treatments, including laser processing. In the present paper, laser remelting treatments, performed with a high power diode laser, were applied to samples of two titanium alloys (TiG2 and Ti6Al4V). The influence of the applied laser fluence on microstructure, microhardness and corrosion resistance is investigated. Results show that laser remelting treatments with appropriate fluences provoke microstructural changes leading to microhardness increase and corrosion resistance improvement.

  18. The corrosion behaviour and structure of amorphous and thermally treated Fe-B-Si alloys

    International Nuclear Information System (INIS)

    Raicheff, R.; Zaprianova, V.; Petrova, E.

    2003-01-01

    The corrosion behaviour of magnetic amorphous alloys Fe 78 B 13 Si 9 , Fe 81 B 13 Si 4 C 2 and Fe 67 Co 18 Bi 4 S 1 obtained by rapid quenching from the melts are investigated in a model corrosive environment of 1N H 2 SO 4 . The structure of the alloys, is, characterized by DTA, SEM, TEM, X-ray and electron diffraction techniques. The dissolution kinetics of the,alloys is studied using gravimetric and electrochemical polarization measurements. It is established that the corrosion rate of the amorphous Fe 67 Co 18 Bt 4 S 1 alloy is up to 50 times lower than that of Fe 78 Bi 3 Si 9 alloy and the addition of cobalt leads to a considerable reduction of the rates of both partial corrosion reactions, while the addition of carbon results only in a moderate decrease (2-3 times) of the corrosion rate. It is also shown that the crystallization of the amorphous Fe 78 B 13 Si 9 alloy (at 700 o C for 3 h) leads to formation of multiphase structure consisting of crystalline phases α-Fe and Fe 3 (B,Si). After crystallization an increase of the rate of both hydrogen evolution and anodic dissolution reactions is observed which results in a considerable (an order of magnitude) increase of the corrosion rate of the alloy. (Original)

  19. Self-cleaning performance of superhydrophobic hybrid nanocomposite coatings on Al with excellent corrosion resistance

    International Nuclear Information System (INIS)

    Raj, V.; Mohan Raj, R.

    2016-01-01

    Highlights: • Ceramic-poly(Ani-co-oPD) coatings were formed on Al by anodization and electro-polymerisation techniques. • The superhydrophobic coating was fabricated on copolymer by electrodeposition of zinc stearate. • The superhydrophobicity mechanism relies on morphologies and chemical components on surface is the key factor. • Ceramic-poly(Ani-co-oPD)-zinc stearate coated Al has excellent corrosion resistance and good self-cleaning performance. - Abstract: Protective ceramic-PANI, ceramic-poly(Ani-co-oPD) and ceramic-poly(Ani-co-oPD)-zinc stearate nanocomposite coatings were formed on Al surface by the processes involving anodization, electropolymerisation and electrodeposition under optimum conditions. The prepared nanocomposite coatings were evaluated by ATR-IR and XRD studies. SEM studies performed on nanocomposite coatings reveal that ceramic-poly(Ani-co-oPD)-zinc stearate nanocomposite coating shows a cauliflower-like cluster with crack-free morphology compared to ceramic-PANI and ceramic-poly(Ani-co-oPD) nanocomposite coatings. The mechanical properties of different nanocomposite coatings were measured using Vicker microhardness tester and Taber Abrasion tester. The ceramic-poly(Ani-co-oPD)-zinc stearate nanocomposite has higher mechanical stability. The corrosion resistance of the coatings measured by Tafel polarization and electrochemical impedance spectroscopy, shows that ceramic-poly(Ani-co-oPD)-zinc stearate nanocomposite coated aluminum has higher corrosion resistance than other coatings and bare Al. Wettability studies prove that superhydrophobic nature of ceramic-poly(Ani-co-oPD)-zinc stearate nanocomposite coating with contact angle of 155.8° is responsible for good self-cleaning property and excellent corrosion resistance of aluminum.

  20. Self-cleaning performance of superhydrophobic hybrid nanocomposite coatings on Al with excellent corrosion resistance

    Energy Technology Data Exchange (ETDEWEB)

    Raj, V., E-mail: alaguraj2@rediffmail.com; Mohan Raj, R., E-mail: chem_mohan@rediffmail.com

    2016-12-15

    Highlights: • Ceramic-poly(Ani-co-oPD) coatings were formed on Al by anodization and electro-polymerisation techniques. • The superhydrophobic coating was fabricated on copolymer by electrodeposition of zinc stearate. • The superhydrophobicity mechanism relies on morphologies and chemical components on surface is the key factor. • Ceramic-poly(Ani-co-oPD)-zinc stearate coated Al has excellent corrosion resistance and good self-cleaning performance. - Abstract: Protective ceramic-PANI, ceramic-poly(Ani-co-oPD) and ceramic-poly(Ani-co-oPD)-zinc stearate nanocomposite coatings were formed on Al surface by the processes involving anodization, electropolymerisation and electrodeposition under optimum conditions. The prepared nanocomposite coatings were evaluated by ATR-IR and XRD studies. SEM studies performed on nanocomposite coatings reveal that ceramic-poly(Ani-co-oPD)-zinc stearate nanocomposite coating shows a cauliflower-like cluster with crack-free morphology compared to ceramic-PANI and ceramic-poly(Ani-co-oPD) nanocomposite coatings. The mechanical properties of different nanocomposite coatings were measured using Vicker microhardness tester and Taber Abrasion tester. The ceramic-poly(Ani-co-oPD)-zinc stearate nanocomposite has higher mechanical stability. The corrosion resistance of the coatings measured by Tafel polarization and electrochemical impedance spectroscopy, shows that ceramic-poly(Ani-co-oPD)-zinc stearate nanocomposite coated aluminum has higher corrosion resistance than other coatings and bare Al. Wettability studies prove that superhydrophobic nature of ceramic-poly(Ani-co-oPD)-zinc stearate nanocomposite coating with contact angle of 155.8° is responsible for good self-cleaning property and excellent corrosion resistance of aluminum.

  1. Evaluation of Joint Performance on High Nitrogen Stainless Steel Which is Expected to Have Higher Allergy Resistance

    Science.gov (United States)

    Nakano, Kouichi

    Austenitic stainless steel, which includes nickel for stabilizing austenitic structure, is used for various purposes, for example, for structural material, corrosion-resistant material, biomaterial etc. Nickel is set as one of the rare metals and economizing on nickel as the natural resources is required. On the other hand, nickel is one of the metals that cause metallic allergy frequently. Therefore, high nitrogen stainless steel, where nitrogen stabilizes austenitic structure instead of nickel, has been developed in Japan and some of the foreign countries for the above reason. When high nitrogen stainless steel is fused and bonded, dissolved nitrogen is released to the atmospheric area, and some of the material properties will change. In this study, we bonded high nitrogen stainless steel by stud welding process, which is able to bond at short time, and we evaluate joint performance. We have got some interesting results from the other tests and examinations.

  2. High performance polypyrrole coating for corrosion protection and biocidal applications

    Science.gov (United States)

    Nautiyal, Amit; Qiao, Mingyu; Cook, Jonathan Edwin; Zhang, Xinyu; Huang, Tung-Shi

    2018-01-01

    Polypyrrole (PPy) coating was electrochemically synthesized on carbon steel using sulfonic acids as dopants: p-toluene sulfonic acid (p-TSA), sulfuric acid (SA), (±) camphor sulfonic acid (CSA), sodium dodecyl sulfate (SDS), and sodium dodecylbenzene sulfonate (SDBS). The effect of acidic dopants (p-TSA, SA, CSA) on passivation of carbon steel was investigated by linear potentiodynamic and compared with morphology and corrosion protection performance of the coating produced. The types of the dopants used were significantly affecting the protection efficiency of the coating against chloride ion attack on the metal surface. The corrosion performance depends on size and alignment of dopant in the polymer backbone. Both p-TSA and SDBS have extra benzene ring that stack together to form a lamellar sheet like barrier to chloride ions thus making them appropriate dopants for PPy coating in suppressing the corrosion at significant level. Further, adhesion performance was enhanced by adding long chain carboxylic acid (decanoic acid) directly in the monomer solution. In addition, PPy coating doped with SDBS displayed excellent biocidal abilities against Staphylococcus aureus. The polypyrrole coatings on carbon steels with dual function of anti-corrosion and excellent biocidal properties shows great potential application in the industry for anti-corrosion/antimicrobial purposes.

  3. Investigation of intergranular corrosion resistance of Cr16Ni25NMo6 steel

    International Nuclear Information System (INIS)

    Kamenev, Yu.B.; Nazarov, A.A.; Kuusk, L.V.; Majdeburova, T.F.

    1990-01-01

    The effect of 08Kh16N25AM6 steel susceptibility to intergranular corrosion on its intergranular cracking resistance in high-temperature water is investigated. In addition, the performed tests point to the susceptibility of sensibilized Kh16N25AM6 steel to intergranular corrosion in media simulating an agressive environment of power generation equipment; the latter requires a strict control over the resistance of weld joints of the above steel to intergranular corrosion. It is shown that Kh16N25AM6 type steel in sensibilized state is susceptible to intercrystalline corrosion cracking in high-temperature water which correlates with its susceptibility to intergranular corrosion established by AM GOST 6032-84 and potentiodynamic reactivation methods

  4. Parasitic corrosion resistant anode for use in metal/air or metal/O.sub.2 cells

    Science.gov (United States)

    Joy, Richard W.; Smith, David F.

    1983-01-01

    A consumable metal anode which is used in refuelable electrochemical cells and wherein at least a peripheral edge portion of the anode is protected against a corrosive alkaline environment of the cell by the application of a thin metal coating, the coating being formed of metals such as nickel, silver, and gold.

  5. Testing of intergranular and pitting corrosion in sensitized welded joints of austenitic stainless steel

    Directory of Open Access Journals (Sweden)

    Bore V. Jegdic

    2017-06-01

    Full Text Available Pitting corrosion resistance and intergranular corrosion of the austenitic stainless steel X5Cr Ni18-10 were tested on the base metal, heat affected zone and weld metal. Testing of pitting corrosion was performed by the potentiodynamic polarization method, while testing of intergranular corrosion was performed by the method of electrochemical potentiokinetic reactivation with double loop. The base metal was completely resistant to intergranular corrosion, while the heat affected zone showed a slight susceptibility to intergranular corrosion. Indicators of pitting corrosion resistance for the weld metal and the base metal were very similar, but their values are significantly higher than the values for the heat affected zone. This was caused by reduction of the chromium concentration in the grain boundary areas in the heat affected zone, even though the carbon content in the examined stainless steel is low (0.04 wt. % C.

  6. Erosion and corrosion resistance of laser cladded AISI 420 stainless steel reinforced with VC

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhe [Center for Laser-aided Manufacturing, Lyle School of Engineering, Southern Methodist University, 3101 Dyer Street, Dallas, TX 75206 (United States); Yu, Ting [Center for Laser-aided Manufacturing, Lyle School of Engineering, Southern Methodist University, 3101 Dyer Street, Dallas, TX 75206 (United States); School of Mechanical and Electrical Engineering, Nanchang University, Nanchang, Jiangxi 330031 (China); Kovacevic, Radovan, E-mail: kovacevi@smu.edu [Center for Laser-aided Manufacturing, Lyle School of Engineering, Southern Methodist University, 3101 Dyer Street, Dallas, TX 75206 (United States)

    2017-07-15

    Highlights: • The coatings of 420 stainless steel reinforced with VC were fabricated by high power direct diode laser. • The erosion resistance of the cladded layer was increased with the increase in the VC fraction. • No obvious improvement of erosion resistance was observed when the VC fraction was above 30 wt.%. • The corrosion resistance of the cladded layer was decreased with the increase in the VC fraction. - Abstract: Metal Matrix Composites (MMC) fabricated by the laser cladding process have been widely applied as protective coatings in industries to improve the wear, erosion, and corrosion resistance of components and prolong their service life. In this study, the AISI 420/VC metal matrix composites with different weight percentage (0 wt.%–40 wt.%) of Vanadium Carbide (VC) were fabricated on a mild steel A36 by a high power direct diode laser. An induction heater was used to preheat the substrate in order to avoid cracks during the cladding process. The effect of carbide content on the microstructure, elements distribution, phases, and microhardness was investigated in detail. The erosion resistance of the coatings was tested by using the abrasive waterjet (AWJ) cutting machine. The corrosion resistance of the coatings was studied utilizing potentiodynamic polarization. The results showed that the surface roughness and crack susceptibility of the laser cladded layer were increased with the increase in VC fraction. The volume fraction of the precipitated carbides was increased with the increase in the VC content. The phases of the coating without VC consisted of martensite and austenite. New phases such as precipitated VC, V{sub 8}C{sub 7}, M{sub 7}C{sub 3}, and M{sub 23}C{sub 6} were formed when the primary VC was added. The microhardness of the clads was increased with the increase in VC. The erosion resistance of the cladded layer was improved after the introduction of VC. The erosion resistance was increased with the increase in the VC content

  7. High Current Plasma Electrolytic Oxidation Coating Processes for Wear and Corrosion Prevention of Al 2024

    Science.gov (United States)

    Wang, Rui

    Plasma electrolytic oxidation (PEO) treatments have been used in the aerospace and automotive industries because the coating formed on light metals or alloys has great hardness, high wear, corrosion, and oxidation resistance, and a low friction coefficient that improves lifetime length and provide a higher surface quality. However, the PEO treatments that are presently used for industrial applications require a long period of time to confirm the quality of the coating. For this reason, the present study seeks to increase the current density of PEO treatments to improve their efficiency and explore the performance of the obtained coatings. It was found that for high current density (0.18A/cm2) PEO treatments, smaller ratio, such as 50% and 70%, is beneficial to obtaining a better performance coating. When compared with the coating of a "normal" (current density: 0.09A/cm2) PEO treatment, it had better wear resistance; however, for corrosion resistance, it had a lower performance than the coatings obtained by the "normal" current density PEO treatment which was attributed to the negative influence of porosity increase.

  8. Transformation processes during annealing of Al-amorphous alloys

    International Nuclear Information System (INIS)

    Petrescu, N.; Petrescu, M.; Calin, M.; Jianu, A.D.; Fecioru, M.

    1993-01-01

    As the amorphous aluminum alloys represent the newest achievement in rapid solidification of Al-based high strength heat resistent materials, a study was undertaken on the amorphous alloys in the Al-RE-TM system, the rare-earth metal being a lanthanide mixture and the transition metal a Ni-Fe substitution in definite proportions. The decomposition on heating of the most highly alloyed amorphous alloy in the investigated series is characterized by differential thermal analysis, electron microscopy and X-ray diffraction. (orig.)

  9. Transformation processes during annealing of Al-amorphous alloys

    Energy Technology Data Exchange (ETDEWEB)

    Petrescu, N. (Polytechnic Inst. Bucharest, Faculty Materials Science and Engineering, Bucharest (Romania)); Petrescu, M. (Polytechnic Inst. Bucharest, Faculty Materials Science and Engineering, Bucharest (Romania)); Calin, M. (Polytechnic Inst. Bucharest, Faculty Materials Science and Engineering, Bucharest (Romania)); Jianu, A.D. (Polytechnic Inst. Bucharest, Faculty Materials Science and Engineering, Bucharest (Romania) IFTM-Bucharest (Romania)); Fecioru, M. (Polytechnic Inst. Bucharest, Faculty Materials Science and Engineering, Bucharest (Romania) DACIA Enterprise-Bucharest (Romania))

    1993-11-01

    As the amorphous aluminum alloys represent the newest achievement in rapid solidification of Al-based high strength heat resistent materials, a study was undertaken on the amorphous alloys in the Al-RE-TM system, the rare-earth metal being a lanthanide mixture and the transition metal a Ni-Fe substitution in definite proportions. The decomposition on heating of the most highly alloyed amorphous alloy in the investigated series is characterized by differential thermal analysis, electron microscopy and X-ray diffraction. (orig.).

  10. Improving the corrosion wear resistance of AISI 316L stainless steel by particulate reinforced Ni matrix composite alloying layer

    Science.gov (United States)

    Xu, Jiang; Zhuo, Chengzhi; Tao, Jie; Jiang, Shuyun; Liu, Linlin

    2009-01-01

    In order to overcome the problem of corrosion wear of AISI 316L stainless steel (SS), two kinds of composite alloying layers were prepared by a duplex treatment, consisting of Ni/nano-SiC and Ni/nano-SiO2 predeposited by brush plating, respectively, and subsequent surface alloying with Ni-Cr-Mo-Cu by a double glow process. The microstructure of the two kinds of nanoparticle reinforced Ni-based composite alloying layers was investigated by means of SEM and TEM. The electrochemical corrosion behaviour of composite alloying layers compared with the Ni-based alloying layer and 316L SS under different conditions was characterized by potentiodynamic polarization test and electrochemical impedance spectroscopy. Results showed that under alloying temperature (1000 °C) conditions, amorphous nano-SiO2 particles still retained the amorphous structure, whereas nano-SiC particles were decomposed and Ni, Cr reacted with SiC to form Cr6.5Ni2.5Si and Cr23C6. In static acidic solution, the corrosion resistance of the composite alloying layer with the brush plating Ni/nano-SiO2 particles interlayer is lower than that of the Ni-based alloying layer. However, the corrosion resistance of the composite alloying layer with the brush plating Ni/nano-SiO2 particles interlayer is prominently superior to that of the Ni-based alloying layer under acidic flow medium condition and acidic slurry flow condition. The corrosion resistance of the composite alloying layer with the brush plating Ni/nano-SiC particles interlayer is evidently lower than that of the Ni-based alloying layer, but higher than that of 316L SS under all test conditions. The results show that the highly dispersive nano-SiO2 particles are helpful in improving the corrosion wear resistance of the Ni-based alloying layer, whereas carbides and silicide phase are deleterious to that of the Ni-based alloying layer due to the fact that the preferential removal of the matrix around the precipitated phase takes place by the chemical

  11. Corrosion resistance of titanium alloys for dentistry

    International Nuclear Information System (INIS)

    Laskawiec, J.; Michalik, R.

    2001-01-01

    Titanium and its alloys belong to biomaterials which the application scope in medicine increases. Some properties of the alloys, such as high mechanical strength, low density, low Young's modulus, high corrosion resistance and good biotolerance decide about it. The main areas of the application of titanium and its alloys are: orthopedics and traumatology, cardiosurgery, faciomaxillary surgery and dentistry. The results of investigations concerning the corrosion resistance of the technical titanium and Ti6Al14V alloy and comparatively a cobalt alloy of the Vitallium type in the artificial saliva is presented in the work. Significantly better corrosion resistance of titanium and the Ti6Al14V than the Co-Cr-Mo alloy was found. (author)

  12. In hydrofluoric acid corrosion-resistant materials

    International Nuclear Information System (INIS)

    Hauffe, K.

    1985-01-01

    Copper, red brass (Cu-15 Zn), special treated carbon steel and chromium-nickel-molybdenum steel represent materials of high resistivity against concentrated hydrofluoric acid ( 2 O 3 ) are employed for windows in the presence of hydrogen fluoride and/or hydrofluoric acid because of their superior optical properties and their excellent corrosion resistance. Polyethylen, polypropylene and polyvinyl chloride (PVC) belong to the cheapest corrosion resistant material for container and for coatings in the presence of hydrofluoric acid. Special polyester resins reinforced by glass or graphite fibers have been successfully employed as material for production units with hydrofluoric acid containing liquids up to 330 K. By carbon reinforced epoxy resin represents a corrosion resistant coating. Because of their excellent friction and corrosion resistance against concentrated hot hydrofluoric acid and HNO 3 -HF-solutions, PTFE and polyvinylidene fluoride are used as material for valves and axles in such environment. The expensive alloys, as for instance hastelloy and monel, are substituted more and more by fiber-reinfored polyolefins, PVC and fluorine containing polymers. (orig.) [de

  13. Corrosion behaviour of 2124 aluminium alloy-silicon carbide metal matrix composites in sodium chloride environment

    International Nuclear Information System (INIS)

    Singh, Nirbhay; Vadera, K.K.; Ramesh Kumar, A.V.; Singh, R.S.; Monga, S.S.; Mathur, G.N.

    1999-01-01

    Aluminium alloy based particle reinforced metal matrix composites (MMCs) are being considered for a range of applications. Their mechanical properties have been investigated in detail, but more information about their corrosion resistance is needed. In this investigation, the corrosion behaviour of silicon carbide particulates (SiC p )-2124 aluminium metal matrix composites was studied in 3 wt% sodium chloride solution by means of electrochemical technique and optical microscope. The effects of weight percentages and particle size of silicon carbide particulates on corrosion behaviour of the composite were studied in NaCl and it was observed that corrosion rate increases linearly with the increasing weight percentage of SiC p . The corrosion rate of the MMC increases by increasing the size of SiC particles. Anodization improved corrosion resistance of the composites. (author)

  14. Highly uniform resistive switching properties of amorphous InGaZnO thin films prepared by a low temperature photochemical solution deposition method.

    Science.gov (United States)

    Hu, Wei; Zou, Lilan; Chen, Xinman; Qin, Ni; Li, Shuwei; Bao, Dinghua

    2014-04-09

    We report on highly uniform resistive switching properties of amorphous InGaZnO (a-IGZO) thin films. The thin films were fabricated by a low temperature photochemical solution deposition method, a simple process combining chemical solution deposition and ultraviolet (UV) irradiation treatment. The a-IGZO based resistive switching devices exhibit long retention, good endurance, uniform switching voltages, and stable distribution of low and high resistance states. Electrical conduction mechanisms were also discussed on the basis of the current-voltage characteristics and their temperature dependence. The excellent resistive switching properties can be attributed to the reduction of organic- and hydrogen-based elements and the formation of enhanced metal-oxide bonding and metal-hydroxide bonding networks by hydrogen bonding due to UV irradiation, based on Fourier-transform-infrared spectroscopy, X-ray photoelectron spectroscopy, and Field emission scanning electron microscopy analysis of the thin films. This study suggests that a-IGZO thin films have potential applications in resistive random access memory and the low temperature photochemical solution deposition method can find the opportunity for further achieving system on panel applications if the a-IGZO resistive switching cells were integrated with a-IGZO thin film transistors.

  15. Parasitic corrosion-resistant anode for use in metal/air or metal/O/sub 2/ cells

    Science.gov (United States)

    Joy, R.W.; Smith, D.F.

    1982-09-20

    A consumable metal anode is described which is used in refuelable electrochemical cells and wherein at least a peripheral edge portion of the anode is protected against a corrosive alkaline environment of the cell by the application of a thin metal coating, the coating being formed of metals such as nickel, silver, and gold.

  16. Research and development on is process components for hydrogen production. (2) Corrosion resistance of glass lining in high temperature sulfuric acid

    International Nuclear Information System (INIS)

    Tanaka, Nobuyuki; Iwatsuki, Jin; Kubo, Shinji; Terada, Atsuhiko; Onuki, Kaoru

    2009-01-01

    Japan Atomic Energy Agency has been conducting a research and development on hydrogen production system using High Temperature Gas-Cooled Reactor. As a part of this effort, thermochemical water-splitting cycle featuring iodine- and sulfur-compounds (IS process) is under development considering its potential of large-scale economical hydrogen production. The IS process constitutes very severe environments on the materials of construction because of the corrosive nature of process chemicals, especially of the high temperature acidic solution of sulfuric acid and hydriodic acid dissolving iodine. Therefore, selection of the corrosion-resistant materials and development of the components has been studied as a crucial subject of the process development. This paper discusses corrosion resistance of commercially available glass-lining material in high temperature sulfuric acid. Corrosion resistance of a soda glass used for glass-lining was examined by immersion tests. The experiments were performed in 47-90wt% sulfuric acids at temperatures of up to 400degC and for the maximum immersion time of 100 hours using an autoclave designed for the concerned tests. In every condition tested, no indication of localized corrosion such as defect formation or pitting corrosion was observed. Also, the corrosion rates decreased with the progress of immersion, and were low enough (≅0.1 mm/year) after 60-90 hours of immersion probably due to formation of a silica rich surface. (author)

  17. Evaluation of cytotoxicity and corrosion resistance of orthodontic mini-implants

    Science.gov (United States)

    Alves, Celha Borges Costa; Segurado, Márcio Nunes; Dorta, Miriam Cristina Leandro; Dias, Fátima Ribeiro; Lenza, Maurício Guilherme; Lenza, Marcos Augusto

    2016-01-01

    ABSTRACT Objective: To evaluate and compare in vitro cytotoxicity and corrosion resistance of mini-implants from three different commercial brands used for orthodontic anchorage. Methods: Six mini-implants (Conexão(tm), Neodent(tm) and SIN(tm)) were separately immersed in artificial saliva (pH 6.76) for 30 and 60 days. The cytotoxicity of the corrosion extracts was assessed in L929 cell cultures using the violet crystal and MTT assays, as well as cell morphology under light microscopy. Metal surface characteristics before and after immersion in artificial saliva were assessed by means of scanning electron microscopy (SEM). The samples underwent atomic absorption spectrophotometry to determine the concentrations of aluminum and vanadium ions, constituent elements of the alloy that present potential toxicity. For statistical analysis, one-way ANOVA/Bonferroni tests were used for comparisons among groups with p corrosion. The extracts assessed by means of atomic absorption spectrophotometry presented concentrations of aluminum and vanadium ions below 1.0 µg/mL and 0.5 µg/mL, respectively. Conclusion: Orthodontic mini-implants manufactured by Conexão(tm), Neodent(tm) and SIN(tm) present high corrosion resistance and are not cytotoxic. PMID:27901227

  18. Electrochemical Corrosion Studies for Modeling Metallic Waste Form Release Rates

    International Nuclear Information System (INIS)

    Poineau, Frederic; Tamalis, Dimitri

    2016-01-01

    The isotope 99 Tc is an important fission product generated from nuclear power production. Because of its long half-life (t 1/2 = 2.13 ∙ 105 years) and beta-radiotoxicity (β - = 292 keV), it is a major concern in the long-term management of spent nuclear fuel. In the spent nuclear fuel, Tc is present as an alloy with Mo, Ru, Rh, and Pd called the epsilon-phase, the relative amount of which increases with fuel burn-up. In some separation schemes for spent nuclear fuel, Tc would be separated from the spent fuel and disposed of in a durable waste form. Technetium waste forms under consideration include metallic alloys, oxide ceramics and borosilicate glass. In the development of a metallic waste form, after separation from the spent fuel, Tc would be converted to the metal, incorporated into an alloy and the resulting waste form stored in a repository. Metallic alloys under consideration include Tc–Zr alloys, Tc–stainless steel alloys and Tc–Inconel alloys (Inconel is an alloy of Ni, Cr and iron which is resistant to corrosion). To predict the long-term behavior of the metallic Tc waste form, understanding the corrosion properties of Tc metal and Tc alloys in various chemical environments is needed, but efforts to model the behavior of Tc metallic alloys are limited. One parameter that should also be considered in predicting the long-term behavior of the Tc waste form is the ingrowth of stable Ru that occurs from the radioactive decay of 99 Tc ( 99 Tc → 99 Ru + β - ). After a geological period of time, significant amounts of Ru will be present in the Tc and may affect its corrosion properties. Studying the effect of Ru on the corrosion behavior of Tc is also of importance. In this context, we studied the electrochemical behavior of Tc metal, Tc-Ni alloys (to model Tc-Inconel alloy) and Tc-Ru alloys in acidic media. The study of Tc-U alloys has also been performed in order to better understand the nature of Tc in metallic spent fuel. Computational modeling

  19. Studies on the Corrosion Resistance of Laser-Welded Inconel 600 and Inconel 625 Nickel-Based Superalloys

    Directory of Open Access Journals (Sweden)

    Łyczkowska K.

    2017-06-01

    Full Text Available The paper presents the results of the electrochemical corrosion tests of Inconel 600 and Inconel 625 laser-welded superalloys. The studies were conducted in order to assess the resistance to general and pitting corrosion in 3.5% NaCl solution. It was found that Inconel 600 possesses good corrosion resistance, however Inconel 625 is characterized by a greater resistance to general and also to pitting corrosion of the weld as well as the base metal.

  20. Metal surface corrosion grade estimation from single image

    Science.gov (United States)

    Chen, Yijun; Qi, Lin; Sun, Huyuan; Fan, Hao; Dong, Junyu

    2018-04-01

    Metal corrosion can cause many problems, how to quickly and effectively assess the grade of metal corrosion and timely remediation is a very important issue. Typically, this is done by trained surveyors at great cost. Assisting them in the inspection process by computer vision and artificial intelligence would decrease the inspection cost. In this paper, we propose a dataset of metal surface correction used for computer vision detection and present a comparison between standard computer vision techniques by using OpenCV and deep learning method for automatic metal surface corrosion grade estimation from single image on this dataset. The test has been performed by classifying images and calculating the accuracy for the two different approaches.

  1. Corrosion performance of SiCsubp/6061 Al metal matrix composites in sodium chloride solution

    International Nuclear Information System (INIS)

    Mohmad Soib bin Selamat

    1995-01-01

    The corrosion performance of silicon carbide particle/aluminium metal matrix composites (SiCsubp/Al) were studied in sodium chloride solution by means of electrochemical, microscopic, gravimetric and analytical techniques. The materials under investigation were compocasting processed 6061 Al reinforced with increasing amounts of SiC particles. Potentiostatic polarization tests were done in 0.1M NaCl solutions that were aerated or deaerated to observe overall corrosion behaviour. It was seen that the corrosion potentials did not vary greatly in relation to the amounts of SiCsubp reinforcement. Corrosion tests showed that the degree of corrosion increased with increasing SiCsubp content. SEM analysis technique was used to study the corroded samples and the pitting morphology. By TEM, no intermetallic layer was found at SiC/Al interface. A model for pitting process was proposed

  2. A high molybdenum stainless steel and its resistance to chloride environments in the welded condition

    International Nuclear Information System (INIS)

    Coppolecchia, V.D.; Jasner, M.; Rockel, M.B.

    1988-01-01

    Highly alloyed stainless steels, such as 1925 hMo UNS N08925 with 6 percent molybdenum, are finding widespread use in high chloride cooling water and process environments. This alloy has good general corrosion resistance to a variety of chloride environments but it's main attraction is excellent resistance to all forms of localized corrosion. In aggressive chloride environments weldments are generally the area of concern with regard to localized corrosion. Temperature-time-sensitization diagrams are presented that demonstrate the resistance of 1925 hMo weldments to intergranular attack. Immersion tests in 10% ferric chloride substantiate that autogenous tube welds, also have excellent pitting resistance. Various filler metals are compared both electrochemically and in immersion tests. These comparisons reveal that an overalloyed filler metal is required to achieve pitting and crevice corrosion resistance equal or better than that of the base metal. Alloy 625 (UNS NO6625) has been selected. Constant extension rate tests in boiling 62% calcium chloride reveal that 1925 hMo weldments are immune to stress corrosion cracking in this environment which virtually guarantees absence of SCC in seawater regardless of temperature as well as in most commercial chemical environments

  3. Influence of alkali metal hydroxides on corrosion of Zr-based alloys

    International Nuclear Information System (INIS)

    Jeong, Y.H.; Ruhmann, H.; Garzarolli, F.

    1997-01-01

    In this study the influence of group-1 alkali hydroxides on different zirconium based alloys has been evaluated. The experiments have been carried out in small stainless steel autoclaves at 350 deg. C in pressurized 17 MPa water, with in low (0.32 mmol), medium (4.3 mmol) and high (31.5 mmol) equimolar concentrations of Li-, Na-, K-, Rb- and Cs-Hydroxides. Two types of alloys have been investigated: Zr-Sn-(Transition metal) and Zr-Sn-Nb-(Transition metal). The corrosion behaviour was evaluated from weight gain measurements. From the experiments the cation could be identified as the responsible species for zirconium alloy corrosion in alkalized water. The radius of the cation governs the corrosion behaviour in the pre accelerated region of zircaloy corrosion. Incorporating of alkali cations into the zirconium oxide lattice is probably the mechanism which allows the corrosion enhancement for Li and Na and the significantly lower effect for the other bases. Nb containing alloys show lower corrosion resistance than alloys from the Zr-Sn-TRM system in all alkali solutions. Both types of alloys corrode significantly more in LiOH and NaOH than in the other alkali environments. Lowest corrosive aggressiveness has been found for CsOH followed by KOH. Concluding from the corrosion behaviour in the different alkali environments and taking into account the tendency to promote accelerate corrosion, CsOH and KOH are possible alternate alkalis for PWR application. (author). 17 refs, 15 figs, 5 tabs

  4. Influence of alkali metal hydroxides on corrosion of Zr-based alloys

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Y H [Korea Atomic Energy Research Inst., Dae Jun (Korea, Republic of); Ruhmann, H; Garzarolli, F [Siemens-KWU, Power Generation Group, Erlangen (Germany)

    1997-02-01

    In this study the influence of group-1 alkali hydroxides on different zirconium based alloys has been evaluated. The experiments have been carried out in small stainless steel autoclaves at 350 deg. C in pressurized 17 MPa water, with in low (0.32 mmol), medium (4.3 mmol) and high (31.5 mmol) equimolar concentrations of Li-, Na-, K-, Rb- and Cs-Hydroxides. Two types of alloys have been investigated: Zr-Sn-(Transition metal) and Zr-Sn-Nb-(Transition metal). The corrosion behaviour was evaluated from weight gain measurements. From the experiments the cation could be identified as the responsible species for zirconium alloy corrosion in alkalized water. The radius of the cation governs the corrosion behaviour in the pre accelerated region of zircaloy corrosion. Incorporating of alkali cations into the zirconium oxide lattice is probably the mechanism which allows the corrosion enhancement for Li and Na and the significantly lower effect for the other bases. Nb containing alloys show lower corrosion resistance than alloys from the Zr-Sn-TRM system in all alkali solutions. Both types of alloys corrode significantly more in LiOH and NaOH than in the other alkali environments. Lowest corrosive aggressiveness has been found for CsOH followed by KOH. Concluding from the corrosion behaviour in the different alkali environments and taking into account the tendency to promote accelerate corrosion, CsOH and KOH are possible alternate alkalis for PWR application. (author). 17 refs, 15 figs, 5 tabs.

  5. Corrosion protective performance of amino trimethylene phosphonic acid-metal complex layers fabricated on the cold-rolled steel substrate via one-step assembly

    Science.gov (United States)

    Yan, Ru; He, Wei; Zhai, Tianhua; Ma, Houyi

    2018-06-01

    Seeing that amino trimethylene phosphonic acid (ATMP) possesses very strong complexation ability to metal ions and the phosphonic acid group has good affinity for the oxidized iron surface, herein a simple and rapid film-forming method (one-step assembly method) was developed to construct the ATMP-Zn complex conversion layers (ATMP-Zn layers for short) on the cold-rolled steel (CRS) substrate. Zinc ions were found to participate in the formation process of ATMP-based composite film, which made the Zn-containing ATMP film significantly different in appearance, thickness, microstructure and film-forming mechanisms from the Zn-free ATMP film. There was mainly iron (ш) phosphonate in the Zn-free ATMP film, whereas there were Zn2+-ATMP complex and a certain amount of ZnO in the ATMP-Zn composite film. In addition, electrochemical test results clearly indicate that corrosion resistance of ATMP-Zn composite film was greatly enhanced due to the presence of Zn component. Moreover, the corrosion resistance performance could be controlled by adjusting film-forming time, pH and ATMP concentration in the film-forming solutions. The present study provides a new method for the design and fabrication of high-quality environmentally-friendly conversion layers.

  6. Influence of alkali metal hydroxides on corrosion of Zr-base alloys

    International Nuclear Information System (INIS)

    Jeong, Yong Hwan

    1996-01-01

    The influence of group-1 alkali hydroxides on different Zr-based alloys have been carried out in static autoclaves at 350 deg C in pressurized water, conditioned in low(0.32 mmol), medium(4.3 mmol) and high(31.5 mmol) equimolar concentration of Li-, Na-, K-, Rb- and Cs-hydroxide. Two types of alloys have been investigated: Zr-Sn-(TRM, Transition metal) and Zr-Sn-Nb-(TRM, Transition metal). From the experiments the cation could be identified as the responsible species for corrosion of Zr alloy in alkalized water. The radius of the cation governs the accelerated corrosion in the pre-transition region of Zr alloy. Incorporation of alkali cation into the zirconium oxide lattice is probably the mechanism which allows the corrosion enhancement for Li and Na and the significant lower effect for the other bases. Nb containing alloys showed lower corrosion resistance than Zr-Sn-TRM alloys in all alkali solutions. Both types of alloys were corroded significantly more in LiOH and NaOH than in the other alkali environments. Lowest corrosive aggressiveness has been found for CsOH followed by KOH. Concluding from the corrosion behavior in the different alkali environments and taking into account the tendency to accelerate the corrosion of Zr alloys, CsOH and KOH are possible alternate alkali for PWR (Pressurized Water Reactor) application. (author)

  7. Corrosion evaluation of metallic HLW/spent fuel disposal containers - review

    International Nuclear Information System (INIS)

    Kursten, B.; Smailos, E.; Azkarate, I.; Werme, L.; Smart, N.R.; Marx, G.; Cunado, M.A.; Santarini, G.

    2004-01-01

    Over the years a lot of investigations have been performed to choose suitable container materials and to characterize their long-term corrosion behaviour in contact with their potential disposal environments, i.e. salt, clay, and granite. Carbon steels, stainless steels, nickel-based alloys, titanium-based alloys, and copper have been widely investigated as potential container materials depending on the studied host rock formation. The results obtained in salt environments indicate that the passively corroding Ti99.8-Pd is the primary choice for the thin-walled corrosion-resistant concept, since its general corrosion rate is negligible and it is highly resistant to localized corrosion and stress corrosion cracking (SCC) in salt brines. The TStE 355 carbon steel is the first candidate for the corrosion-allowance concept because it is resistant to pitting corrosion and SCC and its general corrosion rates are sufficiently low to provide corrosion allowance acceptable for thick-walled containers. Stainless steels, Ni-based alloys, and Ti-based alloys are the most important candidate container materials in clay for the thin-walled concept, while carbon steel is considered the main choice for the thick-walled corrosion-allowance concept. Studies performed in granite seem to indicate that copper containers provide an excellent corrosion barrier with an estimated lifetime exceeding 100,000 years. The TStE 355 carbon steel is also a valid option for a thick-walled container concept in granite. In this paper, some relevant corrosion data of carbon steel and stainless steel in cementitious environments are given in addition because large amounts of concrete will be used as structural materials in most of the envisaged repository design concepts. This paper also provides recommendations for future studies. (authors)

  8. CORROSION ANALYSIS OF METALLIZED FILMS AFTER PRINTING

    OpenAIRE

    Mr. Dhirender*1, Mr. Rajeev2 & Mr.Manoj3

    2017-01-01

    Print quality has always been a point of strong concern among printers and consumers. Metalized films have gain a wide spread popularity among printers because of its low cost and high usages in food packaging applications. But sometimes corrosion spoils the printed products causing huge financial loss to the printers or customers.This paper throws light on major causes of corrosion on metallized films and possible remedies for the same. The metallized films with polyester base were base coat...

  9. Corrosion Resistance Of Electroless Ni-P/Cu/Ni-P Multilayer Coatings

    Directory of Open Access Journals (Sweden)

    Zhao G.L.

    2015-06-01

    Full Text Available Ni-P/Cu/Ni-P multilayer coatings were prepared by deposition of Cu layer between two Ni–P layers. The Cu layer was deposited by metal displacement reaction between Cu2+ and Fe atoms. Corrosion behavior of single-layer Ni-P coatings, double-layer Ni-P/Cu coatings, and three-layer Ni-P/Cu/Ni-P coatings were investigated by electrochemical tests in 3.5% NaCl solution. The three-layer coatings exhibited more positive Ecorr and decreased Icorr compared with conventional single-layer Ni-P coatings, which indicated an improved corrosion resistance. The polarization curves of the three-layer coatings were characterized by two passive regions. The improved corrosion resistance was not only attributed to the function of the blocked pores of Cu. The Cu interlayer also acted as a sacrificial layer instead of a barrier in the coatings, which altered the corrosion mechanism and further improved the corrosion resistance of the coatings.

  10. Effects of sulfur addition on pitting corrosion and machinability behavior of super duplex stainless steel containing rare earth metals: Part 2

    International Nuclear Information System (INIS)

    Jeon, Soon-Hyeok; Kim, Soon-Tae; Lee, In-Sung; Park, Yong-Soo

    2010-01-01

    Research highlights: → The mechanisms on the effects of rare earth metals (REM) and sulfur (S) additions on the initiation and propagation of pitting corrosion and machinabillity of a super duplex stainless steel (SDSS) were elucidated → It was found that, in consideration of the ratio of lifetime (the resistance to pitting corrosion) to cost (machining and raw material), a costly austenitic stainless steel with high Ni , medium Mo and low N can be replaced by the high S and REM added SDSS with 7 wt.% Ni-4 wt% Mo-0.3 wt.% N → The resistance to pitting corrosion of the tested super duplex stainless steel was affected by the type of inclusions, the preferential interface areas between inclusions and the substrate, and the PREN difference between the γ-phase and the α-phase for the initiation and propagation of the pitting corrosion. - Abstract: To elucidate the effects of sulfur addition on pitting corrosion and machinability behavior of alloys containing rare earth metals, a potentiostatic polarization test, a critical pitting temperature test, a SEM-EDS analysis of inclusions, and a tool life test were conducted. As sulfur content increased, the resistance to pitting corrosion decreased due to the formation of numerous manganese sulfides deteriorating the corrosion resistance and an increase in the preferential interface areas for the initiation of the pitting corrosion. With an increase in sulfur content, the tool life increased due to the lubricating films of manganese sulfides adhering to tool surface.

  11. Experimental and numerical investigation on cladding of corrosion-erosion resistant materials by a high power direct diode laser

    Science.gov (United States)

    Farahmand, Parisa

    advantages due to creating coating layers with superior properties in terms of purity, homogeneity, low dilution, hardness, bonding, and microstructure. In the development of modern materials for hardfacing applications, the functionality is often improved by combining materials with different properties into composites. Metal Matrix Composite (MMC) coating is a composite material with two constituent parts, i.e., matrix and the reinforcement. This class of composites are addressing improved mechanical properties such as stiffness, strength, toughness, and tribological and chemical resistance. Fabrication of MMCs is to achieve a combination of properties not achievable by any of the materials acting alone. MMCs have attracted significant attention for decades due to their combination of wear-resistivity, corrosion-resistivity, thermal, electrical and magnetic properties. Presently, there is a strong emphasis on the development of advanced functional coatings for corrosion, erosion, and wear protection for different industrial applications. In this research, a laser cladding system equipped with a high power direct diode laser associated with gas driven metal powder delivery system was used to develop advanced MMC coatings. The high power direct diode laser used in this study offers wider beam spot, shorter wavelength and uniform power distribution. These properties make the cladding set-up ideal for coating due to fewer cladding tracks, lower operation cost, higher laser absorption, and improved coating qualities. In order to prevent crack propagation, porosity, and uniform dispersion of carbides in MMC coating, cladding procedure was assisted by an induction heater as a second heat source. The developed defect free MMC coatings were combined with nano-size particles of WC, rare earth (RE) element (La2O3), and Mo as a refractory metal to enhance mechanical properties, chemical composition, and subsequently improve the tribological performance of the coatings. The resistance

  12. Amorphization of C-implanted Fe(Cr) alloys

    International Nuclear Information System (INIS)

    Knapp, J.A.; Follstaedt, D.M.; Sorensen, N.R.; Pope, L.E.

    1991-01-01

    The amorphous phase formed by implanting C into Fe alloyed with Cr, which is a prototype for the amorphous phase formed by implanting C into stainless steels, is compared to that formed by implanting C and Ti into Fe and steels. The composition range of the phase has been examined; higher Cr and C concentrations are required than needed with Ti and C. The friction and wear benefits obtained by implanting stainless steels with C only do not persist for the long durations and high wear loads found with Ti and C. However, the amorphous Fe-Cr-C alloys exhibit good aqueous corrosion resistance. (orig.)

  13. Effects of Rare Earth Metals addition and aging treatment on the corrosion resistance and mechanical properties of super duplex stainless steels

    Science.gov (United States)

    Park, Yong-Soo; Kim, Soon-Tae; Lee, In-Sung; Song, Chi-Bok

    2002-05-01

    Effects of rare earth metals addition and aging treatment on corrosion resistance and mechanical properties of super duplex stainless steels were investigated using optical/SEM/TEM metallographic examination, an X-ray diffraction test, a potentiodynamic anodic polarization test and a tensile test. The performance of the experimental alloy with 0.32% REM addition was compared with commercial super duplex stainless steel such as SAF 2507 when they were exposed to solution annealing heat treatment and aging treatment. The corrosion resistance in Cl- environments and mechanical properties of the experimental alloy were found superior to those of the commercial duplex stainless steel. The REM with larger atomic radii than those of Cr, Mo and W may fill vacancies inside the matrix and around the grain boundaries, retarding formation of harmful intermetallic σ and η phases. In addition, fine REM oxides/oxy-sulfides (1-3 μm) seemed to enhance the retardation effects. With REM additions, strength and ductility increased due to the phase and grain refinement caused by fine REM oxides and oxy-sulfides.

  14. Stainless steel welding method with excellent nitric acid corrosion resistance

    International Nuclear Information System (INIS)

    Matsushita, Yukinobu; Inazumi, Toru; Hyakubo, Tamako; Masamura, Katsumi.

    1996-01-01

    The present invention concerns a welding method for a stainless steel used in a circumstance being in contact with a highly oxidizing nitric acid solution such as nuclear fuel reprocessing facilities, upon welding 316 type austenite steel containing Mo while giving excellent nitric acid resistance. A method of TIG welding using a filler metal having a composition of C, Si, Mn, P, S, Ni, Cr, Mo and Cu somewhat different from a stainless steel mother material in which C, Si, Mn, P, S, Ni, Cr and Mo are specified comprises a step of TIG-welding the surface of the mother material and a step of TIG-welding the rear face of the mother material, in which the welding conditions for the rear face of the mother material are such that the distance between the surface of the outermost welding metal layer on the side of the surface of the mother material and the bottom of the groove is not less than 5mm, and an amount of welding heat is made constant. As a result, even if the method is used in a circumstance being in contact with a highly corrosive solution such as nitric acid, corrosion resistance is not degraded. (N.H.)

  15. Development of metallic system multi-composite materials for compound environment and corrosion monitoring technology

    International Nuclear Information System (INIS)

    Kiuchi, Kiyoshi

    1996-01-01

    For the structural materials used for the pressure boundary of nuclear power plants and others, the long term durability over several decades under the compound environment, in which the action of radiation and the corrosion and erosion in the environment of use are superposed, is demanded. To its controlling factors, the secular change of materials due to irradiation ageing and the chemical and physical properties of extreme compound environment are related complicatedly. In the first period of this research, the development of the corrosion-resistant alloys with the most excellent adaptability to environments was carried out by the combination of new alloy design and alloy manufacturing technology. In the second period, in order to heighten the adaptability as the pressure boundary materials between different compound environments, the creation of metallic system multi-composite materials has been advanced. Also corrosion monitoring technique is being developed. The stainless steel for water-cooled reactors, the wear and corrosion-resistant superalloy for reactor core, the corrosion-resistant alloy and the metallic refractory material for reprocessing nitric acid reaction vessels are reported. (K.I.)

  16. Advanced Corrosion-Resistant Zr Alloys for High Burnup and Generation IV Applications

    International Nuclear Information System (INIS)

    Arthur Motta; Yong Hwan Jeong; R.J. Comstock; G.S. Was; Y.S. Kim

    2006-01-01

    The objective of this collaboration between four institutions in the US and Korea is to demonstrate a technical basis for the improvement of the corrosion resistance of zirconium-based alloys in more extreme operating environments (such as those present in severe fuel duty, cycles high burnup, boiling, aggressive chemistry) and to investigate the feasibility (from the point of view of corrosion rate) of using advanced zirconium-based alloys in a supercritical water environment

  17. Effect of Zinc Phosphate on the Corrosion Behavior of Waterborne Acrylic Coating/Metal Interface.

    Science.gov (United States)

    Wan, Hongxia; Song, Dongdong; Li, Xiaogang; Zhang, Dawei; Gao, Jin; Du, Cuiwei

    2017-06-14

    Waterborne coating has recently been paid much attention. However, it cannot be used widely due to its performance limitations. Under the specified conditions of the selected resin, selecting the function pigment is key to improving the anticorrosive properties of the coating. Zinc phosphate is an environmentally protective and efficient anticorrosion pigment. In this work, zinc phosphate was used in modifying waterborne acrylic coatings. Moreover, the disbonding resistance of the coating was studied. Results showed that adding zinc phosphate can effectively inhibit the anode process of metal corrosion and enhance the wet adhesion of the coating, and consequently prevent the horizontal diffusion of the corrosive medium into the coating/metal interface and slow down the disbonding of the coating.

  18. Effect of Nb addition on microstructure and corrosion resistance of novel stainless steels fabricated by direct laser metal deposition

    Science.gov (United States)

    Wu, S. Q.; Zhang, C. H.; Zhang, S.; Wang, Q.; Liu, Y.; Abdullah, Adil O.

    2018-03-01

    The study demonstrated the successful fabrication of novel stainless steels by direct laser metal deposition with the aim of investigating the impact of niobium content (Nb = 0, 0.25, 0.75, 1.25 wt%) on their microstructure and electrochemical properties. The microstructure and phase evolution of the as-built stainless steels were studied using scanning electron microscope (SEM) and electron back-scatter diffraction (EBSD). Corrosion behavior of the samples was evaluated using electrochemical workstation in 3.5 wt% NaCl. Experimental results have shown that the crystal structure of as-built stainless steels was BCC with a small trace of dispersive carbides and FCC phase. Grain refinement was observed with increasing niobium content. Large-angle boundaries were obtained in different Nb-containing samples with distribution from 50° to 60°. An increase in niobium content extremely improved the corrosion resistance of as-built stainless steels and the as-built samples with 1.25 wt% exhibited the best corrosion resistance among the tested samples as indicated by its lowest corrosion rate, which was an order of magnitude lower than that of Nb-free samples.

  19. Erosion and corrosion resistance of laser cladded AISI 420 stainless steel reinforced with VC

    Science.gov (United States)

    Zhang, Zhe; Yu, Ting; Kovacevic, Radovan

    2017-07-01

    Metal Matrix Composites (MMC) fabricated by the laser cladding process have been widely applied as protective coatings in industries to improve the wear, erosion, and corrosion resistance of components and prolong their service life. In this study, the AISI 420/VC metal matrix composites with different weight percentage (0 wt.%-40 wt.%) of Vanadium Carbide (VC) were fabricated on a mild steel A36 by a high power direct diode laser. An induction heater was used to preheat the substrate in order to avoid cracks during the cladding process. The effect of carbide content on the microstructure, elements distribution, phases, and microhardness was investigated in detail. The erosion resistance of the coatings was tested by using the abrasive waterjet (AWJ) cutting machine. The corrosion resistance of the coatings was studied utilizing potentiodynamic polarization. The results showed that the surface roughness and crack susceptibility of the laser cladded layer were increased with the increase in VC fraction. The volume fraction of the precipitated carbides was increased with the increase in the VC content. The phases of the coating without VC consisted of martensite and austenite. New phases such as precipitated VC, V8C7, M7C3, and M23C6 were formed when the primary VC was added. The microhardness of the clads was increased with the increase in VC. The erosion resistance of the cladded layer was improved after the introduction of VC. The erosion resistance was increased with the increase in the VC content. No obvious improvement of erosion resistance was observed when the VC fraction was above 30 wt.%. The corrosion resistance of the clads was decreased with the increase in the VC content, demonstrating the negative effect of VC on the corrosion resistance of AISI 420 stainless steel

  20. Linear variable differential transformer sensor using glass-covered amorphous wires as active core

    International Nuclear Information System (INIS)

    Chiriac, H.; Hristoforou, E.; Neagu, Maria; Pieptanariu, M.

    2000-01-01

    Results concerning linear variable differential transformer (LVDT) displacement sensor using as movable core glass-covered amorphous wires are presented. The LVDT response is linear for a displacement of the movable core up to about 14 mm, with an accuracy of 1 μm. LVDT using glass-covered amorphous wire as an active core presents a high sensitivity and good mechanical and corrosion resistance

  1. High strength corrosion-resistant zirconium aluminum alloys

    International Nuclear Information System (INIS)

    Schulson, E.M.; Cameron, D.J.

    1976-01-01

    A zirconium-aluminum alloy is described possessing superior corrosion resistance and mechanical properties. This alloy, preferably 7.5-9.5 wt% aluminum, is cast, worked in the Zr(Al)-Zr 2 Al region, and annealed to a substantially continuous matrix of Zr 3 Al. (E.C.B.)

  2. Structural Characterization of Highly Corrosion-resistant Steel

    Czech Academy of Sciences Publication Activity Database

    Lančok, Adriana; Kmječ, T.; Štefánik, M.; Sklenka, L.; Miglierini, M.

    2015-01-01

    Roč. 88, č. 4 (2015), s. 355-361 ISSN 0011-1643 R&D Projects: GA ČR(CZ) GA14-12449S Institutional support: RVO:61388980 Keywords : Mossbauer spectroscopy * corrosion-resistant steel * LC200 * CEMS Subject RIV: CA - Inorganic Chemistry Impact factor: 0.732, year: 2015

  3. On the corrosion resistance of 01Kh25 ferritic steel

    International Nuclear Information System (INIS)

    Eremeeva, R.A.; Koval', E.K.

    1989-01-01

    Effect of non-ferrous metal ions on corrosion behaviour of 01Kh25 specific low carbon steel as compared to austenitic 12Kh18N10T and 06KhN28MDT steels in boiling solutions of sulfuric and nitric acids and their mixture is studied. Compositions initating commercial ones are chosen the media. It is shown that trough corrosion resistance of 01Kh25 steel in 10% H 2 SO 4 is two order below 06KhN28MDT austenitic steel in presence of Cu 2+ ions as a result of the surface passivation corrosion resistance of ferritic steel is an order higher the austenitic ones. Ferrite steel resistance in the nitric acid and its mixture with sulfuric acid is five timesas much as in 12Kh18N10T austenitic steel

  4. Development of sulfuric acid dew point corrosion resistant stainless steel for smokestacks and its ducts. Entotsu endoyo tairyusan roten fushoku stainless ko no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Sato, E.; Matsuhashi, R.; Koseki, T. (Nippon Steel Corp., Tokyo (Japan)); Ebara, R.; Nakamoto, H. (Mitsubishi Heavy Industries, Ltd., Tokyo (Japan))

    1993-05-20

    A new corrosion resistant steel was developed as a metal system lining material to prevent sulfuric acid dew point corrosion in smokestacks and ducts. SO3 in stack gas turns to sulfuric acid as a result of reacting with coexistent moisture in non-steady conditions during boiler actuation and shutdown when smokestack walls have low temperatures. When sulfuric acid thus generated contacts with metallic materials at temperatures lower than the sulfuric acid dew point temperature, sulfuric acid dew point corrosion occurs. During boiler steady operation, localized corrosion develops at clearance between salt deposits and the metallic materials. In order to improve the corrosion resistance, Mo, Cu and N were added in a reasonable range of amount. Entire surface corrosion resistance and local corrosion resistance were experimented in aqueous solutions simulating the smokestack environments to derive relational formulas with steel compositions. The new corrosion resistant steel met the the entire surface and local corrosion resistance requirements and was found economical. Low torsional velocity tensile and U-bend tests proved the steel satisfying the stress corrosion resistance requirement. Semi-automatic CO2 welding and shielded are welding provided good workability with no cracking, and impact strength and corrosion resistance in joints equivalent to those in the base material. 3 refs., 4 figs., 4 tabs.

  5. The precious metal effect in high temperature corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Wit, J.H.W. de (Lab. for Materials Science, Delft Univ. of Technology (Netherlands)); Manen, P.A. van (Lab. for Materials Science, Delft Univ. of Technology (Netherlands))

    1994-01-01

    Additions of platinum and to a smaller extent rhodium, to aluminium oxide forming alloys are known to improve the high temperature corrosion resistance of the alloys. This effect is known as the ''precious metal effect''. The expensive Pt-additions are used because of the increased lifetime of turbine-vanes especially in marine environments. Only a limited number of coating systems is commercially available, as JML-1, LDC-2 and RT22. Normally Pt is deposited electrochemically or by a fused salt method. After deposition the high or low activity pack-cementation-process is applied to obtain a PtNiAl-coating. In this paper the effect of platinum on the oxidation mechanism is discussed by comparing the oxidation mechanism of [beta]-NiAl and Pt20Ni30Al50. This composition agrees with the average composition of a platinum modified aluminide coating. The alloys were oxidized at temperatures from 1000 to 1200 C. The growth of the oxide scale on the NiAl alloy proceeds both by aluminium and by oxygen diffusion through the scale resulting in growth within the scale. On Pt20Ni30Al50 the growth of the scale is limited to the oxide/gas interface due to a predominant aluminium transport through the scale. The morphology of the oxide scales did not show large differences. However, the extensive void formation at the [beta]-NiAl/oxide interface was not observed on the Pt20Ni30Al50 samples. The absence of voids at the interface and the reduction of growth stresses, as a result of the outward growth of the scale, are the two likely reasons for the improved oxide scale adherence and can thus be considered, to be two elements of the ''precious metal effect''. (orig.)

  6. High-Performance and Omnidirectional Thin-Film Amorphous Silicon Solar Cell Modules Achieved by 3D Geometry Design.

    Science.gov (United States)

    Yu, Dongliang; Yin, Min; Lu, Linfeng; Zhang, Hanzhong; Chen, Xiaoyuan; Zhu, Xufei; Che, Jianfei; Li, Dongdong

    2015-11-01

    High-performance thin-film hydrogenated amorphous silicon solar cells are achieved by combining macroscale 3D tubular substrates and nanoscaled 3D cone-like antireflective films. The tubular geometry delivers a series of advantages for large-scale deployment of photovoltaics, such as omnidirectional performance, easier encapsulation, decreased wind resistance, and easy integration with a second device inside the glass tube. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Resistance of Incoloy 800 steam generator tube to pitting corrosion in PWR secondary water at 250°C

    International Nuclear Information System (INIS)

    Schvartzman, Mônica M.A.M.; Albuquerque, Adriana Silva de; Esteves, Luiza; Rabello, Emerson G.; Mansur, Fábio Abud

    2017-01-01

    The steam generator (SG) is one of the main components of a PWR, so the performance of this type of nuclear power plant depends to a large extent on the trouble-free operation of SGs. Its degradation significantly affects the overall plant performance. Alloy 800NG (Incoloy® 800) is a nickel-iron-chromium alloy used for steam generator tubes in PWRs due to their high strength, good workability and resistance to corrosion. This behavior is attributed to the protective oxide film formed on the metal surface by contact with the high temperature pressurized water. However, chloride is one of major SG impurities that cause the breakdown of the passive film and initiate localized corrosion in passive metals as Alloy 800NG. The aim of this study is to provide information about the pitting corrosion behavior of the Incoloy® 800 steam generator tube under normal secondary circuit parameters (250 deg C and 5 MPa) and abnormal conditions of operation (presence of chloride ions in the secondary water). For this, optical microscopy, XRD and EDS analysis and electrochemical tests have been carried out under simulated PWR secondary water operating conditions. The susceptibility to pitting corrosion was evaluated using electrochemical tests and the oxide layer formed on material was examined by means of scanning electron microscopy (SEM) and energy dispersive X-ray spectrometer (EDS) analyses. (author)

  8. Resistance of Incoloy 800 steam generator tube to pitting corrosion in PWR secondary water at 250°C

    Energy Technology Data Exchange (ETDEWEB)

    Schvartzman, Mônica M.A.M. [Pontifícia Universidade Católica de Minas Gerais (PUC-Minas), Belo Horizonte, MG (Brazil); Albuquerque, Adriana Silva de; Esteves, Luiza; Rabello, Emerson G.; Mansur, Fábio Abud, E-mail: monicacdtn@gmail.com, E-mail: asa@cdtn.br, E-mail: luiza.esteves@cdtn.br, E-mail: egr@cdtn.br, E-mail: fametalurgica@gmail.com [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2017-07-01

    The steam generator (SG) is one of the main components of a PWR, so the performance of this type of nuclear power plant depends to a large extent on the trouble-free operation of SGs. Its degradation significantly affects the overall plant performance. Alloy 800NG (Incoloy® 800) is a nickel-iron-chromium alloy used for steam generator tubes in PWRs due to their high strength, good workability and resistance to corrosion. This behavior is attributed to the protective oxide film formed on the metal surface by contact with the high temperature pressurized water. However, chloride is one of major SG impurities that cause the breakdown of the passive film and initiate localized corrosion in passive metals as Alloy 800NG. The aim of this study is to provide information about the pitting corrosion behavior of the Incoloy® 800 steam generator tube under normal secondary circuit parameters (250 deg C and 5 MPa) and abnormal conditions of operation (presence of chloride ions in the secondary water). For this, optical microscopy, XRD and EDS analysis and electrochemical tests have been carried out under simulated PWR secondary water operating conditions. The susceptibility to pitting corrosion was evaluated using electrochemical tests and the oxide layer formed on material was examined by means of scanning electron microscopy (SEM) and energy dispersive X-ray spectrometer (EDS) analyses. (author)

  9. Metal corrosion inhibitors and ecology

    International Nuclear Information System (INIS)

    Krasts, H.; Svarce, J.; Berge, B.

    1999-01-01

    The use of metal corrosion inhibitors in water is one of the cheapest method to protect metals against corrosion. However, the used inhibitors can come to surface water in the course of time and can become as source of environmental pollution. It is important to co-ordinate amount of substances in the elaborated inhibitors not only with demands for metal protection, but also with demands for quality of surface water and drinking water according to normative statements: 3.5 mg/l (as PO 4 ) for hexametaphosphate, tripolyphosphate and phosphonate; 40 mg/l (as SiO 2 for silicate, up to 1 mg/l for CU 2+ ; up to 5 mg/l for Zn 2+ ; up to 1 mg/l for B; up to 0.5 mg/l for Mo 2+ . The examples of the elaborated inhibitors are given. Many organic substances can be used as corrosion inhibitors, but there is shortage of standard methods for their analysis in water in Latvia. Removing of salt's deposits from boilers needs elaboration of a separate normative statement for dispersing waste water which content chloride at high concentration and heavy metals. (authors)

  10. Microstructure and Corrosion Resistance of Laser Additively Manufactured 316L Stainless Steel

    Science.gov (United States)

    Trelewicz, Jason R.; Halada, Gary P.; Donaldson, Olivia K.; Manogharan, Guha

    2016-03-01

    Additive manufacturing (AM) of metal alloys to produce complex part designs via powder bed fusion methods such as laser melting promises to be a transformative technology for advanced materials processing. However, effective implementation of AM processes requires a clear understanding of the processing-structure-properties-performance relationships in fabricated components. In this study, we report on the formation of micro and nanoscale structures in 316L stainless steel samples printed by laser AM and their implications for general corrosion resistance. A variety of techniques including x-ray diffraction, optical, scanning and transmission electron microscopy, x-ray fluorescence, and energy dispersive x-ray spectroscopy were employed to characterize the microstructure and chemistry of the laser additively manufactured 316L stainless steel, which are compared with wrought 316L coupons via electrochemical polarization. Apparent segregation of Mo has been found to contribute to a loss of passivity and an increased anodic current density. While porosity will also likely impact the environmental performance (e.g., facilitating crevice corrosion) of AM alloys, this work demonstrates the critical influence of microstructure and heterogeneous solute distributions on the corrosion resistance of laser additively manufactured 316L stainless steel.

  11. Straining electrode behavior and corrosion resistance of nickel base alloys in high temperature acidic solution

    International Nuclear Information System (INIS)

    Yamanaka, Kazuo

    1992-01-01

    Repassivation behavior and IGA resistance of nickel base alloys containing 0∼30 wt% chromium was investigated in high temperature acid sulfate solution. (1) The repassivation rate was increased with increasing chromium content. And so the amounts of charge caused by the metal dissolution were decreased with increasing chromium content. (2) Mill-annealed Alloy 600 suffered IGA at low pH environment below about 3.5 at the fixed potentials above the corrosion potential in 10%Na 2 SO 4 +H 2 SO 4 solution at 598K. On the other hand, thermally-treated Alloy 690 was hard to occur IGA at low pH environments which mill-annealed Alloy 600 occurred IGA. (3) It was considered that the reason, why nickel base alloys containing high chromium content such as Alloy 690 (60%Ni-30%Cr-10%Fe) had high IGA/SCC resistance in high temperature acidic solution containing sulfate ion, is due to both the promotion of the repassivation and the suppression of the film dissolution by the formation of the dense chromium oxide film

  12. Corrosion resistant ceramic materials

    Science.gov (United States)

    Kaun, T.D.

    1996-07-23

    Ceramic materials are disclosed which exhibit stability in severely-corrosive environments having high alkali-metal activity, high sulfur/sulfide activity and/or molten halides at temperatures of 200--550 C or organic salt (including SO{sub 2} and SO{sub 2}Cl{sub 2}) at temperatures of 25--200 C. These sulfide ceramics form stoichiometric (single-phase) compounds with sulfides of Ca, Li, Na, K, Al, Mg, Si, Y, La, Ce, Ga, Ba, Zr and Sr and show melting-points that are sufficiently low and have excellent wettability with many metals (Fe, Ni, Mo) to easily form metal/ceramic seals. Ceramic compositions are also formulated to adequately match thermal expansion coefficient of adjacent metal components. 1 fig.

  13. Corrosion resistant ceramic materials

    Science.gov (United States)

    Kaun, Thomas D.

    1996-01-01

    Ceramic materials which exhibit stability in severely-corrosive environments having high alkali-metal activity, high sulfur/sulfide activity and/or molten halides at temperatures of 200.degree.-550.degree. C. or organic salt (including SO.sub.2 and SO.sub.2 Cl.sub.2) at temperatures of 25.degree.-200.degree. C. These sulfide ceramics form stoichiometric (single-phase) compounds with sulfides of Ca, Li, Na, K, Al, Mg, Si, Y, La, Ce, Ga, Ba, Zr and Sr and show melting-points that are sufficiently low and have excellent wettability with many metals (Fe, Ni, Mo) to easily form metal/ceramic seals. Ceramic compositions are also formulated to adequately match thermal expansion coefficient of adjacent metal components.

  14. The influence of Zr substitution for Nb on the corrosion behaviors of the Ni-Nb-Zr bulk metallic glasses

    Science.gov (United States)

    Li, DengKe; Zhu, ZhengWang; Zhang, HaiFeng; Wang, AiMin; Hu, ZhuangQi

    2012-12-01

    The influence of Zr content on corrosion behaviors of the Ni61.5Nb38.5- x Zr x ( x=1, 3, 5, 7, 9 at.%) bulk metallic glasses (BMGs) in 1 M HCl aqueous solution was investigated by potentiodynamic polarization measurements and X-ray photo-electron spectroscopy (XPS). It was found that these BMG alloys possess superior corrosion resistance, that is, with large passive region of about 1.5 V and low passive current density (as low as 0.05 Am-2 for Ni61.5Nb31.5Zr7). XPS analysis indicates that the high corrosion resistance is attributed to the formation of Nb- and Zr-enriched surface films formed in the aggressive acid solution. The Zr substitution for Nb effectively reduces the Ni content, particularly the metallic state Ni content in the surface films, which depresses the electrical conduction of the surface films and reduces the passive current density, thus leading to the enhancement of the corrosion resistance of these Ni-Nb-Zr BMGs. These alloys may potentially be useful for engineering applications.

  15. Corrosion resistance of a laser spot-welded joint of NiTi wire in simulated human body fluids.

    Science.gov (United States)

    Yan, Xiao-Jun; Yang, Da-Zhi

    2006-04-01

    The purpose of this study was to investigate corrosion resistance of a laser spot-welded joint of NiTi alloy wires using potentiodynamic tests in Hank's solution at different PH values and the PH 7.4 NaCl solution for different Cl- concentrations. Scanning electron microscope observations were carried out before and after potentiodynamic tests. The composition of a laser spot-welded joint and base metal were characterized by using an electron probe microanalyzer. The results of potentiodynamic tests showed that corrosion resistance of a laser spot-welded joint of NiTi alloy wire was better than that of base metal, which exhibited a little higher breakdown potential and passive range, and a little lower passive current density. Corrosion resistances of a laser spot-welded joint and base metal decreased with increasing of the Cl- concentration and PH value. The improvement of corrosion resistance of the laser spot-welded joint was due to the decrease of the surface defects and the increase of the Ti/Ni ratio. (c) 2005 Wiley Periodicals, Inc.

  16. A Study on Microstructure Change and Pitting Corrosion Resistance of Ferritic Stainless Steel Weldment According to Nb Contents

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong-Min; Shin, Yong-Taek; Lee, Sang-Hwa; Lee, Jun-Hee; Lee, Hae-Woo [Dong-A University, Busan (Korea, Republic of); Lee, Sung-Riong [Kangwon National University, ChunCheon (Korea, Republic of); Kim, Soon-Ho [Silla University, Busan (Korea, Republic of)

    2014-01-15

    This paper identified the effects of Nb on microstructure. Also, it has studied on uniform and pitting corrosion resistance in a ferritic stainless steel weld metal of the automobile exhaust system. We fabricated 3 flux cored wires designed with 0-1.0 wt% Nb and performed Flux Cored Arc Welding. We observed the microstructure with the SEM/EDS and EBSD. To evaluate the uniform and pitting corrosion resistance, we performed a potentiodynamic polarization test in 0.2 M H{sub 2}SO{sub 4} and 0.1, 0.3, 0.5 M NaCl. As a result of the tests, we found that as the amount of addition of Nb rose, the amount of Cr-carbide fell. The microstructure became more refined. The specimen with 1.0%Nb added had the highest uniform and pitting corrosion resistance. After the pitting corrosion test, a pit was formed at the grain boundary that has no addition of Nb. In addition, in the specimen with added Nb, pits were formed at the inclusions.

  17. Corrosion Resistance of Zinc Coatings With Aluminium Additive

    Directory of Open Access Journals (Sweden)

    Votava Jiří

    2014-08-01

    Full Text Available This paper is focused on evaluation of anticorrosion protection of inorganic metal coatings such as hot-dipped zinc and zinc-galvanized coatings. The thickness and weight of coatings were tested. Further, the evaluation of ductile characteristics in compliance with the norm ČSN EN ISO 20482 was processed. Based on the scratch tests, there was evaluated undercorrosion in the area of artificially made cut. Corrosion resistance was evaluated in compliance with the norm ČSN EN ISO 9227 (salt-spray test. Based on the results of the anticorrosion test, there can be stated corrosion resistance of each individual protective coating. Tests were processed under laboratory conditions and may vary from tests processed under conditions of normal atmosphere.

  18. Is cell viability always directly related to corrosion resistance of stainless steels?

    International Nuclear Information System (INIS)

    Salahinejad, E.; Ghaffari, M.; Vashaee, D.; Tayebi, L.

    2016-01-01

    It has been frequently reported that cell viability on stainless steels is improved by increasing their corrosion resistance. The question that arises is whether human cell viability is always directly related to corrosion resistance in these biostable alloys. In this work, the microstructure and in vitro corrosion behavior of a new class of medical-grade stainless steels were correlated with adult human mesenchymal stem cell viability. The samples were produced by a powder metallurgy route, consisting of mechanical alloying and liquid-phase sintering with a sintering aid of a eutectic Mn–Si alloy at 1050 °C for 30 and 60 min, leading to nanostructures. In accordance with transmission electron microscopic studies, the additive particles for the sintering time of 30 min were not completely melted. Electrochemical impedance spectroscopic experiments suggested the higher corrosion resistance for the sample sintered for 60 min; however, a better cell viability on the surface of the less corrosion-resistant sample was unexpectedly found. This behavior is explained by considering the higher ion release rate of the Mn–Si additive material, as preferred sites to corrosion attack based on scanning electron microscopic observations, which is advantageous to the cells in vitro. In conclusion, cell viability is not always directly related to corrosion resistance in stainless steels. Typically, the introduction of biodegradable and biocompatible phases to biostable alloys, which are conventionally anticipated to be corrosion-resistant, can be advantageous to human cell responses similar to biodegradable metals. - Highlights: • Cell viability vs. corrosion resistance for medical-grade stainless steels • The stainless steel samples were prepared by powder metallurgy. • Unpenetrated additive played a critical role in the correlation.

  19. Is cell viability always directly related to corrosion resistance of stainless steels?

    Energy Technology Data Exchange (ETDEWEB)

    Salahinejad, E., E-mail: salahinejad@kntu.ac.ir [Faculty of Materials Science and Engineering, K.N. Toosi University of Technology, Tehran (Iran, Islamic Republic of); Ghaffari, M. [Bruker AXS Inc., 5465 East Cheryl Parkway, Madison, WI 53711 (United States); Vashaee, D. [Electrical and Computer Engineering Department, North Carolina State University, Raleigh, NC 27606 (United States); Tayebi, L. [Department of Developmental Sciences, Marquette University School of Dentistry, Milwaukee, WI 53201 (United States); Department of Engineering Science, University of Oxford, Oxford OX1 3PJ (United Kingdom)

    2016-05-01

    It has been frequently reported that cell viability on stainless steels is improved by increasing their corrosion resistance. The question that arises is whether human cell viability is always directly related to corrosion resistance in these biostable alloys. In this work, the microstructure and in vitro corrosion behavior of a new class of medical-grade stainless steels were correlated with adult human mesenchymal stem cell viability. The samples were produced by a powder metallurgy route, consisting of mechanical alloying and liquid-phase sintering with a sintering aid of a eutectic Mn–Si alloy at 1050 °C for 30 and 60 min, leading to nanostructures. In accordance with transmission electron microscopic studies, the additive particles for the sintering time of 30 min were not completely melted. Electrochemical impedance spectroscopic experiments suggested the higher corrosion resistance for the sample sintered for 60 min; however, a better cell viability on the surface of the less corrosion-resistant sample was unexpectedly found. This behavior is explained by considering the higher ion release rate of the Mn–Si additive material, as preferred sites to corrosion attack based on scanning electron microscopic observations, which is advantageous to the cells in vitro. In conclusion, cell viability is not always directly related to corrosion resistance in stainless steels. Typically, the introduction of biodegradable and biocompatible phases to biostable alloys, which are conventionally anticipated to be corrosion-resistant, can be advantageous to human cell responses similar to biodegradable metals. - Highlights: • Cell viability vs. corrosion resistance for medical-grade stainless steels • The stainless steel samples were prepared by powder metallurgy. • Unpenetrated additive played a critical role in the correlation.

  20. Electrochemical Corrosion Studies for Modeling Metallic Waste Form Release Rates

    Energy Technology Data Exchange (ETDEWEB)

    Poineau, Frederic [Univ. of Nevada, Las Vegas, NV (United States); Tamalis, Dimitri [Florida Memorial Univ., Miami Gardens, FL (United States)

    2016-08-01

    The isotope 99Tc is an important fission product generated from nuclear power production. Because of its long half-life (t1/2 = 2.13 ∙ 105 years) and beta-radiotoxicity (β⁻ = 292 keV), it is a major concern in the long-term management of spent nuclear fuel. In the spent nuclear fuel, Tc is present as an alloy with Mo, Ru, Rh, and Pd called the epsilon-phase, the relative amount of which increases with fuel burn-up. In some separation schemes for spent nuclear fuel, Tc would be separated from the spent fuel and disposed of in a durable waste form. Technetium waste forms under consideration include metallic alloys, oxide ceramics and borosilicate glass. In the development of a metallic waste form, after separation from the spent fuel, Tc would be converted to the metal, incorporated into an alloy and the resulting waste form stored in a repository. Metallic alloys under consideration include Tc–Zr alloys, Tc–stainless steel alloys and Tc–Inconel alloys (Inconel is an alloy of Ni, Cr and iron which is resistant to corrosion). To predict the long-term behavior of the metallic Tc waste form, understanding the corrosion properties of Tc metal and Tc alloys in various chemical environments is needed, but efforts to model the behavior of Tc metallic alloys are limited. One parameter that should also be considered in predicting the long-term behavior of the Tc waste form is the ingrowth of stable Ru that occurs from the radioactive decay of 99Tc (99Tc → 99Ru + β⁻). After a geological period of time, significant amounts of Ru will be present in the Tc and may affect its corrosion properties. Studying the effect of Ru on the corrosion behavior of Tc is also of importance. In this context, we studied the electrochemical behavior of Tc metal, Tc-Ni alloys (to model Tc-Inconel alloy) and Tc-Ru alloys in acidic media. The study of Tc-U alloys has also been performed in order to better understand the

  1. Predicting the Performance of Organic Corrosion Inhibitors

    Directory of Open Access Journals (Sweden)

    David A. Winkler

    2017-12-01

    Full Text Available The withdrawal of effective but toxic corrosion inhibitors has provided an impetus for the discovery of new, benign organic compounds to fill that role. Concurrently, developments in the high-throughput synthesis of organic compounds, the establishment of large libraries of available chemicals, accelerated corrosion inhibition testing technologies, and the increased capability of machine learning methods have made discovery of new corrosion inhibitors much faster and cheaper than it used to be. We summarize these technical developments in the corrosion inhibition field and describe how data-driven machine learning methods can generate models linking molecular properties to corrosion inhibition that can be used to predict the performance of materials not yet synthesized or tested. We briefly summarize the literature on quantitative structure–property relationships models of small organic molecule corrosion inhibitors. The success of these models provides a paradigm for rapid discovery of novel, effective corrosion inhibitors for a range of metals and alloys in diverse environments.

  2. Annealing effect on corrosion resistance of Bi{sub x}Ti{sub y}O{sub z} coatings

    Energy Technology Data Exchange (ETDEWEB)

    Pinzon, M. J.; Alfonsoa, J. E.; Olaya, J. J. [Universidad Nacional de Colombia, Grupo de Ciencia de Materiales y Superficies, Bogota AA 14490 (Colombia); Pineda Vargas, C. A., E-mail: jealfonsoo@unal.edu.co [iThemba LABS, Materials Research Department, PO Box 722, Somerset West 7129 (South Africa)

    2016-11-01

    Bismuth titanate (Bi-xTi{sub y}O{sub z}) has received widespread attention due to the fact that during recent times it has found important applications in strategic research fields such as optics and optoelectronic, and more recently studies have shown how their physicochemical properties may be harnessed in order to be able to use Bi{sub x}Ti{sub y}O{sub z}, as an anti corrosive coating. In this work bismuth titanate (Bi{sub x}Ti{sub y}O{sub z}) coatings were grown on titanium alloy (Ti6A14V) substrates, using RF magnetron sputtering at room temperature. The main objectives of the work were quantify the evolution of crystallographic phase formation, as a function of the annealing temperature, and establish the chemical composition in order to characterize the behaviour of the bismuth titanate coating as a protective coating of the corrosion. The morphology of the coating was observed via scanning electronic microscopy (Sem); the crystalline structure was characterized by X-ray diffraction (XRD) and the chemical composition was analyzed by Rutherford Backscattering Spectrometry (RBS). The corrosion resistance of the coatings was studied by potentiodynamic polarization (Pp) test (Tafel extrapolation). Sem results showed that the surface roughness of the coatings changed when the temperature of annealing increased. Similar change occurred after Pp tests. The XRD analysis revealed a change in the coatings microstructure as a function of the annealing temperature, since they evolved from a completely amorphous phase to a polycrystalline phase. RBS results indicate that coatings growing at high temperature have a complex chemical composition. Finally, the electrochemical analysis showed that the corrosion resistance of the coating is much better in the amorphous phases of bismuth titanate than in the polycrystalline phases. (Author)

  3. Hardface coating systems and methods for metal alloys and other materials for wear and corrosion resistant applications

    Science.gov (United States)

    Seals, Roland D.

    2015-08-18

    The present disclosure relates generally to hardface coating systems and methods for metal alloys and other materials for wear and corrosion resistant applications. More specifically, the present disclosure relates to hardface coatings that include a network of titanium monoboride (TiB) needles or whiskers in a matrix, which are formed from titanium (Ti) and titanium diboride (TiB.sub.2) precursors by reactions enabled by the inherent energy provided by the process heat associated with coating deposition and, optionally, coating post-heat treatment. These hardface coatings are pyrophoric, thereby generating further reaction energy internally, and may be applied in a functionally graded manner. The hardface coatings may be deposited in the presence of a number of fluxing agents, beta stabilizers, densification aids, diffusional aids, and multimode particle size distributions to further enhance their performance characteristics.

  4. Surface Treatment to Improve Corrosion Resistance in Lead-Alloy Coolants

    International Nuclear Information System (INIS)

    Todd R. Allen; Kumar Sridharan; McLean T. Machut; Lizhen Tan

    2007-01-01

    One of the six proposed advanced reactor designs of the Generation IV Initiative, the Lead-cooled Fast Reactor (LFR) possesses many characteristics that make it a desirable candidate for future nuclear energy production and responsible actinide management. These characteristics include favorable heat transfer, fluid dynamics, and neutronic performance compared to other candidate coolants. However, the use of a heavy liquid metal coolant presents a challenge for reactor designers in regards to reliable structural and fuel cladding materials in both a highly corrosive high temperature liquid metal and an intense radiation field. Flow corrosion studies at the University of Wisconsin have examined the corrosion performance of candidate materials for application in the LFR concept as well as the viability of various surface treatments to improve the materials compatibility. To date this research has included several focus areas, which include the formulation of an understanding of corrosion mechanisms and the examination of the effects of chemical and mechanical surface modifications on the materials performance in liquid lead-bismuth by experimental testing in Los Alamos National Laboratory's DELTA Loop, as well as comparison of experimental findings to numerical and physical models for long term corrosion prediction. This report will first review the literature and introduce the experiments and data that will be used to benchmark theoretical calculations. The experimental results will be followed by a brief review of the underlying theory and methodology for the physical and theoretical models. Finally, the results of theoretical calculations as well as experimentally obtained benchmarks and comparisons to the literature are presented

  5. Surface Treatment to Improve Corrosion Resistance in Lead-Alloy Coolants

    Energy Technology Data Exchange (ETDEWEB)

    Todd R. Allen; Kumar Sridharan; McLean T. Machut; Lizhen Tan

    2007-08-29

    One of the six proposed advanced reactor designs of the Generation IV Initiative, the Leadcooled Fast Reactor (LFR) possesses many characteristics that make it a desirable candidate for future nuclear energy production and responsible actinide management. These characteristics include favorable heat transfer, fluid dynamics, and neutronic performance compared to other candidate coolants. However, the use of a heavy liquid metal coolant presents a challenge for reactor designers in regards to reliable structural and fuel cladding materials in both a highly corrosive high temperature liquid metal and an intense radiation fieldi. Flow corrosion studies at the University of Wisconsin have examined the corrosion performance of candidate materials for application in the LFR concept as well as the viability of various surface treatments to improve the materials’ compatibility. To date this research has included several focus areas, which include the formulation of an understanding of corrosion mechanisms and the examination of the effects of chemical and mechanical surface modifications on the materials’ performance in liquid lead-bismuth by experimental testing in Los Alamos National Laboratory’s DELTA Loop, as well as comparison of experimental findings to numerical and physical models for long term corrosion prediction. This report will first review the literature and introduce the experiments and data that will be used to benchmark theoretical calculations. The experimental results will be followed by a brief review of the underlying theory and methodology for the physical and theoretical models. Finally, the results of theoretical calculations as well as experimentally obtained benchmarks and comparisons to the literature are presented.

  6. Tank vent processing system having a corrosion preventive device

    International Nuclear Information System (INIS)

    Ouchi, Shoichi; Sato, Hirofumi

    1987-01-01

    Purpose: To prevent corrosion of a tank vent processing device by injecting an oxygen gas. Constitution: Oxygen gas and phosphorous at high temperature are poured into a tank vent processing device and amorphous oxide layers optimum to the prevention of external corrosion are formed to the inner surface of the device. Since the corrosion preventive device using the oxygen gas injection can be constituted as a relatively simple device, it is more economical than constituting a relatively large tank vent processing device with corrosion resistant stainless steels. (Kamimura, M.)

  7. Behavior of high resistance to He{sup 2+} induced irradiation damage in metallic glass

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Bin [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024 (China); Mei, Xianxiu, E-mail: xxmei@dlut.edu.cn [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024 (China); Hou, Wenjing; Wang, Younian [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024 (China); Wang, Zhiguang [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Dong, Chuang [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024 (China)

    2013-10-01

    Highlights: •Metallic glasses and W were irradiated with 500 keV He{sup 2+} at different fluences. •Metallic glasses could maintain amorphous state at different irradiation fluences. •The resistance to He{sup 2+} irradiation of metallic glasses was superior to the one in W metal. •Cu- and Zr-based metallic glasses had better resistance to He{sup 2+} irradiation. -- Abstract: This study details the irradiation of various metallic glasses ((Cu{sub 47}Zr{sub 45}Al{sub 8}){sub 98.5}Y{sub 1.5}, Zr{sub 64}Cu{sub 17.8}Ni{sub 10.7}Al{sub 7.5}, Co{sub 61.2}B{sub 26.2}Si{sub 7.8}Ta{sub 4.8}) and metallic W using He{sup 2+} ions with an energy of 500 keV at irradiation fluences of 2 × 10{sup 17}, 1 × 10{sup 18} and 2 × 10{sup 18} ions/cm{sup 2} to investigate the radiation-resistant properties of these metallic glasses compared to the conventional irradiation-resistant material W. These three metallic glasses were able to maintain an amorphous state during these irradiation fluences. There was no significant irradiation damage at the low irradiation fluence. When the irradiation fluence was increased to 2 × 10{sup 18} ions/cm{sup 2}, a damage layer appeared up to a distance corresponding to the range of the ions away from the surfaces of the Cu- and Zr-based metallic glasses without any visible damage on the surface. Significant surface stripping damage appeared in the Co-based metallic glass. Relatively speaking, surface layer peeling appeared in metallic W along the crystal boundary at a fluence of 1 × 10{sup 18} ions/cm{sup 2}. When the fluence was increased to 2 × 10{sup 18} ions/cm{sup 2}, multilayer peeling, stripping, etc. appeared. The roughness of the Cu- and Zr-based metallic glass showed further smoothing with increasing fluence, while the opposite occurred in the Co-based metallic glass. Within the wavelength range of 400–1700 nm, after irradiation of He{sup 2+} at a fluence of 1 × 10{sup 18} ions/cm{sup 2}, the reflectance of the Cu-based and Co

  8. The effect of fatigue on the corrosion resistance of common medical alloys.

    Science.gov (United States)

    Di Prima, Matthew; Gutierrez, Erick; Weaver, Jason D

    2017-10-01

    The effect of mechanical fatigue on the corrosion resistance of medical devices has been a concern for devices that experience significant fatigue during their lifespan and devices made from metallic alloys. The Food and Drug Administration had recommended in some instances for corrosion testing to be performed on post-fatigued devices [Non-clinical tests and recommended labeling for intravascular stents and associated delivery systems: guidance for industry and FDA staff. 2005: Food and Drug Administration, Center for Devices and Radiological Health], although the need for this has been debated [Nagaraja S, et al., J Biomed Mater Res Part B: Appl Biomater 2016, 8.] This study seeks to evaluate the effect of fatigue on the corrosion resistance of 5 different materials commonly used in medical devices: 316 LVM stainless steel, MP35N cobalt chromium, electropolished nitinol, mechanically polished nitinol, and black oxide nitinol. Prior to corrosion testing per ASTM F2129, wires of each alloy were split into subgroups and subjected to either nothing (that is, as received); high strain fatigue for less than 8 min; short-term phosphate buffered saline (PBS) soak for less than 8 min; low strain fatigue for 8 days; or long-term PBS soak for 8 days. Results from corrosion testing showed that the rest potential trended to an equilibrium potential with increasing time in PBS and that there was no statistical (p > 0.05) difference in breakdown potential between the fatigued and matching PBS soak groups for 9 out of 10 test conditions. Our results suggest that under these nonfretting conditions, corrosion susceptibility as measured by breakdown potential per ASTM F2129 was unaffected by the fatigue condition. 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2019-2026, 2017. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

  9. Contribution to the study of metallic materials bio-corrosion phenomena

    International Nuclear Information System (INIS)

    Feron, D.

    2004-05-01

    After having recalled the main electrochemical methods used for the study of metallic materials bio-deterioration phenomena, the corrosion of non or low alloy steels in anaerobic conditions is dealt with: the obtained results reveal a strong interaction between the metallic ions and the growth of sulfato reducing bacteria with inhibiting or accelerating ions of this growth. Concerning the corrosion, the chromium and molybdenum additions have a favourable effect on the resistance of low alloy steels. The sulfides impose the electrochemical behaviour of these materials, whereas the role of hydrogenases on the cathodic reaction is still to be specified to explain the observed localized corrosion, including the pure cultures of sulfato-reducing bacteria. The behaviour of stainless steels in seawater can be explained by an enzymatic catalysis of the cathodic reaction. Such a model takes into account the general behaviour of passivable alloys in natural waters in a general way and has allowed to perfect a synthetic seawater which leads to corrosion phenomena by crevice effect on stainless steels similar to those observed in natural seawater. The coupling of the aerobic conditions with the leading part of the enzymes on the cathodic reaction and of the anaerobic conditions with the presence of sulfides (which decrease the resistance of the passive layer) is the most unfavourable situation for the resistance of passivable alloys. These results lead to the concept of electrochemically activated bio-films which could be used in particular in energy production (fuel cells). (O.M.)

  10. The corrosion resistance of Zr-Nb and Zr-Nb-Sn alloys in high-temperature water and steam

    International Nuclear Information System (INIS)

    Dalgaard, S.B.

    1960-03-01

    An alloy of reactor-grade sponge zirconium-2.5 wt. % niobium was exposed to water and steam at high temperature. The corrosion was twice that of Zircaloy-2 while hydrogen pickup was found to be equal to that of Zircaloy-2. Ternary additions of tin to this alloy in the range 0.5-1.5 had no effect on the corrosion resistance in water at 315 o C up to 100 days. At higher temperatures, tin increased the corrosion, the effect varying with temperature. Heat treatment of the alloys was shown to affect corrosion resistance. (author)

  11. The corrosion resistance of Zr-Nb and Zr-Nb-Sn alloys in high-temperature water and steam

    Energy Technology Data Exchange (ETDEWEB)

    Dalgaard, S B

    1960-03-15

    An alloy of reactor-grade sponge zirconium-2.5 wt. % niobium was exposed to water and steam at high temperature. The corrosion was twice that of Zircaloy-2 while hydrogen pickup was found to be equal to that of Zircaloy-2. Ternary additions of tin to this alloy in the range 0.5-1.5 had no effect on the corrosion resistance in water at 315{sup o}C up to 100 days. At higher temperatures, tin increased the corrosion, the effect varying with temperature. Heat treatment of the alloys was shown to affect corrosion resistance. (author)

  12. Vibrational dynamics of amorphous metals by inelastic neutron and raman scattering

    International Nuclear Information System (INIS)

    Lustig, N.E.

    1986-01-01

    Time-of-flight inelastic neutron scattering and Raman measurements were performed on amorphous (a-) metals. The neutron-weighted vibrational density of states, G(E), obtained for a-Fe 78 P 22 , a-Ni 82 B 18 and a-Ni 67 B 33 transition metal metalloid alloys (TM-m), indicated two major vibrational bands: a low frequency acoustic-like band and a high frequency optic-like band, derived from TM-TM and TM-m interactions, respectively. Similar neutron measurements were performed on the corresponding polycrystalline (c-) alloys, c-Fe 3 P and c-Ni 2 B. A comparison of the amorphous and crystalline densities of states indicates the elimination of sharp features and the addition of vibrational states at low and high frequencies upon amorphization. The experimental G(E) results for a-Fe 78 P 22 are in good agreement with the theoretically predicted spectrum. A comparison between the a-Ni 67 B 33 and the phenomenologically broadened c-Ni 2 B spectrum indicates a change in the short-range order. This finding is consistent with structural measurements on this alloy. Raman measurements were carried out using interference enhanced Raman spectroscopy (IERS) on thin film Ni-B alloys. The measured spectra provide information about the weighted phonon density of states, and is in good agreement with the neutron results

  13. Is cell viability always directly related to corrosion resistance of stainless steels?

    Science.gov (United States)

    Salahinejad, E; Ghaffari, M; Vashaee, D; Tayebi, L

    2016-05-01

    It has been frequently reported that cell viability on stainless steels is improved by increasing their corrosion resistance. The question that arises is whether human cell viability is always directly related to corrosion resistance in these biostable alloys. In this work, the microstructure and in vitro corrosion behavior of a new class of medical-grade stainless steels were correlated with adult human mesenchymal stem cell viability. The samples were produced by a powder metallurgy route, consisting of mechanical alloying and liquid-phase sintering with a sintering aid of a eutectic Mn-Si alloy at 1050 °C for 30 and 60 min, leading to nanostructures. In accordance with transmission electron microscopic studies, the additive particles for the sintering time of 30 min were not completely melted. Electrochemical impedance spectroscopic experiments suggested the higher corrosion resistance for the sample sintered for 60 min; however, a better cell viability on the surface of the less corrosion-resistant sample was unexpectedly found. This behavior is explained by considering the higher ion release rate of the Mn-Si additive material, as preferred sites to corrosion attack based on scanning electron microscopic observations, which is advantageous to the cells in vitro. In conclusion, cell viability is not always directly related to corrosion resistance in stainless steels. Typically, the introduction of biodegradable and biocompatible phases to biostable alloys, which are conventionally anticipated to be corrosion-resistant, can be advantageous to human cell responses similar to biodegradable metals. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. The Formation Mechanism and Corrosion Resistance of a Composite Phosphate Conversion Film on AM60 Alloy.

    Science.gov (United States)

    Chen, Jun; Lan, Xiangna; Wang, Chao; Zhang, Qinyong

    2018-03-08

    Magnesium alloy AM60 has high duc and toughness, which is expected to increase in demand for automotive applications. However, it is too active, and coatings have been extensively studied to prevent corrosion. In this work, a Ba-containing composite phosphate film has been prepared on the surface of AM60. The composition and formation mechanism of the film have been investigated using a scanning electronic microscope equipped with energy dispersive X-ray spectroscopy, Fourier transform infrared, X-ray photoelectron spectroscopy, and X-ray diffractometry tests. The corrosion resistance of the film has been measured by electrochemical and immersion tests. The results show that the deposition film has fully covered the substrate but there are some micro-cracks. The structure of the film is complex, and consists of MgHPO₄·3H₂O, MnHPO₄·2.25H₂O, BaHPO₄·3H₂O, BaMg₂(PO₄)₂, Mg₃(PO₄)₂·22H₂O, Ca₃(PO₄)₂·xH₂O, and some amorphous phases. The composite phosphate film has better anticorrosion performance than the AM60 and can protect the bare alloy from corrosion for more than 12 h in 0.6 M NaCl.

  15. Design of multi materials combining crystalline and amorphous metallic alloys

    International Nuclear Information System (INIS)

    Volland, A.; Ragani, J.; Liu, Y.; Gravier, S.; Suéry, M.; Blandin, J.J.

    2012-01-01

    Highlights: ► Elaboration of multi materials associating metallic glasses and conventional crystalline alloys by co-deformation performed at temperatures close to the glass transition temperature of the metallic glasses. ► Elaboration of filamentary metal matrix composites with a core in metallic glass by co extrusion. ► Sandwich structures produced by co-pressing. ► Detection of atomic diffusion from the glass to the crystalline alloys during the processes. ► Good interfaces between the metallic glasses and the crystalline alloys, as confirmed by mechanical characterisation. - Abstract: Multi materials, associating zirconium based bulk metallic glasses and crystalline metallic alloys like magnesium alloys or copper are elaborated by co-deformation processing performed in the supercooled liquid regions (SLR) of the bulk metallic glasses. Two processes are investigated: co-extrusion and co-pressing. In the first case, filamentary composites with various designs can be produced whereas in the second case sandwich structures are obtained. The experimental window (temperature, time) in which processing can be carried out is directly related to the crystallisation resistance of the glass which requires getting information about the crystallisation conditions in the selected metallic glasses. Thermoforming windows are identified for the studied BMGs by thermal analysis and compression tests in their SLR. The mechanical properties of the produced multi materials are investigated thanks to specifically developed mechanical devices and the interfaces between the amorphous and the crystalline alloys are characterised.

  16. A new corrosion resistant, martensitic stainless steel for improved performance in miniature bearings

    Energy Technology Data Exchange (ETDEWEB)

    Tomasello, C.M.; Maloney, J.L.; Materkowski, J.P. [Latrobe Steel Co., Latrobe, PA (United States); Ward, P.C. [MPB Corp., Keene, NH (United States)

    1998-12-31

    A new alloy, 440 N-DUR{trademark} has been developed which will provide the corrosion resistance of 440C with improved carbide size and distribution for noiseless miniature precision bearing operation. The alloy may be through hardened to achieve a minimum hardness of 60 HRC. Its nominal composition is 0.65 wt.% C, 14.5 wt.% Cr, 0.30 wt.% Si, 0.45 wt.% Mn and 0.10 wt.% N{sub 2}. The development of the alloy is a result of a factorial experimental design including 17 alloy variants. The optimum alloy provides a combination of the best carbide structure, corrosion resistance and heat treat response. The addition of nitrogen combined with this carbon and chromium content improves the alloy`s hardenability and corrosion resistance. The alloy successfully withstands copper sulfate exposure and is currently being tested in several bearing applications. It also has great potential to outperform 440C and other corrosion resistant alloys for other ambient and low temperature applications because of its improved microstructure and heat treat response.

  17. Effect of Carbide Dissolution on Chlorine Induced High Temperature Corrosion of HVOF and HVAF Sprayed Cr3C2-NiCrMoNb Coatings

    Science.gov (United States)

    Fantozzi, D.; Matikainen, V.; Uusitalo, M.; Koivuluoto, H.; Vuoristo, P.

    2018-01-01

    Highly corrosion- and wear-resistant thermally sprayed chromium carbide (Cr3C2)-based cermet coatings are nowadays a potential highly durable solution to allow traditional fluidized bed combustors (FBC) to be operated with ecological waste and biomass fuels. However, the heat input of thermal spray causes carbide dissolution in the metal binder. This results in the formation of carbon saturated metastable phases, which can affect the behavior of the materials during exposure. This study analyses the effect of carbide dissolution in the metal matrix of Cr3C2-50NiCrMoNb coatings and its effect on chlorine-induced high-temperature corrosion. Four coatings were thermally sprayed with HVAF and HVOF techniques in order to obtain microstructures with increasing amount of carbide dissolution in the metal matrix. The coatings were heat-treated in an inert argon atmosphere to induce secondary carbide precipitation. As-sprayed and heat-treated self-standing coatings were covered with KCl, and their corrosion resistance was investigated with thermogravimetric analysis (TGA) and ordinary high-temperature corrosion test at 550 °C for 4 and 72 h, respectively. High carbon dissolution in the metal matrix appeared to be detrimental against chlorine-induced high-temperature corrosion. The microstructural changes induced by the heat treatment hindered the corrosion onset in the coatings.

  18. High corrosion resistance of magnesium coated with hydroxyapatite directly synthesized in an aqueous solution

    International Nuclear Information System (INIS)

    Hiromoto, Sachiko; Yamamoto, Akiko

    2009-01-01

    Anticorrosion coatings are crucial for practical applications of magnesium alloys, which are used to reduce the weight of vehicles, aircraft, electronics enclosures etc. Hydroxyapatite (HAp) potentially offers high corrosion resistance and no environmental toxicity because its thermodynamic structural stability is high and it is a basic component of bone. However, direct synthesis of HAp on magnesium in aqueous solutions has been a scientific challenge because Mg ions prevent HAp crystallization. A new method of direct synthesis of HAp on magnesium was developed using a Ca chelate compound, which can maintain a sufficiently high concentration of Ca ions on the magnesium surface to overcome prevention of HAp crystallization with Mg ions. Highly crystallized HAp coatings were successfully formed on pure magnesium and AZ series alloys. Corrosion behavior of HAp-coated pure magnesium was examined by cyclic dry and wet tests with 1 g m -2 NaCl on the surface and polarization tests in a 3.5 wt% NaCl solution. A HAp-coated pure magnesium showed no noticeable corrosion pits after the dry and wet test. HAp-coated specimens showed 10 3 -10 4 times lower anodic current density than as-polished specimen in the polarization test. The results demonstrate the remarkable anticorrosion performance of HAp coatings on magnesium for the first time.

  19. Analytical theory of noncollinear amorphous metallic magnetism

    International Nuclear Information System (INIS)

    Kakehashi, Y.; Uchida, T.

    2001-01-01

    Analytical theory of noncollinear magnetism in amorphous metals is proposed on the basis of the Gaussian model for the distribution of the interatomic distance and the saddle-point approximation. The theory removes the numerical difficulty in the previous theory based on the Monte-Carlo sampling method, and reasonably describes the magnetic properties of amorphous transition metals

  20. Inspection about the corrosion of metallic archaeological artifacts in ground. 3

    International Nuclear Information System (INIS)

    Honda, Takashi; Yamaguchi, Shingo

    2003-01-01

    The corrosion behaviors of iron-based archaeological remains, which were dug out in six relics in Aomori-ken and Izumotaisya-keidai-iseki, were analyzed mainly with using X-ray CT. Several samples were cut and investigated on the details of metals and oxide films. The soils were also analyzed on redox-potential, resistance, chemical contents, and others. The results indicate that metal remains in 7/14 samples. The corrosion amounts of objects of Aomori-ken were estimated to be from 1 to 4 mm during 400-1000 years. The environments were supposed to be oxidizing. On the other hands, it is supposed that two objects in Izumotaisya-keidai-iseki were in a reducing condition. The corrosion amounts were 0.5-2 mm. Furthermore, the corrosion behavior of the cast gas-pipe, which had been buried for about 130 years, were evaluated. By analyzing analysis data of soil, the environment is estimated to be weak oxidizing, and the maximum graphitic corrosion depth was about 7 mm. (author)

  1. Structure Analysis Of Corrosion Resistant Thermal Sprayed Coatings On Low Alloy Steels

    Science.gov (United States)

    Chaliampalias, D.; Vourlias, G.; Pistofidis, N.; Pavlidou, E.; Stergiou, A.; Stergioudis, G.; Polychroniadis, E. K.

    2007-04-01

    Metallic coatings have been proved to reduce the rate of corrosion of steel in various atmospheres. In this work the structure of Al, Cu-Al and Zn thermal sprayed coatings is examined. The as formed coatings are extremely rough, and they are composed of several phases which increase corrosion resistance as it was determined Salt Spray Chamber tests.

  2. Corrosion Resistance of Some Stainless Steels in Chloride Solutions

    Directory of Open Access Journals (Sweden)

    Kasprzyk D.

    2017-06-01

    Full Text Available The present work compares corrosion behaviour of four types of S30403, S31603, S32615 austenitic and S32404 austenitic-ferritic stainless steels in chloride solutions (1%, 3% NaCl and in Ringer solution, at 37°C temperature. Corrosion resistance was determined by potentiodynamic polarization measurements and a thirty day immersion test conducted in Ringer solution. The immersion test was performed in term of biomedical application. These alloy were spontaneously passivated in all electrolytes, wherein S30403, S31603 and S32404 undergo pitting corrosion. Only S32615 containing 5.5% Si shows resistance to pitting corrosion.

  3. Thermal Spray Coatings for High-Temperature Corrosion Protection in Biomass Co-Fired Boilers

    Science.gov (United States)

    Oksa, M.; Metsäjoki, J.; Kärki, J.

    2015-01-01

    There are over 1000 biomass boilers and about 500 plants using waste as fuel in Europe, and the numbers are increasing. Many of them encounter serious problems with high-temperature corrosion due to detrimental elements such as chlorides, alkali metals, and heavy metals. By HVOF spraying, it is possible to produce very dense and well-adhered coatings, which can be applied for corrosion protection of heat exchanger surfaces in biomass and waste-to-energy power plant boilers. Four HVOF coatings and one arc sprayed coating were exposed to actual biomass co-fired boiler conditions in superheater area with a probe measurement installation for 5900 h at 550 and 750 °C. The coating materials were Ni-Cr, IN625, Fe-Cr-W-Nb-Mo, and Ni-Cr-Ti. CJS and DJ Hybrid spray guns were used for HVOF spraying to compare the corrosion resistance of Ni-Cr coating structures. Reference materials were ferritic steel T92 and nickel super alloy A263. The circulating fluidized bed boiler burnt a mixture of wood, peat and coal. The coatings showed excellent corrosion resistance at 550 °C compared to the ferritic steel. At higher temperature, NiCr sprayed with CJS had the best corrosion resistance. IN625 was consumed almost completely during the exposure at 750 °C.

  4. In vitro corrosion behavior of bioceramic, metallic, and bioceramic-metallic coated stainless steel dental implants.

    Science.gov (United States)

    Fathi, M H; Salehi, M; Saatchi, A; Mortazavi, V; Moosavi, S B

    2003-05-01

    The most common metals and alloys used in dentistry may be exposed to a process of corrosion in vivo that make them cytotoxic. The biocompatibility of dental alloys is primarily related to their corrosion behavior. The aim of this work was to evaluate the corrosion behavior and thus the biocompatibility of the uncoated and coated stainless steels and compare the effect of type of coatings on corrosion behavior. Three types of coatings, hydroxyapatite (HA), titanium (Ti), and a double-layer HA/Ti on AISI 316L stainless steel were made. HA coating was produced using plasma-spraying technique and Ti coating was made using physical vapor deposition process. In order to perform a novel double-layer composite coating, a top layer of HA was plasma-sprayed over a physical vapor deposited Ti layer on AISI 316L stainless steel. Structural characterization techniques including XRD, SEM and EDX were used to investigate the microstructure, morphology and crystallinity of the coatings. Electrochemical potentiodynamic tests were performed in physiological solutions in order to determine and compare the corrosion behavior of the coated and uncoated specimens as an indication of biocompatibility. Double-layer HA/Ti coating on AISI 316L SS had a positive effect on improvement of corrosion behavior. The decrease in corrosion current densities was significant for these coated specimens and was much lower than the values obtained for uncoated and single HA coated specimens. Ti coating on AISI 316L SS also has a beneficial effect on corrosion behavior. The results were compared with the results of corrosion behavior of HA coated commercially pure titanium (cpTi) and uncoated cpTi. These results demonstrated that the double-layer HA/Ti coated 316L SS can be used as an endodontic implant and two goals including improvement of corrosion resistance and bone osteointegration can be obtained simultaneously.

  5. Constructing superhydrophobic WO3@TiO2 nanoflake surface beyond amorphous alloy against electrochemical corrosion on iron steel

    Science.gov (United States)

    Yu, S. Q.; Ling, Y. H.; Wang, R. G.; Zhang, J.; Qin, F.; Zhang, Z. J.

    2018-04-01

    To eliminate harmful localized corrosion, a new approach by constructing superhydrophobic WO3@TiO2 hierarchical nanoflake surface beyond FeW amorphous alloy formed on stainless steel was proposed. Facile dealloying and liquid deposition was employed at low temperature to form a nanostructured layer composing inner WO3 nanoflakes coated with TiO2 nanoparticles (NPs) layer. After further deposition of PFDS on nanoflakes, the contact angle reached 162° while the corrosion potential showed a negative shift of 230 mV under illumination, resulting in high corrosion resistance in 3.5 wt% NaCl solution. The tradeoff between superhydrophobic surface and photo-electro response was investigated. It was found that this surface feature makes 316 SS be immune to localized corrosion and a pronounced photo-induced process of electron storage/release as well as the stability of the functional layer were detected with or without illumination, and the mechanism behind this may be related to the increase of surface potential due to water repellence and the delayed cathodic protection of semiconducting coating derived mainly from the valence state changes of WO3. This study demonstrates a simple and low-cost electrochemical approach for protection of steel and novel means to produce superhydrophobic surface and cathodic protection with controllable electron storage/release on engineering scale.

  6. Stress corrosion in high-strength aluminum alloys

    Science.gov (United States)

    Dorward, R. C.; Hasse, K. R.

    1980-01-01

    Report describes results of stress-corrosion tests on aluminum alloys 7075, 7475, 7050, and 7049. Tests compare performance of original stress-corrosion-resistant (SCR) aluminum, 7075, with newer, higher-strength SCR alloys. Alloys 7050 and 7049 are found superior in short-transverse cross-corrosion resistance to older 7075 alloy; all alloys are subject to self-loading effect caused by wedging of corrosion products in cracks. Effect causes cracks to continue to grow, even at very-low externally applied loads.

  7. Study on corrosion resistance of high - entropy alloy in medium acid liquid and chemical properties

    International Nuclear Information System (INIS)

    Florea, I; Buluc, G; Florea, R M; Carcea, I; Soare, V

    2015-01-01

    High-entropy alloy is a new alloy which is different from traditional alloys. The high entropy alloys were started in Tsing Hua University of Taiwan since 1995 by Yeh et al. Consisting of a variety of elements, each element occupying a similar compared with other alloy elements to form a high entropy. We could define high entropy alloys as having approximately equal concentrations, made up of a group of 5 to 11 major elements. In general, the content of each element is not more than 35% by weight of the alloy. During the investigation it turned out that this alloy has a high hardness and is also corrosion proof and also strength and good thermal stability. In the experimental area, scientists used different tools, including traditional casting, mechanical alloying, sputtering, splat-quenching to obtain the high entropy alloys with different alloying elements and then to investigate the corresponding microstructures and mechanical, chemical, thermal, and electronic performances. The present study is aimed to investigate the corrosion resistance in a different medium acid and try to put in evidence the mechanical properties. Forasmuch of the wide composition range and the enormous number of alloy systems in high entropy alloys, the mechanical properties of high entropy alloys can vary significantly. In terms of hardness, the most critical factors are: hardness/strength of each composing phase in the alloy, distribution of the composing phases. The corrosion resistance of an high entropy alloy was made in acid liquid such as 10%HNO 3 -3%HF, 10%H 2 SO 4 , 5%HCl and then was investigated, respectively with weight loss experiment. Weight loss test was carried out by put the samples into the acid solution for corrosion. The solution was maintained at a constant room temperature. The liquid formulations used for tests were 3% hydrofluoric acid with 10% nitric acid, 10% sulphuric acid, 5% hydrochloric acid. Weight loss of the samples was measured by electronic scale. (paper)

  8. High temperature corrosion of metallic interconnects in solid oxide fuel cells

    International Nuclear Information System (INIS)

    Bastidas, D. M.

    2006-01-01

    Research and development has made it possible to use metallic interconnects in solid oxide fuel cells (SOFC) instead of ceramic materials. The use of metallic interconnects was formerly hindered by the high operating temperature, which made the interconnect degrade too much and too fast to be an efficient alternative. When the operating temperature was lowered, the use of metallic interconnects proved to be favourable since they are easier and cheaper to produce than ceramic interconnects. However, metallic interconnects continue to be degraded despite the lowered temperature, and their corrosion products contribute to electrical degradation in the fuel cell. coatings of nickel, chromium, aluminium, zinc, manganese, yttrium or lanthanum between the interconnect and the electrodes reduce this degradation during operation. (Author) 66 refs

  9. Corrosion of valve metals

    International Nuclear Information System (INIS)

    Draley, J.E.

    1976-01-01

    A general survey related to the corrosion of valve metals or film-forming metals. The way these metals corrode with some general examples is described. Valve metals form relatively perfect oxide films with little breakdown or leakage when anodized

  10. Acoustic emission analysis coupled with thermogravimetric experiments dedicated to high temperature corrosion studies on metallic alloys

    International Nuclear Information System (INIS)

    Serris, Eric; Al Haj, Omar; Peres, Veronique; Cournil, Michel; Kittel, Jean; Grosjean, Francois; Ropital, Francois

    2014-01-01

    High temperature corrosion of metallic alloys (like iron, nickel, zirconium alloys) can damage equipment of many industrial fields (refinery, petrochemical, nuclear..). Acoustic emission (AE) is an interesting method owing to its sensitivity and its non-destructive aspect to quantify the level of damage in use of these alloys under various environmental conditions. High temperature corrosive phenomena create stresses in the materials; the relaxation by cracks of these stresses can be recorded and analyzed using the AE system. The goal of our study is to establish an acoustic signals database which assigns the acoustic signals to the specific corrosion phenomena. For this purpose, thermogravimetric analysis (TGA) is coupled with acoustic emission (AE) devices. The oxidation of a zirconium alloy, zircaloy-4, is first studied using thermogravimetric experiment coupled to acoustic emission analysis at 900 C. An inward zirconium oxide scale, preliminary dense, then porous, grow during the isothermal isobaric step. The kinetic rate increases significantly after a kinetic transition (breakaway). This acceleration occurs with an increase of acoustic emission activity. Most of the acoustic emission bursts are recorded after the kinetic transition. Acoustic emission signals are also observed during the cooling of the sample. AE numerical treatments (using wavelet transform) completed by SEM microscopy characterizations allows us to distinguish the different populations of cracks. Metal dusting represents also a severe form of corrosive degradation of metal alloy. Iron metal dusting corrosion is studied by AE coupled with TGA at 650 C under C 4 H 10 + H 2 + He atmosphere. Acoustic emission signals are detected after a significant increase of the sample mass.

  11. Localized corrosion information using high resolution measurement devices

    DEFF Research Database (Denmark)

    Ambat, Rajan

    2005-01-01

    High performance demand for several engineering alloys and components, and miniaturization of electronics and development of MEMS requires better understanding of local corrosion characteristics frequently down to µm scale. This is because in metallic materials corrosion is a sensitive function...... in conjunction with microstructural analysis, using advanced microscopic tools, becomes very important. Corrosion of microelectronics circuits and MEMs is also a recent problem, which demands measurement resolution down to few microns as the components are extremely small, and measurement needs to be carried out...

  12. Evaluation of cytotoxicity and corrosion resistance of orthodontic mini-implants.

    Science.gov (United States)

    Alves, Celha Borges Costa; Segurado, Márcio Nunes; Dorta, Miriam Cristina Leandro; Dias, Fátima Ribeiro; Lenza, Maurício Guilherme; Lenza, Marcos Augusto

    2016-01-01

    To evaluate and compare in vitro cytotoxicity and corrosion resistance of mini-implants from three different commercial brands used for orthodontic anchorage. Six mini-implants (Conexão(tm), Neodent(tm) and SIN(tm)) were separately immersed in artificial saliva (pH 6.76) for 30 and 60 days. The cytotoxicity of the corrosion extracts was assessed in L929 cell cultures using the violet crystal and MTT assays, as well as cell morphology under light microscopy. Metal surface characteristics before and after immersion in artificial saliva were assessed by means of scanning electron microscopy (SEM). The samples underwent atomic absorption spectrophotometry to determine the concentrations of aluminum and vanadium ions, constituent elements of the alloy that present potential toxicity. For statistical analysis, one-way ANOVA/Bonferroni tests were used for comparisons among groups with p < 0.05 considered significant. Statistical analysis was carried out with Graph Pad PRISM software Version 4.0. No changes in cell viability or morphology were observed. Mini-implants SEM images revealed smooth surfaces with no obvious traces of corrosion. The extracts assessed by means of atomic absorption spectrophotometry presented concentrations of aluminum and vanadium ions below 1.0 µg/mL and 0.5 µg/mL, respectively. Orthodontic mini-implants manufactured by Conexão(tm), Neodent(tm) and SIN(tm) present high corrosion resistance and are not cytotoxic.

  13. Water corrosion resistance of ODS ferritic-martensitic steel tubes

    International Nuclear Information System (INIS)

    Narita, Takeshi; Ukai, Shigeharu; Kaito, Takeji; Ohtsuka, Satoshi; Matsuda, Yasuji

    2008-01-01

    Oxide dispersion strengthened (ODS) ferritic-martensitic steels have superior radiation resistance; it is possible to achieve a service temperature of up to around 973 K because of their superior creep strength. These advantages of ODS steels facilities their application to long-life cladding tubes in advanced fast reactor fuel elements. In addition to neutron radiation resistance, sufficient general corrosion resistance to maintain the strength of the cladding, and the stress corrosion cracking (SCC) resistance for spent-fuel-pool cooling systems and high-temperature oxidation for the fuel-clad chemical interaction (FCCI) of ODS ferritic steel are required. Although the addition of Cr to ODS is effective in preventing water corrosion and high-temperature oxidation, an excessively high amount of Cr leads to embrittlement due to the formation of a Cr-rich α' precipitate. The Cr content in 9Cr-ODS martensite and 12Cr-ODS ferrite, the ODS steels developed by the Japan Atomic Energy Agency (JAEA), is controlled. In a previous paper, it has been demonstrated that the resistances of 9Cr- and 12Cr-ODS ferritic-martensitic steels for high-temperature oxidation are superior to those of conventional 12Cr ferritic steel. However, the water corrosion data of ODS ferritic-martensitic steels are very limited. In this study, a water corrosion test was conducted on ODS steels in consideration of the spent-fuel-pool cooling condition, and the results were compared with those of conventional austenitic stainless steel and ferritic-martensitic stainless steel. (author)

  14. Mechanism of selective corrosion in electrical resistance seam welded carbon steel pipe

    Energy Technology Data Exchange (ETDEWEB)

    Lopez Fajardo, Pedro; Godinez Salcedo, Jesus; Gonzalez Velasquez, Jorge L. [Instituto Politecnico Nacional, Mexico D.F., (Mexico). Escuela Superior de Ingenieria Quimica e Industrias Extractivas. Dept. de Ingenieria Metalurgica

    2009-07-01

    In this investigation the studies of the mechanism of selective corrosion in electrical resistance welded (ERW) carbon steel pipe was started. Metallographic characterizations and evaluations for inclusions were performed. The susceptibility of ERW pipe to selective corrosion in sea water (NACE 1D182, with O{sub 2} or CO{sub 2} + H{sub 2}S) was studied by the stepped potential Potentiostatic electrochemical test method in samples of 1 cm{sup 3} (ASTM G5) internal surface of the pipe (metal base-weld). The tests were looking for means for predicting the susceptibility of ERW pipe to selective corrosion, prior to placing the pipeline in service. Manganese sulfide inclusions are observed deformed by the welding process and they are close to the weld centerline. A slight decarburization at the weld line is observed, and a distinct out bent fiber pattern remains despite the post-weld seam annealing. The microstructure of the weld region consists of primarily polygonal ferrite grains mixed with small islands of pearlite. It is possible to observe the differences of sizes of grain of the present phases in the different zones. Finally, scanning electron microscopic observation revealed that the corrosion initiates with the dissolution of MnS inclusions and with small crack between the base metal and ZAC. (author)

  15. Laser spot welding of cobalt-based amorphous metal foils

    International Nuclear Information System (INIS)

    Runchev, Dobre; Dorn, Lutc; Jaferi, Seifolah; Purbst, Detler

    1997-01-01

    The results concerning weldability of amorphous alloy (VAC 6025F) in shape of foils and the quality of laser-spot welded joints are presented in this paper. The aim of the research was the production of a high quality welding joint, by preserving the amorphous structure. The quality of the joint was tested by shear strength analysis and microhardness measuring. The metallographic studies were made by using optical microscope and SEM. The results show that (1) overlapped Co based amorphous metals foils can be welded with high-quality by a pulsed Nd: YAG-Laser, but only within a very narrow laser parameter window; (2) the laser welded spots show comparably high strength as the basic material; (3) the structure of the welded spot remains amorphous, so that the same characteristics as the base material can be achieved. (author)

  16. Corrosion resistant materials for fluorine and hydrogen fluoride

    International Nuclear Information System (INIS)

    Hauffe, K.

    1984-01-01

    Aluminum and Duralumin are resistant against fluorine and hydrogen fluoride up to 600 and 700 K, respectively. The resistance of nickel and its alloys, particularly monel, against fluorine and hydrogen fluoride is fairly good up to 900 and 800 K. During the attack of nickel-chromium alloys by fluorine between 1000 and 1300 K, it appears an inner fluorination similarly to the inner oxidation. The resistance of titanium in water-free liquid fluorine at lower temperatures with -1 is comparable to that of nickel and monel. However, the corrosion of titanium in gaseous fluorine amounts at 377 K only 0,0082 mm.a -1 . In spite of their limited resistance against fluorine and hydrogen fluoride, very pure molybdenum and tungsten are employed as construction materials in the rocket technology because of their large strength at high temperatures if fluorine-hydrogen and fluorine-hydrazine flames are used. Lanthanum and calcium borides are only little attacked by fluorine hydrazine flames between 1400 and 1800 K; they are superior to all special grade alloys. The same is true in a lower temperature region (290-400 K) with fluorcarbon resins. Organic materials substitute in increasing extent metal alloys and non-metal inorganic materials. (orig.) [de

  17. Corrosion resistant materials for fluorine and hydrogen fluoride

    Energy Technology Data Exchange (ETDEWEB)

    Hauffe, K.

    1984-12-01

    Aluminum and Duralumin are resistant against fluorine and hydrogen fluoride up to 600 and 700 K, respectively. The resistance of nickel and its alloys, particularly monel, against fluorine and hydrogen fluoride is fairly good up to 900 and 800 K. During the attack of nickel-chromium alloys by fluorine between 1000 and 1300 K, it appears an inner fluorination similarly to the inner oxidation. The resistance of titanium in water-free liquid fluorine at lower temperatures with <0,3 mm.a/sup -1/ is comparable to that of nickel and monel. However, the corrosion of titanium in gaseous fluorine amounts at 377 K only 0,0082 mm.a/sup -1/. In spite of their limited resistance against fluorine and hydrogen fluoride, very pure molybdenum and tungsten are employed as construction materials in the rocket technology because of their large strength at high temperatures if fluorine-hydrogen and fluorine-hydrazine flames are used. Lanthanum and calcium borides are only little attacked by fluorine hydrazine flames between 1400 and 1800 K; they are superior to all special grade alloys. The same is true in a lower temperature region (290-400 K) with fluorcarbon resins. Organic materials substitute in increasing extent metal alloys and non-metal inorganic materials.

  18. Effect of Surface Modification on Corrosion Resistance of Uncoated and DLC Coated Stainless Steel Surface

    Science.gov (United States)

    Scendo, Mieczyslaw; Staszewska-Samson, Katarzyna

    2017-08-01

    Corrosion resistance of 4H13 stainless steel (EN-X46Cr13) surface uncoated and coated with an amorphous hydrogenated carbon (a-C:H) film [diamond-like carbon (DLC)] in acidic chloride solution was investigated. The DLC films were deposited on steel surface by a plasma deposition, direct current discharge (PDCD) method. The Fourier transform infrared (FTIR) was used to determine the chemical groups existing on DLC films. The surface of the specimens was observed by a scanning electron microscope (SEM). The tribological properties of the both materials were examined using a ball-on disk tribometer. The microhardness (HV) of diamond-like carbon film increased over five times in relation to the 4H13 stainless steel without of DLC coating. Oxidation kinetic parameters were determined by gravimetric and electrochemical methods. The high value of polarization resistance indicates that the DLC film on substrate was characterized by low electrical conductivity. The corrosion rate of 4H13 stainless steel with of DLC film decreased about eight times in relation to uncoated surface of 4H13 stainless steel.

  19. Characterization of microstructure, chemical composition, corrosion resistance and toughness of a multipass weld joint of superduplex stainless steel UNS S32750

    International Nuclear Information System (INIS)

    Tavares, S.S.M.; Pardal, J.M.; Lima, L.D.; Bastos, I.N.; Nascimento, A.M.; Souza, J.A. de

    2007-01-01

    The superduplex stainless steels have an austeno-ferritic microstructure with an average fraction of each phase of approximately 50%. This duplex microstructure improves simultaneously the mechanical properties and corrosion resistance. Welding of these steels is often a critical operation. In this paper we focus on characterization and analysis of a multipass weld joint of UNS S32750 steel prepared using welding conditions equal to industrial standards. The toughness and corrosion resistance properties of the base metal, root pass welded with gas tungsten arc welding, as well as the filler passes, welded with shielded metal arc welding, were evaluated. The microstructure and chemical composition of the selected areas were also determined and correlated to the corrosion and mechanical properties. The root pass was welded with low nickel filler metal and, as a consequence, presented low austenite content and significant precipitation. This precipitation is reflected in the corrosion and mechanical properties. The filler passes presented an adequate ferrite:austenite proportion but, due to their high oxygen content, the toughness was lower than that of the root pass. Corrosion properties were evaluated by cyclic polarization tests in 3.5% NaCl and H 2 SO 4 media

  20. Corrosion Performance of New Generation Aluminum-Lithium Alloys for Aerospace Applications

    Science.gov (United States)

    Moran, James P.; Bovard, Francine S.; Chrzan, James D.; Vandenburgh, Peter

    Over the past several years, a new generation of aluminum-lithium alloys has been developed. These alloys are characterized by excellent strength, low density, and high modulus of elasticity and are therefore of interest for lightweight structural materials applications particularly for construction of current and future aircraft. These new alloys have also demonstrated significant improvements in corrosion resistance when compared with the legacy and incumbent alloys. This paper documents the superior corrosion resistance of the current commercial tempers of these materials and also discusses the corrosion performance as a function of the degree of artificial aging. Results from laboratory corrosion tests are compared with results from exposures in a seacoast atmosphere to assess the predictive capability of the laboratory tests. The correlations that have been developed between the laboratory tests and the seacoast exposures provide confidence that a set of available methods can provide an accurate assessment of the corrosion performance of this new generation of alloys.

  1. A study of the diffusion mechanisms in amorphous metallic alloys: diffusion and diffusion under high pressure in an amorphous NiZr alloy; Contribution a l`etude des mecanismes de transport dans les materiaux metalliques amorphes: diffusion et diffusion sous pression dans NiZr amorphe

    Energy Technology Data Exchange (ETDEWEB)

    Grandjean, A.

    1996-03-01

    The aim of this work is a better understanding of the diffusion mechanism in amorphous metallic alloys. Then interdiffusion and hafnium diffusion in amorphous NiZr alloy have been studied. Samples used are made by sputtering co-deposition under vacuum and are well relaxed before the diffusion measurements. The time evolution of resistivity during annealing due to the decay of a composition modulated film has been measured and from this change in resistivity interdiffusion coefficients have been determined. Dependence of Hf diffusion on temperature and pressure has been studied using (SIMS). In this two cases, the diffusion process obeys an Arrhenius law and gives an activation energy of 1.33 eV for interdiffusion, and 0.76 eV for Hf diffusion. An effect of pressure on Hf diffusion has been found leading to an activation volume of 8.5 angstrom{sup 3}. Thanks to these results, two approaches of the diffusion mechanisms in these systems have been proposed. The first comes from a comparison with the diffusion mechanisms in crystalline metals, that is to say by point defects. The second is an hypothesis of collective motions in these non crystalline alloys. (author).

  2. Evaporated metal films as indicators of atmospheric pollution. II. Resistance measurements

    Energy Technology Data Exchange (ETDEWEB)

    Lodge, Jr, J P; Frank, E R

    1962-01-01

    There appears to be a direct relationship between gross atmospheric features associated with the accumulation of substances in air that are corrosive to metals and the rate of resistance change of thin metallic films. This behavior is the most striking in aluminum. The suggested apparatus provides an inexpensive and rapid method determining total atmospheric corrosiveness. 1 reference, 10 figures.

  3. Mg amorphous alloys for biodegradable implants; Ligas amorfas de magnesio utilizadas em implantes consumiveis

    Energy Technology Data Exchange (ETDEWEB)

    Danez, G.P., E-mail: gabidanez@hotmail.co [Universidade Federal de Sao Carlos (PPG-CEMUFSCar), SP (Brazil). Programa de Pos-Graduacao em Ciencia e Engenharia de Materiais; Koga, G.Y.; Tonucci, S.; Bolfarini, C.; Kiminami, C.S.; Botta Filho, W.J. [Universidade Federal de Sao Carlos (DEMa/UFSCar), SP (Brazil). Dept. de Engenharia de Materiais

    2010-07-01

    The use of implants made from amorphous alloys magnesium-based with additions of zinc and calcium are promising. Properties such as biocompatibility, low density, high mechanical strength, low modulus (as compared to alloys such as stainless steel and titanium), corrosion resistance and wear resistance make it attractive for use in implants. Moreover, the by-products of corrosion and wear are not toxic and may contribute to fixation. Aiming to understand the tendency of this amorphous ternary (Mg-Zn-Ca) and expand the information about this system, this work involved the use of the topological criterion of instability ({lambda}) and the criterion of electronegativity ({Delta}e) to the choice of compositions. The alloys were processed into wedge-shaped and analyzed structurally and in X-ray diffraction and scanning electron microscopy. (author)

  4. The effect of Nb addition on mechanical properties, corrosion behavior, and metal-ion release of ZrAlCuNi bulk metallic glasses in artificial body fluid.

    Science.gov (United States)

    Qiu, C L; Liu, L; Sun, M; Zhang, S M

    2005-12-15

    Bulk metallic glasses (BMGs) of Zr(65 - x)Nb(x)- Cu(17.5)Ni(10)Al(7.5) with Nb = 0, 2, and 5 at % were prepared by copper mold casting. Compression tests reveal that the two BMGs containing Nb exhibited superior strength and plasticity to the base alloy. The corrosion behavior of the alloys obtained was investigated in artificial body fluid by electrochemical measurements. It was found that the addition of Nb significantly enhanced the corrosion resistance of the Zr-based BMG, as indicated by a remarkable increase in corrosion potential and pitting potential. XPS analysis revealed that the passive film formed after anodic polarization was enriched in aluminum oxide and depleted in phosphate ions for the BMGs containing Nb, which accounts for the improvement of corrosion resistance. On the other hand, metal-ion release of different BMGs were determined in PPb (ng/mL) level with inductively coupled plasma mass spectrometry (ICP-MS) after being immersed in artificial body fluid at 37 degrees C for 20 days. It was found that the addition of Nb considerably reduced the ion release of all kinds of metals of the base system. This is probably attributed to the promoting effect of Nb on a rapid formation of highly protective film.

  5. Corrosion resistance of Ni-Cr-Mo alloys. Chemical composition and metallurgical condition's effects

    International Nuclear Information System (INIS)

    Zadorozne, N.S.; Rebak, Raul B.

    2009-01-01

    Ni-Cr-Mo alloys offer an outstanding corrosion resistance in a wide variety of highly-corrosive environments. This versatility is due to the excellent performance of nickel in hot alkaline solutions and the beneficial effect of chromium and molybdenum in oxidizing and reducing conditions, respectively. Alloy C-22 (22 % Cr-13 % Mo-3% W) is a well known versatile member of this family. Due to its excellent corrosion resistance in a wide variety of environments, Alloy C-22 has been selected for the fabrication of the corrosion-resistant outer shell of the high-level nuclear waste container. The increasing demand of the industry for corrosion resistant alloys with particular properties of corrosion and mechanical resistance has led to the development of new alloys. Alloy C-22HS (Ni-21 % Cr-17 % Mo) is a new high-strength corrosion resistant material recently developed and introduced into the market. This alloy provides a corrosion resistance comparable with that of other C-type alloys, and it can also be age hardened to effectively double its yield strength. HASTELLOY HYBRID-BC1 (Ni-22 % Mo-15 % Cr) is a new development intended for filling the gap between Ni-Mo and Ni-Cr-Mo alloys. This novel alloy is able to withstand HCl and H 2 SO 4 , even in the presence of dissolved oxygen and other oxidizing species. Its resistance to chloride-induced pitting corrosion, crevice corrosion and stress corrosion cracking is also remarkable. Thermal aging of Ni-Cr-Mo alloys leads to microstructure changes depending on the temperature range and exposure time at temperature. A Long Range Ordering (LRO) reaction can occur in the range of 350 C degrees to 600 C degrees, producing an ordered Ni 2 (Cr,Mo) phase. This ordering reaction does not seem to affect the corrosion resistance and produces only a slight loss in ductility. LRO transformation is homogeneous and has proven to be useful to fabricate the age-hard enable Alloy C22-HS. Tetrahedral Close Packed (TCP) phases, like μ, σ and

  6. Improvement of Adhesion Properties and Corrosion Resistance of Sol-Gel Coating on Zinc.

    Science.gov (United States)

    Savignac, Pauline; Menu, Marie-Joëlle; Gressier, Marie; Denat, Bastien; Khadir, Yacine El; Manov, Stephan; Ansart, Florence

    2018-05-03

    Corrosion is a major problem for durability of many metals and alloys. Among the efficient classical surface treatments, chromate-based treatments must be banished from industrial use due to their toxicity. At the same time, sol-gel routes have demonstrated high potential to develop an efficient barrier effect against aggressive environments. By this process, the anti-corrosion property can be also associated to others in the case of the development of multi-functional hybrid coatings. In this paper, the main goal is precisely to improve both the corrosion resistance and the adhesion properties of phosphated zinc substrates by the deposition of a hybrid (organic-inorganic) sol-gel layer. To reach this double objective, a choice between two formulations 3-glycidoxypropyltrimethoxysilane (GPTMS)/aluminum-tri-sec-butoxide (ASB) and 3-(trimethoxysilyl)propylmethacrylate (MAP)/tetraethylorthosilicate (TEOS) was firstly made based on the results obtained by microstructural characterizations using SEM, optical analysis, and mechanical characterization such as shock and/or scratch tests (coupled to climatic chamber and salt spray exposure). Several investigations were performed in this study, and the best formulation and performances of the system were obtained by adding a new precursor (1-[3-(trimethoxysilyl)propyl]ureido-UPS) under controlled conditions, as detailed in this paper.

  7. Microstructure, hardness, corrosion resistance and porcelain shear bond strength comparison between cast and hot pressed CoCrMo alloy for metal-ceramic dental restorations.

    Science.gov (United States)

    Henriques, B; Soares, D; Silva, F S

    2012-08-01

    The purpose of this study was to compare the microstructure, hardness, corrosion resistance and metal-porcelain bond strength of a CoCrMo dental alloy obtained by two routes, cast and hot pressing. CoCrMo alloy substrates were obtained by casting and hot pressing. Substrates' microstructure was examined by the means of Optical Microscopy (OM) and by Scanning Electron Microscope (SEM) and Energy Dispersive X-ray Spectroscopy (EDS). Hardness tests were performed in a microhardness indenter. The electrochemical behavior of substrates was investigated through potentiodynamic tests in a saline solution (8g NaCl/L). Substrates were bonded to dental porcelain and metal-porcelain bond strength was assessed by the means of a shear test performed in a universal test machine (crosshead speed: 0.5 mm/min) until fracture. Fractured surfaces as well as undestroyed interface specimens were examined with Stereomicroscopy and SEM-EDS. Data was analyzed with Shapiro-Wilk test to test the assumption of normality. The t-test (pmicrostructures whereas hot pressed specimens exhibited a typical globular microstructure with a second phase spread through the matrix. The hardness registered for hot pressed substrates was greater than that of cast specimens, 438±24HV/1 and 324±8HV/1, respectively. Hot pressed substrates showed better corrosion properties than cast ones, i.e. higher OCP; higher corrosion potential (E(corr)) and lower current densities (i(corr)). No significant difference was found (p<0.05) in metal-ceramic bond strength between cast (116.5±6.9 MPa) and hot pressed (114.2±11.9 MPa) substrates. The failure type analysis revealed an adhesive failure for all specimens. Hot pressed products arise as an alternative to cast products in dental prosthetics, as they impart enhanced mechanical and electrochemical properties to prostheses without compromising the metal-ceramic bond strength. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Cyclic fatigue of a high-strength corrosion-resistant sheet TRIP steel

    Science.gov (United States)

    Terent'ev, V. F.; Alekseeva, L. E.; Korableva, S. A.; Prosvirnin, D. V.; Pankova, M. N.; Filippov, G. A.

    2014-04-01

    The mechanical properties of 0.3- and 0.8-mm-thick high-strength corrosion-resistant TRIP steel having various levels of strength properties are studied during static and cyclic loading in the high-cycle fatigue range. The fatigue fracture surface is analyzed by fractography, and the obtained results demonstrate ductile and quasi-brittle fracture mechanisms of this steel depending on the strength properties of the steel and the content of deformation martensite in it.

  9. Bioactive glass–ceramic coating for enhancing the in vitro corrosion resistance of biodegradable Mg alloy

    International Nuclear Information System (INIS)

    Ye Xinyu; Cai Shu; Dou Ying; Xu Guohua; Huang Kai; Ren Mengguo; Wang Xuexin

    2012-01-01

    Highlights: ► Sol–gel derived 45S5 glass–ceramic coating was prepared on Mg alloy substrate. ► The corrosion resistance of glass–ceramic coated Mg alloy was markedly improved. ► The corrosion behavior of the coated sample varied due to the cracking of coating. - Abstract: In this work, a bioactive 45S5 glass–ceramic coating was synthesized on magnesium (Mg) alloy substrate by using a sol–gel dip-coating method, to improve the initial corrosion resistance of AZ31 Mg alloy. The surface morphology and phase composition of the glass–ceramic coating were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The coating composed of amorphous phase and crystalline phase Na 2 Ca 2 Si 3 O 9 , with the thickness of ∼1.0 μm, exhibited a uniform and crack-free surface morphology. The corrosion behavior of the uncoated and coated Mg alloy substrates was investigated by the electrochemical measurements and immersion tests in simulated body fluid (SBF). Potentiodynamic polarization tests recorded an increase of potential (E corr ) form −1.60 V to −1.48 V, and a reduction of corrosion current density (i corr ) from 4.48 μA cm −2 to 0.16 μA cm −2 , due to the protection provided by the glass–ceramic coating. Immersion tests also showed the markedly improved corrosion resistance of the coated sample over the immersion period of 7 days. Moreover, after 14 days of immersion in SBF, the corrosion resistance of the coated sample declined due to the cracking of the glass–ceramic coating, which was confirmed by electrochemical impedance spectroscopy (EIS) analysis. The results suggested that the 45S5 glass–ceramic coated Mg alloy could provide a suitable corrosion behavior for use as degradable implants.

  10. Defect kinetics and resistance to amorphization in zirconium carbide

    International Nuclear Information System (INIS)

    Zheng, Ming-Jie; Szlufarska, Izabela; Morgan, Dane

    2015-01-01

    To better understand the radiation response of zirconium carbide (ZrC), and in particular its excellent resistance to amorphization, we have used density functional theory methods to study the kinetics of point defects in ZrC. The migration barriers and recombination barriers of the simple point defects are calculated using the ab initio molecular dynamics simulation and the nudged elastic band method. These barriers are used to estimate C and Zr interstitial and vacancy diffusion and Frenkel pair recombination rates. A significant barrier for C Frenkel pair recombination is found but it is shown that a large concentration of C vacancies reduces this barrier dramatically, allowing facile healing of radiation damage. The mechanisms underlying high resistance to amorphization of ZrC were analyzed from the perspectives of structural, thermodynamic, chemical and kinetic properties. This study provides insights into the amorphization resistance of ZrC as well as a foundation for understanding general radiation damage in this material

  11. Mechanical characteristics of heterogeneous structures obtained by high-temperature brazing of corrosion-resistant steels with rapidly quenched non-boron nickel-based alloys

    Science.gov (United States)

    Kalin, B.; Penyaz, M.; Ivannikov, A.; Sevryukov, O.; Bachurina, D.; Fedotov, I.; Voennov, A.; Abramov, E.

    2018-01-01

    Recently, the use rapidly quenched boron-containing nickel filler metals for high temperature brazing corrosion resistance steels different classes is perspective. The use of these alloys leads to the formation of a complex heterogeneous structure in the diffusion zone that contains separations of intermediate phases such as silicides and borides. This structure negatively affects the strength characteristics of the joint, especially under dynamic loads and in corrosive environment. The use of non-boron filler metals based on the Ni-Si-Be system is proposed to eliminate this structure in the brazed seam. Widely used austenitic 12Cr18Ni10Ti and ferrite-martensitic 16Cr12MoSiWNiVNb reactor steels were selected for research and brazing was carried out. The mechanical characteristics of brazed joints were determined using uniaxial tensile and impact toughness tests, and fractography was investigated by electron microscopy.

  12. Microstructural characterization of Mg-based bulk metallic glass and nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Babilas, Rafał, E-mail: rafal.babilas@polsl.pl [Institute of Engineering Materials and Biomaterials, Silesian University of Technology, Konarskiego 18a St., 44-100 Gliwice (Poland); Nowosielski, Ryszard; Pawlyta, Mirosława [Institute of Engineering Materials and Biomaterials, Silesian University of Technology, Konarskiego 18a St., 44-100 Gliwice (Poland); Fitch, Andy [European Synchrotron Radiation Facility, CS40220, 38043 Grenoble (France); Burian, Andrzej [A. Chelkowski Institute of Physics, University of Silesia, Uniwersytecka 4 St., 40-007 Katowice (Poland)

    2015-04-15

    New magnesium-based bulk metallic glasses Mg{sub 60}Cu{sub 30}Y{sub 10} have been prepared by pressure casting. Glassy alloys were successfully annealed to become nanocomposite containing 200 nm crystallites in an amorphous matrix. The microstructure of bulk glassy alloy and nanocomposite obtained during heat treatment was examined by X-ray diffraction and scanning and high-resolution electron microscopy. Metallic glass has been also studied to explain the structural characteristics by the reverse Monte Carlo (RMC) modeling based on the diffraction data. The HRTEM images allow to indicate some medium-range order (MRO) regions about 2–3 nm in size and formation of local atomic clusters. The RMC modeling results confirmed some kinds of short range order (SRO) structures. It was found that the structure of bulk metallic glass formed by the pressure casting is homogeneous. The composite material contained very small particles in the amorphous matrix. Homogeneous glassy alloy had better corrosion resistance than a composite containing nanocrystalline particles in a glassy matrix. - Highlights: • RMC modeling demonstrates some kinds of SRO structures in Mg-based BMGs. • HRTEM indicated MRO regions about 2–3 nm and SRO regions about 0.5 nm in size. • Mg-based glassy alloys were successfully annealed to become nanocomposite material. • Crystalline particles have spherical morphology with an average diameter of 200 nm. • Glassy alloy had higher corrosion resistance than a nanocomposite sample.

  13. Inverse Resistance Change Cr2Ge2Te6-Based PCRAM Enabling Ultralow-Energy Amorphization.

    Science.gov (United States)

    Hatayama, Shogo; Sutou, Yuji; Shindo, Satoshi; Saito, Yuta; Song, Yun-Heub; Ando, Daisuke; Koike, Junichi

    2018-01-24

    Phase-change random access memory (PCRAM) has attracted much attention for next-generation nonvolatile memory that can replace flash memory and can be used for storage-class memory. Generally, PCRAM relies on the change in the electrical resistance of a phase-change material between high-resistance amorphous (reset) and low-resistance crystalline (set) states. Herein, we present an inverse resistance change PCRAM with Cr 2 Ge 2 Te 6 (CrGT) that shows a high-resistance crystalline reset state and a low-resistance amorphous set state. The inverse resistance change was found to be due to a drastic decrease in the carrier density upon crystallization, which causes a large increase in contact resistivity between CrGT and the electrode. The CrGT memory cell was demonstrated to show fast reversible resistance switching with a much lower operating energy for amorphization than a Ge 2 Sb 2 Te 5 memory cell. This low operating energy in CrGT should be due to a small programmed amorphous volume, which can be realized by a high-resistance crystalline matrix and a dominant contact resistance. Simultaneously, CrGT can break the trade-off relationship between the crystallization temperature and operating speed.

  14. A new contact electric resistance technique for in-situ measurement of the electric resistance of surface films on metals in electrolytes at high temperatures and pressures

    International Nuclear Information System (INIS)

    Saario, T.; Marichev, V.A.

    1993-01-01

    Surface films play a major role in corrosion assisted cracking. A new Contact Electric Resistance (CER) method has been recently developed for in situ measurement of the electric resistance of surface films. The method has been upgraded for high temperature high pressure application. The technique can be used for any electrically conductive material in any environment including liquid, gas or vacuum. The technique has been used to determine in situ the electric resistance of films on metals during adsorption of water and anions, formation and destruction of oxides and hydrides, electroplating of metals and to study the electric resistance of films on semiconductors. The resolution of the CER technique is 10 -9 Ω, which corresponds to about 0.03 monolayers of deposited copper during electrochemical deposition Cu/Cu 2+ . Electric resistance data can be measured with a frequency of the order of one hertz, which enables one to follow in situ the kinetics of surface film related processes. The kinetics of these processes and their dependence on the environment, temperature, pH and electrochemical potential can be investigated

  15. Corrosion resistance of zirconium: general mechanisms, behaviour in nitric acid

    International Nuclear Information System (INIS)

    Pinard Legry, G.

    1990-01-01

    Corrosion resistance of zirconium results from the strong affinity of this metal for oxygen; as a result a thin protective oxide film is spontaneously formed in air or aqueous media, its thickness and properties depending on the physicochemical conditions at the interface. This film passivates the underlying metal but obviously if the passive film is partially or completely removed, localised or generalised corrosion phenomena will occur. In nitric acid, this depassivation may be chemical (fluorides) or mechanical (straining, creep, fretting). In these cases it is useful to determine the physicochemical conditions (concentration, temperature, potential, stress) which will have to be observed to use safely zirconium and its alloys in nitric acid solutions [fr

  16. Development of Custom 465® Corrosion-Resisting Steel for Landing Gear Applications

    Science.gov (United States)

    Daymond, Benjamin T.; Binot, Nicolas; Schmidt, Michael L.; Preston, Steve; Collins, Richard; Shepherd, Alan

    2016-04-01

    Existing high-strength low-alloy steels have been in place on landing gear for many years owing to their superior strength and cost performance. However, there have been major advances in improving the strength of high-performance corrosion-resisting steels. These materials have superior environmental robustness and remove the need for harmful protective coatings such as chromates and cadmium now on the list for removal under REACH legislation. A UK government-funded collaborative project is underway targeting a refined specification Custom 465® precipitation hardened stainless steel to replace the current material on Airbus A320 family aircraft main landing gear, a main fitting component developed by Messier-Bugatti-Dowty. This is a collaborative project between Airbus, Messier-Bugatti-Dowty, and Carpenter Technology Corporation. An extensive series of coupon tests on four production Heats of the material have been conducted, to obtain a full range of mechanical, fatigue, and corrosion properties. Custom 465® is an excellent replacement to the current material, with comparable tensile strength and fracture toughness, better ductility, and very good general corrosion and stress corrosion cracking resistance. Fatigue performance is the only significant area of deficit with respect to incumbent materials, fatigue initiation being often related to carbo-titanium-nitride particles and cleavage zones.

  17. Metal-dusting resistance of uncoated and coated iron and nickel base materials against metal-dusting in heat treatment furnaces with carbonaceous atmospheres

    International Nuclear Information System (INIS)

    Kleingries, Mirko; Ackermann, Helen; Lucka, Klaus; Hoja, Timo; Mehner, Andeas; Zoch, Hans-Werner; Altena, Herwig

    2010-01-01

    Metal-Dusting is a well-known corrosion problem that occurs in carburizing atmospheres in industrial thermal processing plants. In literature almost no quantitative data on the metal dusting resistance of typical alloys employed in industrial furnaces are available. Therefore, a series of experiments with uncoated and sol gel ZrO 2 coated high temperature materials was conducted in order to quantify their metal dusting behaviour under conditions close to those in case hardening furnaces. The experimental results show a strong influence of the surface conditions on the alloys resistance and a noticeable enhancement of the resistance by sol gel coatings. (orig.)

  18. Anomalous magnetoresistance in amorphous metals

    International Nuclear Information System (INIS)

    Kuz'menko, V.M.; Vladychkin, A.N.; Mel'nikov, V.I.; Sudovtsev, A.I.

    1984-01-01

    The magnetoresistance of amorphous Bi, Ca, V and Yb films is investigated in fields up to 4 T at low temperatures. For all metals the magnetoresistance is positive, sharply decreases with growth of temperature and depends anomalously on the magnetic field strength. For amorphous superconductors the results agree satisfactorily with the theory of anomalous magnetoresistance in which allowance is made for scattering of electrons by the superconducting fluctuations

  19. High corrosion resistance of magnesium coated with hydroxyapatite directly synthesized in an aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Hiromoto, Sachiko [Biomaterials Center, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044 (Japan); International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044 (Japan)], E-mail: hiromoto.sachiko@nims.go.jp; Yamamoto, Akiko [Biomaterials Center, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044 (Japan); International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044 (Japan)

    2009-11-30

    Anticorrosion coatings are crucial for practical applications of magnesium alloys, which are used to reduce the weight of vehicles, aircraft, electronics enclosures etc. Hydroxyapatite (HAp) potentially offers high corrosion resistance and no environmental toxicity because its thermodynamic structural stability is high and it is a basic component of bone. However, direct synthesis of HAp on magnesium in aqueous solutions has been a scientific challenge because Mg ions prevent HAp crystallization. A new method of direct synthesis of HAp on magnesium was developed using a Ca chelate compound, which can maintain a sufficiently high concentration of Ca ions on the magnesium surface to overcome prevention of HAp crystallization with Mg ions. Highly crystallized HAp coatings were successfully formed on pure magnesium and AZ series alloys. Corrosion behavior of HAp-coated pure magnesium was examined by cyclic dry and wet tests with 1 g m{sup -2} NaCl on the surface and polarization tests in a 3.5 wt% NaCl solution. A HAp-coated pure magnesium showed no noticeable corrosion pits after the dry and wet test. HAp-coated specimens showed 10{sup 3}-10{sup 4} times lower anodic current density than as-polished specimen in the polarization test. The results demonstrate the remarkable anticorrosion performance of HAp coatings on magnesium for the first time.

  20. Sulfide stress corrosion study of a super martensitic stainless steel in H2S sour environments: Metallic sulfides formation and hydrogen embrittlement

    Science.gov (United States)

    Monnot, Martin; Nogueira, Ricardo P.; Roche, Virginie; Berthomé, Grégory; Chauveau, Eric; Estevez, Rafael; Mantel, Marc

    2017-02-01

    Thanks to their high corrosion resistance, super martensitic stainless steels are commonly used in the oil and gas industry, particularly in sour environments. Some grades are however susceptible to undergo hydrogen and mechanically-assisted corrosion processes in the presence of H2S, depending on the pH. The martensitic stainless steel EN 1.4418 grade exhibits a clear protective passive behavior with no sulfide stress corrosion cracking when exposed to sour environments of pH ≥ 4, but undergoes a steep decrease in its corrosion resistance at lower pH conditions. The present paper investigated this abrupt loss of corrosion resistance with electrochemical measurements as well as different physicochemical characterization techniques. Results indicated that below pH 4.0 the metal surface is covered by a thick (ca 40 μm) porous and defect-full sulfide-rich corrosion products layer shown to be straightforwardly related to the onset of hydrogen and sulfide mechanically-assisted corrosion phenomena.

  1. Enhanced performance of amorphous In-Ga-Zn-O thin-film transistors using different metals for source/drain electrodes

    Science.gov (United States)

    Pyo, Ju-Young; Cho, Won-Ju

    2017-09-01

    In this paper, we propose an amorphous indium gallium zinc oxide (a-IGZO) thin-film transistor (TFT) with off-planed source/drain electrodes. We applied different metals for the source/drain electrodes with Ni and Ti to control the work function as high and low. When we measured the configuration of Ni to drain and source to Ti, the a-IGZO TFT showed increased driving current, decreased leakage current, a high on/off current ratio, low subthreshold swing, and high mobility. In addition, we conducted a reliability test with a gate bias stress test at various temperatures. The results of the reliability test showed the Ni drain and Ti drain had an equivalent effective energy barrier height. Thus, we confirmed that the proposed off-planed structure improved the electrical characteristics of the fabricated devices without any degradation of characteristics. Through the a-IGZO TFT with different source/drain electrode metal engineering, we realized high-performance TFTs for next-generation display devices.

  2. ASSET, An Information System for Alloy Corrosion in High Temperature Gases

    International Nuclear Information System (INIS)

    R. C. John; A. D. Pelton; A. L. Young; W. T. Thompson; I. G. Wright

    2001-01-01

    A large database for corrosion data and a corrosion prediction information system for metals and alloys corroding in high-temperature gases have been created. Corrosion data for about 75 commercial alloys, 4600 corrosion data measurements, and six million exposure hours have been compiled into an information system, ASSET. ASSET allows prediction of sound metal thickness losses for metals and alloys corroding by several common corrosion mechanisms at high-temperatures as functions of gas composition, temperature, time, and alloy. This paper presents examples of predicted metal losses of alloys corroding in standard conditions for several corrosion mechanisms expected in high-temperature gases. ASSET also provides a comprehensive capability to analyze the thermochemical interactions between alloys, corrosion products and exposure conditions. Some of the uses of the data compilation and the corrosion prediction feature are illustrated for oxidizing, sulfidizing, sulfidizing/oxidizing , and carburizing conditions

  3. Evaluation of Microstructure, Mechanical Properties and Corrosion Resistance of Friction Stir-Welded Aluminum and Magnesium Dissimilar Alloys

    Science.gov (United States)

    Verma, Jagesvar; Taiwade, Ravindra V.; Sapate, Sanjay G.; Patil, Awanikumar P.; Dhoble, Ashwinkumar S.

    2017-10-01

    Microstructure, mechanical properties and corrosion resistance of dissimilar friction stir-welded aluminum and magnesium alloys were investigated by applying three different rotational speeds at two different travel speeds. Sound joints were obtained in all the conditions. The microstructure was examined by an optical and scanning electron microscope, whereas localized chemical information was studied by energy-dispersive spectroscopy. Stir zone microstructure showed mixed bands of Al and Mg with coarse and fine equiaxed grains. Grain size of stir zone reduced compared to base metals, indicated by dynamic recrystallization. More Al patches were observed in the stir zone as rotational speed increased. X-ray diffraction showed the presence of intermetallics in the stir zone. Higher tensile strength and hardness were obtained at a high rotational speed corresponding to low travel speed. Tensile fractured surface indicated brittle nature of joints. Dissimilar friction stir weld joints showed different behaviors in different corrosive environments, and better corrosion resistance was observed at a high rotational speed corresponding to low travel speed (FW3) in a sulfuric and chloride environments. Increasing travel speed did not significantly affect on microstructure, mechanical properties and corrosion resistance as much as the rotational speed.

  4. Investigations into the corrosion resistance of copper aluminium alloys. Effect of phosphorus as corrosion resistant third alloying element in the ternary system CuAl20P1

    International Nuclear Information System (INIS)

    Allwardt, A.

    1997-01-01

    The effect of phosphorus on the corrosion resistance of Al-bronzes is studied in detail in this work. A literature review showed that there are a lot of things known about the microstructure and the mechanical properties of Al-bronzes. In spite of their corrosion resistance the corrosion properties and the structure of the protective oxide films of Al-bronzes were seldom a matter of interest. Systematic studies of the influence of different alloying elements on the oxide film and the corrosion properties are rare. Therefore, it is not possible to predict the corrosion resistance of Al-bronzes, made by alloying particular elements. The high corrosion resistance of the new alloy CuAl 20 P 1 was the reason to investigate the influence of phosphorus on the corrosion properties of Al-bronzes in more detail. A systematic study of the microstructure and the corrosion properties of Cu, CuP x , CuAl 20 and CuAl 20 P x offers an insight into the effect of aluminium and phosphorus on the formation of the oxide film on Al-bronzes. It was found that there exists a critical amount of 1 at.-% of phosphorus. Above and below this amount the corrosion resistance becomes worse. This behaviour could be explained by XPS-and electrochemical measurements. Although there are still some questions about the influence of phosphorus on the corrosion resistance of Al-bronzes, this work has produced some important results, which in the future may be helpful to develop new high corrosion resistant Al-bronzes more efficiently: - on clean surface Al-bronze, the oxidation of Al and Cu takes place simultaneously, - Al promotes the formation of Cu 2 O but impedes the formation of Cu(II)-oxide/-hydride in neutral solutions, - P impedes the formation of Cu 2 O and as a consequence promotes the formation of aluminium oxide. This results in a higher amount of Al in the oxide film on the surface of the alloy, which leads to a better corrosion resistance. (author) figs., tabs., 106 refs

  5. Titanium and zirconium based wrought alloys and bulk metallic glasses for fluoride ion containing 11.5 M HNO3 medium

    International Nuclear Information System (INIS)

    Jayaraj, J.; Ningshen, S.; Mallika, C.; Kamachi Mudali, U.

    2016-01-01

    Aqueous reprocessing of plutonium-rich mixed oxide fuels require fluoride as a catalyst in boiling nitric acid for an effective dissolution of the spent fuel. The corrosion behavior of the candidate dissolver materials zircaloy-4 (Zr-4) and commercial pure titanium (CP-Ti grade 2) in boiling 11.5 M HNO 3 + 0.05 M NaF has been established. High corrosion rates were obtained for Zr- 4 and CP-Ti in nitric acid containing fluoride ions. Complexing the fluoride ions either with Al(NO 3 ) 3 or ZrO(NO 3 ) 2 aided in decreasing the corrosion rates of Zr-4 and CP-Ti. High corrosion resistance is claimed as one of the principal property of the amorphous alloy when compared to the crystalline alloy. Thus Ni 60 Nb 40 and Ni 60 Nb 30 Ta 10 amorphous ribbons were prepared and exposed in boiling 11.5 M HNO 3 and 11.5 M HNO 3 + 0.05 M NaF. In nitric acid these alloys did not show any sign of corrosion attack. XPS analysis confirmed that the passivity was due to the formation passive films of thickness ≈3 nm enriched with Nb 2 O 5 and of ≈1.5 nm enriched with both Nb 2 O 5 and Ta 2 O 5 on the respective surfaces of the ribbons. In boiling 11.5 M HNO 3 + 0.05 M NaF, severe corrosion attack was observed on Ni 60 Nb 40 ribbon, due to the instability of the oxide/metal interface. The Ni 60 Nb 30 Ta 10 amorphous ribbon exhibited corrosion resistance of at least an order of magnitude higher than that for Ni 60 Nb 40 ribbon

  6. Experimental Study of Laser - enhanced 5A03 Aluminum Alloy and Its Stress Corrosion Resistance

    Science.gov (United States)

    Wang, Guicheng; Chen, Jing; Pang, Tao

    2018-02-01

    Based on the study of improving the stress corrosion resistance of 5A03 aluminum alloy for ship, this paper mainly studied the tensile test, surface morphology and residual stress under laser shock, high temperature and stress corrosion. It is found that the residual compressive stress and the grain refinement on the surface of the material during the heat strengthening process increase the breaking strength of the sample in the stress corrosion environment. Appropriate high temperature maintenance helps to enhance the effect of deformation strengthening. In the 300°C environment insulation, due to recrystallization of the material, the performance decreased significantly. This study provides an experimental basis for effectively improving the stress corrosion resistance of 5A03 aluminum alloy.

  7. Online monitoring of corrosion behavior in molten metal using laser-induced breakdown spectroscopy

    Science.gov (United States)

    Zeng, Qiang; Pan, Congyuan; Li, Chaoyang; Fei, Teng; Ding, Xiaokang; Du, Xuewei; Wang, Qiuping

    2018-04-01

    The corrosion behavior of structure materials in direct contact with molten metals is widespread in metallurgical industry. The corrosion of casting equipment by molten metals is detrimental to the production process, and the corroded materials can also contaminate the metals being produced. Conventional methods for studying the corrosion behavior by molten metal are offline. This work explored the application of laser-induced breakdown spectroscopy (LIBS) for online monitoring of the corrosion behavior of molten metal. The compositional changes of molten aluminum in crucibles made of 304 stainless steel were obtained online at 1000 °C. Several offline techniques were combined to determine the corrosion mechanism, which was highly consistent with previous studies. Results proved that LIBS was an efficient method to study the corrosion mechanism of solid materials in molten metal.

  8. Corrosion Behavior of Metal Active Gas Welded Joints of a High-Strength Steel for Automotive Application

    Science.gov (United States)

    Garcia, Mainã Portella; Mantovani, Gerson Luiz; Vasant Kumar, R.; Antunes, Renato Altobelli

    2017-10-01

    In this work, the corrosion behavior of metal active gas-welded joints of a high-strength steel with tensile yield strength of 900 MPa was investigated. The welded joints were obtained using two different heat inputs. The corrosion behavior has been studied in a 3.5 wt.% NaCl aqueous solution using electrochemical impedance spectroscopy and potentiodynamic polarization tests. Optical microscopy images, scanning electron microscopy and transmission electron microscopy with energy-dispersive x-ray revealed different microstructural features in the heat-affected zone (HAZ) and the weld metal (WM). Before and after the corrosion process, the sample was evaluated by confocal laser scanning microscopy to measure the depth difference between HAZ and WM. The results showed that the heat input did not play an important role on corrosion behavior of HSLA steel. The anodic and cathodic areas of the welded joints could be associated with depth differences. The HAZ was found to be the anodic area, while the WM was cathodic with respect to the HAZ. The corrosion behavior was related to the amount and orientation nature of carbides in the HAZ. The microstructure of the HAZ consisted of martensite and bainite, whereas acicular ferrite was observed in the weld metal.

  9. In vitro corrosion and biocompatibility screening of sputtered Ti{sub 40}Cu{sub 36}Pd{sub 14}Zr{sub 10} thin film metallic glasses on steels

    Energy Technology Data Exchange (ETDEWEB)

    Subramanian, B., E-mail: subramanianb3@gmail.com

    2015-02-01

    The growth of multi-component thin film metallic glasses (TFMGs) of Ti{sub 40}Cu{sub 36}Pd{sub 14}Zr{sub 10} (at.%) alloys fabricated using magnetron sputtering on bioimplantable 316L stainless steel substrates has been investigated. The vapor–solid quenching during sputtering enables the amorphous phases to be formed. The amorphous films consist of a single glassy phase, as evidenced by a broad hump and no detectable crystalline peaks as observed from XRD and selective area electron diffraction (SAED) patterns. The average surface roughness (Ra) of the coated film as observed from AFM was 0.3 nm. Nanohardness of about 7.7 GPa and Young's modulus of 110 GPa were measured from nanoindentation analysis. The potentiodynamic polarization and impedance measurements showed that coated stainless steel substrates have higher corrosion resistance compared to uncoated SS substrate in simulated body fluid (SBF) solution. The cytotoxicity studies using L929 fibroblast cells showed that these coatings were non-cytotoxic in nature. The interactions between the coated surface and bacteria were investigated by agar diffusion method, solution suspension and wet interfacial contact methods. - Highlights: • Ti-based TFMG coated specimen showed superior corrosion resistance. • Ti-based TFMG coated SS 316L specimen was non-cytotoxic in nature. • Antimicrobial activity of Ti-based TFMG was noticed.

  10. High performance corrosion and wear resistant composite titanium nitride layers produced on the AZ91D magnesium alloy by a hybrid method

    Directory of Open Access Journals (Sweden)

    Michał Tacikowski

    2014-09-01

    Full Text Available Composite, diffusive titanium nitride layers formed on a titanium and aluminum sub-layer were produced on the AZ91D magnesium alloy. The layers were obtained using a hybrid method which combined the PVD processes with the final sealing by a hydrothermal treatment. The microstructure, resistance to corrosion, mechanical damage, and frictional wear of the layers were examined. The properties of the AZ91D alloy covered with these layers were compared with those of the untreated alloy and of some engineering materials such as 316L stainless steel, 100Cr6 bearing steel, and the AZ91D alloy subjected to commercial anodizing. It has been found that the composite diffusive nitride layer produced on the AZ91D alloy and then sealed by the hydrothermal treatment ensures the corrosion resistance comparable with that of 316L stainless steel. The layers are characterized by higher electrochemical durability which is due to the surface being overbuilt with the titanium oxides formed, as shown by the XPS examinations, from titanium nitride during the hydrothermal treatment. The composite titanium nitride layers exhibit high resistance to mechanical damage and wear, including frictional wear which is comparable with that of 100Cr6 bearing steel. The performance properties of the AZ91D magnesium alloy covered with the composite titanium nitride coating are substantially superior to those of the alloy subjected to commercial anodizing which is the dominant technique employed in industrial practice.

  11. Superhydrophobic copper surfaces fabricated by fatty acid soaps in aqueous solution for excellent corrosion resistance

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Wenlong; Hu, Yuanyuan; Bao, Wenda; Xie, Xiaoyu; Liu, Yiran; Song, Aixin, E-mail: songaixin@sdu.edu.cn; Hao, Jingcheng

    2017-03-31

    Highlights: • The superhydrophobic property can be realized in a much quicker process (7.5 min) in aqueous solution than in ethanol. • The fabrication process of superhydrophobic metal surfaces greatly increases the safety in industrial manufacture in commercial scale. • The superhydrophobic copper surfaces show excellent corrosion resistance. - Abstract: A simple and safe one-step immersion method was developed to obtain the stable superhydrophobic copper surfaces with excellent corrosion resistance ability using fatty acids in water-medium instead of ethanol. An organic alkali, N,N-dimethylcyclohexylamine (DMCHA), was chosen to solve the poor solubility of fatty acids in water and the high Krafft point of carboxylate salts with inorganic counterions. The superhydrophobic property can be realized in a much quicker process (7.5 min) in aqueous solution than in ethanol (more than 2 d), which is universally feasible for the fabrication of superhydrophobic metal surfaces in industry scale, thereby greatly increasing the safety in industrial manufacture.

  12. Bridge maintenance to enhance corrosion resistance and performance of steel girder bridges

    Science.gov (United States)

    Moran Yanez, Luis M.

    The integrity and efficiency of any national highway system relies on the condition of the various components. Bridges are fundamental elements of a highway system, representing an important investment and a strategic link that facilitates the transport of persons and goods. The cost to rehabilitate or replace a highway bridge represents an important expenditure to the owner, who needs to evaluate the correct time to assume that cost. Among the several factors that affect the condition of steel highway bridges, corrosion is identified as the main problem. In the USA corrosion is the primary cause of structurally deficient steel bridges. The benefit of regular high-pressure superstructure washing and spot painting were evaluated as effective maintenance activities to reduce the corrosion process. The effectiveness of steel girder washing was assessed by developing models of corrosion deterioration of composite steel girders and analyzing steel coupons at the laboratory under atmospheric corrosion for two alternatives: when high-pressure washing was performed and when washing was not considered. The effectiveness of spot painting was assessed by analyzing the corrosion on steel coupons, with small damages, unprotected and protected by spot painting. A parametric analysis of corroded steel girder bridges was considered. The emphasis was focused on the parametric analyses of corroded steel girder bridges under two alternatives: (a) when steel bridge girder washing is performed according to a particular frequency, and (b) when no bridge washing is performed to the girders. The reduction of structural capacity was observed for both alternatives along the structure service life, estimated at 100 years. An economic analysis, using the Life-Cycle Cost Analysis method, demonstrated that it is more cost-effective to perform steel girder washing as a scheduled maintenance activity in contrast to the no washing alternative.

  13. Corrosion Resistance of Co-Cr-Mo Alloy Used in Dentistry

    Directory of Open Access Journals (Sweden)

    Łukaszczyk A.

    2015-04-01

    Full Text Available The presented paper studies the effect of the casting technology on the corrosion resistance of Co-Cr-Mo alloy. The investigations were conducted on a commercial alloy with the brand name ARGELOY N.P SPECIAL (Co-Cr-Mo produced by Argen as well as the same alloy melted and cast by the lost wax casting method performed by a dental technician. The corrosion behavior of the dental alloys in an artificial saliva was studied with the use of the following electrochemical techniques: open circuit potential and voltammetry. After the electrochemical tests, studies of the surface of the examined alloys were performed by means of a scanning electron microscope with an X-ray microanalyzer. The results of the electrochemical studies show that the dependence of the corrosion resistance on the microstructure associated with the recasting process is marginal. The results of the electrochemical studies of the considered alloy clearly point to their good corrosion resistance in the discussed environment.

  14. Structure and thermal stability of biodegradable Mg-Zn-Ca based amorphous alloys synthesized by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Datta, Moni Kanchan; Chou, Da-Tren; Hong, Daeho; Saha, Partha [Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Chung, Sung Jae [Mechanical Engineering and Materials Science, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Lee, Bouen [Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Sirinterlikci, Arif [Department of Engineering, Robert Morris University, Moon Township, Pittsburgh, PA 15108 (United States); Ramanathan, Madhumati; Roy, Abhijit [Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Kumta, Prashant N., E-mail: matscib@gmail.com [Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Mechanical Engineering and Materials Science, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Chemical and Petroleum Engineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); School of Dental Medicine, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Center for Complex Engineered Multifunctional Materials, University of Pittsburgh, Pittsburgh, PA 15261 (United States)

    2011-12-15

    Room temperature solid state diffusion reaction induced by mechanical alloying (MA) of elemental blends of Mg, Zn and Ca of nominal composition 60 at.% Mg-35 at.% Zn-5 at.% Ca has been studied. Formation of fully amorphous structure has been identified after 5 h of MA performed in a SPEX 8000M shaker mill, with milling continued up to 8 h to confirm the formation of homogeneous amorphous phase. Thermal stability of the amorphous phase has been studied using differential scanning calorimetry (DSC) and isothermal heat treatment at different temperatures. The amorphous powder consolidated using cold isostatic pressing (CIP) showed an envelope density {approx}80% of absolute density, which increased to an envelope density {approx}84% of absolute density after sintering at an optimized temperature of {approx}523 K for 9 h. Electrochemical bio-corrosion testing of the CIP compacted amorphous pellet as well as the sintered pellet performed in Dulbecco's Modified Eagle Medium, showed improved corrosion resistance in comparison to the as-cast pure Mg. Cytotoxicity testing of the CIP compacted amorphous pellet, performed using the MTT assay with MC3T3 osteoblastic cells, showed low cytotoxicity in comparison to the as-cast pure Mg.

  15. A Theoretical Model for Metal Corrosion Degradation

    Directory of Open Access Journals (Sweden)

    David V. Svintradze

    2010-01-01

    Full Text Available Many aluminum and stainless steel alloys contain thin oxide layers on the metal surface which greatly reduce the corrosion rate. Pitting corrosion, a result of localized breakdown of such films, results in accelerated dissolution of the underlying metal through pits. Many researchers have studied pitting corrosion for several decades and the exact governing equation for corrosion pit degradation has not been obtained. In this study, the governing equation for corrosion degradation due to pitting corrosion behavior was derived from solid-state physics and some solutions and simulations are presented and discussed.

  16. [The effect of hydrogen peroxide on the electrochemical corrosion properties and metal ions release of nickel-chromium dental alloys].

    Science.gov (United States)

    Wang, Jue; Qiao, Guang-yan

    2013-04-01

    To investigate the effect of hydrogen peroxide on the electrochemical corrosion and metal ions release of nickel-chromium dental alloys. The corrosion resistance of nickel-chromium dental alloys was compared by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curve (PD) methods in artificial saliva after immersed in different concentrations of hydrogen peroxide for 112 h. The metal ions released from nickel-chromium dental alloys to the artificial saliva were detected after electrochemical measurements using inductively coupled plasma mass spectrometry (ICP-MS). The data was statistically analyzed by analysis of variance (ANOVA) using SPSS 13.0 software package. The electrochemical experiment showed that the sequence of polarization resistance in equivalent circuit (Rct), corrosion potential (Ecorr), pitting breakdown potential (Eb), and the difference between Ecorr and Eb representing the "pseudo-passivation" (δE) of nickel-chromium alloys in artificial saliva was 30% alloys to the artificial saliva, and the order of the concentrations of metal ions was 0% corrosion resistance of nickel-chromium dental alloys decrease after immersed in different concentrations of hydrogen peroxide for 112 h. Nickel-chromium dental alloys are more prone to corrosion in the artificial saliva with the concentration of hydrogen peroxide increased, and more metal ions are released in the artificial saliva.

  17. Effect of Sn4+ Additives on the Microstructure and Corrosion Resistance of Anodic Coating Formed on AZ31 Magnesium Alloy in Alkaline Solution

    Science.gov (United States)

    Salman, S. A.; Kuroda, K.; Saito, N.; Okido, M.

    Magnesium is the lightest structural metal with high specific strength and good mechanical properties. However, poor corrosion resistance limits its widespread use in many applications. Magnesium is usually treated with Chromate conversion coatings. However, due to changing environmental regulations and pollution prevention requirements, a significant push exists to find new, alternative for poisonous Cr6+. Therefore, we aim to improve corrosion resistance of anodic coatings on AZ31 alloys using low cost non-chromate electrolyte. Anodizing was carried out in alkaline solutions with tin additives. The effect of tin additives on the coating film was characterized by SEM and XRD. The corrosion resistance was evaluated using anodic and cathodic polarizations and electrochemical impedance spectroscopy (EIS). Corrosion resistance property was improved with tin additives and the best anti-corrosion property was obtained with addition of 0.03 M Na2SnO3.3H2O to anodizing solution.

  18. Corrosion resistance properties of enamels with high B2O3-P2O5 content to molten aluminum

    International Nuclear Information System (INIS)

    Zhou, M.; Li, K.; Shu, D.; Sun, B.D.; Wang, J.

    2003-01-01

    Anticorrosive properties of borophosphate and boron-free enamels to molten aluminum were investigated using SEM and electron probe. Carbonates of alkali metal and alkaline earth metal were added in an appropriate weight ratio to achieve desired melting temperature of the enamels. SEM examination on the solidified interface between the enamels and aluminum alloy show that the enamels can spread slightly on aluminum alloy. For anticorrosive sample of borophosphate enamel, phosphorus was not detected by electron probe at the side of aluminum alloy near the interface, but silicon was detected in the silica-free enamels side. For the sample of boron-free enamels, however, phosphorus was found at the side of aluminum alloy near the interface. It was revealed that the enamels with high B 2 O 3 -P 2 O 5 content have high corrosion resistance to molten aluminum

  19. Electroless Ni-P/Ni-B duplex coatings: preparation and evaluation of microhardness, wear and corrosion resistance

    International Nuclear Information System (INIS)

    Narayanan, T.S.N. Sankara; Krishnaveni, K.; Seshadri, S.K.

    2003-01-01

    The present work deals with the formation of Ni-P/Ni-B duplex coatings by electroless plating process and evaluation of their hardness, wear resistance and corrosion resistance. The Ni-P/Ni-B duplex coatings were prepared using dual baths (acidic hypophosphite- and alkaline borohydride-reduced electroless nickel baths) with both Ni-P and Ni-B as inner layers and with varying single layer thickness. Scanning electron microscopy (SEM) was used to assess the duplex interface. The microhardness, wear resistance and corrosion resistance of electroless nickel duplex coatings were compared with electroless Ni-P and Ni-B coatings of similar thickness. The study reveals that the Ni-P and Ni-B coatings are amorphous in their as-plated condition and upon heat-treatment at 450 deg. C for 1 h, both Ni-P and Ni-B coatings crystallize and produce nickel, nickel phosphide and nickel borides in the respective coatings. All the three phases are formed when Ni-P/Ni-B and Ni-B/Ni-P duplex coatings are heat-treated at 450 deg. C for 1 h. The duplex coatings are uniform and the compatibility between the layers is good. The microhardness, wear resistance and corrosion resistance of the duplex coating is higher than Ni-P and Ni-B coatings of similar thickness. Among the two types of duplex coatings studied, hardness and wear resistance is higher for coatings having Ni-B coating as the outer layer whereas better corrosion resistance is offered by coatings having Ni-P coating as the outer layer

  20. Effects of noble-metal ion implantation on corrosion inhibition and charge injection capability of surgical Ti and Ti-6Al-4V

    International Nuclear Information System (INIS)

    Lee, I.S.

    1989-01-01

    Studies are described involving effects of noble-metal ion implantation on corrosion inhibition and charge injection capabilities of surgical Ti and Ti-6Al-4V. With surgical alloys, harmful biological responses are principally due to the type and quantity of metal ions released by the corrosion process. One approach to improve long-term biological performance involves surface modifications to significantly reduce degradation rates. With regard to surface-modifications, one of the most effective methods is through ion implantation. Results are presented for ion-implanted Au, Rh, and Ir. For the static in vitro corrosion properties, the noble-metal ion implanted Ti-6Al-4V and commercially-pure (CP) Ti were investigated in non-passivating acid and passivating saline solutions. It was postulated that during the early stages of corrosion (or during a corrosion pretreatment) the implanted noble-metal would enrich at the surface and significantly reduce subsequent corrosion rates. The observed behavior for the Ir and Rh implanted materials appeared to follow the postulated mechanism, with both initial and time-dependent improvements in corrosion resistance. However, the Au implanted material yielded early benefits, but the enhanced corrosion resistance deteriorated with time. X-ray photoelectron spectroscopy (XPS) analysis indicated that the implanted Au atoms remained as pure metallic Au, while the Ir and Rh atoms were in some oxide state, which gave the good adhesion of the Ir or Rh enriched surface to the Ti substrate. For a stimulating neural electrode, the charge density should be as large as possible to provide adequate stimulation of the nervous system while allowing for miniaturization of the electrode. Activated Ir has been known as having the highest charge injection capability of any material known

  1. Hollow Amorphous MnSnO3 Nanohybrid with Nitrogen-Doped Graphene for High-Performance Lithium Storage

    International Nuclear Information System (INIS)

    Liu, Peng; Hao, Qingli; Xia, Xifeng; Lei, Wu; Xia, Hui; Chen, Ziyang; Wang, Xin

    2016-01-01

    Graphical abstract: A novel hybrid of hollow amorphous MnSnO 3 nanoparticles and nitrogen-doped reduced graphene oxide was fabricated. The unique structure and well-combination of both components account for the ultra long-term cyclic life with high reversible capacity of 610 mAh g −1 over 1000 cycles at 400 mA g −1 . - Highlights: • Novel hybrid of MnSnO 3 and nitrogen-doped reduced graphene oxide was fabricated. • The MnSnO 3 nanoparticles possess amorphous and hollow structure in the composite. • The excellent electrochemical performance benefits from unique nanostructure. • The reversible capacity of as-prepared hybrid is 610 mAh g −1 after 1000 cycles. • A long-term life with 97.3% capacity retention over 1000 cycles was obtained. - Abstract: Tin-based metal oxides usually suffer from severe capacity fading resulting from aggregation and considerable volume variation during the charge/discharge process in lithium ion batteries. In this work, a novel nanocomposite (MTO/N-RGO) of hollow amorphous MnSnO 3 (MTO) nanoparticles and nitrogen-doped reduced graphene oxide (N-RGO) has been designed and synthesized by a two-step method. Firstly, the nitrogen-doped graphene nanocomposite (MTO/N-RGO-P) with MnSn(OH) 6 crystal nanoparticles was synthesized by a facile solvothermal method. Subsequently, the MTO/N-RGO nanocomposite was obtained through the post heat treatment of MTO/N-RGO-P. The designed heterostructure and well-combination of the hollow amorphous MTO and N-RGO matrix can accelerate the ionic and electronic transport, and simultaneously accommodate the aggregation and volume variation of MTO nanoparticles during the lithiation–delithiation cycles. The as-prepared hybrid of MTO and N-RGO (MTO/N-RGO) exhibits a high reversible capacity of 707 mAh g −1 after 110 cycles at 200 mA g −1 , superior rate capability, and long-term cyclic life with high capacity of 610 mAh g −1 over 1000 cycles at 400 mA g −1 . Superior capacity retention of

  2. Sputtered carbon as a corrosion barrier for x-ray detector windows

    Energy Technology Data Exchange (ETDEWEB)

    Rowley, Joseph; Pei, Lei; Davis, Robert C., E-mail: davis@byu.edu; Vanfleet, Richard R. [Department of Physics and Astronomy, Brigham Young University, Provo, Utah 84602 (United States); Liddiard, Steven; Harker, Mallorie; Abbott, Jonathan [Moxtek, Inc., 452 W 1260 N, Orem, Utah 84057 (United States)

    2016-09-15

    Sputtered amorphous carbon thin films were explored as corrosion resistant coatings on aluminum thin films to be incorporated into x-ray detector windows. The requirements for this application include high corrosion resistance, low intrinsic stress, high strains at failure, and high x-ray transmission. Low temperature sputtering was used because of its compatibility with the rest of the window fabrication process. Corrosion resistance was tested by exposure of carbon coated and uncoated Al thin films to humidity. Substrate curvature and bulge testing measurements were used to determine intrinsic stress and ultimate strain at failure. The composition and bonding of the carbon films were further characterized by electron energy loss spectroscopy, Raman spectroscopy, and carbon, hydrogen, and nitrogen elemental analyses. Samples had low compressive stress (down to.08 GPa), a high strain at failure (3%), and a low fraction of sp{sup 3} carbon–carbon bonds (less than 5%). The high breaking strain and excellent x-ray transmission of these sputtered carbon films indicate that they will work well as corrosion barriers in this application.

  3. The Formation Mechanism and Corrosion Resistance of a Composite Phosphate Conversion Film on AM60 Alloy

    Science.gov (United States)

    Lan, Xiangna; Wang, Chao; Zhang, Qinyong

    2018-01-01

    Magnesium alloy AM60 has high duc and toughness, which is expected to increase in demand for automotive applications. However, it is too active, and coatings have been extensively studied to prevent corrosion. In this work, a Ba-containing composite phosphate film has been prepared on the surface of AM60. The composition and formation mechanism of the film have been investigated using a scanning electronic microscope equipped with energy dispersive X-ray spectroscopy, Fourier transform infrared, X-ray photoelectron spectroscopy, and X-ray diffractometry tests. The corrosion resistance of the film has been measured by electrochemical and immersion tests. The results show that the deposition film has fully covered the substrate but there are some micro-cracks. The structure of the film is complex, and consists of MgHPO4·3H2O, MnHPO4·2.25H2O, BaHPO4·3H2O, BaMg2(PO4)2, Mg3(PO4)2·22H2O, Ca3(PO4)2·xH2O, and some amorphous phases. The composite phosphate film has better anticorrosion performance than the AM60 and can protect the bare alloy from corrosion for more than 12 h in 0.6 M NaCl. PMID:29518038

  4. Alkali activated slag mortars provide high resistance to chloride-induced corrosion of steel

    Science.gov (United States)

    Criado, Maria; Provis, John L.

    2018-06-01

    The pore solutions of alkali-activated slag cements and Portland-based cements are very different in terms of their chemical and redox characteristics, particularly due to the high alkalinity and high sulfide content of alkali-activated slag cement. Therefore, differences in corrosion mechanisms of steel elements embedded in these cements could be expected, with important implications for the durability of reinforced concrete elements. This study assesses the corrosion behaviour of steel embedded in alkali-activated blast furnace slag (BFS) mortars exposed to alkaline solution, alkaline chloride-rich solution, water, and standard laboratory conditions, using electrochemical techniques. White Portland cement (WPC) mortars and blended cement mortars (white Portland cement and blast furnace slag) were also tested for comparative purposes. The steel elements embedded in immersed alkali-activated slag mortars presented very negative redox potentials and high apparent corrosion current values; the presence of sulfide reduced the redox potential, and the oxidation of the reduced sulfur-containing species within the cement itself gave an electrochemical signal that classical electrochemical tests for reinforced concrete durability would interpret as being due to steel corrosion processes. However, the actual observed resistance to chloride-induced corrosion was very high, as measured by extraction and characterisation of the steel at the end of a 9-month exposure period, whereas the steel embedded in white Portland cement mortars was significantly damaged under the same conditions.

  5. Evaluation of cytotoxicity and corrosion resistance of orthodontic mini-implants

    Directory of Open Access Journals (Sweden)

    Celha Borges Costa Alves

    Full Text Available ABSTRACT Objective: To evaluate and compare in vitro cytotoxicity and corrosion resistance of mini-implants from three different commercial brands used for orthodontic anchorage. Methods: Six mini-implants (Conexão(tm, Neodent(tm and SIN(tm were separately immersed in artificial saliva (pH 6.76 for 30 and 60 days. The cytotoxicity of the corrosion extracts was assessed in L929 cell cultures using the violet crystal and MTT assays, as well as cell morphology under light microscopy. Metal surface characteristics before and after immersion in artificial saliva were assessed by means of scanning electron microscopy (SEM. The samples underwent atomic absorption spectrophotometry to determine the concentrations of aluminum and vanadium ions, constituent elements of the alloy that present potential toxicity. For statistical analysis, one-way ANOVA/Bonferroni tests were used for comparisons among groups with p < 0.05 considered significant. Statistical analysis was carried out with Graph Pad PRISM software Version 4.0. Results: No changes in cell viability or morphology were observed. Mini-implants SEM images revealed smooth surfaces with no obvious traces of corrosion. The extracts assessed by means of atomic absorption spectrophotometry presented concentrations of aluminum and vanadium ions below 1.0 µg/mL and 0.5 µg/mL, respectively. Conclusion: Orthodontic mini-implants manufactured by Conexão(tm, Neodent(tm and SIN(tm present high corrosion resistance and are not cytotoxic.

  6. Inhibitors for the corrosion of reactive metals: titanium and zirconium and their alloys in acid media

    International Nuclear Information System (INIS)

    Petit, J.A.; Chatainier, G.; Dabosi, F.

    1981-01-01

    The search for effective corrosion inhibitors for titanium and zirconium in acid media is growing because of the considerable increase in the use of these materials in chemical process equipment. It still remains limited, as appears from this review, because of the exceptionally high corrosion resistance of the metals. Titanium has received the greater attention. Its corrosion rate can be lowered by introduction in the medium of multivalent ions, inorganic and organic oxidants. Care should be taken to hold the concentration at a level exceeding some critical value, otherwise the corrosion rate increases. Complexing organic agents do not show such hazardous behaviour. The very rapid corrosion of titanium and zirconium in fluoride media may be lessened by complexing the fluoride ions. Though rarely encountered, localized corrosion may be avoided by using inhibitors. In some cases good corrosion inhibitors for titanium are dissolution accelerators for zirconium. (author)

  7. Evaluation of the electrical conductivity and corrosion resistance for layers deposited via sputtering on stainless steel

    Science.gov (United States)

    Blanco, J.; Salas, Y.; Jiménez, C.; Pineda, Y.; Bustamante, A.

    2017-12-01

    In some Engineering fields, we need that conductive materials have a mechanic performance and specific electrical for that they maintain conditions or corrosive attack if they are in the environment or if they are closed structure. The stainless steels have an inert film on their surface and it has the function to act in contrast to external agents who generates the corrosion, especially for stings, spoiling the film until to fail. We found a solution taking into account the electrical performance and the anticorrosive; into the process we put recovering of specific oxides on, stainless steel using the method of sputtering with Unbalanced Magnetron, (UBM) varying the oxygen in the reactive environment. The coating obtained had a thickness one micron approximately and we saw on serious structural uniformity [1]. The corrosion resistance was evaluated through the potentiodynamics polarization and electrochemical spectroscopy impedance in NACL according to the standard. The cathode protection is the most important method employed for the corrosion prevention of metallic structures in the soil or immersed on the water. The electrical resistivity was evaluated with the four points methods and it showed a behaviour of diode type in some substrates with a threshold potential in several volts. We noticed a simple resistance solution when it was analysed in the Nyquist graphics whit the Electrochemical Impedance Spectroscopy technique. With on equivalent circuit, for this reason we determinate a variation in the corrosion speed in almost two orders of magnitude when we analysed the potentiodynamics curve by Tafel approximation. The data obtained and analysed show that this type of surface modification maintains the conductivity condition at the interface, improving the resistance in relation whit the corrosion of these elements where the recovering allowed the ionic flow wished for overcoming threshold voltage, acting as an insulator in different cases.

  8. Ferritic stainless steels: corrosion resistance + economy

    International Nuclear Information System (INIS)

    Remus, A.L.

    1976-01-01

    Ferritic stainless steels provide corrosion resistance at lower cost. They include Type 409, Type 439, 18SR, 20-Mo (1.6 Mo), 18-2 (2 Mo), 26-1S, E-Brite 26-1, 29 Cr-4 Mo, and 29 Cr-4 Mo-2 Ni. Their corrosion and mechanical properties are examined. Resistance to stress-corrosion cracking is an advantage compared to austenitic types

  9. Influence of alkali metal oxides and alkaline earth metal oxides on the mitigation of stress corrosion cracking in CANDU fuel sheathing

    Energy Technology Data Exchange (ETDEWEB)

    Metzler, J.; Ferrier, G.A.; Farahani, M.; Chan, P.K.; Corcoran, E.C., E-mail: Joseph.Metzler@rmc.ca [Royal Military College of Canada, Kingston, ON (Canada)

    2015-07-01

    Stress corrosion cracking (SCC)can cause failures of CANDU Zircaloy-4 fuel sheathing. The process occurs when a corrosive element (i.e.,iodine) interacts with a susceptible material that is under sufficient strain at a high temperature. Currently, there is an ongoing effort to improve SCC mitigation strategies for future iterations of CANDU reactors. A potential mechanism for SCC mitigation involves utilizing alkali metal oxides and alkaline earth metal oxides that will sequester corrosive iodine while actively repairing a protective oxide layer on the sheath. SCC tests performed with sodium oxide (Na{sub 2}O) and calcium oxide (CaO) have shown to decrease significantly the sheath degradation. (author)

  10. Electrical and Magnetic Properties of Binary Amorphous Transition Metal Alloys.

    Science.gov (United States)

    Liou, Sy-Hwang

    The electrical, superconductive and magnetic properties of several binary transition metal amorphous and metastable crystalline alloys, Fe(,x)Ti(,100-x) (30 (LESSTHEQ) x (LESSTHEQ) 100), Fe(,x)Zr(,100-x) (20 (LESSTHEQ) x (LESSTHEQ) 93), Fe(,x)Hf(,100-x) (20 (LESSTHEQ) x (LESSTHEQ) 100), Fe(,x)Nb(,100 -x) (22 (LESSTHEQ) x (LESSTHEQ) 85), Ni(,x)Nb(,100-x) (20 (LESSTHEQ) x (LESSTHEQ) 80), Cu(,x)Nb(,100-x) (10 (LESSTHEQ) x (LESSTHEQ) 90) were studied over a wide composition range. Films were made using a magnetron sputtering system, and the structure of the films was investigated by energy dispersive x-ray diffraction. The composition region of each amorphous alloys system was determined and found in good agreement with a model proposed by Egami and Waseda. The magnetic properties and hyperfine interactions in the films were investigated using a conventional Mossbauer spectrometer and a ('57)Co in Rh matrix source. In all Fe-early transition metal binary alloys systems, Fe does not retain its moment in the low iron concentration region and the result is that the critical concentration for magnetic order (x(,c)) is much larger than anticipated from percolation considerations. A direct comparison between crystalline alloys and their amorphous counterparts of the same composition illustrate no clear correlation between crystalline and amorphous states. Pronounced discontinuities in the magnetic properties with variation in Fe content of all Fe-early transition metal alloys at phase boundaries separating amorphous and crystalline states have been observed. This is caused by the differences in the atomic arrangement and the electronic structure between crystalline and amorphous solids. The temperature dependence of resistivity, (rho)(T), of several binary amorphous alloys of Fe-TM (where TM = Ti, Zr, Hf, Nb etc.) has been studied from 2K to 300K. The Fe-poor (x x(,c)) samples have distinctive differences in (rho)(T) at low temperature (below 30K). All the magnetic samples

  11. Electrodeposition of zinc-doped silane films for corrosion protection of mild steels

    International Nuclear Information System (INIS)

    Wu Liankui; Hu Jiming; Zhang Jianqing

    2012-01-01

    Highlights: ► Metallic zinc is doped into organosilane films by one-step electrodeposition. ► The composite films exhibit the improved corrosion resistance of mild steels. ► Zinc-doping provides additional cathodic protection to the mild steels. - Abstract: Organosilane/zinc composite films are prepared by one-step electrodeposition onto cold-rolled steels for corrosion protection. Electrochemical impedance spectroscopy measurement, bulk solution immersion and wet heat tests all show that the composite films have improved corrosion performance. X-ray photoelectron spectroscopy measurement suggests the successful encapsulation of metallic zinc. The embedding of metallic zinc results in negative shift in open-circuit potential of the film-covered electrodes. Such cathodic protection effect given by the metallic zinc provides the improved corrosion resistance of the composite films.

  12. Studies of corrosion in metallic container for storage of high level radioactive wastes; Estudios de corrosion de materiales metalicos para capsulas de almacenamiento de residuos de alta actividad

    Energy Technology Data Exchange (ETDEWEB)

    Azkarate, I; Madina, V; Insausti, M

    1999-11-01

    The metallic container is one of the most important barriers that, along with engineered and natural barriers, will isolate high level nuclear waste in saline and granite geological formations from the geosphere. However, general and localized corrosion modes such as stress corrosion cracking (SCC), pitting, crevice corrosion and hydrogen damage can be active under disposal conditions, so the corrosion behaviour of the metal container material must be carefully studied. Several metals and their alloys have been proposed for the fabrication of nuclear waste containers including carbon steels, stainless steels, titanium and titanium alloys and copper and copper-base alloys. Carbon steels and copper alloys are considered for the two rock formations, titanium is considered for salt environments and the stainless steel only in the case of a granite formation. (Author)

  13. Electrochemical stability and corrosion resistance of Ti-Mo alloys for biomedical applications.

    Science.gov (United States)

    Oliveira, N T C; Guastaldi, A C

    2009-01-01

    Electrochemical behavior of pure Ti and Ti-Mo alloys (6-20wt.% Mo) was investigated as a function of immersion time in electrolyte simulating physiological media. Open-circuit potential values indicated that all Ti-Mo alloys studied and pure Ti undergo spontaneous passivation due to spontaneously formed oxide film passivating the metallic surface, in the chloride-containing solution. It also indicated that the addition of Mo to pure Ti up to 15wt.% seems to improve the protection characteristics of its spontaneous oxides. Electrochemical impedance spectroscopy (EIS) studies showed high impedance values for all samples, increasing with immersion time, indicating an improvement in corrosion resistance of the spontaneous oxide film. The fit obtained suggests a single passive film present on the metals' surface, improving their resistance with immersion time, presenting the highest values to Ti-15Mo alloy. Potentiodynamic polarization showed a typical valve-metal behavior, with anodic formation of barrier-type oxide films, without pitting corrosion, even in chloride-containing solution. In all cases, the passive current values were quite small, and decrease after 360h of immersion. All these electrochemical results suggest that the Ti-15Mo alloy is a promising material for orthopedic devices, since electrochemical stability is directly associated with biocompatibility and is a necessary condition for applying a material as biomaterial.

  14. Corrosion Map for Metal Pipes in Coastal Louisiana

    Science.gov (United States)

    2017-12-01

    Transportation agencies often allow metal pipes as an option for cross drains under/along roads and highways. Metal culverts can corrode over time at various rates based on their environmental conditions (e.g., corrosive nature of coastal soils, high...

  15. Study on metal material corrosion behavior of packaging of cement solidified form

    International Nuclear Information System (INIS)

    He Zhouguo; Lin Meiqiong; Fan Xianhua

    1997-01-01

    The corrosion behavior of A3 carbon steel is studied by the specimens that are exposed to atmosphere, embedded in cement solidified form or immersed in corrosion liquid. The corrosion rate is determined by mass change of the specimens. In order to compare the corrosion resistant performance of various coatings, the specimens painted with various material such as epoxide resin, propionic acid resin, propane ether resin and Ti-white paint are tested. The results of the tests show that corrosion rate of A3 carbon steel is less than 10 -3 mm·a -1 in the atmosphere and the cement solidified from, less than 0.1 mm·a -1 in the corrosion liquids, and pH value in the corrosion liquids also affect the corrosion rate of A3 carbon steel. The corrosion resistant performance of Ti-white paint is better than that of other paints. So, A3 carbon steel as packaging material can meet the requirements during storage

  16. Effects of annealing on the microstructure, corrosion resistance, and mechanical properties of RE{sub 65}Co{sub 25}Al{sub 10} (RE=Ce, La, Pr, Sm, and Gd) bulk metallic glasses

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Zhou [School of Materials Science and Engineering, University of Jinan, No. 336, West Road of Nan Xinzhuang, Jinan 250022 (China); Shandong Provincial Key Laboratory of Preparation and Measurement of Building Materials, University of Jinan, No. 336, West Road of Nan Xinzhuang, Jinan 250022 (China); Xing, Qi; Sun, Zhenxi; Xu, Jing; Zhao, Zhengfeng [School of Materials Science and Engineering, University of Jinan, No. 336, West Road of Nan Xinzhuang, Jinan 250022 (China); Chen, Shuying; Liaw, Peter K. [Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN (United States); Wang, Yan, E-mail: mse_wangy@ujn.edu.cn [School of Materials Science and Engineering, University of Jinan, No. 336, West Road of Nan Xinzhuang, Jinan 250022 (China); Shandong Provincial Key Laboratory of Preparation and Measurement of Building Materials, University of Jinan, No. 336, West Road of Nan Xinzhuang, Jinan 250022 (China)

    2015-02-25

    The effects of annealing on the microstructure, corrosion resistance and mechanical properties of the RE{sub 65}Co{sub 25}Al{sub 10} (RE=Ce, La, Pr, Sm, and Gd) bulk metallic glasses (BMGs) were studied. Microstructural changes are induced after annealing below the onset crystallization temperature of 484 K, resulting in the variation of thermal stability and crystallization behavior. A proper annealing enhances the corrosion resistance in 3.5 wt% NaCl solution, which can be attributed to reduction of the electrochemical activity and galvanic coupling effects in the chloride solution. Moreover, the RE-based BMG annealed at 484 K possesses the higher corrosion potential and lower corrosion current density, combined with the corrosion morphologies, which suggests the best corrosion resistance. Annealing can also obviously change the mechanical properties and fracture morphologies. It presents that free volume annihilation can cause more difficulty in the elastic atom rearrangement for the as-annealed RE-based BMGs.

  17. Bioactive glass-ceramic coating for enhancing the in vitro corrosion resistance of biodegradable Mg alloy

    Science.gov (United States)

    Ye, Xinyu; Cai, Shu; Dou, Ying; Xu, Guohua; Huang, Kai; Ren, Mengguo; Wang, Xuexin

    2012-10-01

    In this work, a bioactive 45S5 glass-ceramic coating was synthesized on magnesium (Mg) alloy substrate by using a sol-gel dip-coating method, to improve the initial corrosion resistance of AZ31 Mg alloy. The surface morphology and phase composition of the glass-ceramic coating were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The coating composed of amorphous phase and crystalline phase Na2Ca2Si3O9, with the thickness of ∼1.0 μm, exhibited a uniform and crack-free surface morphology. The corrosion behavior of the uncoated and coated Mg alloy substrates was investigated by the electrochemical measurements and immersion tests in simulated body fluid (SBF). Potentiodynamic polarization tests recorded an increase of potential (Ecorr) form -1.60 V to -1.48 V, and a reduction of corrosion current density (icorr) from 4.48 μA cm-2 to 0.16 μA cm-2, due to the protection provided by the glass-ceramic coating. Immersion tests also showed the markedly improved corrosion resistance of the coated sample over the immersion period of 7 days. Moreover, after 14 days of immersion in SBF, the corrosion resistance of the coated sample declined due to the cracking of the glass-ceramic coating, which was confirmed by electrochemical impedance spectroscopy (EIS) analysis. The results suggested that the 45S5 glass-ceramic coated Mg alloy could provide a suitable corrosion behavior for use as degradable implants.

  18. Corrosion Performance of Fe-Cr-Ni Alloys in Artificial Saliva and Mouthwash Solution

    Science.gov (United States)

    Porcayo-Calderon, J.; Casales-Diaz, M.; Salinas-Bravo, V. M.; Martinez-Gomez, L.

    2015-01-01

    Several austenitic stainless steels suitable for high temperature applications because of their high corrosion resistance and excellent mechanical properties were investigated as biomaterials for dental use. The steels were evaluated by electrochemical techniques such as potentiodynamic polarization curves, cyclic polarization curves, measurements of open circuit potential, and linear polarization resistance. The performance of steels was evaluated in two types of environments: artificial saliva and mouthwash solution at 37°C for 48 hours. In order to compare the behavior of steels, titanium a material commonly used in dental applications was also tested in the same conditions. Results show that tested steels have characteristics that may make them attractive as biomaterials for dental applications. Contents of Cr, Ni, and other minor alloying elements (Mo, Ti, and Nb) determine the performance of stainless steels. In artificial saliva steels show a corrosion rate of the same order of magnitude as titanium and in mouthwash have greater corrosion resistance than titanium. PMID:26064083

  19. Materials corrosion and protection at high temperatures

    International Nuclear Information System (INIS)

    Balbaud, F.; Desgranges, Clara; Martinelli, Laure; Rouillard, Fabien; Duhamel, Cecile; Marchetti, Loic; Perrin, Stephane; Molins, Regine; Chevalier, S.; Heintz, O.; David, N.; Fiorani, J.M.; Vilasi, M.; Wouters, Y.; Galerie, A.; Mangelinck, D.; Viguier, B.; Monceau, D.; Soustelle, M.; Pijolat, M.; Favergeon, J.; Brancherie, D.; Moulin, G.; Dawi, K.; Wolski, K.; Barnier, V.; Rebillat, F.; Lavigne, O.; Brossard, J.M.; Ropital, F.; Mougin, J.

    2011-01-01

    This book was made from the lectures given in 2010 at the thematic school on 'materials corrosion and protection at high temperatures'. It gathers the contributions from scientists and engineers coming from various communities and presents a state-of-the-art of the scientific and technological developments concerning the behaviour of materials at high temperature, in aggressive environments and in various domains (aerospace, nuclear, energy valorization, and chemical industries). It supplies pedagogical tools to grasp high temperature corrosion thanks to the understanding of oxidation mechanisms. It proposes some protection solutions for materials and structures. Content: 1 - corrosion costs; macro-economical and metallurgical approach; 2 - basic concepts of thermo-chemistry; 3 - introduction to the Calphad (calculation of phase diagrams) method; 4 - use of the thermodynamic tool: application to pack-cementation; 5 - elements of crystallography and of real solids description; 6 - diffusion in solids; 7 - notions of mechanics inside crystals; 8 - high temperature corrosion: phenomena, models, simulations; 9 - pseudo-stationary regime in heterogeneous kinetics; 10 - nucleation, growth and kinetic models; 11 - test experiments in heterogeneous kinetics; 12 - mechanical aspects of metal/oxide systems; 13 - coupling phenomena in high temperature oxidation; 14 - other corrosion types; 15 - methods of oxidized surfaces analysis at micro- and nano-scales; 16 - use of SIMS in the study of high temperature corrosion of metals and alloys; 17 - oxidation of ceramics and of ceramic matrix composite materials; 18 - protective coatings against corrosion and oxidation; 19 - high temperature corrosion in the 4. generation of nuclear reactor systems; 20 - heat exchangers corrosion in municipal waste energy valorization facilities; 21 - high temperature corrosion in oil refining and petrochemistry; 22 - high temperature corrosion in new energies industry. (J.S.)

  20. Corrosion and antifouling characteristics of technetium 99 in seawater

    International Nuclear Information System (INIS)

    Spitsyn, V.I.; Strekalov, P.V.; Balakhovskij, O.A.; Mikhajlovskij, Yu.N.

    1982-01-01

    The results are presented of studying the corrosive and antifouling properties of metallic technetium-99 in the Barents Sea and the Sea of Japan. Foil of 99 Tc glued on acrylic plastic served as a sample. High corrosion resistance and antifouling properties exhibited by 99 Tc in seawater point to favorable prospects of further studies aimed at development of new methods for protection against corrosion and fouling of metallic structures and parts with the use of technetium. The antifouling properties of technetium would evidently be used most efficiently when coating materials of high corrosion resistance to seawater (titanium, stainless steels, special alloys, etc.) with layers of technetium. The use of technetium for coating low-alloyed or carbon steels employed in seawater is yet problematic

  1. Microstructure and Corrosion Resistance Property of a Zn-AI-Mg Alloy with Different Solidification Processes

    Directory of Open Access Journals (Sweden)

    Jiang Guang-rui

    2017-01-01

    Full Text Available Zn-Al-Mg alloy coating attracted much attention due to its high corrosion resistance properties, especially high anti-corrosion performance at the cut edge. As the Zn-Al-Mg alloy coating was usually produced by hot-dip galvanizing method, solidification process was considered to influence its microstructure and corrosion properties. In this work, a Zn-Al-Mg cast alloy was melted and cooled to room temperature with different solidification processes, including water quench, air cooling and furnace cooling. Microstructure of the alloy with different solidification processes was characterized by scanning electron microscopy (SEM. Result shows that the microstructure of the Zn-Al-Mg alloy are strongly influenced by solidification process. With increasing solidification rate, more Al is remained in the primary crystal. Electrochemical analysis indicates that with lowering solidification rate, the corrosion current density of the Zn-Al-Mg alloy decreases, which means higher corrosion resistance.

  2. Effects of sulfate on heavy metal release from iron corrosion scales in drinking water distribution system.

    Science.gov (United States)

    Sun, Huifang; Shi, Baoyou; Yang, Fan; Wang, Dongsheng

    2017-05-01

    Trace heavy metals accumulated in iron corrosion scales within a drinking water distribution system (DWDS) could potentially be released to bulk water and consequently deteriorate the tap water quality. The objective of this study was to identify and evaluate the release of trace heavy metals in DWDS under changing source water conditions. Experimental pipe loops with different iron corrosion scales were set up to simulate the actual DWDS. The effects of sulfate levels on heavy metal release were systemically investigated. Heavy metal releases of Mn, Ni, Cu, Pb, Cr and As could be rapidly triggered by sulfate addition but the releases slowly decreased over time. Heavy metal release was more severe in pipes transporting groundwater (GW) than in pipes transporting surface water (SW). There were strong positive correlations (R 2  > 0.8) between the releases of Fe and Mn, Fe and Ni, Fe and Cu, and Fe and Pb. When switching to higher sulfate water, iron corrosion scales in all pipe loops tended to be more stable (especially in pipes transporting GW), with a larger proportion of stable constituents (mainly Fe 3 O 4 ) and fewer unstable compounds (β-FeOOH, γ-FeOOH, FeCO 3 and amorphous iron oxides). The main functional iron reducing bacteria (IRB) communities were favorable for the formation of Fe 3 O 4 . The transformation of corrosion scales and the growth of sulfate reducing bacteria (SRB) accounted for the gradually reduced heavy metal release with time. The higher metal release in pipes transporting GW could be due to increased Fe 6 (OH) 12 CO 3 content under higher sulfate concentrations. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Corrosion performance of metals and alloys in a tuff geochemical environment

    International Nuclear Information System (INIS)

    Van Konynenburg, R.A.; McCright, R.D.

    1985-01-01

    Reference and alternate alloy systems have been chosen for use in fabricating waste packages for a potential high-level nuclear waste repository in tuff. The main corrosion concerns have been identified. Testing performed to date indicates that austenitic stainless steels woul perform well as package materials under the expected conditions as well as the less likely extreme conditions so far postulated. Carbon steel appears to be adequate as a material for borehole liners. Copper-based alloys and Zircaloys are also undergoing corrosion testing, the former as alternate package materials, and the latter because of their presence as spent fuel cladding. 17 references, 2 tables

  4. Three-dimensional shear transformation zone dynamics model for amorphous metals

    International Nuclear Information System (INIS)

    Homer, Eric R; Schuh, Christopher A

    2010-01-01

    A fully three-dimensional (3D) mesoscale modeling framework for the mechanical behavior of amorphous metals is proposed. The model considers the coarse-grained action of shear transformation zones (STZs) as the fundamental deformation event. The simulations are controlled through the kinetic Monte Carlo algorithm and the mechanical response of the system is captured through finite-element analysis, where STZs are mapped onto a 3D finite-element mesh and are allowed to shear in any direction in three dimensions. Implementation of the technique in uniaxial creep tests over a wide range of conditions validates the model's ability to capture the expected behaviors of an amorphous metal, including high temperature flow conforming to the expected constitutive law and low temperature localization in the form of a nascent shear band. The simulation results are combined to construct a deformation map that is comparable to experimental deformation maps. The flexibility of the modeling framework is illustrated by performing a contact test (simulated nanoindentation) in which the model deforms through STZ activity in the region experiencing the highest shear stress

  5. Corrosion mitigation of rare-earth metals containing magnesium EV31A-T6 alloy via chrome-free conversion coating treatment

    International Nuclear Information System (INIS)

    Hamdy, Abdel Salam; Butt, Darryl P.

    2013-01-01

    Highlights: • Protective stannate coatings have been proposed for rare-earth-EV31A-T6 magnesium alloy. • A simple coating method based on direct treatment of EV31A-T6 in a diluted stannate was found promising. • Surface modification prior to stannate coating offer no substantial advantage over directly coating. • Stannate conversion coatings decrease corrosion rates by a factor of 1/7. • The coating does not display any self-healing characteristics as shown in AZ91D. -- Abstract: Magnesium alloys posses unique mechanical and physical characteristics making them attractive light-weight materials for several strategic industries such as electronics, computer, automotive and aerospace. Due to their high chemical reactivity and poor corrosion resistance, the protection of magnesium alloys from corrosion is one of the hottest topics in materials science and engineering. Addition of rare-earth metals (RE) as alloying elements to magnesium alloys is one of the common approaches to improve their mechanical properties and, sometimes, the corrosion resistance. However, the potential difference between the RE metals phase formed in the Mg matrix enhances the galvanic corrosion at the interfaces where RE metals inert phase acts as cathode and the active Mg matrix acts as anode. This paper introduces a simple one-step clean conversion coating treatment for improving the protection of RE containing magnesium EV31A-T6 alloy in Cl − media

  6. Development of high performance cladding

    International Nuclear Information System (INIS)

    Kiuchi, Kiyoshi

    2003-01-01

    The developments of superior next-generation light water reactor are requested on the basis of general view points, such as improvement of safety, economics, reduction of radiation waste and effective utilization of plutonium, until 2030 year in which conventional reactor plants should be renovate. Improvements of stainless steel cladding for conventional high burn-up reactor to more than 100 GWd/t, developments of manufacturing technology for reduced moderation-light water reactor (RMWR) of breeding ratio beyond 1.0 and researches of water-materials interaction on super critical pressure-water cooled reactor are carried out in Japan Atomic Energy Research Institute. Stable austenite stainless steel has been selected for fuel element cladding of advanced boiling water reactor (ABWR). The austenite stain less has the superiority for anti-irradiation properties, corrosion resistance and mechanical strength. A hard spectrum of neutron energy up above 0.1 MeV takes place in core of the reduced moderation-light water reactor, as liquid metal-fast breeding reactor (LMFBR). High performance cladding for the RMWR fuel elements is required to get anti-irradiation properties, corrosion resistance and mechanical strength also. Slow strain rate test (SSRT) of SUS 304 and SUS 316 are carried out for studying stress corrosion cracking (SCC). Irradiation tests in LMFBR are intended to obtain irradiation data for damaged quantity of the cladding materials. (M. Suetake)

  7. Specification for corrosion-resisting chromium and chromium-nickel steel welding rods and bare electrodes - approved 1969

    International Nuclear Information System (INIS)

    Anon.

    1975-01-01

    This specification covers corrosion-resisting chromium and chromium-nickel steel welding rods for use with the atomic hydrogen and gas-tungsten-arc welding processes and bare electrodes for use with the submerged arc and gas metal-arc welding processes. These welding rods and electrodes include those alloy steels designated as corrosion- or heat-resisting chromium and chromium-nickel steels, in which chromium exceeds 4% and nickel does not exceed 50%

  8. Corrosion behaviour of non-ferrous metals in sea water

    Energy Technology Data Exchange (ETDEWEB)

    Birn, Jerzy; Skalski, Igor [Ship Design and Research Centre, Al. Rzeczypospolitej 8, 80-369 Gdansk (Poland)

    2004-07-01

    The most typical kinds of corrosion of brasses are selective corrosion (dezincification) and stress corrosion. Prevention against these kinds of corrosion lies in application of arsenic alloy addition and appropriate heat treatment removing internal stresses as well as in maintaining the arsenic and phosphorus contents on a proper level. The most typical corrosion of cupronickels is the local corrosion. Selective corrosion occurs less often and corrosion cracking caused by stress corrosion in sea water does not usually occur. Crevice corrosion is found especially in places of an heterogeneous oxidation of the surface under inorganic deposits or under bio-film. Common corrosive phenomena for brasses and cupronickels are the effects caused by sea water flow and most often the impingement attack. Alloy additions improve resistance to the action of intensive sea water flow but situation in this field requires further improvement, especially if the cheaper kinds of alloys are concerned. Contaminants of sea water such as ammonia and hydrogen sulphide are also the cause of common corrosion processes for all copper alloys. Corrosion of copper alloys may be caused also by sulphate reducing bacteria (SRB). Galvanic corrosion caused by a contact with titanium alloys e.g. in plate heat exchangers may cause corrosion of both kinds copper alloys. Bronzes belong to copper alloys of the highest corrosion resistance. Failures that sometimes occur are caused most often by the cavitation erosion, by an incorrect chemical composition of alloys or at last by their inadequate structure. The main problems of aluminium alloys service in sea water are following phenomena: local corrosion (pitting and crevice corrosion), galvanic corrosion, exfoliation and corrosion in the presence of OH- ions. The cause of local corrosion are caused by presence of passive film on the alloy's surface and presence of chlorides in sea water which are able to damage the passive film. Galvanic corrosion is

  9. Compatibility tests between molten salts and metal materials (2)

    International Nuclear Information System (INIS)

    Shiina, Yasuaki

    2003-08-01

    Latent heat storage technology using molten salts can reduce temperature fluctuations of heat transfer fluid by latent heat for middle and high temperature regions. This enables us to operate several heat utilization systems in cascade connected to High Temperature Gas Cooled Reactors (HTGRs) from high to low temperature range by setting the latent heat storage system after a heat utilization system to reduce thermal load after the heat utilization systems. This latent heat technology is expected to be used for effective use of heat such as equalization of electric load between night and daytime. In the application of the latent heat technology, compatibility between molten salts and metal materials is very important because molten salts are corrosive, and heat transfer pipes and vessels will contact with the molten salts. It will be necessary to prevail the latent heat storage technique that normal metal materials can be used for the pipes and vessels. However, a few studies have been reported of compatibility between molten salts and metals in middle and high temperature ranges. In this study, four molten salts, range of the melting temperature from 490degC to 800degC, are selected and five metals, high temperature and corrosion resistance steels of Alloy600, HastelloyB2, HastelloyC276, SUS310S and pure Nickel are selected for the test with the consideration of metal composition. Test was performed in an electric furnace by setting the molten salts and the metals in melting pots in an atmosphere of nitrogen. Results revealed excellent corrosion resistance of pure Nickel and comparatively low corrosion resistance of nickel base alloys such as Alloy600 and Hastelloys against Li 2 CO 3 . Corrosion resistance of SUS310S was about same as nickel based alloys. Therefore, if some amount of corrosion is permitted, SUS310S would be one of the candidate alloys for structure materials. These results will be used as reference data to select metals in latent heat technology

  10. Investigation on corrosion resistance of metal superficially modified with alkoxy titanates

    International Nuclear Information System (INIS)

    Yao Kangde; Song Shizhe; Shen Ningxiang

    1991-01-01

    A study has been made in order to determine corrosion protection performance of alkoxy titanate modified iron in a 3% NaCl solution. The effectiveness of alkoxy titanates as corrosion retarders for chloride environments is confirmed by both stepped potential sweep technique and electrochemical impedance spectroscopy (EIS). Ion microanalysis (IMA) depth profiles are used to elucidate the corrosion inhibitive action of different alkoxy titanate. (orig.)

  11. Corrosion of materials for heat exchangers and the countermeasures

    International Nuclear Information System (INIS)

    Kawamoto, Teruaki

    1978-01-01

    When the materials for heat exchangers are selected, the heat transfer performance, mechanical strength, workability, cost, corrosion resistance and so on are taken in consideration. Most of the failure of heat exchangers is due to corrosion, and the corrosion failure on cooling water side occurs frequently, to which attention is not paid much usually. The rate of occurrence of corrosion failure is overwhelmingly high in heating tubes, and the failure owing to cooling water exceeds that owing to process fluid. The material of heating tubes is mostly aluminum brass, and local failure such as pitting corrosion or stress corrosion cracking holds a majority. The cause of corrosion failure due to cooling water is mostly the poor water quality. The mechanism of corrosion of metals can be explained by the electrochemical reaction between the metals and solutions. As for the factors affecting corrosion, dissolved oxygen, pH, Cl - ions, temperature, flow velocity, and foreign matters are enumerated. Copper alloys are sensitive to the effect of polluted sea water. Erosion corrosion is caused by eddies and bubbles owing to high flow velocity, and impingement attack is caused by scratching foreign matters. The quality of fresh water affects corrosion more than sea water in case of copper alloys. The preliminary examination of water quality is essential. (Kako, I.)

  12. A new corrosion monitoring technique

    International Nuclear Information System (INIS)

    Brown, Gerald K.

    2000-01-01

    Internal Corrosion Monitoring has relied upon 5 basic techniques. Little improvement in performance has been achieved in any of these. Many newer internal corrosion monitoring techniques have proved of little value in the field although some have instances of success in the laboratory. Industry has many high value hydrocarbon applications requiring corrosion rate monitoring for real-time problem solving and control. The high value of assets and the cost of asset replacement makes it necessary to practice cost effective process and corrosion control with sensitivity beyond the 5 basic techniques. This new metal loss technology offers this sensitivity. Traditional metal loss technology today provides either high sensitivity with short life, or conversely, long life but with substantially reduced sensitivity. The new metal loss technology offers an improved working life of sensors without significantly compromising performance. The paper discusses the limitations of existing on-line technologies and describes the performance of a new technology. This new metal loss technology was introduced at NACE Corrosion 99'. Since that time several field projects have been completed or are ongoing. This paper will discuss the new metal loss technology and report on some of the data that has been obtained.(author)

  13. Bioactive glass-ceramic coating for enhancing the in vitro corrosion resistance of biodegradable Mg alloy

    Energy Technology Data Exchange (ETDEWEB)

    Ye Xinyu [Key Laboratory for Advanced Ceramics and Machining Technology of Ministry of Education, Tianjin University, Tianjin 300072 (China); Cai Shu, E-mail: caishu@tju.edu.cn [Key Laboratory for Advanced Ceramics and Machining Technology of Ministry of Education, Tianjin University, Tianjin 300072 (China); Dou Ying [Key Laboratory for Advanced Ceramics and Machining Technology of Ministry of Education, Tianjin University, Tianjin 300072 (China); Xu Guohua [Shanghai Changzheng Hospital, Shanghai 200003 (China); Huang Kai; Ren Mengguo; Wang Xuexin [Key Laboratory for Advanced Ceramics and Machining Technology of Ministry of Education, Tianjin University, Tianjin 300072 (China)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer Sol-gel derived 45S5 glass-ceramic coating was prepared on Mg alloy substrate. Black-Right-Pointing-Pointer The corrosion resistance of glass-ceramic coated Mg alloy was markedly improved. Black-Right-Pointing-Pointer The corrosion behavior of the coated sample varied due to the cracking of coating. - Abstract: In this work, a bioactive 45S5 glass-ceramic coating was synthesized on magnesium (Mg) alloy substrate by using a sol-gel dip-coating method, to improve the initial corrosion resistance of AZ31 Mg alloy. The surface morphology and phase composition of the glass-ceramic coating were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The coating composed of amorphous phase and crystalline phase Na{sub 2}Ca{sub 2}Si{sub 3}O{sub 9}, with the thickness of {approx}1.0 {mu}m, exhibited a uniform and crack-free surface morphology. The corrosion behavior of the uncoated and coated Mg alloy substrates was investigated by the electrochemical measurements and immersion tests in simulated body fluid (SBF). Potentiodynamic polarization tests recorded an increase of potential (E{sub corr}) form -1.60 V to -1.48 V, and a reduction of corrosion current density (i{sub corr}) from 4.48 {mu}A cm{sup -2} to 0.16 {mu}A cm{sup -2}, due to the protection provided by the glass-ceramic coating. Immersion tests also showed the markedly improved corrosion resistance of the coated sample over the immersion period of 7 days. Moreover, after 14 days of immersion in SBF, the corrosion resistance of the coated sample declined due to the cracking of the glass-ceramic coating, which was confirmed by electrochemical impedance spectroscopy (EIS) analysis. The results suggested that the 45S5 glass-ceramic coated Mg alloy could provide a suitable corrosion behavior for use as degradable implants.

  14. Albumin coatings by alternating current electrophoretic deposition for improving corrosion resistance and bioactivity of titanium implants.

    Science.gov (United States)

    Höhn, Sarah; Braem, Annabel; Neirinck, Bram; Virtanen, Sannakaisa

    2017-04-01

    Although Ti alloys are generally regarded to be highly corrosion resistant, inflammatory conditions following surgery can instigate breakdown of the TiO 2 passivation layer leading to an increased metal ion release. Furthermore proteins present in the surrounding tissue will readily adsorb on a titanium surface after implantation. In this paper alternating current electrophoretic deposition (AC-EPD) of bovine serum albumin (BSA) on Ti6Al4V was investigated in order to increase the corrosion resistance and control the protein adsorption capability of the implant surface. The Ti6Al4V surface was characterized with SEM, XPS and ToF-SIMS after long-term immersion tests under physiological conditions and simulated inflammatory conditions either in Dulbecco's Modified Eagle Medium (DMEM) or DMEM supplemented with fetal calf serum (FCS). The analysis showed an increased adsorption of amino acids and proteins from the different immersion solutions. The BSA coating was shown to prevent selective dissolution of the vanadium (V) rich β-phase, thus effectively limiting metal ion release to the environment. Electrochemical impedance spectroscopy measurements confirmed an increase of the corrosion resistance for BSA coated surfaces as a function of immersion time due to the time-dependent adsorption of the different amino acids (from DMEM) and proteins (from FCS) as observed by ToF-SIMS analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Characterization and corrosion behavior of phytic acid coatings, obtained by chemical conversion on magnesium substrates in physiological solution; Caracterizacion y comportamiento frente a la corrosion de recubrimientos de acido fitico, obtenidos por conversion quimica, sobre substratos de magnesio en solucion fisiologica

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Alvarado, L. A.; Lomeli, M. A.; Hernandez, L. S.; Miranda, J. M.; Narvaez, L.; Diaz, I.; Garcia-Alonso, M. C.; Escudero, M. L.

    2014-10-01

    In order to improve the corrosion resistance of biodegradable magnesium and AZ31 magnesium alloy implants, a phytic acid coating has been applied on both substrates and their protective effect against corrosion has been assessed. The morphology and the chemical nature of the conversion coating were analyzed by SEM/EDX, XRD and FTIR. The spectra showed that the conversion coating was amorphous, and it was composed of Mg, O, and P on magnesium surface, along with Al, Zn and C on AZ31 alloy. The main coating components were chelate compounds formed by phytic acid and metallic ions. The corrosion resistance of bare and coated samples was evaluated by potentiodynamic polarization technique in Hank's solution at 37 degree centigrade. The results indicate that phytic acid conversion coatings provided a very effective protection to the magnesium substrates studied. (Author)

  16. Application of amorphous filler metals in production of fusion reactor high heat flux components

    Energy Technology Data Exchange (ETDEWEB)

    Kalin, B A [Moskovskij Inzhenerno-Fizicheskij Inst., Moscow (Russian Federation); Fedotov, V T [Moskovskij Inzhenerno-Fizicheskij Inst., Moscow (Russian Federation); Grigoriev, A E [Moskovskij Inzhenerno-Fizicheskij Inst., Moscow (Russian Federation); Sevriukov, O N [Moskovskij Inzhenerno-Fizicheskij Inst., Moscow (Russian Federation); Pliushev, A N [Moskovskij Inzhenerno-Fizicheskij Inst., Moscow (Russian Federation); Skuratov, L A [Moskovskij Inzhenerno-Fizicheskij Inst., Moscow (Russian Federation); Polsky, V I [Moskovskij Inzhenerno-Fizicheskij Inst., Moscow (Russian Federation); Yakushin, V L [Moskovskij Inzhenerno-Fizicheskij Inst., Moscow (Russian Federation); Virgiliev, Yu S [State Research Institute of Graphite, Electrodnaya St. 2, 115524 Moscow (Russian Federation); Vasiliev, V L [TRINITI, Troitsk, 142092 Moscow District (Russian Federation); Tserevitinov, S S [TRINITI, Troitsk, 142092 Moscow District (Russian Federation)

    1995-03-01

    Amorphous ribbon-type filler metals represent a promising facility for fastening heterogeneous materials together. The advantage results from the homogeneity of element and phase compositions and the strictly specified geometrical dimensions of such fillers. Amorphous fillers Zr-Ti-Fe-Be, Zr-Ti-Ni-Cu and Ti-Zr-Ni-Cu and microcrystalline fillers Al-Si and Cu-Sn-Mn-In-Ni were produced by quenching at a rate of about 10{sup 6}Ks{sup -1}. Brazing of graphite with metals (Cu+MPG-6, Cu+RGT, Mo+MIG-1, V+MIG-1, V+RGT) was accomplished using ribbon-type fillers. Two types of metal-based samples were produced in the form of plates and rakes. The rakes were made by brazing three small graphite bars to the metal, the 2mm space between the bars being 0.25 of the bar height. The results of metallographic studies of the brazing zone and of tests on brazed structures treated by pulsed energy fluxes are discussed. (orig.).

  17. Erosion-corrosion resistance properties of 316L austenitic stainless steels after low-temperature liquid nitriding

    Science.gov (United States)

    Zhang, Xiangfeng; Wang, Jun; Fan, Hongyuan; Pan, Dong

    2018-05-01

    The low-temperature liquid nitriding of stainless steels can result in the formation of a surface zone of so-called expanded austenite (S-phase) by the dissolution of large amounts of nitrogen in the solid solution and formation of a precipitate-free layer supersaturated with high hardness. Erosion-corrosion measurements were performed on low-temperature nitrided and non-nitrided 316L stainless steels. The total erosion-corrosion, erosion-only, and corrosion-only wastages were measured directly. As expected, it was shown that low-temperature nitriding dramatically reduces the degree of erosion-corrosion in stainless steels, caused by the impingement of particles in a corrosive medium. The nitrided 316L stainless steels exhibited an improvement of almost 84% in the erosion-corrosion resistance compared to their non-nitrided counterparts. The erosion-only rates and synergistic levels showed a general decline after low-temperature nitriding. Low-temperature liquid nitriding can not only reduce the weight loss due to erosion but also significantly reduce the weight loss rate of interactions, so that the total loss of material decreased evidently. Therefore, 316L stainless steels displayed excellent erosion-corrosion behaviors as a consequence of their highly favorable corrosion resistances and superior wear properties.

  18. Pitting Corrosion of the Resistance Welding Joints of Stainless Steel Ventilation Grille Operated in Swimming Pool Environment

    Directory of Open Access Journals (Sweden)

    Mirosław Szala

    2018-01-01

    Full Text Available This work focuses on the pitting corrosion of ventilation grilles operated in swimming pool environments. The ventilation grille was made by resistance welding of stainless steel rods. Based on the macroscopic and microscopic examinations, the mechanism of the pitting corrosion was confirmed. Chemical composition microanalysis of sediments as well as base metal using scanning electron microscopy and energy-dispersive spectroscopy (SEM-EDS method was carried out. The weldments did not meet the operating conditions of the swimming pool environment. The wear due to the pitting corrosion was identified in heat affected zones of stainless steel weldment and was more severe than the corrosion of base metal. The low quality finish of the joints and influence of the welding process on the weld metal microstructure lead to accelerated deposition of corrosion effecting elements such as chlorine.

  19. Properties of corrosion resistance in C + Mo multi implanted steel

    International Nuclear Information System (INIS)

    Zhang Tonghe; Wu Yuguang; Wang Xiaoyan

    2001-01-01

    The influence of multi-implantation on the corrosion resistance of H13 steel was studied using multi-sweep cyclic voltammetry. The formation conditions of phases and its effects on corrosion resistance were studied. The mechanism of improvement in corrosion resistance was discussed. The experimental results show that the increase of Mo dose can improve corrosion resistance, however the increase of C dose can enhance pitting corrosion potential. Both effects were obtained using dual-and multi-implantation. The passivation layer consists of the phases of Fe 2 Mo, FeMo, MoC, Fe 5 C 3 and Fe 7 C 3 in dual implantation surface of steel. It can improve corrosion resistance and increase pitting corrosion potential. Multi-implantation can further improve corrosion and pitting corrosion resistance compared with dual implantation

  20. Comparison of the crevice corrosion resistance of alloys 625 and 22

    International Nuclear Information System (INIS)

    Palmer, J.; Kehler, B.; Iloybare, G.O.; Scully, J.R.

    1999-01-01

    The Yucca Mountain Site Characterization Project is concerned with the corrosion resistance of candidate engineered waste package materials. A variety of waste package designs have been proposed for US and Canadian High Level Nuclear Waste Repositories. A common feature of each design is the possibility of utilizing a corrosion resistant material such as a nickel-based super alloy or titanium-based alloy. A suitable corrosion resistant material may provide (a) kinetic immunity if the combination of repository environmental conditions and alloy resistance assure both: (i) a passive condition with negligible chance of localized corrosion stabilization, as well as (ii) low enough passive dissolution rates to insure conventional corrosion allowance over geological times, (b) a second form of ''corrosion allowance,'' if it can be scientifically demonstrated that a mechanism for stifling (i.e., death) of localized corrosion propagation occurs well before waste canisters are penetrated, or (c) such a low probability of initiation and continued propagation that a tolerably low degree of penetration occurs. Unfortunately, a large database on the crevice corrosion properties of alloy 22 does not exist in comparison to alloy 625. Alloy screening tests in oxidizing acids containing FeCl3 indicate that alloy 22 is more resistant to crevice corrosion than 625 as indicated by critical pit and crevice temperatures. Differences in alloying element compositions as expressed by pitting resistance equivalency number calculations support these findings. However, these data only provide the relative ranking of these alloys in terms of crevice corrosion and do not answer the critical questions proposed above

  1. The effects of argon ion bombardment on the corrosion resistance of tantalum

    Science.gov (United States)

    Ramezani, A. H.; Sari, A. H.; Shokouhy, A.

    2017-02-01

    Application of ion beam has been widely used as a surface modification method to improve surface properties. This paper investigates the effect of argon ion implantation on surface structure as well as resistance against tantalum corrosion. In this experiment, argon ions with energy of 30 keV and in doses of 1 × 1017-10 × 1017 ions/cm2 were used. The surface bombardment with inert gases mainly produces modified topography and morphology of the surface. Atomic Force Microscopy was also used to patterned the roughness variations prior to and after the implantation phase. Additionally, the corrosion investigation apparatus wear was applied to compare resistance against tantalum corrosion both before and after ion implantation. The results show that argon ion implantation has a substantial impact on increasing resistance against tantalum corrosion. After the corrosion test, scanning electron microscopy (SEM) analyzed the samples' surface morphologies. In addition, the elemental composition is characterized by energy-dispersive X-ray (EDX) analysis. The purpose of this paper was to obtain the perfect condition for the formation of tantalum corrosion resistance. In order to evaluate the effect of the ion implantation on the corrosion behavior, potentiodynamic tests were performed. The results show that the corrosion resistance of the samples strongly depends on the implantation doses.

  2. Characterization and corrosion resistance of anodic electrodeposited titanium oxide/phosphate films on Ti-20Nb-10Zr-5Ta bioalloy

    Energy Technology Data Exchange (ETDEWEB)

    Popa, Monica; Vasilescu, Cora; Drob, Silviu I.; Osiceanu, Petre; Anastasescu, Mihai; Calderon-Moreno, Jose M., E-mail: josecalderonmoreno@yahoo.com [Institute of Physical Chemistry ' Ilie Murgulescu' of the Romanian Academy, Bucharest (Romania)

    2013-07-15

    In this work, the anodic galvanostatic electrodeposition of an oxidation film containing phosphates on Ti-20Nb-10Zr-5Ta alloy from orthophosphoric acid solution is presented. Its composition was determined by X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR) and Raman micro-spectroscopy, and its topography by atomic force microscopy (AFM). The corrosion resistance of the coated alloy in simulated human fluid (by linear polarization method and monitoring of open circuit potentials, corresponding open circuit potential gradients) as well as the characterization of the coating (by Raman spectroscopy and depth profile X-ray photoelectron spectroscopy (XPS)) deposited in a period of 300 h soaking in simulated human body fluid were studied. The electrodeposited film was composed of amorphous titanium dioxide and contained phosphate groups. The corrosion resistance of the coated Ti-20Nb-10Zr-5Ta alloy in neutral and alkaline Ringer's solutions was higher than that of the bare alloy due to the protective properties of the electrodeposited film. The corrosion parameters improved over time as result of the thickening of the surface film by the deposition from the physiological solution. The deposited coating presented a variable composition in depth: at the deeper layer nucleated nanocrystalline hydroxyapatite and at the outer layer amorphous calcium phosphate. (author)

  3. Characterization and corrosion resistance of anodic electrodeposited titanium oxide/phosphate films on Ti-20Nb-10Zr-5Ta bioalloy

    International Nuclear Information System (INIS)

    Popa, Monica; Vasilescu, Cora; Drob, Silviu I.; Osiceanu, Petre; Anastasescu, Mihai; Calderon-Moreno, Jose M.

    2013-01-01

    In this work, the anodic galvanostatic electrodeposition of an oxidation film containing phosphates on Ti-20Nb-10Zr-5Ta alloy from orthophosphoric acid solution is presented. Its composition was determined by X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR) and Raman micro-spectroscopy, and its topography by atomic force microscopy (AFM). The corrosion resistance of the coated alloy in simulated human fluid (by linear polarization method and monitoring of open circuit potentials, corresponding open circuit potential gradients) as well as the characterization of the coating (by Raman spectroscopy and depth profile X-ray photoelectron spectroscopy (XPS)) deposited in a period of 300 h soaking in simulated human body fluid were studied. The electrodeposited film was composed of amorphous titanium dioxide and contained phosphate groups. The corrosion resistance of the coated Ti-20Nb-10Zr-5Ta alloy in neutral and alkaline Ringer's solutions was higher than that of the bare alloy due to the protective properties of the electrodeposited film. The corrosion parameters improved over time as result of the thickening of the surface film by the deposition from the physiological solution. The deposited coating presented a variable composition in depth: at the deeper layer nucleated nanocrystalline hydroxyapatite and at the outer layer amorphous calcium phosphate. (author)

  4. Amorphous Silicon-Germanium Films with Embedded Nanocrystals for Thermal Detectors with Very High Sensitivity

    Directory of Open Access Journals (Sweden)

    Cesar Calleja

    2016-01-01

    Full Text Available We have optimized the deposition conditions of amorphous silicon-germanium films with embedded nanocrystals in a plasma enhanced chemical vapor deposition (PECVD reactor, working at a standard frequency of 13.56 MHz. The objective was to produce films with very large Temperature Coefficient of Resistance (TCR, which is a signature of the sensitivity in thermal detectors (microbolometers. Morphological, electrical, and optical characterization were performed in the films, and we found optimal conditions for obtaining films with very high values of thermal coefficient of resistance (TCR = 7.9% K−1. Our results show that amorphous silicon-germanium films with embedded nanocrystals can be used as thermosensitive films in high performance infrared focal plane arrays (IRFPAs used in commercial thermal cameras.

  5. Assessment of high performance concrete containing fly ash and calcium nitrite based corrosion inhibitor as a mean to prevent the corrosion of reinforcing steel

    International Nuclear Information System (INIS)

    Montes-García, P; Jiménez-Quero, V; López-Calvo, H

    2015-01-01

    This research analyses the effectiveness of the water-to-cement ratio (w/c), fly ash and a calcium nitrite based corrosion inhibitor to prevent the corrosion of reinforcing steel embedded in high performance concrete. The interactive effect between the inhibitor and fly ash was evaluated because the occurrence of a negative effect when both ingredients are added together in a concrete mixture has been reported. All the concrete mixtures studied in this investigation had 8.2% of silica fume. Twenty seven prismatic concrete specimens were fabricated with dimensions of 55 × 230 × 300 mm each containing two steel rods embedded for the purpose of corrosion monitoring. The specimens were exposed to a simulated marine environment with two daily cycles of wetting and drying for one year. To evaluate the deterioration of the specimens corrosion potentials and linear polarization resistance tests were carried out. The results indicate that the use of a low w/c, the addition of fly ash and the addition of the corrosion inhibitor contributed to the reduction of the corrosion of steel in the concrete specimens. The results further suggest that the combination of fly ash and corrosion inhibitor does not promote the deterioration of the concrete matrix

  6. Corrosion performance of new Zircaloy-2-based alloys

    International Nuclear Information System (INIS)

    Rudling, P.; Mikes-Lindbaeck, M.; Lethinen, B.; Andren, H.O.; Stiller, K.

    1994-01-01

    A material development project was initiated to develop a new zirconium alloy, outside the ASTM specifications for Zircaloy-2 and Zircaloy-4, with optimized hydriding and corrosion properties for both boiling water reactors and pressurized water reactors. A number of different alloys were manufactured. These alloys were long-term corrosion tested in autoclaves at 400 C in steam. Also, a 520 C/24 h steam test was carried out. The zirconium metal microstructure and the chemistry of precipitates were characterized by analytical electron microscopy. The metal matrix chemistry was determined by atom probe analysis. The paper describes the correlations between corrosion material performance and zirconium alloy microstructure

  7. Promising Ta-Ti-Zr-Si metallic glass coating without cytotoxic elements for bio-implant applications

    Science.gov (United States)

    Lai, J. J.; Lin, Y. S.; Chang, C. H.; Wei, T. Y.; Huang, J. C.; Liao, Z. X.; Lin, C. H.; Chen, C. H.

    2018-01-01

    Tantalum (Ta) is considered as one of the most promising metal due to its high corrosion resistance, excellent biocompatibility and cell adhesion/in-growth capabilities. Although there are some researches exploring the biomedical aspects of Ta and Ta based alloys, systematic characterizations of newly developed Ta-based metallic glasses in bio-implant applications is still lacking. This study employs sputtering approach to produced thin-film Ti-based metallic glasses due to the high melting temperature of Ta (3020 °C). Two fully amorphous Ta-based metallic glasses composed of Ta57Ti17Zr15Si11 and Ta75Ti10Zr8Si7 are produced and experimentally characterized in terms of their mechanical properties, bio-corrosion properties, surface hydrophilic characteristics, and in-vitro cell viability and cells attachment tests. Compare to conventional pure Ti and Ta metals, the developed Ta-based metallic glasses exhibit higher hardness and lower modulus which are better match to the mechanical properties of bone. MTS assay results show that Ta-based metallic glasses show comparable cell viability and cell attachment rate compared to that of pure Ti and Ta surface in a 72 h in-vitro test.

  8. Albumin coatings by alternating current electrophoretic deposition for improving corrosion resistance and bioactivity of titanium implants

    International Nuclear Information System (INIS)

    Höhn, Sarah; Braem, Annabel; Neirinck, Bram; Virtanen, Sannakaisa

    2017-01-01

    Although Ti alloys are generally regarded to be highly corrosion resistant, inflammatory conditions following surgery can instigate breakdown of the TiO 2 passivation layer leading to an increased metal ion release. Furthermore proteins present in the surrounding tissue will readily adsorb on a titanium surface after implantation. In this paper alternating current electrophoretic deposition (AC-EPD) of bovine serum albumin (BSA) on Ti6Al4V was investigated in order to increase the corrosion resistance and control the protein adsorption capability of the implant surface. The Ti6Al4V surface was characterized with SEM, XPS and ToF-SIMS after long-term immersion tests under physiological conditions and simulated inflammatory conditions either in Dulbecco's Modified Eagle Medium (DMEM) or DMEM supplemented with fetal calf serum (FCS). The analysis showed an increased adsorption of amino acids and proteins from the different immersion solutions. The BSA coating was shown to prevent selective dissolution of the vanadium (V) rich β-phase, thus effectively limiting metal ion release to the environment. Electrochemical impedance spectroscopy measurements confirmed an increase of the corrosion resistance for BSA coated surfaces as a function of immersion time due to the time-dependent adsorption of the different amino acids (from DMEM) and proteins (from FCS) as observed by ToF-SIMS analysis. - Highlights: • Alternating current electrophoretic deposition (AC-EPD) of bovine serum albumin was investigated on Ti6Al4V. • The surface was characterized with SEM, XPS and ToF-SIMS after long-term immersion tests at pH 7 and pH 5. • The analysis showed an increased adsorption of amino acids (DMEM) and proteins (DMEM + FCS). • BSA was shown to prevent dissolution of the β-phase, limiting metal ion release and increase of corrosion resistance. • Ratios calculated by means of ToF-SIMS show that the protein will have different orientations during adsorption.

  9. Albumin coatings by alternating current electrophoretic deposition for improving corrosion resistance and bioactivity of titanium implants

    Energy Technology Data Exchange (ETDEWEB)

    Höhn, Sarah, E-mail: sarah.hoehn@fau.de [Institute for Surface Science and Corrosion, Dept. of Mat. Science, University of Erlangen-Nürnberg, 91058 Erlangen, Germany. (Germany); Braem, Annabel, E-mail: annabel.braem@kuleuven.be [KU Leuven Department of Materials Engineering, Kasteelpark Arenberg 44, Box 2450, 3001 Leuven (Belgium); Neirinck, Bram, E-mail: bram.neirinck@3DSystems.com [KU Leuven Department of Materials Engineering, Kasteelpark Arenberg 44, Box 2450, 3001 Leuven (Belgium); Virtanen, Sannakaisa, E-mail: virtanen@ww.uni-erlangen.de [Institute for Surface Science and Corrosion, Dept. of Mat. Science, University of Erlangen-Nürnberg, 91058 Erlangen, Germany. (Germany)

    2017-04-01

    Although Ti alloys are generally regarded to be highly corrosion resistant, inflammatory conditions following surgery can instigate breakdown of the TiO{sub 2} passivation layer leading to an increased metal ion release. Furthermore proteins present in the surrounding tissue will readily adsorb on a titanium surface after implantation. In this paper alternating current electrophoretic deposition (AC-EPD) of bovine serum albumin (BSA) on Ti6Al4V was investigated in order to increase the corrosion resistance and control the protein adsorption capability of the implant surface. The Ti6Al4V surface was characterized with SEM, XPS and ToF-SIMS after long-term immersion tests under physiological conditions and simulated inflammatory conditions either in Dulbecco's Modified Eagle Medium (DMEM) or DMEM supplemented with fetal calf serum (FCS). The analysis showed an increased adsorption of amino acids and proteins from the different immersion solutions. The BSA coating was shown to prevent selective dissolution of the vanadium (V) rich β-phase, thus effectively limiting metal ion release to the environment. Electrochemical impedance spectroscopy measurements confirmed an increase of the corrosion resistance for BSA coated surfaces as a function of immersion time due to the time-dependent adsorption of the different amino acids (from DMEM) and proteins (from FCS) as observed by ToF-SIMS analysis. - Highlights: • Alternating current electrophoretic deposition (AC-EPD) of bovine serum albumin was investigated on Ti6Al4V. • The surface was characterized with SEM, XPS and ToF-SIMS after long-term immersion tests at pH 7 and pH 5. • The analysis showed an increased adsorption of amino acids (DMEM) and proteins (DMEM + FCS). • BSA was shown to prevent dissolution of the β-phase, limiting metal ion release and increase of corrosion resistance. • Ratios calculated by means of ToF-SIMS show that the protein will have different orientations during adsorption.

  10. The corrosion and corrosion mechanical properties evaluation for the LBB concept in VVERs

    Energy Technology Data Exchange (ETDEWEB)

    Ruscak, M.; Chvatal, P.; Karnik, D.

    1997-04-01

    One of the conditions required for Leak Before Break application is the verification that the influence of corrosion environment on the material of the component can be neglected. Both the general corrosion and/or the initiation and, growth of corrosion-mechanical cracks must not cause the degradation. The primary piping in the VVER nuclear power plant is made from austenitic steels (VVER 440) and low alloy steels protected with the austenitic cladding (VVER 1000). Inspection of the base metal and heterogeneous weldments from the VVER 440 showed that the crack growth rates are below 10 m/s if a low oxygen level is kept in the primary environment. No intergranular cracking was observed in low and high oxygen water after any type of testing, with constant or periodic loading. In the framework of the LBB assessment of the VVER 1000, the corrosion and corrosion mechanical properties were also evaluated. The corrosion and corrosion mechanical testing was oriented predominantly to three types of tests: stress corrosion cracking tests corrosion fatigue tests evaluation of the resistance against corrosion damage. In this paper, the methods used for these tests are described and the materials are compared from the point of view of response on static and periodic mechanical stress on the low alloyed steel 10GN2WA and weld metal exposed in the primary circuit environment. The slow strain rate tests and static loading of both C-rings and CT specimens were performed in order to assess the stress corrosion cracking characteristics. Cyclic loading of CT specimens was done to evaluate the kinetics of the crack growth under periodical loading. Results are shown to illustrate the approaches used. The data obtained were evaluated also from the point of view of comparison of the influence of different structure on the stress corrosion cracking appearance. The results obtained for the base metal and weld metal of the piping are presented here.

  11. Corrosion resistant neutron absorbing coatings

    Science.gov (United States)

    Choi, Jor-Shan [El Cerrito, CA; Farmer, Joseph C [Tracy, CA; Lee, Chuck K [Hayward, CA; Walker, Jeffrey [Gaithersburg, MD; Russell, Paige [Las Vegas, NV; Kirkwood, Jon [Saint Leonard, MD; Yang, Nancy [Lafayette, CA; Champagne, Victor [Oxford, PA

    2012-05-29

    A method of forming a corrosion resistant neutron absorbing coating comprising the steps of spray or deposition or sputtering or welding processing to form a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material. Also a corrosion resistant neutron absorbing coating comprising a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material.

  12. Investigation of SiO{sub 2}:Na{sub 2}O ratio as a corrosion inhibitor for metal alloys

    Energy Technology Data Exchange (ETDEWEB)

    Mohamad, N.; Othman, N. K. [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor Darul Ehsan (Malaysia); Jalar, A. [Institute of Micro Engineering and Nanoelectronics (IMEN), Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor Darul Ehsan (Malaysia)

    2013-11-27

    The silicate is one of the potential compounds used as a corrosion inhibitor for metal alloys. The mixture between silica and sodium hydroxide (NaOH) succeeded to produce the silicate product. The formulation of a silicate product normally variable depended by the different ratio of SiO{sub 2}:Na{sub 2}O. This research utilized the agriculture waste product of paddy using its rice husk. In this study, the amorphous silica content in rice husk ash was used after rice husk burnt in a muffle furnace at a certain temperature. The X-ray diffraction (XRD) analysis was done to determine the existence of amorphous phase of silica in the rice husk ash. There are several studies that recognized rice husk as an alternative source that obtained high silica content. The X-ray fluorescence (XRF) analysis was carried out to clarify the percentage amount of Si and O elements, which referred the silica compound in rice husk ash. The preparation of sodium silicate formulation were differ based on the SiO{sub 2}:Na{sub 2}O ratio (SiO{sub 2}:Na{sub 2}O ratio = 1.00, 2.00 and 3.00). These silicate based corrosion inhibitors were tested on several testing samples, which were copper (99.9%), aluminum alloy (AA 6061) and carbon steel (SAE 1045). The purpose of this study is to determine the appropriate SiO{sub 2}:Na{sub 2}O ratio and understand how this SiO{sub 2}:Na{sub 2}O ratio can affect the corrosion rate of each metal alloys immersed in acidic medium. In order to investigate this study, weight loss test was conducted in 0.5 M hydrochloric acid (HCl) for 24 hours at room temperature.

  13. Plasma nitrocarburizing process - a solution to improve wear and corrosion resistance

    International Nuclear Information System (INIS)

    Joseph, Alphonsa J.; Ghanshyam, J.; Mukherjee, S.

    2015-01-01

    To prevent wear and corrosion problems in steam turbines, coatings have proved to have an advantage of isolating the component substrate from the corrosive environment with minimal changes in turbine material and design. Diffusion based coatings like plasma nitriding and plasma nitrocarburizing have been used for improving the wear and corrosion resistance of components undergoing wear during their operation. In this study plasma nitrocarburizing process was carried out on ferritic alloys like ASTM A182 Grade F22 and ATM A105 alloy steels and austenitic stainless steels like AISI 304 and AISI 316 which are used to make trim parts of control valves used for high pressure and high temperature steam lines to enhance their wear and corrosion resistance properties. The corrosion rate was measured by a potentiodynamic set up and salt spray unit in two different environments viz., tap water and 5% NaCl solutions. The Tafel plots of ferritic alloys and austenitic stainless steels show that plasma nitrocarburizing process show better corrosion resistance compared to that of the untreated steel. It was found that after plasma nitrocarburizing process the hardness of the alloy steels increased by a factor of two. The corrosion resistance of all the steels mentioned above improved in comparison to the untreated steels. This improvement can be attributed to the nitrogen and carbon incorporation in the surface of the material. This process can be also applied to components used in nuclear industries to cater to the wear and corrosion problems. (author)

  14. Twin-Wire Pulsed Tandem Gas Metal Arc Welding of API X80 Steel Linepipe

    Directory of Open Access Journals (Sweden)

    Wenhao Wu

    2018-01-01

    Full Text Available Twin-Wire Pulsed Tandem Gas Metal Arc Welding process with high welding production efficiency was used to join the girth weld seam of API X80 steel linepipe of 18.4 mm wall thickness and 1422 mm diameter. The macrostructure, microstructure, hardness, and electrochemical corrosion behavior of welded joints were studied. Effects of temperature and Cl− concentration on the corrosion behavior of base metal and weld metal were investigated. Results show that the welded joint has good morphology, mechanical properties, and corrosion resistance. The corrosion resistance of both the base metal and the weld metal decreases with increasing temperature or Cl− concentration. In the solution with high Cl− concentration, the base metal and weld metal are more susceptible to pitting. The corrosion resistance of the weld metal is slightly lower than that of the base metal.

  15. A Study of Magnesium-Base Metallic Systems and Development of Principles for Creation of Corrosion-Resistant Magnesium Alloys

    Science.gov (United States)

    Mukhina, I. Yu.

    2014-11-01

    The effect of 26 alloying elements on the corrosion resistance of high-purity magnesium in a 0.5-n solution of sodium chloride and in a humid atmosphere (0.005 n) is studied. The Mg - Li, Mg - Ag, Mg - Zn, Mg - Cu, Mg - Gd, Mg - Al, Mg - Zr, Mg - Mn and other binary systems, which present interest as a base for commercial or perspective castable magnesium alloys, are studied. The characteristics of corrosion resistance of the binary alloys are analyzed in accordance with the group and period of the Mendeleev's periodic law. The roles of the electrochemical and volume factors and of the factor of the valence of the dissolved element are determined.

  16. Investigation of the long term stability and corrosion resistance of engineering barriers

    International Nuclear Information System (INIS)

    Aoyama, Eri; Tachikawa, Hirokazu; Shimizu, Akihiko

    2005-03-01

    The Japan Nuclear Cycle Development Institute submitted 'Second Progress Report on Research and Development for the Geological Disposal of HLW in Japan' to the Japanese government. This report contains investigations of the long term behavior of alteration of bentonite, and of the corrosion life time of overpack on the basis of experimental data and past research, assuming the ranging geological environment of Japan. However some subjects, such as the behavior of the bentonite and overpack under high pH conditions and the behavior of the engineering barrier with change of near-field environmental condition with time for promoting reliability have still been left. To take into account these conditions, expert committees composed of clay science and metal corrosion science experts were established in the Nuclear Safety Research Association and past research outcomes and the theory of safety assessment were investigated from the view points of long term stability and corrosion resistance of engineering barrier. (author)

  17. Magnetoconductance of amorphous Yx-Si1-x alloys near the metal-insulator transition

    International Nuclear Information System (INIS)

    Sanquer, M.; Tourbot, R.; Boucher, B.

    1989-01-01

    We have performed magnetoresistance experiments across the Metal-Insulator transition in amorphous Y x -Si 1-x alloys using very high fields (H = 40T) and very low temperatures (T = 0.05K). Different and unusual behaviours are observed and can be explained assuming that the electron-electron interaction contribution dominates at low fields and localization corrections appears at very high fields. This is the opposite situation compared to usual weak localization regime

  18. Corrosion resistance of Mo-Fe-Ti alloy for overpack in simulating underground environment

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, Toshiyasu, E-mail: NISHIMURA.Toshiyasu@nims.go.jp [Structural metals Center, National Institute for Materials Science (NIMS), 1-2-1, Sengen, Tsukuba, Ibaraki 305-0047 (Japan)

    2011-12-15

    Highlights: Black-Right-Pointing-Pointer Aging heat-treated Mo-Fe-Ti alloy showed lower corrosion resistance than solution treated one, but much higher than pure Ti in EIS measurement. Black-Right-Pointing-Pointer As {alpha}-phases showed lower Mo content by TEM, they were preferentially dissolved from base metal in the corrosion test. Black-Right-Pointing-Pointer As Fe was involved in {beta} (b)-phase with Mo which increased the corrosion resistance, the addition of Fe did not decrease the corrosion resistance. - Abstract: In order to examine the application of Mo-Fe-Ti alloy for overpak, the corrosion resistance of heat-treated its alloys was investigated by electrochemical impedance spectroscopy (EIS) and transmission electron microscopy (TEM). The sample subjected to solution heat treatment (ST) had a single {beta} phase and samples subjected to aging heat treatment at 600-700 Degree-Sign C had {alpha} phase precipitation in {beta} phase. EIS results showed that the corrosion resistance of the aging heat-treated samples was lower than that of the ST sample, but much higher than that of pure Ti in 10% NaCl solution of pH 0.5 at 97 Degree-Sign C which simulating the crevice solution. Laser micrographs of the aging heat-treated samples indicated that {alpha} phase was caused selective dissolution in test solution. The TEM combined with EDAX (energy dispersive X-ray) analyses showed that {beta} phase matrix composed of 2.7 wt.% Mo and 4.8 wt.% Fe, and {alpha} phase composed of 0.7 wt.% Mo and 0.1 wt.% Fe in sample aged at 600 Degree-Sign C. Thus, Mo-poor {alpha} phase was selectively dissolved in a test solution. In EIS, the ST sample of only {beta} phase showed the highest resistance, and aging heat-treated samples containing {alpha} phase (0.7 wt.% Mo) showed higher values than pure Ti in the corrosion test. As Fe was involved in {beta} phase with Mo which increased remarkably the corrosion resistance, the addition of Fe did not decrease the corrosion resistance

  19. Vibrational and optical properties of amorphous metals: Progress report, July 1, 1987--June 30, 1988

    International Nuclear Information System (INIS)

    Lannin, J.S.

    1988-02-01

    Substantial progress has been achieved in the three areas of Raman scattering, inelastic neutron scattering and optical studies of amorphous metal alloys. In the Raman area, studies of amorphous disilicides of Ni and W, a-NiSi 2 and a-WSi 2 , were obtained that provide information on both the dynamics and short range order in the amorphous phase. Measurements of the Raman spectra have been compared to the neutron weighted densities of states of the corresponding crystalline systems. A detailed evaluation of the inelastic neutron spectra of the concentrated Ni alloy of a-Ni/sub .95/Tb/sub .05/ has recently been completed. Optical measurements of the real and imaginary parts of the dielectric function of a-Ni/sub .95/Tb/sub .05/ were also performed during this year using the technique of spectroscopic ellipsometry. Raman scattering measurements were performed on the amorphous state of the counterpart of the high temperature superconductor of crystalline YBa 2 Cu 3 O/sub x/

  20. Development of a metallic high integrity container

    International Nuclear Information System (INIS)

    Haelsig, R.T.

    1986-01-01

    Nuclear Packaging, a Pacific Nuclear Company, developed a metallic high integrity container (HIC) for the burial of low level radioactive waste. This class of container has received the most extensive review of any burial container licensed in the United States. It is also the first container that has been licensed to meet the requirements of Nuclear Regulatory Commission Regulations 10CFR61. The design and subsequent review considered 300 years corrosion at a depth of 55 feet with no degradation of container structural integrity. The design also included a technical requirement that the container possess a positive vent that would exclude moisture. The alloy that was selected, allows for significant flexibility in container size and configuration which is essential to accommodating the various waste forms. This allowed the development of containers in various sizes and with a variety of closures, that accommodate the internal dimensions of various shipping shields and help minimize radiation exposure during packaging operations. The material used in the metallic container is high corrosion resistant which reduces the need for strict chemical controls at the waste generating facility. This acts to ease the operational requirements in the treatment of several waste streams. The design result is a family of metallic High Integrity Containers (HIC)s that meet all the performance criteria imposed by the regulations, as well as provide a disposable waste container with good transportation efficiency and minimum operational constraints

  1. Seismic load resistance of reinforcing steels in the as delivered condition and after corrosion - relevant material characteristics for performance evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Moersch, Ing. Joerg [Max Aicher Engineering GmbH, Freilassing (Germany)

    2016-10-15

    This type of accelerated corrosion test was used to study the high number of test samples in due time. The corrosion phenomena obtained in salt spray testing deviate significantly from corrosion phenomena (pitting factor) obtained in practical conditions. Salt spray testing represents practical conditions for the more uniform corrosion as a result of a severe carbonation of the concrete and/or for higher chloride contents at the surface of the rebar. At low corrosion current densities the effect of pit depth on residual mechanical performance might be underestimated. Reinforced concrete (r.c.) buildings in seismic areas shall be designed to guarantee enough ductile resources as for example a sufficient rotational capacity to allow for load re-distribution. The rotational capacity is directly dependent on the ductility of the reinforcing steel which is generally expressed as elongation at maximum load (A+g{sub t}) and the hardening ratio (R{sub m}/R{sub e}). A direct testing of the seismic load resistance of reinforcing steels is not part of the construction product standards. Therefore it was decided by European Commission to introduce this performance requirement in the mandate for the revision of EN 10080:2005. In parallel to the standardization process a research project was carried out to deliver the scientific background.

  2. Increased corrosion resistance of basalt reinforced cement compositions with nanosilica

    OpenAIRE

    URKHANOVA Larisa Alekseevna; LKHASARANOV Solbon Aleksandrovich; ROZINA Victoria Yevgenievna; BUYANTUEV Sergey Lubsanovich; BARDAKHANOV Sergey Prokopievich

    2014-01-01

    Disperse fiber reinforcement is used to improve deformation and shrinkage characteristics, flexural strength of concrete. Basalt roving and thin staple fiber are often used as mineral fibers. The paper considers the problems of using thin basalt fiber produced by centrifugal-blow method. Evaluation of the corrosion resistance of basalt fiber as part of the cement matrix was performed. Nanodispersed silica produced by electron beam accelerator was used to increase corrosion resistance of ba...

  3. High performance fuel technology development : Development of high performance cladding materials

    International Nuclear Information System (INIS)

    Park, Jeongyong; Jeong, Y. H.; Park, S. Y.

    2012-04-01

    The superior in-pile performance of the HANA claddings have been verified by the successful irradiation test and in the Halden research reactor up to the high burn-up of 67GWD/MTU. The in-pile corrosion and creep resistances of HANA claddings were improved by 40% and 50%, respectively, over Zircaloy-4. HANA claddings have been also irradiated in the commercial reactor up to 2 reactor cycles, showing the corrosion resistance 40% better than that of ZIRLO in the same fuel assembly. Long-term out-of-pile performance tests for the candidates of the next generation cladding materials have produced the highly reliable test results. The final candidate alloys were selected and they showed the corrosion resistance 50% better than the foreign advanced claddings, which is beyond the original target. The LOCA-related properties were also improved by 20% over the foreign advanced claddings. In order to establish the optimal manufacturing process for the inner and outer claddings of the dual-cooled fuel, 18 different kinds of specimens were fabricated with various cold working and annealing conditions. Based on the performance tests and various out-of-pile test results obtained from the specimens, the optimal manufacturing process was established for the inner and outer cladding tubes of the dual-cooled fuel

  4. High-throughput exploration of thermoelectric and mechanical properties of amorphous NbO_2 with transition metal additions

    International Nuclear Information System (INIS)

    Music, Denis; Geyer, Richard W.; Hans, Marcus

    2016-01-01

    To increase the thermoelectric efficiency and reduce the thermal fatigue upon cyclic heat loading, alloying of amorphous NbO_2 with all 3d and 5d transition metals has systematically been investigated using density functional theory. It was found that Ta fulfills the key design criteria, namely, enhancement of the Seebeck coefficient and positive Cauchy pressure (ductility gauge). These quantum mechanical predictions were validated by assessing the thermoelectric and elastic properties on combinatorial thin films, which is a high-throughput approach. The maximum power factor is 2813 μW m"−"1 K"−"2 for the Ta/Nb ratio of 0.25, which is a hundredfold increment compared to pure NbO_2 and exceeds many oxide thermoelectrics. Based on the elasticity measurements, the consistency between theory and experiment for the Cauchy pressure was attained within 2%. On the basis of the electronic structure analysis, these configurations can be perceived as metallic, which is consistent with low electrical resistivity and ductile behavior. Furthermore, a pronounced quantum confinement effect occurs, which is identified as the physical origin for the Seebeck coefficient enhancement.

  5. Fundamental corrosion characterization of high-strength titanium alloys

    International Nuclear Information System (INIS)

    Schutz, R.W.; Grauman, J.S.

    1984-01-01

    Many commercially available and several developmental high-strength titanium alloys were evaluated for application in chloride-containing environments with respect to general, crevice, and stress corrosion resistance. Studies in boiling reducing and oxidizing acid chloride media permitted identification of certain high-strength titanium alloys, containing ≥4 weight % molybdenum, which are significantly more resistant than unalloyed titanium with respect to general and crevice attack. Data regression analysis suggests that molybdenum and vanadium impart a significant positive effect on alloy corrosion resistance under reducing acid chloride conditions, whereas aluminum is detrimental. Little effect of metallurgical condition (that is, annealed versus aged) on corrosion behavior of the higher molybdenum-containing alloys was noted. No obvious susceptibility to chloride and sulfide stress corrosion cracking (SCC) was detected utilizing U-bend specimens at 177 0 C

  6. Corrosion resistance of uranium with carbon ion implantation

    International Nuclear Information System (INIS)

    Liang Hongwei; Yan Dongxu; Bai Bin; Lang Dingmu; Xiao Hong; Wang Xiaohong

    2008-01-01

    The carbon modified layers prepared on uranium surface by carbon ion implantation, gradient implantation, recoil implantation and ion beam assisted deposition process techniques were studied. Depth profile elements of the samples based on Auger electron spectroscopy, phase composition identified by X-ray diffraction as well as corrosion resistance of the surface modified layers by electrochemistry tester and humid-thermal oxidation test were carried out. The carbon modified layers can be obtained by above techniques. The samples deposited with 45 keV ion bombardment, implanted by 50 keV ions and implanted with gradient energies are of better corrosion resistance properties. The samples deposited carbon before C + implantation and C + assisted deposition exhibit worse corrosion resistance properties. The modified layers are dominantly dot-corraded, which grows from the dots into substructure, however, the assisted deposition samples have comparatively high carbon composition and are corraded weakly. (authors)

  7. FY 1998 annual summary report on advanced fabrication techniques for high-melting metal-based members. Development of techniques for creating members for high-efficiency power generation; 1998 nendo koyuten kinzokukei buzai no kodo kako gijutsu seika hokokusho. Kokoritsu hatsuden'yo buzai sosei gijutsu kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    The R and D programs were implemented to develop techniques for creating members of high-melting metals, having a very high melting point and potentially excellent high-temperature strength characteristics. These are expected to replace Ni-based superalloys for gas turbine members, to further increase operating temperature of the turbine. The programs were aimed to improve their high-temperature strength and toughness and hence their reliability by microscopically controlling their compositions and structures, and also aimed to improve their durability by coating them with a film capable of preventing oxidation and resisting to gas-induced corrosion to impart resistance to oxidation and corrosion to them. For the design of Nb-based solid solution alloys, it is found that dissolution of Mo at around 30 at.% or less and W at 20 at.% or less in Nb improves their high-temperature strength and toughness. For the design of high-strength Nb-based composite materials, it is found that Si-containing Nb-based composite materials, prepared by mechanical alloying, are amorphous or present in the form of solid solution of Ni supersaturated with Si. The R and D activities were also directed to development of techniques for creating Nb-based superhigh-temperature members, their evaluation, and imparting oxidation resistance to them. (NEDO)

  8. Corrosion resistance and durability of superhydrophobic surface formed on magnesium alloy coated with nanostructured cerium oxide film and fluoroalkylsilane molecules in corrosive NaCl aqueous solution.

    Science.gov (United States)

    Ishizaki, Takahiro; Masuda, Yoshitake; Sakamoto, Michiru

    2011-04-19

    The corrosion resistant performance and durability of the superhydrophobic surface on magnesium alloy coated with nanostructured cerium oxide film and fluoroalkylsilane molecules in corrosive NaCl aqueous solution were investigated using electrochemical and contact angle measurements. The durability of the superhydrophobic surface in corrosive 5 wt% NaCl aqueous solution was elucidated. The corrosion resistant performance of the superhydrophobic surface formed on magnesium alloy was estimated by electrochemical impedance spectroscopy (EIS) measurements. The EIS measurements and appropriate equivalent circuit models revealed that the superhydrophobic surface considerably improved the corrosion resistant performance of magnesium alloy AZ31. American Society for Testing and Materials (ASTM) standard D 3359-02 cross cut tape test was performed to investigate the adhesion of the superhydrophobic film to the magnesium alloy surface. The corrosion formation mechanism of the superhydrophobic surface formed on the magnesium alloy was also proposed. © 2011 American Chemical Society

  9. Zirconium alloy barrier having improved corrosion resistance

    International Nuclear Information System (INIS)

    Adamson, R.B.; Rosenbaum, H.S.

    1983-01-01

    A nuclear fuel element for use in the core of a nuclear reactor has a composite cladding container having a substrate and a dilute zirconium alloy liner bonded to the inside surface of the substrate. The dilute zirconium alloy liner forms about 1 to about 20 percent of the thickness of the cladding and is comprised of zirconium and a metal selected from the group consisting of iron, chromium, iron plus chromium, and copper. The dilute zirconium alloy liner shields the substrate from impurities or fission products from the nuclear fuel material and protects the substrate from stress corrosion and stress cracking. The dilute zirconium alloy liner displays greater corrosion resistance, especially to oxidation by hot water or steam than unalloyed zirconium. The substrate material is selected from conventional cladding materials, and preferably is a zirconium alloy. (author)

  10. Three-terminal nanoelectromechanical switch based on tungsten nitride—an amorphous metallic material

    KAUST Repository

    Mayet, Abdulilah M.; Hussain, Aftab M.; Hussain, Muhammad Mustafa

    2015-01-01

    © 2016 IOP Publishing Ltd. Nanoelectromechanical (NEM) switches inherently have zero off-state leakage current and nearly ideal sub-threshold swing due to their mechanical nature of operation, in contrast to semiconductor switches. A challenge for NEM switches to be practical for low-power digital logic application is their relatively large operation voltage which can result in higher dynamic power consumption. Herein we report a three-terminal laterally actuated NEM switch fabricated with an amorphous metallic material: tungsten nitride (WNx). As-deposited WNx thin films have high Young's modulus (300 GPa) and reasonably high hardness (3 GPa), which are advantageous for high wear resistance. The first prototype WNx switches are demonstrated to operate with relatively low control voltage, down to 0.8 V for an air gap thickness of 150 nm.

  11. Three-terminal nanoelectromechanical switch based on tungsten nitride—an amorphous metallic material

    KAUST Repository

    Mayet, Abdulilah M.

    2015-12-04

    © 2016 IOP Publishing Ltd. Nanoelectromechanical (NEM) switches inherently have zero off-state leakage current and nearly ideal sub-threshold swing due to their mechanical nature of operation, in contrast to semiconductor switches. A challenge for NEM switches to be practical for low-power digital logic application is their relatively large operation voltage which can result in higher dynamic power consumption. Herein we report a three-terminal laterally actuated NEM switch fabricated with an amorphous metallic material: tungsten nitride (WNx). As-deposited WNx thin films have high Young\\'s modulus (300 GPa) and reasonably high hardness (3 GPa), which are advantageous for high wear resistance. The first prototype WNx switches are demonstrated to operate with relatively low control voltage, down to 0.8 V for an air gap thickness of 150 nm.

  12. Effect of silicon ion implantation upon the structure and corrosion resistance of the surface layer of stainless steel 316L, Vitalium and titanium alloy Ti6Al14V

    International Nuclear Information System (INIS)

    Baszkiewicz, J.; Kaminski, M.; Krupa, D.; Kozubowski, J.; Barcz, A.; Gawlik, A.; Jagielski, J.

    1995-01-01

    Samples of 316L stainless steel, Vitalium and Ti6A14V titanium alloy have been implanted with doses of 1.5, 3, and 4.5 x 10 17 Si + /cm 2 . Transmission electron microscopy shows that during ion implantation amorphous layers are formed. When samples of titanium alloy were implanted with a dose of 0.5 x 10 17 Si + /cm 2 , the implanted layer consisted of a dispersion of fine silicide crystallites instead of being amorphous. The corrosion resistance was analyzed by electrochemical techniques in 0.9% NaCl at the temperature of 37 C. The increase of corrosion resistance has been observed as a result of structural modifications of the surface layer. (author). 7 refs, 4 tabs

  13. Development of materials resistant to metal dusting degradation.

    Energy Technology Data Exchange (ETDEWEB)

    Natesan, K.; Zeng, Z.

    2006-04-24

    Metal dusting corrosion has been a serious problem in the petroleum and petrochemical industries, such as reforming and syngas production systems. This form of deterioration has led to worldwide material loss for 50 years. For the past three years, we have studied the mechanism of metal dusting for Fe- and Ni-base alloys. In this report, we present a correlation between the weight loss and depth of pits that form in Ni-base alloys. Nickel-base alloys were also tested at 1 and 14.8 atm (210 psi), in a high carbon activity environment. Higher system pressure was found to accelerate corrosion in most Ni-base alloys. To reduce testing time, a pre-pitting method was developed. Mechanical scratches on the alloy surface led to fast metal dusting corrosion. We have also developed preliminary data on the performance of weldments of several Ni-base alloys in a metal dusting environment. Finally, Alloy 800 tubes and plates used in a reformer plant were examined by scanning electron microscopy, energy dispersive X-ray, and Raman spectroscopy. The oxide scale on the surface of the Alloy 800 primarily consists of Fe{sub 1+x}Cr{sub 2-X}O{sub 4} spinel phase with high Fe content. Carbon can diffuse through this oxide scale. It was discovered that the growth of metal dusting pits could be stopped by means of a slightly oxidized alloy surface. This leads to a new way to solve metal dusting problem.

  14. Surface and corrosion characteristics of carbon plasma implanted and deposited nickel-titanium alloy

    International Nuclear Information System (INIS)

    Poon, R.W.Y.; Liu, X.Y.; Chung, C.Y.; Chu, P.K.; Yeung, K.W.K.; Lu, W.W.; Cheung, K.M.C.

    2005-01-01

    Nickel-titanium shape memory alloys (NiTi) are potentially useful in orthopedic implants on account of their super-elastic and shape memory properties. However, the materials are prone to surface corrosion and the most common problem is out-diffusion of harmful Ni ions from the substrate into body tissues and fluids. In order to improve the corrosion resistance and related surface properties, we used the technique of plasma immersion ion implantation and deposition to deposit an amorphous hydrogenated carbon coating onto NiTi and implant carbon into NiTi. Both the deposited amorphous carbon film and carbon plasma implanted samples exhibit much improved corrosion resistances and surface mechanical properties and possible mechanisms are suggested

  15. Research on Performance and Microstructure of Sewage Pipe Mortar Strengthened with Different Anti-Corrosion Technologies

    Science.gov (United States)

    Mu, Song; Zhou, Huaxin; Shi, Liang; Liu, Jianzhong; Cai, Jingshun; Wang, Feng

    2017-10-01

    Mostly urban underground sewage is the acidic corrosion environment with a high concentration of aggressive ions and microbe, which resulted in performance deterioration and service-life decrease of sewage concrete pipe. In order to effectively protect durability of the concrete pipe, the present paper briefly analysed the main degradation mechanism of concrete pipe attacked by urban underground sewage, and proposed that using penetrating and strengthening surface sealer based on inorganic chemistry. In addition, using index of compressive strength, weight loss and appearance level to investigate the influence of the sealer on corrosion resistance of mortar samples after different dry-wet cycles. Besides, comparative research on effect of the sealer, aluminate cement and admixture of corrosion resistance was also addressed. At last, the SEM technology was used to reveal the improvement mechanism of different technologies of corrosion resistance. The results indicated that the sealer and aluminate cement can significantly improve corrosion resistance of mortar. Besides, the improvement effect can be described as the descending order: the penetrating and strengthening surface sealer > aluminate cement > admixture of corrosion resistance. The mortar sample treated with the sealer displayed the condensed and sound microstructure which proved that the sealer can improve the corrosion resistance to urban underground sewage.

  16. Structural models for amorphous transition metal binary alloys

    International Nuclear Information System (INIS)

    Ching, W.Y.; Lin, C.C.

    1976-01-01

    A dense random packing of 445 hard spheres with two different diameters in a concentration ratio of 3 : 1 was hand-built to simulate the structure of amorphous transition metal-metalloid alloys. By introducing appropriate pair potentials of the Lennard-Jones type, the structure is dynamically relaxed by minimizing the total energy. The radial distribution functions (RDF) for amorphous Fe 0 . 75 P 0 . 25 , Ni 0 . 75 P 0 . 25 , Co 0 . 75 P 0 . 25 are obtained and compared with the experimental data. The calculated RDF's are resolved into their partial components. The results indicate that such dynamically constructed models are capable of accounting for some subtle features in the RDF of amorphous transition metal-metalloid alloys

  17. Applications of electricity and corrosion. Precautions for use of metals and stainless and refractory alloys

    International Nuclear Information System (INIS)

    Gras, J.M.

    1993-09-01

    The development of applications of electricity poses highly diversified problems with materials where the resistance to corrosion prevails. Corrosion occurs under various conditions, which sometimes look harmless, and it covers diverse phenomenons linked to the nature of materials and to the physical and chemical context. However, in spite of the diversity of the processes used (electrical boilers, mechanical steam compression, heat pumps, Joule effect,) the knowledge required to approach the corrosion problems corresponds to a limited number of generic situations with regard not only to the phenomenons proper (general corrosion of copper, pitting and stress corrosion cracking of stainless steels, refractory alloys oxidation,) but also to chemical conditions which favour the corrosion (natural waters, acidic condensates, hot gases). This report is a short guide to anti-corrosion. With the aid of questions asked during the past few years, it aims to provide engineers in charge of the development of applications of electricity with a few recommendations upon the precautions for use of metallic materials. We analyze in turn the problems met with wet air and drying mists, chloride-containing neutral waters, alkaline waters and caustic media, acidic waters and concentrated acids, and, last, hot gases. We lay stress upon the behaviour of materials deemed to withstand corrosion under aqueous conditions (stainless steels and alloys, copper,titanium) and corrosion at high temperatures (refractory alloys). (author). 11 figs., 43 refs., 11 tabs

  18. Assessment of Stress Corrosion Cracking Resistance of Activated Tungsten Inert Gas-Welded Duplex Stainless Steel Joints

    Science.gov (United States)

    Alwin, B.; Lakshminarayanan, A. K.; Vasudevan, M.; Vasantharaja, P.

    2017-12-01

    The stress corrosion cracking behavior of duplex stainless steel (DSS) weld joint largely depends on the ferrite-austenite phase microstructure balance. This phase balance is decided by the welding process used, heat input, welding conditions and the weld metal chemistry. In this investigation, the influence of activated tungsten inert gas (ATIG) and tungsten inert gas (TIG) welding processes on the stress corrosion cracking (SCC) resistance of DSS joints was evaluated and compared. Boiling magnesium chloride (45 wt.%) environment maintained at 155 °C was used. The microstructure and ferrite content of different weld zones are correlated with the outcome of sustained load, SCC test. Irrespective of the welding processes used, SCC resistance of weld joints was inferior to that of the base metal. However, ATIG weld joint exhibited superior resistance to SCC than the TIG weld joint. The crack initiation and final failure were in the weld metal for the ATIG weld joint; they were in the heat-affected zone for the TIG weld joint.

  19. Ductile fracture surface morphology of amorphous metallic alloys

    NARCIS (Netherlands)

    Miskuf, J; Csach, K; Ocelik, [No Value; Bengus, VZ; Tabachnikova, ED; Duhaj, P; Ocelik, Vaclav

    1999-01-01

    Fracture surfaces of ductile failure of two types bulk amorphous metallic alloys were studied using quantitative and qualitative fractographic analysis. The observed fractographic behaviour of ductile failure in comparison with the ductile failure of amorphous alloy ribbons shows signs of the same

  20. Enhanced corrosion resistance of stainless steel type 316 in sulphuric acid solution using eco-friendly waste product

    Science.gov (United States)

    Sanni, O.; Popoola, A. P. I.; Fayomi, O. S. I.

    2018-06-01

    Literature has shown that different organic compounds are effective corrosion inhibitors for metal in acidic environments. Such compounds usually contain oxygen, nitrogen or sulphur and function through adsorption on the metal surface, thereby creating a barrier for corrosion attack. Unfortunately, these organic compounds are toxic, scarce and expensive. Therefore, plants, natural product and natural oils have been posed as cheap, environmentally acceptable, abundant, readily available and effective molecules having low environmental impact. The corrosion resistance of austenitic stainless steel Type 316 in the presence of eco-friendly waste product was studied using weight loss and potentiodynamic polarization techniques in 0.5 M H2SO4. The corrosion rate and corrosion potential of the steel was significantly altered by the studied inhibitor. Results show that increase in concentration of the inhibitor hinders the formation of the passive film. Experimental observation shows that its pitting potential depends on the concentration of the inhibitor in the acid solution due to adsorption of anions at the metal film interface. The presence of egg shell powder had a strong influence on the corrosion resistance of stainless steel Type 316 with highest inhibition efficiency of 94.74% from weight loss analysis, this is as a result of electrochemical action and inhibition of the steel by the ionized molecules of the inhibiting compound which influenced the mechanism of the redox reactions responsible for corrosion and surface deterioration. Inhibitor adsorption fits the Langmuir isotherm model. The two methods employed for the corrosion assessment were in good agreement.

  1. Increased corrosion resistance of basalt reinforced cement compositions with nanosilica

    Directory of Open Access Journals (Sweden)

    URKHANOVA Larisa Alekseevna

    2014-08-01

    Full Text Available Disperse fiber reinforcement is used to improve deformation and shrinkage characteristics, flexural strength of concrete. Basalt roving and thin staple fiber are often used as mineral fibers. The paper considers the problems of using thin basalt fiber produced by centrifugal-blow method. Evaluation of the corrosion resistance of basalt fiber as part of the cement matrix was performed. Nanodispersed silica produced by electron beam accelerator was used to increase corrosion resistance of basalt fiber.

  2. Effect of thermal aging on corrosion resistance of C-22 alloy in chloride solutions

    International Nuclear Information System (INIS)

    Carranza, Ricardo M.; Rodriguez, Martin A.

    2007-01-01

    Alloy 22 (N06022) belongs to the Ni-Cr-Mo family and it is highly resistant to localized corrosion. The anodic behavior of mill annealed (MA) and thermally aged (10 hours at 760 C degrees) Alloy 22 was studied in chloride solutions with different pH values at 90 C degrees. Thermal aging leads to a microstructure of full grain boundary precipitation of topologically closed packed (TCP) phases. Electrochemical tests included monitoring of open circuit potential, potentiodynamic polarization and electrochemical impedance spectroscopy. Assessment of general and localized (crevice) corrosion was performed. Re passivation potentials were obtained from cyclic potentiodynamic polarization tests. Results indicate that MA and TCP material show similar general corrosion rates and crevice corrosion resistance in the tested environments. MA and TCP specimens suffered general corrosion in an active state when tested in low pH chloride solutions. The grain structure of the alloy was revealed for MA material, while TCP material suffered a preferential attack at grain boundaries. (author)

  3. Corrosion and compatibility in liquid alkali metals

    International Nuclear Information System (INIS)

    Anon.

    1978-01-01

    The literature dealing with liquid alkali metal corrosion of vanadium and its alloys is reviewed in the following subsections. Attention is given to both lithium and sodium data. Preceding this review, a brief outline of the current state of understanding of liquid metal corrosion mechanisms is provided

  4. Analysis Of Corrosion Resistant Film On AI-Mg-Si Coated By Rare Earth Metal

    International Nuclear Information System (INIS)

    Darajati, Rusdiana; Ihsan, Mohammad; Wuryanto

    2001-01-01

    Corrosion analysis of AI-Mg-Si alloy which given corrosion-resistant film of a rare earth oxide coating incorporated with a uniform aluminum oxide film which has been formed on the aluminum alloy surface has been done. The measurement techniques were E corr versus time, polarization resistance, potentiodynamic and SEM (Scanning Electron Microscope for surface analysis. Potential corrosion in water environment tend to bigger with more time for four samples except sample AIMgSi that dipped into triethanolamine. ln HCl pH=1 potential corrosion sample AIMgSi, AIMgSi that dipped into triethanolamine, AIMgSi that dipped into triethanolamine and Ce Cl) tend to bigger with more time while sample AIMgSi that dipped into triethanolamine and YCI 3 or RECI 3 tend to smaller with more time. Potential corrosion in NaOH pH= 13 tend to bigger with more time for all samples. Corrosion rate for sample AIMgSi that dipped into triethanolamine in water environment relatively slower (0,0205 mpy), while in HCl pH=1 and NaOH pH=13 corrosion rate sample AIMgSi that dipped into triethanolamine and YCI 3 relatively slower, respectively are 0,1157 mpy and 2468,26 mpy. Sample AIMgSi that dipped into triethanolamine and RECI 3 in water environment has passivation and trans passivation area while four simple don't have passivation area, in H CI pH=1 all samples generally have passivation area at the same current density range while in NaOH pH= 13 sample AIMgSi has trans passivation area at a potential of about 800 mV while four other sample have passivation area at a potential of about-850-1500 mV. SEM analysis show that the coating layer which formed on the sample surface less protective especially in HCl pH= land NaOH pH=13

  5. Investigation on the corrosion resistance of zirconium in nitric acid

    International Nuclear Information System (INIS)

    Fauvet, P.; Mur, P.

    1990-01-01

    Zirconium in nitric solutions exhibits an excellent corrosion resistance in the passive state, and a mediocre corrosion resistance in the unpassive state with risk of stress corrosion cracking. Results of the influence of some parameters (medium, potential, temperature, stress, friction, metallurgical structure and surface state) on zirconium passivation are presented. Zirconium remains passive in a large range of HNO 3 concentration (at least up to 14.4N), in the presence of oxidizing ions (Cr 4 , Ce 4 ), in a spent fuel dissolution solution. Zirconium is depassived by friction at high speed and pressure, by platinum coupling in boiling 14.4N HNO 3 with or without stress, or by imposed deformation speed under high potential. (A.B.)

  6. Improved corrosion resistance of spin-valve film

    International Nuclear Information System (INIS)

    Tetsukawa, H.; Hommura, H.; Okabe, A.; Soda, Y.

    2007-01-01

    We investigated the corrosion behavior and magnetoresistance of spin-valve film in order to improve the corrosion resistance of the spin-valve head for a tape recording system. The conventional spin-valve head (sub./Ta/NiFe/CoFe/Cu/CoFe/PtMn/Ta) with no diamond-like carbon (DLC) protective layer showed poor corrosion resistance. This is because the CoFe for ferromagnetic layer and Cu for spacer in the spin-valve film exhibited poor corrosion resistance. The corrosion resistance of the CoFe film and Cu film improved with the addition of Ni and Au, respectively. The spin-valve film (sub./Ta/NiFe/CoNiFe/CuAu/CoNiFe/PtMn/Ta) showed higher pitting potential than the conventional spin-valve film by +0.45 V. This presents a significant improvement over the conventional spin-valve film. We also investigated the effect of the composition of ferromagnetic layer and spacer on the magnetoresistance of the spin-valve film. The magnetoresistance of the spin-valve film by substitution of CoNiFe for CoFe in ferromagnetic layer decreased slightly. The magnetoresistance of the spin-valve film decreased as the addition of Au of the spacer increased. The diffusion at CoNiFe/CuAu interface has not been observed in annealing process. The quantitative relation between corrosion resistance and magnetoresistance of spin-valve film, and its ferromagnetic layer and spacer's compositions have been clarified. The output voltage at 50 Oe of the corrosion-resistant spin-valve head with CoNiFe ferromagnetic layer and CuAu spacer was about 50% of that of the conventional spin-valve head

  7. Improved corrosion resistance of spin-valve film

    Energy Technology Data Exchange (ETDEWEB)

    Tetsukawa, H. [Sony Corporation, 6-7-35 Kitashinagawa, Shinagawa-ku, Tokyo 141-0001 (Japan)]. E-mail: tetsukaw@arc.sony.co.jp; Hommura, H. [Sony Corporation, 6-7-35 Kitashinagawa, Shinagawa-ku, Tokyo 141-0001 (Japan); Okabe, A. [Sony Corporation, 6-7-35 Kitashinagawa, Shinagawa-ku, Tokyo 141-0001 (Japan); Soda, Y. [Sony Corporation, 6-7-35 Kitashinagawa, Shinagawa-ku, Tokyo 141-0001 (Japan)

    2007-06-15

    We investigated the corrosion behavior and magnetoresistance of spin-valve film in order to improve the corrosion resistance of the spin-valve head for a tape recording system. The conventional spin-valve head (sub./Ta/NiFe/CoFe/Cu/CoFe/PtMn/Ta) with no diamond-like carbon (DLC) protective layer showed poor corrosion resistance. This is because the CoFe for ferromagnetic layer and Cu for spacer in the spin-valve film exhibited poor corrosion resistance. The corrosion resistance of the CoFe film and Cu film improved with the addition of Ni and Au, respectively. The spin-valve film (sub./Ta/NiFe/CoNiFe/CuAu/CoNiFe/PtMn/Ta) showed higher pitting potential than the conventional spin-valve film by +0.45 V. This presents a significant improvement over the conventional spin-valve film. We also investigated the effect of the composition of ferromagnetic layer and spacer on the magnetoresistance of the spin-valve film. The magnetoresistance of the spin-valve film by substitution of CoNiFe for CoFe in ferromagnetic layer decreased slightly. The magnetoresistance of the spin-valve film decreased as the addition of Au of the spacer increased. The diffusion at CoNiFe/CuAu interface has not been observed in annealing process. The quantitative relation between corrosion resistance and magnetoresistance of spin-valve film, and its ferromagnetic layer and spacer's compositions have been clarified. The output voltage at 50 Oe of the corrosion-resistant spin-valve head with CoNiFe ferromagnetic layer and CuAu spacer was about 50% of that of the conventional spin-valve head.

  8. Osseoconductive and Corrosion-Inhibiting Plasma-Sprayed Calcium Phosphate Coatings for Metallic Medical Implants

    Directory of Open Access Journals (Sweden)

    Robert B. Heimann

    2017-11-01

    Full Text Available During the last several decades, research into bioceramic coatings for medical implants has emerged as a hot topic among materials scientists and clinical practitioners alike. In particular, today, calcium phosphate-based bioceramic materials are ubiquitously used in clinical applications to coat the stems of metallic endoprosthetic hips as well as the surfaces of dental root implants. Such implants frequently consist of titanium alloys, CoCrMo alloy, or austenitic surgical stainless steels, and aim at replacing lost body parts or restoring functions to diseased or damaged tissues of the human body. In addition, besides such inherently corrosion-resistant metals, increasingly, biodegradable metals such as magnesium alloys are being researched for osseosynthetic devices and coronary stents both of which are intended to remain in the human body for only a short time. Biocompatible coatings provide not only vital biological functions by supporting osseoconductivity but may serve also to protect the metallic parts of implants from corrosion in the aggressive metabolic environment. Moreover, the essential properties of hydroxylapatite-based bioceramic coatings including their in vitro alteration in contact with simulated body fluids will be addressed in this current review paper. In addition, a paradigmatic shift is suggested towards the development of transition metal-substituted calcium hexa-orthophosphates with the NaSiCON (Na superionic conductor structure to be used for implant coatings with superior degradation resistance in the corrosive body environment and with pronounced ionic conductivity that might be utilized in novel devices for electrical bone growth stimulation.

  9. Influence of microstructure and elemental partitioning on pitting corrosion resistance of duplex stainless steel welding joints

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhiqiang; Jing, Hongyang [School of Materials Science and Engineering, Tianjin University, Tianjin 300350 (China); Tianjin Key Laboratory of Advanced Joining Technology, Tianjin 300350 (China); Xu, Lianyong, E-mail: xulianyong@tju.edu.cn [School of Materials Science and Engineering, Tianjin University, Tianjin 300350 (China); Tianjin Key Laboratory of Advanced Joining Technology, Tianjin 300350 (China); Han, Yongdian; Zhao, Lei [School of Materials Science and Engineering, Tianjin University, Tianjin 300350 (China); Tianjin Key Laboratory of Advanced Joining Technology, Tianjin 300350 (China); Zhang, Jianli [Welding laboratory, Offshore Oil Engineering (Qing Dao) Company, Qing Dao 266520 (China)

    2017-02-01

    Highlights: • N{sub 2}-supplemented shielding gas promoted nitrogen solid-solution in the austenite. • Secondary austenite had higher Ni but lower Cr and Mo than primary austenite. • Pitting corrosion preferentially occurred at secondary austenite and Cr{sub 2}N. • Adding N{sub 2} in shielding gas improved pitting corrosion resistance of GTAW joint. • E2209T{sub 1} weld metal had very poor pitting corrosion resistance due to inclusions. - Abstract: The influences of microstructure and elemental partitioning on pitting corrosion resistance of duplex stainless steel joints welded by gas tungsten arc welding (GTAW) and flux-cored arc welding (FCAW) with different shielding gas compositions were studied by optical microscopy, electron backscatter diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive spectroscopy, electron probe microanalysis, and potentiostatic and potentiodynamic polarization methods The adding 2% N{sub 2} in shielding gas facilitated primary austenite formation in GTAW weld metal (WM) and suppressed Cr{sub 2}N precipitation in GTAW weld root. In the HAZ, the banded microstructure disappeared while the coarse ferrite grains maintained same orientation as the banded ferrite in the BM. In the WM, the ferrite had one single orientation throughout a grain, whereas several families of austenite appeared. The austenite both in BM and WM enriched in Ni and nitrogen, while Cr and Mo were concentrated in the ferrite and thus no element showed clear dendritic distribution in the WM (ER2209 and E2209T{sub 1}). In addition, the secondary austenite had higher Ni content but lower Cr and Mo content than the primary austenite. The N{sub 2}-supplemented shielding gas promoted nitrogen solid-solution in the primary and secondary austenite. Furthermore, the secondary austenite had relatively lower pitting resistance equivalent number (PREN) than the ferrite and primary austenite, thereby resulting in its preferential

  10. Corrosion behaviour of container materials for geological disposal of high-level waste. Joint annual progress report 1983

    International Nuclear Information System (INIS)

    1985-01-01

    Within the framework of the Community R and D programme on management and storage of radioactive waste (shared-cost action), a research activity is aiming at the assessment of corrosion behaviour of potential container materials for geological disposal of vitrified high-level wastes. In this report, the results obtained during the year 1983 are described. Research performed at the Studiecentrum voor Kernenergie/Centre d'Etudes de l'Energie Nucleaire (SCK/CEN) at Mol (B), concerns the corrosion behaviour in clay environments. The behaviour in salt is tested by the Kernforschungszentrum (KfK) at Karlsruhe (D). Corrosion behaviour in granitic environments is being examined by the Commissariat a l'Energie Atomique (CEA) at Fontenay-aux-Roses (F) and the Atomic Energy Research Establishment (AERE) at Harwell (UK); the first is concentrating on corrosion-resistant materials and the latter on corrosion-allowance materials. Finally, the Centre National de la Recherche Scientifique (CNRS) at Vitry (F) is examining the formation and behaviour of passive layers on the metal alloys in the various environments

  11. PPM-based System for Guided Waves Communication Through Corrosion Resistant Multi-wire Cables

    Science.gov (United States)

    Trane, G.; Mijarez, R.; Guevara, R.; Pascacio, D.

    Novel wireless communication channels are a necessity in applications surrounded by harsh environments, for instance down-hole oil reservoirs. Traditional radio frequency (RF) communication schemes are not capable of transmitting signals through metal enclosures surrounded by corrosive gases and liquids. As an alternative to RF, a pulse position modulation (PPM) guided waves communication system has been developed and evaluated using a corrosion resistant 4H18 multi-wire cable, commonly used to descend electronic gauges in down-hole oil applications, as the communication medium. The system consists of a transmitter and a receiver that utilizes a PZT crystal, for electrical/mechanical coupling, attached to each extreme of the multi-wire cable. The modulator is based on a microcontroller, which transmits60 kHz guided wave pulses, and the demodulator is based on a commercial digital signal processor (DSP) module that performs real time DSP algorithms. Experimental results are presented, which were obtained using a 1m corrosion resistant 4H18multi-wire cable, commonly used with downhole electronic gauges in the oil sector. Although there was significant dispersion and multiple mode excitations of the transmitted guided wave energy pulses, the results show that data rates on the order of 500 bits per second are readily available employing PPM and simple communications techniques.

  12. Mechanism and degree of chemical elements effect on atmosphere corrosion resistance of steels

    International Nuclear Information System (INIS)

    Vu Din' Vuj

    1991-01-01

    It follows from the proposed regression equations that falourable effect of chemical elements on steel resistance to atmospheric corrosion is determined by their ability to increase interatom bond stability in iron crystal lattice and form corrosion products with high protection properties. Element positive influence on steel corrosion resistance decreases in the following order: S, P, Si, Mn, Cu, Cr, Ni, C in semiurban tropical atmosphere and S, Mn, Sr, Cu, Ni, Cr in coastal atmosphere. In the latter case C increases corrosion in a greater degree as compared to P. Small ammounts of Mo decrease steel resistance in semiurban atmosphere and almost do not influence it in the coastal one. Possible mechanisms of individual element influence on steel corrosion resistance are considered

  13. Choice of corrosion-resistant metal for fluotitanic acid

    International Nuclear Information System (INIS)

    Reingeverts, M.D.; Lapchenko, E.P.; Semenyuk, E.Y.

    1986-01-01

    The authors investigate the corrosion and anodic behavior of steels 12Kh18N10T, 08Kh21N6M2T, and 06KhN28MDT, nickel, and molybdenum in 10-40% naturally aerated solutions of H 2 TiF 6 at 20 and 50 degrees C. The authors found that in solutions of fluotitanic acid, as also in tetrafluoroboric and hydrofluoric acids, the most stable alloys are chromium-nickel-molybdenum alloy of type 06KhN28MDT and (for acid concentrations above 20%) copper-nickel-alloys of the monel metal type. Steels 12Kh18N10T and 08Kh21N6M2T can be used in acid concentrations of less than 10% and temperatures up to 20 degrees C with anodic protection

  14. Active corrosion protection performance of an epoxy coating applied on the mild steel modified with an eco-friendly sol-gel film impregnated with green corrosion inhibitor loaded nanocontainers

    Science.gov (United States)

    Izadi, M.; Shahrabi, T.; Ramezanzadeh, B.

    2018-05-01

    In this study the corrosion resistance, active protection, and cathodic disbonding performance of an epoxy coating were improved through surface modification of steel by a hybrid sol-gel system filled with green corrosion inhibitors loaded nanocontainer as intermediate layer on mild steel substrate. The green inhibitor loaded nanocontainers (GIN) were used to induce active inhibition performance in the protective coating system. The corrosion protection performance of the coated panels was investigated by electrochemical impedance spectroscopy (EIS), salt spray, and cathodic disbonding tests. It was observed that the corrosion inhibition performance of the coated mild steel panels was significantly improved by utilization of active multilayer coating system. The inhibitor release from nanocontainers at the epoxy-silane film/steel interface resulted in the anodic and cathodic reactions restriction, leading to the lower coating delamination from the substrate and corrosion products progress. Also, the active inhibition performance of the coating system was approved by electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and energy dispersive X-ray (EDS) analysis on the panels with artificial defects. The inhibitive agents were released to the scratch region and blocked the active sites on the metal surface.

  15. Amorphous Silicon-Germanium Films with Embedded Nano crystals for Thermal Detectors with Very High Sensitivity

    International Nuclear Information System (INIS)

    Calleja, C.; Torres, A.; Rosales-Quintero, P.; Moreno, M.

    2016-01-01

    We have optimized the deposition conditions of amorphous silicon-germanium films with embedded nano crystals in a plasma enhanced chemical vapor deposition (PECVD) reactor, working at a standard frequency of 13.56 MHz. The objective was to produce films with very large Temperature Coefficient of Resistance (TCR), which is a signature of the sensitivity in thermal detectors (micro bolometers). Morphological, electrical, and optical characterization were performed in the films, and we found optimal conditions for obtaining films with very high values of thermal coefficient of resistance (TCR = 7.9%K -1 ). Our results show that amorphous silicon-germanium films with embedded nano crystals can be used as thermo sensitive films in high performance infrared focal plane arrays (IRFPAs) used in commercial thermal cameras.

  16. TEM characterization of corrosion products formed on a SS-15ZR alloy

    International Nuclear Information System (INIS)

    Luo, J. S.; Abraham, D. P.

    2000-01-01

    The corrosion products formed on a stainless steel-15Zr (SS-15Zr) alloy have been characterized by transmission electron microscopy (TEM) and energy dispersive x-ray spectroscopy (EDS). Examination of alloy particles that were immersed in 90 C deionized water for two years revealed that different corrosion products were formed on the stainless steel and intermetallic phases. Two corrosion products were identified on an austenite particle: trevorite (NiFe 2 O 4 ) in the layer close to the metal and maghemite (Fe 2 O 3 ) in the outer layer. The corrosion layer formed on the intermetallic was uniform, adherent, and amorphous. The EDS analysis indicated that the layer was enriched in zirconium when compared with the intermetallic composition. High-resolution TEM images of the intermetallic-corrosion layer interface show an interlocking metal-oxide interface which may explain the relatively strong adherence of the corrosion layer to the intermetallic surface. These results will be used to evaluate corrosion mechanisms and predict long-term corrosion behavior of the alloy waste form

  17. Corrosion of candidate materials for canister: applications in rock salt formations

    International Nuclear Information System (INIS)

    Azkarate, I.; Madina, V.; Barrio, A. del; Macarro, J.M.

    1994-01-01

    Previous corrosion studies carried out on various metallic materials in typical salt rock environments show that carbon steel and titanium alloys are the most promising candidates for canister applications in this geological formation. Although carbon steels have a low corrosion resistance, they are considered acceptable as corrosion-allowance materials for a thick walled container due to their practical immunity to the localized corrosion phenomena such as stress corrosion cracking, pitting or crevice corrosion. Aiming to improve the performances of these materials, studies on the effect of small additions of Ni and V on the general corrosion are in process. The improvement in the resistance to general corrosion should not be accompanied by a sensitivity to stress corrosion cracking. On the contrary, alfa titanium alloys are considered the most resistant materials to general corrosion in salt brines. However, pitting, are potential deficiencies of this corrosion-resistant materials for a thin walled container. (Author)

  18. Localized corrosion of high alloyed austenitic stainless steels

    International Nuclear Information System (INIS)

    Morach, R.; Schmuki, P.; Boehni, H.

    1992-01-01

    The susceptibility of several high alloyed stainless steels against localized corrosion was investigated by traditional potentiostatic and -kinetic methods and the current transient technique. Different test cells, proposed in literature, were evaluated for use in testing of plate materials. The AVESTA-cell showed to be not useful for potentiokinetic current density potential curves, but useable for pitting experiments. After pickling and prepassivation epoxy embedded materials proved to be resistant to crevice corrosion at the metal-resin interface. The electrode in form of a wire was the most reliable crevice free cell design. The grinding of the samples in the pretreatment procedure was found to have a large effect on the pitting corrosion behaviour. Using different paper types with varying grit, a drop in pitting potential for rougher surfaces and an increase in metastable pitting activity was found. Increasing surface roughness led also to changes in the electronic structure of the passive film reflected by a lower bandgap energy. High alloyed stainless steels showed no breakdown potential within the examined potential range. Compared to 18/8 type stainless steels significantly less transients were found. The number of transients decreases with increasing molybdenum and chromium content

  19. Properties of amorphous and microcrystalline superconductors

    International Nuclear Information System (INIS)

    Johnson, W.L.; Poon, S.J.

    1975-01-01

    Results of x-ray diffraction, electrical resistivity, critical field(H/sub c2/) and transport measurements are presented and discussed for bulk amorphous and microcrystalline transition metal alloys (Au--La, Nb--Rh, Nb--Ni--Rh, and Pd--Zr) obtained by liquid quenching. The transition temperature of the alloys is in the range 1.5 to 4.7 0 K. The J/sub c/--H/sub c2/--T/sub c/ relations are rather simple for this class of material and are compared with the theories of type II superconductors. The high resistance of bulk metallic glass to radiation damage might render them suitable for magnetic field applications in high radiation environments

  20. Influence of Heat Treatments on the Corrosion Resistance of Medium -Carbon Steel using Sulfuric Spring Water

    Directory of Open Access Journals (Sweden)

    Ikhlas Basheer

    2015-02-01

    Full Text Available The corrosion is one of the important problems that may be occur to the parts of machinery and equipment after manufactured and when used as a result of exposure to corrosive media. Plain-carbon steel is considered as one of the most common minerals used in industrial applications. Some of heat treatments can have direct effect on the corrosion rate of steel by building up galvanic corrosion cells between its microscopic phases. Therefore, to adopt one of kinds of the plain-carbon steel and the most commonly used in industry to be study subject, that is medium carbon steel and took samples of this steel has been treated thermally in three methods which the normalising, annealing, and hardening .The corrosive media used in the research is Sulfuric Spring, it contains many chemical compounds to show its influence on the corrosion of steel. The weight loss method is used to determine corrosion rate and to compare between the results obtained, show that the greatest corrosion resistance of the annealed steel and the corrosion resistance of the hardened steel is the lowest while the corrosion  resistance of the normalised steel is in-between them.         Calcium carbonate was formed on the metal surface which acts as an isolating layer which decrease corrosion rate with time