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1

Protection of Steel Constructions from Corrosive Destruction  

International Science & Technology Center (ISTC)

Development of the New Effective Sacrificial Anodes on the Basis of Secondary Aluminum for Protection of Steel Constructions of Hydropower Stations and Heat Stations of the Republic of Tajikistan from Corrosion Destruction

2

Guidelines for the Protection of Steel Piles : Corrosive Marine Environment  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The corrosion of steel is a common phenomenon. In a marine environment, steel is corroded at an accelerated rate due to the atmospheric conditions. To combat this corrosion, steel piles are coated in order to protect them. As a major supplier of steel piles, Rautaruukki Oyj (Ruukki) commissioned thi...

Rhodes, Graham

3

Electric corrosion protection method for steel material  

International Nuclear Information System (INIS)

[en] A semiconductor having a thermoelectric performance of 920?V/K or more is incorporated between a steel material of a light water reactor to be in contact with high temperature water and an aqueous solution. This shifts the corrosion potential of the steel material in a high temperature water to more basic side. Satisfactory corrosion resistant metal silicate, for example, FeSi2 is preferably used for the thermoelectric semiconductor. Co is added to FeSi2 to form an n-type semiconductor. A layer of Si3N4 is formed to the circumference of a cylindrical FeSi2 to form an insulation layer. This member is disposed to a hole bored to a stainless steel pipe, and the one surface is brought into contact with high temperature water on the inner side of the stainless steel. On the other side in contact with the outer atmosphere is bonded to the outer surface of the stainless steel pipe by a lead wire. Since the n-type semiconductor has a positive potential on the side at a higher temperature, the potential of the stainless steel is determined to negative. (I.N.)

1995-10-12

4

Investigation of Corrosion and Cathodic Protection in Reinforced Concrete. II: Properties of Steel Surface Layers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The present study explores the formation of corrosion products on the steel surface (using as-received low carbon construction steel) in reinforced concrete in conditions of corrosion and subsequent transformation of these layers in conditions of cathodic protection (CP).

Koleva, D.A.; De Wit, J.H.W.; Van Breugel, K.; Lodhi, Z.F.; Ye, G.

5

The corrosion and protection of less carbon containing steel in subsoil  

International Nuclear Information System (INIS)

[en] Full text: The protection and corrosion resistance of steel in subsoil waters of Baku subway were investigated. Kinetic curves were drawn. The results obtained from the experiment coincide with calculated results. There have been revealed and proposed hudron and fuel oil mixture protecting steel from corrosion in subsoil waters (97.8%) for the internal surface of steel pipes

2007-01-01

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Studies and research work on the reinforcement steel and concrete surface corrosion protection methods  

Directory of Open Access Journals (Sweden)

Full Text Available Methods for reinforcement steel corrosion protection and concrete surface protection are analyzed. Knowing the corrosion process mechanism reinforcement steel can be protected by different protection methods even in the presence of crevices larger than those anticipated by design. The selection of the corrosion protection method depends on the reduction level of the reinforcement steel corrosion which in its turn is determined by the atmospheric conditions. The selection of the accelerated corrosion test conditions was made revealing the mechanism of the processes that take place at the steel reinforcement surface under natural weathering conditions. Crevices ranging from 0.05mm to 1.00mm or larger were opened by bending reinforced concrete girders on special equipment and were maintained all over the period of the corrosion resistance study.

Gheorghe Croitoru

2013-01-01

7

Electrodeposition of zinc-doped silane films for corrosion protection of mild steels  

International Nuclear Information System (INIS)

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.

2012-01-01

8

Marine corrosion protective coatings of hexagonal boron nitride thin films on stainless steel.  

Science.gov (United States)

Recently, two-dimensional, layered materials such as graphene and hexagonal boron nitride (h-BN) have been identified as interesting materials for a range of applications. Here, we demonstrate the corrosion prevention applications of h-BN in marine coatings. The performance of h-BN/polymer hybrid coatings, applied on stainless steel, were evaluated using electrochemical techniques in simulated seawater media [marine media]. h-BN/polymer coating shows an efficient corrosion protection with a low corrosion current density of 5.14 × 10(-8) A/cm(2) and corrosion rate of 1.19 × 10(-3) mm/year and it is attributed to the hydrofobic, inert and dielectric nature of boron nitride. The results indicated that the stainless steel with coatings exhibited improved corrosion resistance. Electrochemical impedance spectroscopy and potentiodynamic analysis were used to propose a mechanism for the increased corrosion resistance of h-BN coatings. PMID:23618222

Husain, Esam; Narayanan, Tharangattu N; Taha-Tijerina, Jose Jaime; Vinod, Soumya; Vajtai, Robert; Ajayan, Pulickel M

2013-05-07

9

Marine corrosion protective coatings of hexagonal boron nitride thin films on stainless steel.  

UK PubMed Central (United Kingdom)

Recently, two-dimensional, layered materials such as graphene and hexagonal boron nitride (h-BN) have been identified as interesting materials for a range of applications. Here, we demonstrate the corrosion prevention applications of h-BN in marine coatings. The performance of h-BN/polymer hybrid coatings, applied on stainless steel, were evaluated using electrochemical techniques in simulated seawater media [marine media]. h-BN/polymer coating shows an efficient corrosion protection with a low corrosion current density of 5.14 × 10(-8) A/cm(2) and corrosion rate of 1.19 × 10(-3) mm/year and it is attributed to the hydrofobic, inert and dielectric nature of boron nitride. The results indicated that the stainless steel with coatings exhibited improved corrosion resistance. Electrochemical impedance spectroscopy and potentiodynamic analysis were used to propose a mechanism for the increased corrosion resistance of h-BN coatings.

Husain E; Narayanan TN; Taha-Tijerina JJ; Vinod S; Vajtai R; Ajayan PM

2013-05-01

10

Evaluation of the effectiveness of selected corrosion inhibitors for protection of prestressing steels in PCPVs  

International Nuclear Information System (INIS)

The corrosion protection provided prestressing steel by portland cement-based grout in the presence of sulfide, nitrate, and chloride ion environments was evaluated. Results were compared to those obtained from selected, commercially available petroleum-microcrystalline waxes (petrolatums) compounded with organic corrosion inhibitors. The investigation was conducted in two phases: (1) a review of literature to establish the mechanisms of prestressing steel corrosion, techniques available for protection of prestressing steel in hostile environments, and the performance of structures that have utilized either nongrouted- or grouted-tendon prestressing systems; and (2) a laboratory study to develop relative performance data for portland cement grout and selected commercial petroleum-based greases and waxes containing inhibitors. Conclusions derived from the investigation indicate that (1) sulfide, nitrate, and chloride salts must be excluded from prestressing materials; (2) prestressing materials must be continuously protected from inimical environments; (3) the effectiveness of the protection provided by both the organic- and cement-based corrosion inhibitors is reduced unless the steel is completely covered; and (4) both cement- and organic-based corrosion inhibitors completely protect prestressing materials when properly applied

1979-01-01

11

Spectroscopic study of the final protective corrosion product on weathering steel  

Energy Technology Data Exchange (ETDEWEB)

Recent progress in understanding the structure and properties of final protective rust layer on weathering steel and its application for structural steels is shown based on the data obtained mainly by spectroscopic characterization. The main constituent of the weathering steel rust layer is changed with exposure period from {gamma}- FeOOH (less than a few years) via, amorphous substance (several years), to {alpha}-FeOOH goethite phase (decades). The corrosion rate of the weathering steel decreased with this phase transformation. The final protective rust layer possesses the structure of {alpha}- (Fe{sub 1} - X{sub p} Cr x)O OH, Cr substitute goethite; the crystal size decreases with its Cr-content. It is shown that the Cr content in the Cr-substituted goethite increases gradiently with reaching the rust/steel interface. This increase in the Cr content and resultant aggregation of fine crystals lead a densely packed Cr-substituted goethite rust layers which provides higher protective ability for atmospheric corrosives. It is found that the Cr-substituted goethite possesses the cation selective ability at the vicinity of the rust/steel interface where the Cr content can be estimated approximately 5-10 mass %. Thus, the final protective rust layer of the Cr-substituted goethite impedes the penetration of aggressive corrosive anions such as Cl{sup -} and SO{sub 4} {sup 2-}, besides the physically prevention effect of its densely aggregated structure for corrosive penetration. It is found that Cr{sub 2} (SO{sub 4}){sub 3} is effective for obtaining the final protective rust layer in a short period. SO{sub 4} {sup 2} accelerates rust formation and Cr{sup 3-} substitutes goethite crystal lattice point at the initial stage of corrosion; resultantly the rust layer formed suppresses dissolution of the steel even in the severe environment. (Author)

Yamashita, M. [Faculty of Engineering, Himeji Institute of Technology, Himeji, Hyogo, Japan (Japan); Misawa, T. [Faculty of Engineering, Muroran Institute of Technology, Muroran, Hokkaido, Japan (Japan)

1998-12-31

12

Evaluation of the corrosion protection of aluminum coatings on steel substrates  

Energy Technology Data Exchange (ETDEWEB)

Finding good protective coatings that hold up to harsh marine environments has always been an important goal to US Navy. Because of the large quantity of steel used in ship construction and repair, and the tremendous amount of money spent annually for corrosion control, it is imperative that good protective coatings are found to protect topside systems. To achieve this objective, a long term study was conducted to evaluate the performance of some aluminum pigmented coatings on carbon steel in various marine environments. An attempt is made to correlate the results obtained from the field and laboratory tests. Several coatings appear to be promising candidates for harsh marine usage for surface combatants.

Lindsey, N.; Vasanth, K.L. [Naval Surface Warfare Center, Bethesda, MD (United States)

1997-12-01

13

Methods for protection of high-strength welded stainless steel from corrosion cracking  

International Nuclear Information System (INIS)

[en] The efficiency of protection from corrosion cracking under a bending stress of 100 kgf/mm2 in a salt mist and in a sulphur dioxide atmosphere, of welded joints of steel 08Kh15N5D2T with metallizing, galvanic and varnish coatings and lubricants, and of steel 1Kh15N4AM3 with sealing compounds has been investigated. Metallization of welded joints with aluminium and zinc efficiently increases corrosion resistance in a salt mist. Galvanic coatings of Cd, Zn, and Cr increase the time to cracking in a salt mist from 2-3 to 60-80 days. The protective properties of varnishes under the effect of a salt mist decrease in the following sequence: epoxy-polyamide enamel EP-140, acrylic enamel C-38, silicone enamels KO-834, KO-811, and KO-814. In an atmosphere containing SO2 0.15 vol.% at 100% relative humidity, the varnishes investigated, with the exception of the inhibited coating XC-596, show lower protective properties than in a salt mist. The high efficiency of protection from corrosion cracking in a salt mist of slots of steel 1Kh15N4AM3 when using organic sealing compounds U4-21 and U5-21, and also slushing lubricants and oils PVK, TsIATIM-201, K17, and AMS3 was established

1978-01-01

14

A polyaniline based intrinsically conducting coating for corrosion protection of structural steels.  

UK PubMed Central (United Kingdom)

Among the various corrosion protection strategies for structural steels, coating techniques provide the most cost-effective protection and have been used as the primary mode of corrosion protection. Existing coating techniques however have been used mainly for their barrier capability and therefore all have a limited service life due to oxidation aging, electrolytic degradation, or various inadvertent defects and flaws occurred in and after coating applications. This work investigated the anti-corrosion potential of a ?-conjugated polymer-polyaniline (PANi), which was doped into an intrinsically conducting polymer and then included in a two-layer coating system as a primer layer. To achieve a long service life, the primer layer was made by mixing the conductive PANi in a waterborne poly-vinyl butyral solution to provide strong adhesion to steel surface, and then topcoated with a layer of elastomer-modified polyethylene to obtain extra mechanical and barrier protections. Two ASTM standard tests were conducted to evaluate the corrosion durability and tensile adhesion of the two-layer system, in which the system demonstrated superior performance. The Scanning Kelvin Probe Force Microscopy (SKPFM) was used to provide the microscopic evidences for the outstanding performance. Microsc. Res. Tech., 2013. © 2013 Wiley Periodicals, Inc.

Pan T; Wang Z

2013-09-01

15

Prevention of crevice corrosion in duplex SS flanges using carbon steel bolts with cathodic protection  

Energy Technology Data Exchange (ETDEWEB)

Achieving reliable long-term performance of high strength bolts for flange connections in subsea service is a critical issue for the offshore industry. Viable bolting materials with high strength that are not susceptible to embrittlement or galvanic corrosion when the flanges are made of stainless steels are limited. A laboratory study was performed to determine the viability of using B7 carbon steel stud bolts and 316 stainless steel (SS) seal rings in a Duplex SS flange for subsea service The laboratory test system used full size commercial flanges, bolts and seal rings to simulate electrochemical conditions that will occur in crevices associated with carbon steel bolts in a Duplex SS flange and with the use of a 316 stainless steel seal ring in a Duplex SS flange. The flange systems were instrumented to enable monitoring of current densities and potentials at precise locations within the crevices throughout the tests as test parameters were changed. Test parameters included cathodic protection level, temperature, and sealing the outer flange gap. Cathodic protection was provided by remote aluminum sacrificial anodes to achieve potentials typical for a sub sea manifold. Both electrochemical data and examination of the components at the end of the 164 day exposure indicated that sufficient cathodic protection occurred in the crevices to provide long term corrosion control to all of the components involved. The capability to use B7 bolts rather than high alloy bolts enables a significant project savings.

Thomason, W.H.; Ivie, R.G.; Marlow, J.A.

1999-07-01

16

Evaluation of the protection behaviour of reinforcement steel against corrosion induced by chlorides in reinforced mortar specimens  

International Nuclear Information System (INIS)

In this work various treatments for protecting reinforcing steels against corrosion induced by chlorides have been evaluated. Additives to mortars and surface treatments given to reinforcing steels were evaluated as corrosion protection measures. In the preliminary tests the corrosion resistance of a CA 50 steel treated by immersion in nearly 50 different solutions, was determined. The solutions were prepared with tannins (from various sources) and/or benzotriazole, and during immersion, a surface film formed on the steel. The corrosion resistance of the coated steels was evaluated in a saturated Ca(OH)2 solution with 5% (wt) NaCl. Preliminary tests were also carried out with mortars reinforced with uncoated steel to which tannin or lignin was added. Two organic coatings, a monocomponent and a bicomponent type, formulated specially for this investigation, with both tannin and benzotriazole, were also tested in the preliminary tests to select the coating with better corrosion protection property. The bicomponent type (epoxy coating) showed better performance than the monocomponent type coating, and the former was therefore chosen to investigate the corrosion performance on CA 50 steel inside mortar specimens. From the preliminary tests, two solutions with tannin from two sources, Black Wattle (Acacia mearnsii) and Brazilian tea (Ilex paraguariensis St. Hill), to which benzotriazole and phosphoric acid were added, were chosen. Mortar specimens reinforced with CA50 steel treated by immersion in these two solutions were prepared. Also, epoxy coated CA50 steel was tested as reinforcement inside mortar specimens. Mortars reinforced with uncoated CA50 steel were also prepared and corrosion tested for comparison. The effect of tannin and lignin as separate additives to the mortar on the corrosion resistance of uncoated steel was also studied. The reinforced mortar specimens were tested with various cycles of immersion for 2 days in 3.5% (wt) NaCl followed by with air drying for 5 days. The corrosion tests used in this investigation were gravimetric and electrochemical tests. The results showed satisfactory corrosion performance for all kinds of protection measures. However, the performance depended on the type of protection used. The best performance was obtained with tannin containing epoxy coated steel, followed by the steel treated by immersion in tannin containing solutions and finally by the addition of tannin (Black Wattle) or lignin to the mortar. All the protection measures evaluated in this study are economically viable and environmentally friendly and can therefore be considered for protecting reinforcement steels against corrosion. (author)

2002-01-01

17

Protective properties of zinc-containing oil-based coatings against steel atmospheric corrosion  

Energy Technology Data Exchange (ETDEWEB)

The protective efficiency of the compositions of zinc powder and fresh and waste oils has been studied with respect to the atmospheric corrosion of carbonaceous steel (St3). The oil compositions contained 25-75 wt.% of zinc powder. Waste motor oil (WMO), filtered fraction of WMO (FWMO), waste and fresh industrial I-20A oils have been used as a solvent-support. The influence of zinc concentration in the oil compositions on the thickness of the oil based coatings and the inhibitor effect in 3% NaCl solution, in the apparatus for heat and moisture treatment and in an open site has been investigated. The coatings on base of WMO and FWMO and 75% concentration of Zn powder show the highest protective action. Kinetics of the partial electrode reactions on steel in conditions of a presence of the protective coatings and water mass transfer through the oil composition films has been studied. (authors)

Tsygankova, L. E.; Shel, N.V.; Paramonov, S.Yu.; Vigdorovich, V. I. [Derzhavin State University 33, Internatsionalnaya St., Tambov, 392622 (Russian Federation)

2004-07-01

18

Protecting old oil tanks made of steel against internal corrosion using organic coatings. Oeljysaeilioeiden sisaepuolisen korroosion estaeminen orgaanisilla osapinnoitteilla  

Energy Technology Data Exchange (ETDEWEB)

Water containing chlorides and sulphates can cause corrosion on the internal surfaces of buried steel tanks. After 1974 at least the bottom area os all new tanks has been painted to prevent corrosion. Older tanks are normally without any internal corrosion protection. Laboratory and field tests were carried out to investigate the applicability of glass fiber reinforced plastics and four different types of epoxy coating to the corrosion protection of the bottom area of old steel tanks. Glass fiber reinforced plastics, solventless epoxy paint and epoxy paint with normal or low content of solvent investigated showed good adhesion to steel and chemical resistance. The adherence of the resin-modified epoxy paint tested was very sensitive to the cleaning of the steel surface and its chemical resistance in petrol tanks was poor. Consequently, it is not recommended for coating petrol tanks.

Kaunisto, T.

1987-06-15

19

Selection of varnish-and-paint system for protection of 20Kh3MVF steel from atmospheric corrosion  

International Nuclear Information System (INIS)

[en] A varish-and-paint system has been selected for protecting steel 20Kh3MVF against atmospheric corrosion under conditions of elevated temperatures and humidity. It has been established that optimum protection of steel can be achieved by coating it with epoxy enamel EhP-525 in combination with surface phosphating. For lono.-term protection, enamel ML-12 coatings on the phosphate layer are recommended

1977-01-01

20

POLYPHENYLENESULFIED/MONTOMORILLONITE CLAY NANOCOMPOSITE COATINGS: THEIR EFFICACY IN PROTECTING STEEL AGAINST CORROSION.  

Energy Technology Data Exchange (ETDEWEB)

Nanoscale montomorillonite (MMT) clay fillers became dispersed in a polyphenylenesulfied (PPS) matrix through the processes of octadecylamine (ODA) intercalation {yields} molten PPS co-intercalation {yields} exfoliation. Cooling this molten exfoliated material led to the formation of a PPS/MMT nanocomposite. The MMT nanofiller conferred three advanced properties on the semi-crystalline PPS: First, it raised its melting point by nearly 40 C to 290 C; second, it increased its crystallization energy, implying that an excellent adherence of the nanofillers surfaces to PPS in terms of a good interfacial bond; and, third, it abated the degree of its hydrothermal oxidation due to sulfide {yields} sulfite linkage transformations. When this advanced PPS nanocomposite was used as a corrosion-preventing coating for carbon steel in a simulated geothermal environment at 300 C, a coating of {approx}150 {micro}m thickness adequately protected the steel against hot brine-caused corrosion. In contrast, an MMT-free PPS coating of similar thickness was not nearly as effective in mitigating corrosion as was the nanocompsite; in fact, the uptake of corrosive ionic electrolyte by the unmodified coating increased with an extending exposure time.

SUGAMA, T.; GAWLIK, K.

2006-06-01

 
 
 
 
21

Electrochemical determination of the minimum cathodic protection potential and underground steel corrosion rate. On the moderate criteria for the protection efficiency  

International Nuclear Information System (INIS)

Experimentally are determined the minimum protection potential Emin and steel corrosion rate in a number of soils by means of calculation using the cathode polarization curve. Their correlation is shown with results of weight tests in conditions of the free corrosion and cathode polarization. It is shown too that Emin is not connected directly with the steel free corrosion rate but when lowering Emin normally is decreased. Using Emin as a characteristic for the soil corrosion effect and features of the cathode protection when softening the criteria of its efficiency are discussed. 21 refs., 4 figs., 2 tabs.

1994-01-01

22

Study on cerium-doped nano-TiO2 coatings for corrosion protection of 316?L stainless steel  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Many methods have been reported on improving the photogenerated cathodic protection of nano-TiO2 coatings for metals. In this work, nano-TiO2 coatings doped with cerium nitrate have been developed by sol–gel method for corrosion protection of 316?L stainless steel. Surface morphology, structure, and...

Li, Suning; Wang, Qian; Chen, Tao; Zhou, Zhihua; Wang, Ying; Fu, Jiajun

23

Corrosion protection of low-carbon steel using exopolysaccharide coatings from Leuconostoc mesenteroides  

Science.gov (United States)

Corrosion is one of the most serious and challenging problems faced worldwide by industry. This research investigates the inhibition of corrosive behavior of SAE1010 steel by bacterial exopolysaccharides. Electrochemical Impedance Spectroscopy was used to evaluate the corrosion inhibition of diffe...

24

Corrosion Protection of Stainless Steel by Polyaniline/Polypyrrole Composite Coating  

Directory of Open Access Journals (Sweden)

Full Text Available Electrochemical deposition of polyaniline/polypyrrole coatings on stainless steel was carried out by the constant potential technique. The surface properties and corrosion behavior of the coatings were studied by varying the time of deposition and the initial monomer concentration. The corrosion current and corrosion potential were measured by direct current polarization test. The changes in corrosion current and corrosion potential with the deposition timeand the initial monomer concentration were thoroughly investigated. The surface energy of coated stainless steel was calculated by using dynamic contact angle analyzer.

A.Subathira; RM.Meyyappan

2010-01-01

25

Development of Hybrid Nano-sol Gel Coatings for Corrosion Protection of Carbon Steel  

Directory of Open Access Journals (Sweden)

Full Text Available This study was aimed to develop and study the anticorrosion of nanofilms for carbon steel based on the sol-gel coating technique. The sols were synthesized by copolymerization of epoxy resin and hardener with TiO2-SiO2-ZnO-CeO3 pigments. Epoxy and hardener were acted as a host while TiO2, ZnO, SiO2 and CeO2 nanoparticles were acted as guest components. There were 25 formulations had been synthesized and the average coatings of 0.625 mm thickness were applied on carbon steel substrates. The structures of these formulated pigments were confirmed by FT-IR spectral. The formulated coating had shown excellent adhesion strength. The corrosion protective behavior performance of coated carbon steels were analyzed using 3.5% of NaCl salt solution based on ASTM B117-94. Formulation that contained TiO2-ZnO-SiO2-CeO2 of 6, 4, 1 and 9 wt% respectively appeared to be the best formulation to resist corrosion.

Norzita N.; Haziq M.; Zurina M.

2012-01-01

26

Foamed glass insulating block ends costly baghouse corrosion and protects new steel stack  

Energy Technology Data Exchange (ETDEWEB)

A secondary smelter company on the West Coast, that reclaims certain metals from scrap products such as wet cell batteries, was spending hundreds of thousands of dollars each year to replace corroded metal in the baghouses at one of its installations. Various types of protective coatings and special steels had been tried, but the maximum life of each unit was about a year due to condensation of flue gas corrosives on the inside surface of the metal walls. In 1979, at one of its sites, the company decided to test an acid/corrosion protection system specifically designed for stack, duct, and breeching installations and related equipment. The system consists of totally inorganic formed borosilicate glass block that can handle temperatures to 960/sup 0/F and is resistant to atttack by most acids and corrosives except fluorides and strong alkalis. The closed-cell structure provides a strong, lightweight product that reduces installation costs, and has extremely low thermal conductivity for an efficient heat barrier. The 12 X 18'' block is directly bonded to a clean metal surface by an 1/8'' thick layer of urethane asphalt that forms a virtually impervious flexible membrane to further protect the metal from corrosive attack. The flexible bond also absorbs expansion and contraction due to thermal changes, and reduces the probability of cracked blocks and dropoff. The protection provided by the foamed glass block and adhesive membrane system has eliminated the very expensive annual replacement of corroded baghouse walls. The performance of the lining system in the baghouses was so successful that the smelter decided to use it in a new metal stack that is 165' high.

1982-03-01

27

The minimum protective potential and underground corrosion rate of cathodically protected steel: Electrochemical determination and problems in application of mild criteria  

Energy Technology Data Exchange (ETDEWEB)

An earlier method of calculating the minimum cathodic protection potential (E{sub min}) and underground steel corrosion rate from cathodic polarization curve has been justified. It has been shown that E{sub min}, can be estimated from the free corrosion potential.

Freiman, L.I. [Pamfilov Academy of Municipal Service (Russian Federation)

1994-05-01

28

Corrosion protection of low-carbon steel using exopolysaccharide coatings from Leuconostoc mesenteroides.  

UK PubMed Central (United Kingdom)

Corrosion of metals is a serious and challenging problem faced worldwide by industry. Purified Leuconostoc mesenteroides exopolysaccharide (EPS) coatings, cast from aqueous solution, inhibited the corrosion of low-carbon steel as determined by electrochemical impedance spectroscopy (EIS). There were two different corrosion behaviors exhibited when EPS films from different strains were cast onto the steel. One EPS coating reacted immediately with the steel substrate to form an iron (III) oxide layer ("rust") during the drying process while another did not. The samples that did not flash corrode had higher corrosion inhibition and formed an iron (II) passivation layer during EIS testing that persisted after the cells were disassembled. Corrosion inhibition was strain-specific as polysaccharides with similar structure did not have the same corrosion potential.

Finkenstadt VL; Côté GL; Willett JL

2011-06-01

29

Corrosion protection of low-carbon steel using exopolysaccharide coatings from Leuconostoc mesenteroides  

UK PubMed Central (United Kingdom)

Corrosion of metals is a serious and challenging problem faced worldwide by industry. Purified Leuconostoc mesenteroides exopolysaccharide (EPS) coatings, cast from aqueous solution, inhibited the corrosion of low-carbon steel as determined by electrochemical impedance spectroscopy (EIS). There were two different corrosion behaviors exhibited when EPS films from different strains were cast onto the steel. One EPS coating reacted immediately with the steel substrate to form an iron (III) oxide layer (“rust”) during the drying process while another did not. The samples that did not flash corrode had higher corrosion inhibition and formed an iron (II) passivation layer during EIS testing that persisted after the cells were disassembled. Corrosion inhibition was strain-specific as polysaccharides with similar structure did not have the same corrosion potential.

Finkenstadt VictoriaL; Co?te? GregoryL; Willett JL

2011-06-01

30

Corrosion protection of low-carbon steel using exopolysaccharide coatings from Leuconostoc mesenteroides.  

Science.gov (United States)

Corrosion of metals is a serious and challenging problem faced worldwide by industry. Purified Leuconostoc mesenteroides exopolysaccharide (EPS) coatings, cast from aqueous solution, inhibited the corrosion of low-carbon steel as determined by electrochemical impedance spectroscopy (EIS). There were two different corrosion behaviors exhibited when EPS films from different strains were cast onto the steel. One EPS coating reacted immediately with the steel substrate to form an iron (III) oxide layer ("rust") during the drying process while another did not. The samples that did not flash corrode had higher corrosion inhibition and formed an iron (II) passivation layer during EIS testing that persisted after the cells were disassembled. Corrosion inhibition was strain-specific as polysaccharides with similar structure did not have the same corrosion potential. PMID:21290167

Finkenstadt, Victoria L; Côté, Gregory L; Willett, J L

2011-02-03

31

Characterization of organic-inorganic hybrid coatings for corrosion protection of galvanized steel and electroplated ZnFe steel  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english The development of hybrids materials has been extensively investigated in recent years. The combination of a wide variety of compositions and production processes had permitted the use of these materials in different applications like coatings for corrosion protection of metals. In this work organic-inorganic hybrid materials have been prepared from the hydrolysis of tetraethylorthosilicate and silanol-terminated polidymetilmetoxysilane using a sol-gel process. These mate (more) rials have been applied on galvanized steel and on steel electroplated with a ZnFe. In order to evaluate the degradation behavior of these coatings, electrochemical techniques (Electrochemical Impedance Spectroscopy and Potentiodynamic Polarization) were used. EIS data was fitted to an equivalent circuit from which the electrochemical parameters were obtained. Results show a good protective character of the hybrid films, when compared with uncovered specimens. The overall performance of the coating systems appears to be highly dependent on the kind of metallic coating applied to the steel.

Souza, Maria Eliziane Pires de; Ariza, Edith; Ballester, Margarita; Yoshida, Inez Valéria Pagotto; Rocha, Luis Augusto; Freire, Célia Marina de Alvarenga

2006-03-01

32

Protection of steel from corrosion and hydrogen absorption by organic inhibitors: experimental and quantum-chemical studies  

Directory of Open Access Journals (Sweden)

Full Text Available The step-strip anodic dissolution technique was used to obtain concentration profiles of cathodic evolved H2 across the depth of Cr-Ni1810 steel under corrosion in water-salt media in the presence of SRB. The proposed approximation of the experimentally obtained distribution of hydrogen along the depth of steel by means of standard Gaussian function made it possible to establish the integral hydrogen content of the sub-layer (up to 80 ?m) with high degree of accuracy. The efficiency of protective actions of the studied organic compounds against corrosion and hydrogen absorption by steel were compared with the data of quantum chemical computations performed for isolated molecules of the studied inhibitors with the help of the MNDO method. The results obtained point to a difference in the protective mechanisms of the studies inhibitors in case of anticorrosion action and hydrogen absorption by steel.

Beloglazov G.; Beloglazov S.

2013-01-01

33

Synthesis, characterization, and corrosion protection properties of poly(N-(methacryloyloxymethyl) benzotriazole-co-methyl methacrylate) on mild steel  

Energy Technology Data Exchange (ETDEWEB)

The copolymers from different feed ratios of N-(methacryloyloxymethyl) benzotriazole (MMBT) and methyl methacrylate (MMA) has been synthesised using free radical solution polymerization technique and characterized using FT-IR and {sup 13}C NMR spectroscopy. The thermal stability of the polymers was studied using theremogravimetrtic analysis (TGA). The corrosion behaviors of mild steel specimens dip coated with different composition of copolymers have been evaluated by potentiodynamic polarization and electrochemical impedance spectroscopic (EIS) method. These electrochemical properties were observed in 0.1 M HCl medium. The polarization and impedance measurements showed different corrosion protection efficiency with change in composition of the copolymers. It was found that the corrosion protection properties are owing to the barrier effect of the polymer layer covered on the mild steel surfaces. However, it was observed that the copolymer obtained from 1:1 mole ratio of MMBT and MMA exhibited better protection efficiency than other combinations.

Srikanth, A.P. [Department of Applied Sciences and Humanities, MIT Campus, Anna University, Chennai 600044 (India); Lavanya, A. [Department of Chemistry, CEG Campus, Anna University, Chennai 600025 (India); Nanjundan, S. [Department of Chemistry, CEG Campus, Anna University, Chennai 600025 (India); Rajendran, N. [Department of Applied Sciences and Humanities, MIT Campus, Anna University, Chennai 600044 (India)]. E-mail: nrajendran@annauniv.edu

2006-12-15

34

Synthesis, characterization, and corrosion protection properties of poly(N-(methacryloyloxymethyl) benzotriazole-co-methyl methacrylate) on mild steel  

Science.gov (United States)

The copolymers from different feed ratios of N-(methacryloyloxymethyl) benzotriazole (MMBT) and methyl methacrylate (MMA) has been synthesised using free radical solution polymerization technique and characterized using FT-IR and 13C NMR spectroscopy. The thermal stability of the polymers was studied using theremogravimetrtic analysis (TGA). The corrosion behaviors of mild steel specimens dip coated with different composition of copolymers have been evaluated by potentiodynamic polarization and electrochemical impedance spectroscopic (EIS) method. These electrochemical properties were observed in 0.1 M HCl medium. The polarization and impedance measurements showed different corrosion protection efficiency with change in composition of the copolymers. It was found that the corrosion protection properties are owing to the barrier effect of the polymer layer covered on the mild steel surfaces. However, it was observed that the copolymer obtained from 1:1 mole ratio of MMBT and MMA exhibited better protection efficiency than other combinations.

Srikanth, A. P.; Lavanya, A.; Nanjundan, S.; Rajendran, N.

2006-12-01

35

Synthesis, characterization and corrosion protection properties of poly(N-(acryloyloxymethyl) benzotriazole-co-glycidyl methacrylate) coatings on mild steel  

International Nuclear Information System (INIS)

The synthesis of copolymers from different feed ratios of N-(acryloyloxymethyl) benzotriazole (AMBT) and glycidyl methacrylate (GMA) was achieved by using free radical solution polymerization technique and characterised using FT-IR and 13C NMR spectroscopy. The thermal stability of the synthesized copolymers was studied using theremogravimetrtic analysis (TGA). The corrosion performances of mild steel specimens dip coated with different composition of copolymers were investigated in 0.1 M HCl by using potentiodynamic polarization and electrochemical impedance spectroscopic (EIS) method. The polarization and impedance measurements showed different corrosion protection efficiency with change in composition of the copolymers. It was found that the corrosion protection properties are owing to the barrier effect of the polymer layer covered on the mild steel surfaces. However, it was observed that the copolymer obtained from 1:1 mole ratio of AMBT and GMA exhibited better protection efficiency than other combinations

2007-06-15

36

Parameters Governing the Corrosion Protection Efficiency of Fusion-Bonded Epoxy Coatings on Reinforcing Steel.  

Science.gov (United States)

The purpose of this study was to investigate various epoxy coating and exposure parameters to determine their effects on the corrosion of reinforcing steel. The parameters investigated were: chloride content at the bar depth, coated bar corroded area, cor...

A. Ramniceanu M. C. Brown M. M. Sprinkel R. E. Weyers

2008-01-01

37

Corrosion Protection of Steel by Thin Coatings of Starch-oil Emulsions  

Science.gov (United States)

Corrosion of materials is one of the most serious and challenging problems faced worldwide by industry. This research investigated the inhibition of corrosive behavior by jet-cooked starch-soybean oil composites on SAE 1010 steel. Electrochemical Impedance Spectroscopy (EIS) was used to evaluate t...

38

SVET study of the corrosion protection of electrodeposited Zn and Zn-Co-Fe alloy coated steels  

Energy Technology Data Exchange (ETDEWEB)

The scanning vibrating electrode technique (SVET) was applied to study the corrosion resistance of partially coated (Zn and various Zn-Co-Fe alloys) and partially exposed steel samples in 10 mM NaCl solution. The sacrificial properties and the protection range decreases with increase in Co content in the alloy. For high Co content in the alloy, the coating becomes more noble to steel and loses its sacrificial protection. The barrier resistance of the coatings increases with the increase in Co content in the alloy coating. Zn-Co-Fe alloys with high Co content (i.e., 32 wt% Co and 1 wt% Fe) showed excellent barrier properties due to passivation after dezincification protecting the underlying steel. An intermediate region of compositions can be distinguished in which the coatings provide a good combination of sacrificial and barrier resistance properties and also a reasonable protection range. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

Lodhi, Z.F.; Zhan, H. [Netherlands Institute for Metals Research, Delft (Netherlands); Mol, J.M.C.; Wit, J.H.W. de [Delft University of Technology, Department of Materials Science and Engineering (Netherlands); Terryn, H. [Netherlands Institute for Metals Research, Delft (Netherlands); Department of Metallurgy, Electrochemistry and Materials Science, Vrije Universiteit Brussel (Belgium)

2008-10-15

39

Dansk Ingenioerforening's recommendation for corrosion protection of steel structures in marine environments. Dansk Ingenioerforenings anvisning for korrosionsbeskyttelse af staalkonstruktioner i marine omgivelser  

Energy Technology Data Exchange (ETDEWEB)

The recommendation aims to secure a reasonable standard for corrosion protection of steel structures and structural members in contact with seawater including structures in splash zone and in marine sediments. (SM).

1988-01-01

40

The effect of cathodic protection potential on corrosion fatigue crack growth rate of an offshore structural steel  

Energy Technology Data Exchange (ETDEWEB)

Duplicate tests have been performed to determine the effect of cathodic protection potential on corrosion fatigue crack growth rate of a modern offshore structural steel, produced by thermo-mechanically controlled processes. The experiments were carried out using compact tension specimens exposed to artificial seawater at 10{sup o}C and subjected to constant amplitude loading at 0.35 Hz. Reproducible results showed that the merits of cathodic protection potentials are strongly dependent on stress intensity ratio R and stress intensity range {Delta}K. It appears that a specific value of cathodic potential may not give comprehensive protection against corrosion fatigue within the spectrum of variable amplitude loading experienced in service. Fractography showed the initiation of secondary cracks on the fracture surface to be associated with the dissolution of calcium sulphide inclusions, regardless of imposed cathodic potential. (Author)

Yu, J. [Sheffield Hallam Univ. (United Kingdom); Brook, R. [Sheffield Univ. (United Kingdom); Cole, I. [Commonwealth Scientific and Industrial Research Organization (CSIRO), Melbourne, VIC (Australia); Morabito, D.; Demofonti, G. [Centro Sviluppo Materiali SpA, Rome (Italy)

1996-12-31

 
 
 
 
41

Electrochemical synthesis of bilayer coatings of poly(N-methylaniline) and polypyrrole on mild steel and their corrosion protection performances  

International Nuclear Information System (INIS)

Highlights: ? The bilayers of poly(N-methylaniline) and polypyrrole-dodecylsulfate were synthesized. ? These films on mild steel were characterized by cyclic voltammetry, FTIR and FESEM. ? DS dopant allows permeation to cations and decreases the ingress of chloride ions. ? The PNMA/PPy-DS bilayer coating exhibited the best corrosion resistance in 0.5 M HCl. ? The protective properties of polymers was developed by preparing their bilayer coatings. - Abstract: Homopolymer and bilayer coatings of poly(N-methylaniline) (PNMA) and polypyrrole-dodecylsulfate (PPy-DS) have been electropolymerized on a mild steel (MS) surface by the potentiodynamic method in aqueous oxalic acid solutions. In order to include dodecylsulfate ion as dopant in the polypyrrole, sodium dodecylsulfate was also added to the polymerization solution of pyrrole. Characterization of coatings was carried out by the cyclic voltammetry, Fourier transform infrared (FTIR) spectroscopy and field emission scanning electron microscopy (FESEM). Corrosion behavior of the polymer coated MS electrodes was investigated in highly aggressive 0.5 M HCl solution by the Tafel test and electrochemical impedance spectroscopy (EIS) techniques. Corrosion test revealed that among the protective coatings obtained, the PNMA/PPy-DS bilayer exhibited the best corrosion resistance at all immersion times.

2011-10-30

42

Electrochemical synthesis of bilayer coatings of poly(N-methylaniline) and polypyrrole on mild steel and their corrosion protection performances  

Energy Technology Data Exchange (ETDEWEB)

Highlights: > The bilayers of poly(N-methylaniline) and polypyrrole-dodecylsulfate were synthesized. > These films on mild steel were characterized by cyclic voltammetry, FTIR and FESEM. > DS dopant allows permeation to cations and decreases the ingress of chloride ions. > The PNMA/PPy-DS bilayer coating exhibited the best corrosion resistance in 0.5 M HCl. > The protective properties of polymers was developed by preparing their bilayer coatings. - Abstract: Homopolymer and bilayer coatings of poly(N-methylaniline) (PNMA) and polypyrrole-dodecylsulfate (PPy-DS) have been electropolymerized on a mild steel (MS) surface by the potentiodynamic method in aqueous oxalic acid solutions. In order to include dodecylsulfate ion as dopant in the polypyrrole, sodium dodecylsulfate was also added to the polymerization solution of pyrrole. Characterization of coatings was carried out by the cyclic voltammetry, Fourier transform infrared (FTIR) spectroscopy and field emission scanning electron microscopy (FESEM). Corrosion behavior of the polymer coated MS electrodes was investigated in highly aggressive 0.5 M HCl solution by the Tafel test and electrochemical impedance spectroscopy (EIS) techniques. Corrosion test revealed that among the protective coatings obtained, the PNMA/PPy-DS bilayer exhibited the best corrosion resistance at all immersion times.

Zeybek, Buelent [Ankara University, Faculty of Science, Department of Chemistry, Ankara (Turkey); Dumlupinar University, Faculty of Arts and Sciences, Department of Chemistry, Kuetahya (Turkey); Ozcicek Pekmez, Nuran, E-mail: npekmez@hacettepe.edu.t [Hacettepe University, Faculty of Science, Department of Chemistry, Ankara (Turkey); Kilic, Esma [Ankara University, Faculty of Science, Department of Chemistry, Ankara (Turkey)

2011-10-30

43

Protection of type 316 austenitic stainless steel from intergranular stress corrosion cracking by thermo-mechanical treatment  

International Nuclear Information System (INIS)

Thermomechanical treatment that causes carbide stabilizing aging of cold worked material followed by recrystallization heating made standard stainless steels highly resistant to intergranular corrosion and stress corrosion cracking in different test environments. After a typical thermal history of simulated welding, several IGSCC susceptibility tests were made. The results showed that the treatment was successful in type 316 steel in wide range of conditions, while type 304 was protected only to a small extent even by closely controlled treatment. Response of the materials to the sensitizing heating in terms of impurity segregation at grain boundaries was also examined by means of microchemical analysis. Advantage of method is that no special care is required in selecting heats of material, so that conventional type 316 is usable by improving the mechanical properties substantially through the treatment. In some optimized cases the mechanical property improvement was typically recognized by the yield strength by about 20% higher at room temperature, compared with the material mill annealed. (author)

1980-01-01

44

Composition and Morphology of Product Layers in the Steel/Cement Paste Interface in Conditions of Corrosion and Cathodic Protection in Reinforced Concrete  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The present study explores the formation of corrosion products on the steel surface in reinforced concrete in conditions of corrosion and subsequent transformation of these layers in conditions of cathodic protection (CP). Of particular interest was to investigate if the introduced pulse CP (as cost...

Koleva, D.A.; Van Breugel, K.; De Wit, J.H.W.; Fraaij, A.L.A.; Boshkov, N.

45

Resistance to aqueous corrosion of steels protected by a Cr-Si diffusion coating  

Energy Technology Data Exchange (ETDEWEB)

The simultaneous deposition of Cr and Si to form a diffusion coating on two steels (AISI 1045 and 4140) was studied. In halide-activated cementation packs the use of either a {open_quotes}ternary activator{close_quotes} (e.g., NaF+NaCl+AlF{sub 3}) combined with the elemental metal powders, or else a {open_quotes}dual activator{close_quotes} (e.g., NaF + NaCl) combined with a Cr-Si masteralloy powder, allows for the formation of a surface composition approximating 30Cr-3 to 4Si. Coated coupons were corrosion tested in either 1 N H{sub 2}SO{sub 4} or 3.5 wt % NaCl solution at room temperature. Coupons coated using the Cr-Si masteralloy had superior corrosion resistance in 1 N H{sub 2}SO{sub 4}, while steels coated in packs containing elemental metal powders suffered pitting corrosion. The coated coupons were not adequately resistant to pitting corrosion in 3.5 wt % NaCl solution.

Wang, X.W.G.; Rapp, R.A. [Ohio State Univ., Columbus, OH (United States)

1993-07-01

46

Fabrication of continuous mesoporous organic-inorganic nanocomposite films for corrosion protection of stainless steel in PEM fuel cells  

International Nuclear Information System (INIS)

Graphical abstract: Ordered mesoporous organic-inorganic composite film has been achieved by sol-gel and spin-coating techniques. We believe that the mesoporous composite films have a potential application as a protect coating of bipolar plate material. Display Omitted Research highlights: ? Ordered mesoporous composite film was deposited on the 304 stainless steel. ? This composite film exhibited excellent protective performance in 0.5 M H2SO4. ? The film exhibited a high surface tension with water contact angle close to 90o. - Abstract: The organic-inorganic composite film was deposited on the 304 stainless steel as bipolar plate material for proton exchange membrane fuel cells by spin-coating method. As shown by XRD, N2 adsorption-desorption and TEM, the composite films exhibit ordered mesoporous structures. The corrosion tests in 0.5 M H2SO4 system displayed that, compared with 304SS, the composite films made corrosion potential shifted to positive direction by 250-1000 mV (SCE) and corrosion current decreased by 1-3 orders of magnitude. Wherein, the C-50-60% composite film showed the optimal protective performance, its corresponding potentiostatic polarization process was extremely stable in the simulated fuel cells environment.

2011-01-01

47

Study on cerium-doped nano-TiO2 coatings for corrosion protection of 316?L stainless steel.  

UK PubMed Central (United Kingdom)

Many methods have been reported on improving the photogenerated cathodic protection of nano-TiO2 coatings for metals. In this work, nano-TiO2 coatings doped with cerium nitrate have been developed by sol-gel method for corrosion protection of 316?L stainless steel. Surface morphology, structure, and properties of the prepared coatings were investigated by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy. The corrosion protection performance of the prepared coatings was evaluated in 3?wt% NaCl solution by using electrochemical techniques in the presence and absence of simulated sunlight illumination. The results indicated that the 1.2% Ce-TiO2 coating with three layers exhibited an excellent photogenerated cathodic protection under illumination attributed to the higher separation efficiency of electron-hole pairs and higher photoelectric conversion efficiency. The results also showed that after doping with an appropriate concentration of cerium nitrate, the anti-corrosion performance of the TiO2 coating was improved even without irradiation due to the self-healing property of cerium ions.

Li S; Wang Q; Chen T; Zhou Z; Wang Y; Fu J

2012-01-01

48

Application of scanning Kelvin probe to study the corrosion protection of chromated hot-dip galvanized steel  

Energy Technology Data Exchange (ETDEWEB)

The scanning Kelvin probe has been used to study the inhibition mechanisms and the efficiency of chromating of hot-dip galvanized steel. Our results show that chromate coatings influence the cathodic partial reaction, i.e. oxygen reduction. The beneficial influence of phosphates on the inhibition efficiency of chromate coatings is also evidenced. Scanning Kelvin probe allows to evaluate the quality (efficiency and homogeneity) of the chromating. Finally we can observe that the protective properties of chromating in a lightly corrosive environment are kept. (orig.)

Forget, L. [Facultes Universitaires Notre-Dame de la Paix, Namur (Belgium). Lab. Interdisciplinaire de Spectroscopie; Delhalle, J.; Mekhalif, Z. [Lab. Interdisciplinaire de Spectroscopie Electronique (L.I.S.E.), Facultes Univ. Notre-Dame de la Paix, Namur (Belgium)

2001-03-01

49

Corrosion Protection of Electro-Galvanized Steel by Ceria-Based Coatings: Effect of Polyethylene Glycol (PEG) Addition  

Science.gov (United States)

A cerium oxide thin layer was deposited onto galvanized steel by cathodic electrodeposition from 0.1 M concentrated cerium nitrate solution. In this work, the influence of polyethylene glycol (PEG) addition on the composition and morphology of the deposits is examined. The results showed that the addition of PEG to the cerium nitrate solutions leads to a decrease in the cracks in the deposits by decreasing the hydrogen reduction reaction and by decreasing the film thickness which provided enhanced corrosion protection. Moreover, the substrate dissolution reaction is inhibited.

Hamlaoui, Y.; Tifouti, L.; Pedraza, F.

2013-09-01

50

Corrosion Protection of Electro-Galvanized Steel by Ceria-Based Coatings: Effect of Polyethylene Glycol (PEG) Addition  

Science.gov (United States)

A cerium oxide thin layer was deposited onto galvanized steel by cathodic electrodeposition from 0.1 M concentrated cerium nitrate solution. In this work, the influence of polyethylene glycol (PEG) addition on the composition and morphology of the deposits is examined. The results showed that the addition of PEG to the cerium nitrate solutions leads to a decrease in the cracks in the deposits by decreasing the hydrogen reduction reaction and by decreasing the film thickness which provided enhanced corrosion protection. Moreover, the substrate dissolution reaction is inhibited.

Hamlaoui, Y.; Tifouti, L.; Pedraza, F.

2013-05-01

51

Ormocer (ZrO2-PMMA) films for stainless steel corrosion protection  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The chemical protection of 316 L stainless steel coated with ORMOCER coatings of polymethylmethacrylate (PMMA) and ZrO2 has been verified. The coatings were dip-coated on the substrates from sols prepared by mixing zirconium propoxide (ZrOC3H7)4, isopropanol (C3H7OH), glacial acetic acid (CH3COOH), ...

Luna, Fernando P.; Atik, Mohamed; Messaddeq, Sandra H.; Aegerter, Michel A.

52

Corrosion protection of 316 L stainless steel by a TiO2 nanoparticle coating prepared by sol-gel method  

International Nuclear Information System (INIS)

A uniform and TiO2 nanoparticle coating on steels has been prepared using sol-gel method and hydrothermal post-treatments. The morphology and structure of the coatings were analysed using atomic force microscopy and X-ray diffraction. The anticorrosion performances of the coatings in dark and under ultraviolet illumination have been evaluated by using electrochemical techniques. The influences of coating thickness, pH and NaCl concentration on corrosion protection have been examined as well. The results indicate that the TiO2 nanoparticle coatings on steels exhibit an excellent corrosion resistance due to a ceramic protective barrier on metal surface in dark, and a photo-generated cathodic protection current under UV illumination. The electrochemical impedance spectroscopy measurements provide an explanation to the increased resistance of nano TiO2 particles coated 316 L stainless steel against corrosion.

2005-10-01

53

Migrating corrosion inhibitor protection of concrete  

Energy Technology Data Exchange (ETDEWEB)

Migrating corrosion inhibitors (MCI) were developed to protect steel rebar from corrosion in concrete. They were designed to be incorporated as an admixture during concrete batching or used for surface impregnation of existing concrete structures. Two investigations are summarized. One studied the effectiveness of MCIs as a corrosion inhibitor for steel rebar when used as an admixture in fresh concrete mix. The other is a long-term study of MCI concrete impregnation that chronicles corrosion rates of rebar in concrete specimens. Based on data from each study, it was concluded that migrating corrosion inhibitors are compatible with concrete and effectively delay the onset of corrosion.

Bjegovic, D.; Miksic, B.

1999-11-01

54

Effect of zinc phosphate chemical conversion coating on corrosion behaviour of mild steel in alkaline medium: protection of rebars in reinforced concrete  

Directory of Open Access Journals (Sweden)

Full Text Available We outline the ability of zinc phosphate coatings, obtained by chemical conversion, to protect mild steel rebars against localized corrosion, generated by chloride ions in alkaline media. The corrosion resistance of coated steel, in comparison with uncoated rebars and coated and uncoated steel rebars embedded in mortar, were evaluated by open-circuit potential, potentiodynamic polarization, cronoamperometry and electrochemical impedance spectroscopy. The coated surfaces were characterized by x-ray diffraction and scanning electron microscopy. First, coated mild steel rebars were studied in an alkaline solution with and without chloride simulating a concrete pore solution. The results showed that the slow dissolution of the coating generates hydroxyapatite Ca10(PO4)6(OH)2. After a long immersion, the coating became dense and provided an effective corrosion resistance compared with the mild steel rebar. Secondly, the coated and uncoated steel rebars embedded in mortar and immersed in chloride solution showed no corrosion or deterioration of the coated steel. Corrosion rate is considerably lowered by this phosphate coating.

Florica Simescu and Hassane Idrissi

2008-01-01

55

Long term corrosion on T91 and AISI1 316L steel in flowing lead alloy and corrosion protection barrier development: Experiments and models  

Energy Technology Data Exchange (ETDEWEB)

Considering the status of knowledge on corrosion and corrosion protection and especially the need for long term compatibility data of structural materials in HLM a set of experiments to generate reliable long term data was defined and performed. The long term corrosion behaviour of the two structural materials foreseen in ADS, 316L and T91, was investigated in the design relevant temperature field, i.e. from 300 to 550 deg. C. The operational window of the two steels in this temperature range was identified and all oxidation data were used to develop and validate the models of oxide scale growth in PbBi. A mechanistic model capable to predict the oxidation rate applying some experimentally fitted parameters has been developed. This model assumes parabolic oxidation and might be used for design and safety relevant investigations in future. Studies on corrosion barrier development allowed to define the required Al content for the formation of thin alumina scales in LBE. These results as well as future steps and required improvements are discussed. Variation of experimental conditions clearly showed that specific care has to be taken with respect to local flow conditions and oxygen concentrations.

Weisenburger, A., E-mail: Alfons.weisenburger@kit.edu [KIT: Karlsruhe Instiute of Technology, Hermann-von-Helmholtz platz 1, 76344, Eggenstein-Leopoldshafen (Germany); Schroer, C.; Jianu, A.; Heinzel, A.; Konys, J.; Steiner, H.; Mueller, G.; Fazio, C. [KIT: Karlsruhe Instiute of Technology, Hermann-von-Helmholtz platz 1, 76344, Eggenstein-Leopoldshafen (Germany); Gessi, A. [ENEA: ENEA, CR Brasimone, 40032 Camugnano, Bologna (Italy); Babayan, S.; Kobzova, A. [NRI: Ustav jaderneho vyzkumu Rez a.s., Husinec 130, Rez 256068 (Czech Republic); Martinelli, L.; Ginestar, K.; Balbaud-Celerier, F. [CEA: CEA, DEN, Service de la Corrosion et du Comportement des Materiaux dans leur Environnement, F-91191 Gif sur Yvette (France); Martin-Munoz, F.J.; Soler Crespo, L. [CIEMAT: CIEMAT, Avda. Complutense, 22, 28040, Madrid (Spain)

2011-08-31

56

Oxide and nitride protective layers formed on stainless steel by thermal treatment: SEM, AES, WDS and corrosion measurements  

Directory of Open Access Journals (Sweden)

Full Text Available Protective oxide and/or nitride layers on AISI 321 stainless steel were prepared by thermal treatment in air and two controlled atmospheres in a laboratory simulation of an actual technological procedure. Samples’ surface was imaged by Scanning Electron Microscopy (SEM), elemental composition of the substrates was checked by Wavelength Dispersive Spectroscopy (WDS) and depth profiles of the samples were measured by Auger Electron Spectroscopy (AES). Since protective layer thicknesses were found to be of the order of hundreds of nanometers an attempt was made to obtain some fast averaged information about layers composition by Wavelength Dispersive Spectroscopy (WDS) with appropriately adjusted primary beam energy. Electrochemical corrosion testing was also performed on samples.

Mandrino, DJ.; Godec, M.; Kocijan, A.; Lamut, M.; Torkar, M.; Jenko, M.

2008-01-01

57

Hybrid layers deposited by an atmospheric pressure plasma process for corrosion protection of galvanized steel.  

Science.gov (United States)

Finding alternative treatments to reproduce anticorrosion properties of chromated coatings is challenging since both physical barrier and self-healing effects are needed. Siloxane based treatments are known to be a promising way to achieve physical barrier coatings, mainly plasma polymerized hexamethyldisiloxane (ppHMDSO). In addition, it is known that cerium-based coatings can also provide corrosion protection of metals by means of self-healing effect. In this frame, innovative nanoAlCeO3/ppHMDSO layers have thus been deposited and studied. These combinations allow to afford a good physical barrier effect and active properties. Liquid siloxane and cerium-based particles mixture is atomized and introduced as precursors into a carrier gas. Gas mixture is then injected into an atmospheric pressure dielectric barrier discharge (DBD) where plasma polymerization of the siloxane precursor occurs. The influence of cerium concentration on the coating properties is investigated: coating structure and topography have been studied by scanning electron microscopy (SEM) and interferometry, and corrosion resistance of these different coatings is compared by electrochemistry techniques: polarization curves and electrochemical impedance spectroscopy (EIS). Potential self-healing property afforded by cerium in the layer was studied by associating EIS measurements and nanoscratch controlled damaging. Among the different combinations investigated, mixing of plasma polymerized HMDSO and AICeO3 nanoparticles seems to give promising results with a good physical barrier and interesting electroactive properties. Indeed, corrosion currents measured on such coatings are almost as low as those measured with the chromated film. Combination of nanoscratch damaging of layers with EIS experiments to investigate self-healing also allow to measure the active protection property of such layers. PMID:20355472

Del Frari, D; Bour, J; Bardon, J; Buchheit, O; Arnoult, C; Ruch, D

2010-04-01

58

Hybrid layers deposited by an atmospheric pressure plasma process for corrosion protection of galvanized steel.  

UK PubMed Central (United Kingdom)

Finding alternative treatments to reproduce anticorrosion properties of chromated coatings is challenging since both physical barrier and self-healing effects are needed. Siloxane based treatments are known to be a promising way to achieve physical barrier coatings, mainly plasma polymerized hexamethyldisiloxane (ppHMDSO). In addition, it is known that cerium-based coatings can also provide corrosion protection of metals by means of self-healing effect. In this frame, innovative nanoAlCeO3/ppHMDSO layers have thus been deposited and studied. These combinations allow to afford a good physical barrier effect and active properties. Liquid siloxane and cerium-based particles mixture is atomized and introduced as precursors into a carrier gas. Gas mixture is then injected into an atmospheric pressure dielectric barrier discharge (DBD) where plasma polymerization of the siloxane precursor occurs. The influence of cerium concentration on the coating properties is investigated: coating structure and topography have been studied by scanning electron microscopy (SEM) and interferometry, and corrosion resistance of these different coatings is compared by electrochemistry techniques: polarization curves and electrochemical impedance spectroscopy (EIS). Potential self-healing property afforded by cerium in the layer was studied by associating EIS measurements and nanoscratch controlled damaging. Among the different combinations investigated, mixing of plasma polymerized HMDSO and AICeO3 nanoparticles seems to give promising results with a good physical barrier and interesting electroactive properties. Indeed, corrosion currents measured on such coatings are almost as low as those measured with the chromated film. Combination of nanoscratch damaging of layers with EIS experiments to investigate self-healing also allow to measure the active protection property of such layers.

Del Frari D; Bour J; Bardon J; Buchheit O; Arnoult C; Ruch D

2010-04-01

59

Steel corrosion protection by means of alkyd paints pigmented with calcium acid phosphate  

Energy Technology Data Exchange (ETDEWEB)

The use of classic anticorrosive pigments is becoming more and more restricted by increasing environmental concerns; they are gradually being replaced by zinc phosphate and related compounds. Other anticorrosive pigments such as surface-exchanged silicas were also proposed. The object of this research is to study the anticorrosive properties of calcium acid phosphate as an inhibitive pigment, introducing a careful selection of complementary pigments in order to achieve an efficient anticorrosive protection. Several alkyd paints were prepared and evaluated through accelerated and electrochemical tests. The nature of the passive film formed was also studied. Paint containing zinc oxide and calcium carbonate (50/50) as complementary pigments showed the best performance in the salt spray test. Zinc oxide and calcium carbonate decreased film permeability and improved steel passivation. The passive film was composed of ferric oxyhydroxide, the pores of which became plugged by ferric phosphate.

Amo, B. del; Romagnoli, R.; Vetere, V.F. [CIC-CONICET, La Plata (Argentina)

1999-06-01

60

Lubricant composition for protecting a rolling stock of carbon steel from corrosion and process for preparing it  

Energy Technology Data Exchange (ETDEWEB)

The lubricant composition being patented and consisting of a film former, inhibitor, and suitable solvent is for protecting a rolling stock of carbon steel from corrosion during its storage and transport. The inhibitor: film former weight ratio is 7-100:40-100, and the (film former + inhibitor):solvent weight ratio is 20:100 - 100:100. Zn naphthenates or ammonium or sodium salts of naphthenic acids appear as inhibitors. Plastic calcium greases with drop points of 85/sup 0/, industrial petrolatum with a drop point of 55/sup 0/, a residue from deparaffination (petrolatum), and mazut or petroleum oil with a pour point of -10/sup 0/ and a viscosity of 76-142 cSt/50/sup 0/ serve as the film formers; the solvents are white spirit or diesel fuel. For preparing the composition, the film former is melted, 75% of the total amount of solvent is added, the inhibitor is dissolved in the remaining 25% of the solvent, and both solutions are poured in and stirred until complete homogenization. The composition can be applied on a metal by brushing, spraying, or immersion. Example -- taken for preparing the composition is 14-55.8 g of a calcium plastic grease composition with a drop point of 85/sup 0/; it is melted and 1.4-13.5 g of Zn naphthenate and 50-100 mL of white spirit or diesel fuel are introduced. The lubricant assures protection from corrosion in the temperature range -20 to 50/sup 0/; for 1 m/sup 2/ of surface to be protected 0.1-0.15 kg of lubricant is required.

Bejan, F.I.; Balaban, L.; Focsaneanu, M.; Iliescu, E.; Radoviel, O.; Stancescu, M.; Streba, V.

1980-01-15

 
 
 
 
61

Some peculiarities of corrosion of wheel steel  

Directory of Open Access Journals (Sweden)

Full Text Available Corrosion mechanism and rate of different chemical composition and structural condition of wheel steel were investigated. It was shown that “white layers”, variation in grain size and banding of wheel steel structure results in corrosion rate. Microstructure of steel from different elements of railway wheels after operation with corrosion was investigated. Wheel steel with addition of vanadium corroded more quickly than steel without vanadium. Non-metallic inclusions are the centre of corrosion nucleation and their influence on corrosion depends on type of inclusion. Mechanism of corrosion of wheel steel corrosion was discussed.

Svetlana GUBENKO; Sofia PINCHUK; Yuriy PROIDAK; Elena BELAJA; Alfred KOZLOWSKY; Alexander SHRAMKO

2009-01-01

62

Corrosion and cathodic protection at disbonded coatings  

Energy Technology Data Exchange (ETDEWEB)

The effectiveness of cathodic protection to control corrosion and the resulting corrosion rate of pipelines are determined by the chemical and electrochemical conditions at local areas along the pipeline. The disbonding of coatings and tapes is also controlled to a large extent by the chemical and electrochemical conditions. Processes that occur on the metal surface and their effect on corrosion and cathodic protection are discussed with respect to real pipeline conditions. Disbonded coatings on steel can interfere with the current distribution from cathodic protection. Shielding the current under disbonded coatings can affect the level of protection, the corrosion behavior and the disbonding of coatings. A major thrust in the laboratories has been the use of laboratory measurements and computational models to determine the changes in the corrosive environment that occur beneath disbonded coatings as a function of applied potential, disbonded area geometry, prior corrosion products and wet/dry cycles. These results are summarized here.

Payer, J.H.; Fink, K.M.; Perdomo, J.J.; Rodriguez, R.E.; Song, I.; Trautman, B. [Case Western Reserve Univ., Cleveland, OH (United States). Dept. of Materials Science and Engineering

1996-12-31

63

Corrosion of steel in concrete  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The research work that is presented in this thesis aims at mapping out the various mechanisms which control the process of steel corrosion in concrete. The process of corrosion is illustrated with a schematic model where the service life is divided into a period of initiation and a period of propaga...

Tuutti, Kyösti

64

Evaluation of the protection behaviour of reinforcement steel against corrosion induced by chlorides in reinforced mortar specimens; Avaliacao do comportamento frente a corrosao pelo ataque de cloreto de argamassa armada apos varios tratamentos protetores  

Energy Technology Data Exchange (ETDEWEB)

In this work various treatments for protecting reinforcing steels against corrosion induced by chlorides have been evaluated. Additives to mortars and surface treatments given to reinforcing steels were evaluated as corrosion protection measures. In the preliminary tests the corrosion resistance of a CA 50 steel treated by immersion in nearly 50 different solutions, was determined. The solutions were prepared with tannins (from various sources) and/or benzotriazole, and during immersion, a surface film formed on the steel. The corrosion resistance of the coated steels was evaluated in a saturated Ca(OH){sub 2} solution with 5% (wt) NaCl. Preliminary tests were also carried out with mortars reinforced with uncoated steel to which tannin or lignin was added. Two organic coatings, a monocomponent and a bicomponent type, formulated specially for this investigation, with both tannin and benzotriazole, were also tested in the preliminary tests to select the coating with better corrosion protection property. The bicomponent type (epoxy coating) showed better performance than the monocomponent type coating, and the former was therefore chosen to investigate the corrosion performance on CA 50 steel inside mortar specimens. From the preliminary tests, two solutions with tannin from two sources, Black Wattle (Acacia mearnsii) and Brazilian tea (Ilex paraguariensis St. Hill), to which benzotriazole and phosphoric acid were added, were chosen. Mortar specimens reinforced with CA50 steel treated by immersion in these two solutions were prepared. Also, epoxy coated CA50 steel was tested as reinforcement inside mortar specimens. Mortars reinforced with uncoated CA50 steel were also prepared and corrosion tested for comparison. The effect of tannin and lignin as separate additives to the mortar on the corrosion resistance of uncoated steel was also studied. The reinforced mortar specimens were tested with various cycles of immersion for 2 days in 3.5% (wt) NaCl followed by with air drying for 5 days. The corrosion tests used in this investigation were gravimetric and electrochemical tests. The results showed satisfactory corrosion performance for all kinds of protection measures. However, the performance depended on the type of protection used. The best performance was obtained with tannin containing epoxy coated steel, followed by the steel treated by immersion in tannin containing solutions and finally by the addition of tannin (Black Wattle) or lignin to the mortar. All the protection measures evaluated in this study are economically viable and environmentally friendly and can therefore be considered for protecting reinforcement steels against corrosion. (author)

Crivelaro, Marcos

2002-07-01

65

Corrosion characteristics of DMR-1700 steel and comparison with different steels in marine environment  

Energy Technology Data Exchange (ETDEWEB)

In the present paper, a systematic corrosion study has been carried out on DMR-1700 steel to understand the protective nature of oxide scale that forms on its surface under marine environmental conditions. Further, the studies related to oxide scales as well as pitting and crevice corrosion resistance of both stainless steels and widely used low alloy steel EN24 in marine environment have been studied for comparison purpose. The surface morphologies of corroded steels have been observed under scanning electron microscope (SEM) in order to understand the nature of corrosion. A high performance protective coating that has been developed for protection of low alloy steels DMR-1700 and EN24 against corrosion is presented after stressing the importance of surface engineering in enhancing the life of steels. Based on the studies with different techniques, DMR-1700 steel has been recommended for manufacture of components used in aerospace systems in association with appropriate protective coating for improving their efficiency.

Gurrappa, I. [Defence Metallurgical Research Laboratory, Kanchanbagh PO, Hyderabad, Andhra Pradesh 500058 (India)]. E-mail: igpl@rediffmail.com; Malakondaiah, G. [Defence Metallurgical Research Laboratory, Kanchanbagh PO, Hyderabad, Andhra Pradesh 500058 (India)

2005-01-25

66

Corrosion characteristics of DMR-1700 steel and comparison with different steels in marine environment  

International Nuclear Information System (INIS)

[en] In the present paper, a systematic corrosion study has been carried out on DMR-1700 steel to understand the protective nature of oxide scale that forms on its surface under marine environmental conditions. Further, the studies related to oxide scales as well as pitting and crevice corrosion resistance of both stainless steels and widely used low alloy steel EN24 in marine environment have been studied for comparison purpose. The surface morphologies of corroded steels have been observed under scanning electron microscope (SEM) in order to understand the nature of corrosion. A high performance protective coating that has been developed for protection of low alloy steels DMR-1700 and EN24 against corrosion is presented after stressing the importance of surface engineering in enhancing the life of steels. Based on the studies with different techniques, DMR-1700 steel has been recommended for manufacture of components used in aerospace systems in association with appropriate protective coating for improving their efficiency

2005-01-25

67

Development of Nb2O5|Cu composite as AISI 1020 steel thermal spray coating for protection against corrosion by soil in buried structures  

International Nuclear Information System (INIS)

An Nb2O|Cu corrosion-resistant coating was developed and applied onto AISI 1020 steel substrate by Powder Flame Spray. A galvanostatic electrochemical technique was employed, with and without ohmic drop, in four different soils (two corrosively aggressive and two less aggressive). Behavior of coatings in different soils was compared using a cathodic hydrogen reduction reaction (equilibrium potential, overvoltage and exchange current density) focusing on the effect of ohmic drop. Results allow recommendation of Nb2O5|Cu composite for use in buried structure protection. (author)

2012-01-01

68

Cathodic protection to control microbiologically influenced corrosion  

International Nuclear Information System (INIS)

Information about the cathodic protection performance in environments with microbiologically influenced corrosion (MIC) effects is very fragmented and often contradictory. Not enough is known about the microbial effects on cathodic protection effectiveness, criteria, calcareous deposits, corrosion rates and possible hydrogen embrittlement of titanium and some stainless steel condenser tubes. This paper presents a review of cathodic protection systems, describes several examples of cathodic protection in environments with MIC effects and provides preliminary conclusions about cathodic protection design parameters, criteria and effectiveness in MIC environments. 30 refs

1988-10-18

69

Steel corrosion in radioactive waste storage tanks  

International Nuclear Information System (INIS)

A collaborative study is being conducted by CNEA and USDOE (Department of Energy of the United States of America) to investigate the effects of tank waste chemistry on radioactive waste storage tank corrosion. Radioactive waste is stored in underground storage tanks that contain a combination of salts, consisting primarily of sodium nitrate, sodium nitrite and sodium hydroxide. The USDOE, Office of River Protection at the Hanford Site, has identified a need to conduct a laboratory study to better understand the effects of radioactive waste chemistry on the corrosion of waste storage tanks at the Hanford Site. The USDOE science need (RL-WT079-S Double-Shell Tanks Corrosion Chemistry) called for a multi year effort to identify waste chemistries and temperatures within the double-shell tank (DST) operating limits for corrosion control and operating temperature range that may not provide the expected corrosion protection and to evaluate future operations for the conditions outside the existing corrosion database. Assessment of corrosion damage using simulated (non-radioactive) waste is being made of the double-shell tank wall carbon steel alloy. Evaluation of the influence of exposure time, and electrolyte composition and/or concentration is being also conducted. (author)

2004-01-01

70

Volatile corrosion inhibitor film formation on carbon steel surface and its inhibition effect on the atmospheric corrosion of carbon steel  

Science.gov (United States)

A novel volatile corrosion inhibitor (VCI), bis-piperidiniummethyl-urea (BPMU), was developed for temporary protection of carbon steel. Its vapor corrosion inhibition property was evaluated under simulated operational conditions. Electrochemical impedance spectroscopy was applied to study the inhibition effect of BPMU on the corrosion of carbon steel with a thin stimulated atmospheric corrosion water layers. Adsorption of BPMU on carbon steel surfaces was investigated by atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The results indicate that BPMU can form a protective film on the metal surface, which protects the metal against further corrosion. The structure of the protective film was suggested as one BPMU molecule chelated with one Fe atom to form a complex with two hexa-rings.

Zhang, Da-quan; An, Zhong-xun; Pan, Qing-yi; Gao, Li-xin; Zhou, Guo-ding

2006-11-01

71

Volatile corrosion inhibitor film formation on carbon steel surface and its inhibition effect on the atmospheric corrosion of carbon steel  

International Nuclear Information System (INIS)

[en] A novel volatile corrosion inhibitor (VCI), bis-piperidiniummethyl-urea (BPMU), was developed for temporary protection of carbon steel. Its vapor corrosion inhibition property was evaluated under simulated operational conditions. Electrochemical impedance spectroscopy was applied to study the inhibition effect of BPMU on the corrosion of carbon steel with a thin stimulated atmospheric corrosion water layers. Adsorption of BPMU on carbon steel surfaces was investigated by atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The results indicate that BPMU can form a protective film on the metal surface, which protects the metal against further corrosion. The structure of the protective film was suggested as one BPMU molecule chelated with one Fe atom to form a complex with two hexa-rings

2000-01-00

72

Atmospheric corrosion of mild steel  

Directory of Open Access Journals (Sweden)

Full Text Available The atmospheric corrosion of mild steel is an extensive topic that has been studied by many authors in different regions throughout the world. This compilation paper incorporates relevant publications on the subject, in particular about the nature of atmospheric corrosion products, mechanisms of atmospheric corrosion and kinetics of the atmospheric corrosion process, paying special attention to two matters upon which relatively less information has been published: a) the morphology of steel corrosion products and corrosion product layers; and b) long-term atmospheric corrosion ( > 10 years).La corrosión atmosférica del acero suave es un tema de gran amplitud que ha sido tratado por muchos autores en numerosas regiones del mundo. Este artículo de compilación incorpora publicaciones relevantes sobre esta temática, en particular sobre la naturaleza de los productos de corrosión atmosférica, mecanismos y cinética de los procesos de corrosión atmosférica, prestando una atención especial a dos aspectos sobre los que la información publicada ha sido menos abundante: a) morfología de los productos de corrosión del acero y capas de productos de corrosión, y b) corrosión atmosférica a larga duración (> 10 años).

Morcillo, M.; de la Fuente, D.; Díaz, I.; Cano, H.

2011-01-01

73

Atmospheric corrosion of carbon steel in the prairie regions  

Energy Technology Data Exchange (ETDEWEB)

A study of atmospheric corrosion and carbon steel located in the prairie regions of Canada was presented. The study considered corrosion behaviour as well as the standards currently used to establish and predict corrosion in atmospheric conditions. The aim of the study was to develop an accurate predictive method of establishing corrosion amounts over time. The controlling parameters for atmospheric corrosion included acidic rainfall; temperature and humidity; time of wetness; and the presence of major contaminants such as sulfur dioxide (SO{sub 2}). The predictive approach involved the study of a protective film of magnetite iron oxide that establishes itself on carbon steel over time. The presence of the film provides increased atmospheric corrosion resistance. An analysis of the atmospheric corrosion of steel tanks at the Hardisty terminal was used to demonstrate the method. 22 refs., 5 tabs., 7 figs.

Shaw, W.J. [Calgary Univ., AB (Canada). Dept. of Mechanical and Manufacturing Engineering; Andersson, J.I. [Husky Oil Operations Ltd., Calgary, AB (Canada)

2010-07-01

74

Thermally Sprayed Aluminum (TSA) with Cathodic Protection as Corrosion Protection for Steel in Natural Seawater : Characterization of Properties on TSA and Calcareous Deposit  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Cathodic protection is an effective corrosion protection for structures submerged in seawater. In addition to applying the current need to lower the metal below the protection potential, a resulting increase in interfacial pH leads to precipitation of calcareous deposit. This deposited layer act as ...

Egtvedt, Solveig

75

Steel corrosion rate in potash treatment of gases to remove CO/sub 2/  

Energy Technology Data Exchange (ETDEWEB)

In order to develop effective measures for the corrosion protection of equipment in hot potash treating units, electrochemical and gravimetric methods were used to investigate the corrosion of carbon steel in hot potash solution. A kinetic study of the corrosion of St3sp steel indicates that the corrosion rate gradually drops off and is stabilized. Commercial tests of various steels indicated that such self-passivation makes corrosion rates in the vessels of the potash treating system acceptable.

Nikitina, A.K.; Khvatkova, V.P.; Umnyashkina, V.M.; Vershinina, L.P.

1983-07-01

76

Corrosion protection in mining: actual state and prognosis  

Energy Technology Data Exchange (ETDEWEB)

Losses caused in coal mining in Poland by corrosion are increasing due to: increased mechanization and growing number of steel machines and installations both underground and on the surface, increased air pollution and corrosive power of mine water. Polish coal mining industry consumes 1.5 Mt steel yearly, of this 60% is for machines and installations. In 1979 about 600,000 t of steel were scrapped in coal mining; 30% due to corrosion. The largest losses are caused by corrosion of steel supports, followed by losses caused by corrosion of pipelines and pipes, and the losses caused on the surface by corrosion of steel constructions. Basic methods of protecting machines, installations and supports in coal mining from corrosion are evaluated: paint coat, metallic coating, electrodeposit, conversion coating. The economic plan for 1981 to 1985 foresees increase of paint coat in coal mining by 65%, metallic coating by 35% and conversion coating by 25%. (6 refs.) (In Polish)

Boba, J.

1980-12-01

77

Corrosion of carbon steel welds  

International Nuclear Information System (INIS)

This report assesses the factors which cause preferential attack to occur in carbon steel fusion welds. It was concluded that the main factors were: the inclusion content of the weld metal, the potential of the weld metal being less noble than that of the parent, and the presence of low-temperature transformation products in the heat-affected zone of the weld. These factors should be minimized or eliminated as appropriate so that the corrosion allowances determined for carbon steel waste drums is also adequate for the welds. An experimental/theoretical approach is recommended to evaluate the relative corrosion resistance of welds prepared from BS 4360 grade 43A steel to that of the parent material. (author)

1988-01-01

78

Effect of cathodic protection on the state of steel reinforcement  

International Nuclear Information System (INIS)

Damage of reinforced concrete structures is mainly caused by chloride or carbonation induced corrosion of steel. Cathodic protection is a very effective measure for corrosion control of steel in concrete, especially in chloride contaminated concrete. In this paper, effect of cathodic protection on the state of steel reinforcement is presented. Cathodic polarization of reinforcements in concrete was done under different submerged conditions. Cyclic potentiodynamic tests were used to determine the effect of cathodic protection on the behavior of the steel. Pitting appeared on the non-protected steel, but was not observed on the cathodically protected steel. microscopic photographs show that a close film exists on the protected steel, while the non-protected steel's film is loose. Investigated results have proved the effect of cathodic protection in restoring or strengthening passive film on the steel reinforcement

2002-01-01

79

Corrosion protection in coking plants  

Energy Technology Data Exchange (ETDEWEB)

In coking plants, the corrosion of equipment and pipe lines can result in detriments to chemical processes. The reaction steps of the corrosion and the damage observed on materials are explained. There exist four basic possibilities for the corrosion protection: 1. Preventing the corrosion through the selection of suitable materials; 2. The alteration of corroding agent, for example through separation from the reaction products; 3. Addition of corrosion inhibitors; 4. Constructive measures. Examples are given in tabular form for well-tried corrosion protection systems in the operation of coking plants.

Neff, I.

1982-01-01

80

Monitoring Techniques for Microbially Influenced Corrosion of Carbon Steel  

DEFF Research Database (Denmark)

Abstract Monitoring Techniques for Microbially Influenced Corrosion of Carbon Steel Microbially influenced corrosion (MIC) of carbon steel may occur in media with microbiological activity of especially sulphate-reducing bacteria, e.g. on pipelines buried in soil and on marine structures. MIC of carbon steel must be monitored on-line in order to provide an efficient protection and control the corrosion. A number of monitoring techniques is industrially used today, and the applicability and reliability of these for monitoring MIC is evaluated. Coupons and ER are recommended as necessary basic techniques even though localised corrosion rate cannot be measured. FSM measures general corrosion and detects localised corrosion, but the sensitivity is not high enough for monitoring initiation of pitting and small attacks. Electrochemical techniques as LPR and EIS give distorted data and unreliable corrosion rates, when biofilm and corrosion products cover the steel surface. However, EIS might be used for detection ofMIC. EN is a suitable technique to characterise the type of corrosion attack, but is unsuitable for corrosion rate estimation. The concentric electrodes galvanic probe arrangement initiates localised corrosion on the anode and seems applicable to evaluate the risk of MIC. Hydrogen permeation measurements are very useful to monitor hydrogen induced cracking accelerated by MIC.

Hilbert, Lisbeth Rischel

2000-01-01

 
 
 
 
81

Cathode protection for underground steel tanks  

International Nuclear Information System (INIS)

Cathodic protection of underground petroleum storage tanks and piping systems is acceptable for both economic and ecological reasons. With out the cathodic protection of underground steel reservoirs, short time after the exploitation, there was a bore as a result of underground corrosion. The bore causes ecological consequences and at the same time its repair needs big investments. Furthermore, there are great number of tanks placed near cities, so in the future this problem needs a special attention in order to preserve ecological surrounding. The topic of this paper is underground corrosion as well as cathodic protection of steel tanks for oil derivatives storage. (author)

1998-01-01

82

EXPERIMENTAL STUDY ON EFFECTS OF CATHODIC PROTECTION TO PREVENT MACRO-CELL CORROSION OF STEEL IN CONCRETE  

Science.gov (United States)

Reinforcing bars embedded in concrete tend to corrode due to salt attack under marine environments. Corrosion of bars might be often caused with phenomenon of macro-cell. Cathodic protection has been, so far, applied to control the corrosion of reinforcing bars in RC members. In order to make clear the mechanisms of macro-cell corr osion and the effect of cathodic protecti on, laboratory tests were carried out. Testing concrete specimens contained two reinforcing bars which were buried at upper area of specimens and at lower area of ones, respectively. Lower zone of the concrete specimens were immersed in water. Testing results indicated as follows: (1) reinforci ng bars under wetting condition were anode and reinforcing bars under drying one cathode, (2) current density of macro-cell between two bars increased according as the potential difference increased and electric resistance of the concrete between two bars decreased, and (3) cathodic protection was effective to prevented macro-cell corrosion of reinforcing bars in concrete. Furthermore, it was presumed that corroded iron might be reduced to metal iron due to the protection current.

Yamamoto, Satoru; Ueno, Moe; Ishii, Kouji; Seki, Hiroshi

83

Corrosion behavior of 2205 duplex stainless steel.  

Science.gov (United States)

The corrosion of 2205 duplex stainless steel was compared with that of AISI type 316L stainless steel. The 2205 stainless steel is a potential orthodontic bracket material with low nickel content (4 to 6 wt%), whereas the 316L stainless steel (nickel content: 10 to 14 wt%) is a currently used bracket material. Both stainless steels were subjected to electrochemical and immersion (crevice) corrosion tests in 37 degrees C, 0.9 wt% sodium chloride solution. Electrochemical testing indicates that 2205 has a longer passivation range than 316L. The corrosion rate of 2205 was 0.416 MPY (milli-inch per year), whereas 316L exhibited 0.647 MPY. When 2205 was coupled to 316L with equal surface area ratio, the corrosion rate of 2205 reduced to 0.260 MPY, indicating that 316L stainless steel behaved like a sacrificial anode. When 316L is coupled with NiTi, TMA, or stainless steel arch wire and was subjected to the immersion corrosion test, it was found that 316L suffered from crevice corrosion. On the other hand, 2205 stainless steel did not show any localized crevice corrosion, although the surface of 2205 was covered with corrosion products, formed when coupled to NiTi and stainless steel wires. This study indicates that considering corrosion resistance, 2205 duplex stainless steel is an improved alternative to 316L for orthodontic bracket fabrication when used in conjunction with titanium, its alloys, or stainless steel arch wires. PMID:9228844

Platt, J A; Guzman, A; Zuccari, A; Thornburg, D W; Rhodes, B F; Oshida, Y; Moore, B K

1997-07-01

84

Corrosion behavior of 2205 duplex stainless steel.  

UK PubMed Central (United Kingdom)

The corrosion of 2205 duplex stainless steel was compared with that of AISI type 316L stainless steel. The 2205 stainless steel is a potential orthodontic bracket material with low nickel content (4 to 6 wt%), whereas the 316L stainless steel (nickel content: 10 to 14 wt%) is a currently used bracket material. Both stainless steels were subjected to electrochemical and immersion (crevice) corrosion tests in 37 degrees C, 0.9 wt% sodium chloride solution. Electrochemical testing indicates that 2205 has a longer passivation range than 316L. The corrosion rate of 2205 was 0.416 MPY (milli-inch per year), whereas 316L exhibited 0.647 MPY. When 2205 was coupled to 316L with equal surface area ratio, the corrosion rate of 2205 reduced to 0.260 MPY, indicating that 316L stainless steel behaved like a sacrificial anode. When 316L is coupled with NiTi, TMA, or stainless steel arch wire and was subjected to the immersion corrosion test, it was found that 316L suffered from crevice corrosion. On the other hand, 2205 stainless steel did not show any localized crevice corrosion, although the surface of 2205 was covered with corrosion products, formed when coupled to NiTi and stainless steel wires. This study indicates that considering corrosion resistance, 2205 duplex stainless steel is an improved alternative to 316L for orthodontic bracket fabrication when used in conjunction with titanium, its alloys, or stainless steel arch wires.

Platt JA; Guzman A; Zuccari A; Thornburg DW; Rhodes BF; Oshida Y; Moore BK

1997-07-01

85

Expert system corrosion and corrosion protection CORIS. Selection of protection measures against atmospheric corrosion. Expertensystem Korrosion und Korrosionsschutz CORIS. Auswahl von Schutzmassnahmen gegen atmosphaerische Korrosion. Schlussbericht  

Energy Technology Data Exchange (ETDEWEB)

The present project was dedicated to the corrosion information system 'CORIS' with the purpose of elaborating a knowledge-based system for the selection of protection measures against atmospheric corrosion. The range of knowledge of the system is the corrosion system unalloyed or low alloy steel/atmosphere and its purpose is the selection of protection measures for unalloyed and low-alloy steel structures exposed to the atmosphere. (orig./MM)

Baumann, K.H.; Pietsch, S.

1994-06-06

86

Failure mechanism of thin Al{sub 2}O{sub 3} coatings grown by atomic layer deposition for corrosion protection of carbon steel  

Energy Technology Data Exchange (ETDEWEB)

Combined analysis by electrochemical impedance spectroscopy (EIS), time-of-flight secondary ion mass spectrometry (ToF-SIMS) and field emission scanning electron microscopy (FESEM) of the corrosion protection provided to carbon steel by thin (50 nm) Al{sub 2}O{sub 3} coatings grown by atomic layer deposition (ALD) and its failure mechanism is reported. In spite of excellent sealing properties, the results show an average dissolution rate of the alumina coating of {approx}7 nm h{sup -1} in neutral 0.2 M NaCl and increasing porosity of the remaining layers with increasing immersion time. Alumina dissolution is triggered by the penetration of the solution via cracks/pinholes through the coating to the substrate surface where oxygen reduction takes place, raising the pH. At defective substrate surface sites of high aspect ratio and concentrated residual mechanical stress (along scratches) presumably exposing a higher steel surface fraction, localized dissolution of the coating is promoted by a more facile access of the solution to the substrate surface enhancing oxygen reduction. De-adhesion of the coating is also promoted in these sites by the ingress of the anodic dissolution trenching the steel surface. Localized corrosion of the alloy (i.e. pitting) is triggered prior to complete dissolution of the alumina film on the elsewhere still coated surface matrix.

Diaz, Belen [Chimie ParisTech, Laboratoire de Physico-Chimie des Surfaces (LPCS), 11 rue Pierre et Marie Curie, F-75005 Paris (France); CNRS UMR 7045, 11 rue Pierre et Marie Curie, F-75005 Paris (France); Haerkoenen, Emma [Laboratory of Inorganic Chemistry, University of Helsinki, P.O. Box 55, FIN-00014 Helsinki (Finland); Maurice, Vincent, E-mail: vincent-maurice@chimie-paristech.fr [Chimie ParisTech, Laboratoire de Physico-Chimie des Surfaces (LPCS), 11 rue Pierre et Marie Curie, F-75005 Paris (France); CNRS UMR 7045, 11 rue Pierre et Marie Curie, F-75005 Paris (France); Swiatowska, Jolanta; Seyeux, Antoine [Chimie ParisTech, Laboratoire de Physico-Chimie des Surfaces (LPCS), 11 rue Pierre et Marie Curie, F-75005 Paris (France); CNRS UMR 7045, 11 rue Pierre et Marie Curie, F-75005 Paris (France); Ritala, Mikko, E-mail: Mikko.Ritala@Helsinki.fi [Laboratory of Inorganic Chemistry, University of Helsinki, P.O. Box 55, FIN-00014 Helsinki (Finland); Marcus, Philippe, E-mail: philippe-marcus@chimie-paristech.fr [Chimie ParisTech, Laboratoire de Physico-Chimie des Surfaces (LPCS), 11 rue Pierre et Marie Curie, F-75005 Paris (France); CNRS UMR 7045, 11 rue Pierre et Marie Curie, F-75005 Paris (France)

2011-11-01

87

The impedance and optimum protection when carbon steel protected cathodically  

UK PubMed Central (United Kingdom)

The measured Faraday impedance of carbon steel in 3.5% NaCl solution, agreed with the theoretical. Marimum cathodic protection effecience (r) (protection effeciency p and utilization ratio of protection current q, r=p×q) is realized at around the corrosion potenntial E'_(cor) which can be regarded as the optimum protection potential. As the Faraday impedance can be easily measured, a new method for assessingand setting up cathodic protection is possible.

Hou Baarong; Atsushi Nishikata; Tooru Tsuru; Shiro Haruyama

1993-01-01

88

Corrosion Characteristics Of Aluminum And Stainless Steel  

International Nuclear Information System (INIS)

Corrosion phenomena on metals and alloys often need serious treatment, because such phenomena affect to the lifetime of the materials . Even in certain cases, unsupervised and uncontrolled corrosion processes my result in an installation accident. This study investigates corrosion phenomena n metals, among others are conditions which affect corrosion and its kinds occurring on aluminum and stainless steel.

2001-01-01

89

A STUDY OF CORROSION AND STRESS CORROSION CRACKING OF CARBON STEEL NUCLEAR WASTE STORAGE TANKS  

International Nuclear Information System (INIS)

[en] The Hanford reservation Tank Farms in Washington State has 177 underground storage tanks that contain approximately 50 million gallons of liquid legacy radioactive waste from cold war plutonium production. These tanks will continue to store waste until it is treated and disposed. These nuclear wastes were converted to highly alkaline pH wastes to protect the carbon steel storage tanks from corrosion. However, the carbon steel is still susceptible to localized corrosion and stress corrosion cracking. The waste chemistry varies from tank to tank, and contains various combinations of hydroxide, nitrate, nitrite, chloride, carbonate, aluminate and other species. The effect of each of these species and any synergistic effects on localized corrosion and stress corrosion cracking of carbon steel have been investigated with electrochemical polarization, slow strain rate, and crack growth rate testing. The effect of solution chemistry, pH, temperature and applied potential are all considered and their role in the corrosion behavior will be discussed

2007-01-01

90

Microbial corrosion and cracking in steel. A concept for evaluation of hydrogen-assisted stress corrosion cracking in cathodically protected high-pressure gas transmission pipelines  

DEFF Research Database (Denmark)

An effort has been undertaken in order to develop a concept for evaluation of the risk of hydrogen-assisted cracking in cathodically protected gas transmission pipelines. The effort was divided into the following subtasks: A. Establish a correlation between the fracture mechanical properties of high-strength pipeline steel and the concentration of hydrogen present in the steel. B. Determine the degree hydrogen absorption by cathodically protected steel exposed in natural soil sediment, which include activity of sulphate-reducing bacteria (SRB). C. Compare the above points with fracture mechanical considerations on the level of stress intensity actually present in pipelines during normal operational conditions. The results were used for a discussion - based on well established fracture mechanical relations - on which set of conditions (CP-level and operating pipeline pressure) could give crack propagation. This resulted in threshold curves that can be used for assessment of the risk of hydrogen-assisted cracking as a function of operating pressure and hydrogen content - having the flaw size as discrete parameter. The results are to be used mainly on a conceptual basis, but it was indicated that the requirements for crack propagation include an overprotective CP-condition, a severe sulphate-reducing environment, as well as a large flaw (8 mm or a leak in the present case). A 1 mm flaw (which may be the maximum realistic flaw size) is believed to be unable to provoke crack propagation in this steel.

Nielsen, Lars Vendelbo

1998-01-01

91

Microbial corrosion and cracking in steel. A concept for evaluation of hydrogen-assisted stress corrosion cracking in cathodically protected high-pressure gas transmission pipelines  

Energy Technology Data Exchange (ETDEWEB)

An effort has been undertaken in order to develop a concept for evaluation of the risk of hydrogen-assisted cracking in cathodically protected gas transmission pipelines. The effort was divided into the following subtasks: A. Establish a correlation between the fracture mechanical properties of high-strength pipeline steel and the concentration of hydrogen present in the steel. B. Determine the degree hydrogen absorption by cathodically protected steel exposed in natural soil sediment, which include activity of sulphate-reducing bacteria (SRB). C. Compare the above points with fracture mechanical considerations on the level of stress intensity actually present in pipelines during normal operational conditions. The results were used for a discussion - based on well established fracture mechanical relations - on which set of conditions (CP-level and operating pipeline pressure) could give crack propagation. This resulted in threshold curves that can be used for assessment of the risk of hydrogen-assisted cracking as a function of operating pressure and hydrogen content - having the flaw size as discrete parameter. The results are to be used mainly on a conceptual basis, but it was indicated that the requirements for crack propagation include an overprotective CP-condition, a severe sulphate-reducing environment, as well as a large flaw (8 mm or a leak in the present case). A 1 mm flaw (which may be the maximum realistic flaw size) is believed to be unable to provoke crack propagation in this steel. (EG) EFP-95. 16 refs.

Vendelbo Nielsen, L.

1998-08-01

92

Corrosion-resistant metallic coatings on low carbon steel  

Energy Technology Data Exchange (ETDEWEB)

Corrosion resistant coatings of various metals and alloys such as Si, Ti, Ni and Ti-Ni were formed on steel rebars by fluidized bed chemical vapor deposition (FBR-CVD), paint-and-heat or FBR-plasma spray techniques. The paint-and-heat metallization and FBR-plasma spray are powder coating techniques that can be applied easily and economically on new components as well as on existing steel structures, such as bridges. These metallic powder coatings provide non-sacrificial, superior corrosion protection for a long time. Ti-Ni (70:30 wt.%) coatings on steel rebars provided a 20 fold increase in corrosion resistance over uncoated steel. These metallic coatings can be used to prevent corrosion in many industrial applications. (orig.)

Jayaweera, P. [SRI Int., Menlo Park, CA (United States). Mater. and Chem. Eng. Lab.; Lowe, D.M. [SRI Int., Menlo Park, CA (United States). Mater. and Chem. Eng. Lab.; Sanjurjo, A. [SRI Int., Menlo Park, CA (United States). Mater. and Chem. Eng. Lab.; Lau, K.H. [SRI Int., Menlo Park, CA (United States). Mater. and Chem. Eng. Lab.; Jiang, L. [SRI Int., Menlo Park, CA (United States). Mater. and Chem. Eng. Lab.

1996-12-15

93

METHOD FOR ARRANGEMENT OF HIGH-STRENGTH CORROSION-RESISTANT FOR EFFICIENT PROTECTION OF STEEL PIPELINES OPERATED IN THE EXTREME NORTH  

Directory of Open Access Journals (Sweden)

Full Text Available Problem statement. At present, the problem of main pipeline protection from corrosion is extremelyimportant. Principal gas-transport routes have the biggest length in the North areas whereclimatic and geotechnical conditions are adverse. Scientists of Voronezh State University of Architectureand Civil Engineering have developed new material, rubber concrete. This material isbased on liquid oligodienes and has unique set of operational characteristics. The material can beefficiently used as insulation material for metal pipe in the conditions of the Extreme North.Results. The method for arrangement of protective coating of metal pipe is developed on the basisof rubber concrete. The method is patented. Laboratory device which allows one to perform structuresformation of rubber mastic on the surface of metal pipe is constructed. Physicomechanicalproperties of rubber concrete as insulation material for steel pipes are determined.Conclusions. The results of experiments allow us to draw a conclusion on the expediency of the useof rubber concrete as a protection coating material for steel pipes operated in the Extreme North.

I. S. Surovtsev; Yu. M. Borisov; S. I. Matreninsky; R. I. Sapelkin

2011-01-01

94

Microbial corrosion inhibition of mild steel in salty water environment  

International Nuclear Information System (INIS)

The use of antimicrobial corrosion inhibitor is increasingly being curtailed by recent corrosion restrictions. This paper represents the results of the study of new biocide, antimicrobial corrosion inhibitor named 8-hydroxy-N'-(2-(quinolin-8-yloxy)acetyl)quinoline-5-sulfonohydrazide (HQS) was used to inhibit corrosion causing sulphate reducing bacteria (SRB). The effects of the inhibitor on mild steel dissolution in salty water environment were studied through weight loss measurements, electrochemical and microorganism tests. The results obtained from this study show that, the new inhibitor can decrease corrosion and microbial growth under the conditions tested. The mass loss for the protected mild steel coupons shows lower corrosion rate compared to the unprotected once. Cyclic polarization test reveals that, the biocide minimizes the pitting area (hysteresis). The nature of protective film formed on mild steel was studied by scanning electron microscopy (SEM). SEM images revealed that, the corrosion inhibition by the HQS on the mild steel surface significantly improved in the presence of biocide.

2009-03-15

95

Low-temperature atomic layer deposition of Al{sub 2}O{sub 3} thin coatings for corrosion protection of steel: Surface and electrochemical analysis  

Energy Technology Data Exchange (ETDEWEB)

Highlights: {yields} 10-100 nm Alumina coatings grown by ALD at 160 {sup o}C for protection of steel. {yields} Al{sub 2}O{sub 3} stoichiometry of the coating and trace contamination by growth precursors. {yields} Iron oxide and siloxane presence at the buried coating/steel interface. {yields} Exponential decay of coating porosity over four orders of magnitude with thickness increase. {yields} Coating thickness increase required to seal the defective first deposited 10 nm. - Abstract: ToF-SIMS, XPS, voltammetry and EIS investigation of the anti-corrosion properties of thin (10, 50 and 100 nm) alumina coatings grown by atomic layer deposition at 160 {sup o}C on steel is reported. Surface analysis shows a thickness-independent Al{sub 2}O{sub 3} stoichiometry of the coating and trace contamination by the growth precursors. The buried coating/alloy interface has iron oxide formed in ambient air and/or resulting from the growth of spurious traces in the initial stages of deposition. Electrochemical analysis yields an exponential decay of the coating porosity over four orders of magnitude with increasing thickness, achieved by sealing of the more defective first deposited 10 nm.

Diaz, Belen [Laboratoire de Physico-Chimie des Surfaces, CNRS (UMR 7045) - Chimie-ParisTech (ENSCP), 11 rue Pierre et Marie Curie, F-75005 Paris (France); Haerkoenen, Emma [Laboratory of Inorganic Chemistry, University of Helsinki, P.O. Box 55, FIN-00014 Helsinki (Finland); Swiatowska, Jolanta [Laboratoire de Physico-Chimie des Surfaces, CNRS (UMR 7045) - Chimie-ParisTech (ENSCP), 11 rue Pierre et Marie Curie, F-75005 Paris (France); Maurice, Vincent, E-mail: vincent-maurice@chimie-paristech.f [Laboratoire de Physico-Chimie des Surfaces, CNRS (UMR 7045) - Chimie-ParisTech (ENSCP), 11 rue Pierre et Marie Curie, F-75005 Paris (France); Seyeux, Antoine [Laboratoire de Physico-Chimie des Surfaces, CNRS (UMR 7045) - Chimie-ParisTech (ENSCP), 11 rue Pierre et Marie Curie, F-75005 Paris (France); Marcus, Philippe, E-mail: philippe-marcus@chimie-paristech.f [Laboratoire de Physico-Chimie des Surfaces, CNRS (UMR 7045) - Chimie-ParisTech (ENSCP), 11 rue Pierre et Marie Curie, F-75005 Paris (France); Ritala, Mikko, E-mail: Mikko.Ritala@Helsinki.f [Laboratory of Inorganic Chemistry, University of Helsinki, P.O. Box 55, FIN-00014 Helsinki (Finland)

2011-06-15

96

Corrosion of Electrogalvanized Steel in 0.1 M NaCl Studied by SVET  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english The corrosion of electrogalvanized steel exposed to 0.1 M NaCl was studied using the SVET. Situations of localized corrosion, cathodic protection and corrosion protection due to surface pre-treatment were analyzed, putting in evidence the possibilities of the technique.

Bastos, A.C.; Simões, A.M.; Ferreira, M.G.

2003-01-01

97

Corrosion of Electrogalvanized Steel in 0.1 M NaCl Studied by SVET  

Directory of Open Access Journals (Sweden)

Full Text Available The corrosion of electrogalvanized steel exposed to 0.1 M NaCl was studied using the SVET. Situations of localized corrosion, cathodic protection and corrosion protection due to surface pre-treatment were analyzed, putting in evidence the possibilities of the technique.

A.C. Bastos; A.M. Simões; M.G. Ferreira

2003-01-01

98

Characterization of iron oxides and atmospheric corrosion of steel  

Science.gov (United States)

Research has been performed on steel coupons exposed to the atmosphere in order to improve the understanding of the formation and development of iron oxides which control atmospheric corrosion, and to establish data for predicting corrosion behavior taking place under specific atmospheric conditions. Improving the analytical techniques required for studying corrosion behavior was another goal of this research. Then, different analytical techniques can provide additional information, such as identification, fractions and layering of iron oxides formed on steels. The study of corrosion behavior was performed using three different analytical techniques, which provided information on the formation, development and layering of iron oxides on the corrosion products as a function of atmospheric conditions, exposure time and type of steel. In particular, the protective layer formed on weathering steel was investigated as a function of different amounts of alloying elements in the steel, atmospheric conditions and exposure times. Combined together, the results provided a better understanding of the atmospheric corrosion behavior of steel, and formed a part of database of the atmospheric corrosion characteristics. Accurate characterization of the iron oxides often formed on steel surfaces was one of the aims for this research. Seven iron oxides, goethite (?-FeOOH), akaganeite (?-FeOOH), lepidocrocite (?-FeOOH), ?-FeOOH, hematite (/alpha- F2O3), maghemite (?- F2O3) and magnetite (F3O4), which are often found in corrosion products present on steel, were characterized by Mossbauer spectroscopy, Raman spectrometry and x-ray diffraction analysis. Complete identification of the corrosion products formed on steel required more than one and most often three of the analytical techniques. In particular, the Mossbauer characterization of the iron oxides included measuring the relative recoilless fraction (F-value), which was defined as the ratio of recoil-free fractions of two different materials. The relative recoilless fractions of the iron oxides allowed the conversion of Mossbauer subspectral areas to the relative atomic, molecular, or weight fraction of each present in a mixed iron oxide sample. The characterization of the iron oxides was used to study the atmospheric corrosion behavior of weathering, copper bearing and carbon steels as a function of environmental condition, exposure time and type of steel. Goethite, akaganeite, lepidocrocite, maghemite and magnetite were identified in the corrosion products formed on the steel coupons. The formation of superparamagnetic goethite showed a correlation with the corrosion rate for seven types of steels. After long term exposure, superparamagnetic goethite on weathering steel, was the final iron oxide formed in the corrosion products. The conosion products typically formed in two layers. The protective layer, the inner layer, was formed by goethite and superparamagnetic maghemite. Increased amounts silicon and smaller amounts of phosphorus in the steel substrate increased the relative fraction of superparamagnetic goethite, in marine and rural environments. However, different amounts of nickel did not affect the formation of the iron oxides even after long term exposure. Increasing the silicon content in steel would be helpful in enhancing corrosion resistance for the long term lifetime of steel structures under atmospheric conditions.

Oh, Sei Jin

99

Corrosion protection of rebar using a zinc wire  

Energy Technology Data Exchange (ETDEWEB)

A novel method was proposed to mitigate the corrosion of steel rebar inside concrete. In this patented method, a rebar was protected galvanically by attaching a zinc wire along the length of the rebar. The zinc wire acted as a sacrificial anode when the rebar embedded inside the concrete was exposed to corrosive substances such as moisture and salt.

Zhang, X.G. [Cominco Ltd., Mississauga, Ontario (Canada). Product Technology Centre

1995-09-01

100

General corrosion of carbon steels in high temperature water  

International Nuclear Information System (INIS)

[en] This short paper seeks to provide a summary of the main knowledge about the general corrosion of carbon steels in high temperature water. In pure water or slightly alkaline deaerated water, steels develop a protective coating of magnetite in a double layer (Potter and Mann oxide) or a single layer (Bloom oxide). The morphology of the oxide layer and the kinetics of corrosion depend on the test parameters controlling the solubility of iron. The parameters exercising the greatest influence are partial hydrogen pressure and mass transfer: hydrogen favours the solubilization of the magnetite; the entrainment of the dissolved iron prevents a redeposition of magnetite on the surface of the steel. Cubic or parabolic in static conditions, the kinetics of corrosion tends to be linear in dynamic conditions. In dynamic operation, corrosion is at least one order of magnitude lower in water with a pH of 10 than in pure water with a pH of 7. The activation energy of corrosion is 130 kJ/mol (31 kcal/mol). This results in the doubling of corrosion at around 300 deg C for a temperature increase of 15 deg C. Present in small quantities (100-200 ppb), oxygen decreases general corrosion but increases the risk of pitting corrosion - even for a low chloride content - and stress corrosion cracking or corrosion-fatigue. The steel composition has probably an influence on the kinetics of corrosion in dynamic conditions; further work would be required to clarify the effect of some residual elements. (author). 31 refs., 9 figs., 2 tabs

1994-01-01

 
 
 
 
101

Corrosion of steel in cracked concrete  

Energy Technology Data Exchange (ETDEWEB)

Corrosion of steel in concrete is studied typically in uncracked concrete. In the field, however, concrete often has cracks that extend to the reinforcing steel. Electrochemical corrosion testing was performed in cracked concrete of two qualities. Results were compared to physical examination of the embedded reinforcement. Corrosion resistance improved significantly as the concrete properties and reinforcement cover approached that recommended in American Concrete Institute 318. Calcium nitrite additions to the concrete reduced corrosion significantly. Results indicated testing in cracked concrete should be performed in concrete representative of that specified in ACl 318.

Berke, N.S.; Dallaire, M.P.; Hicks, M.C.; Hoopes, R.J. (W.R. Grace and Co.-Conn., Cambridge, MA (United States))

1993-11-01

102

Effect of the crude oil on corrosion of steel in crude oil/brine production  

Energy Technology Data Exchange (ETDEWEB)

The specific crude oil present is shown to have a major effect on the corrosion of steel in crude oil/brine production environments. The addition of crude oil to a brine (chloride-containing water) lowers the measured corrosion rate of steel exposed to the mixture, but different crude oils can have significantly different effects on steel corrosion, with identical brie compositions. The primary effect of the crude oil on steel corrosion in crude oil/brine mixtures is apparently on the protectiveness of the corrosion product layer formed on the steel. The algebraic product of the organic nitrogen concentration in weight percent and the acid number exhibits an inverse relationship to the steel corrosion rate, implying that the organic nitrogen and acid contents of the crude oil are potentially major variables affecting corrosion product formation and resulting protectiveness. This means that corrosion tests conducted on steel in brine environments without the crude oil present cannot give an accurate picture of the behavior of steel in the crude oil/brine production environment, which can lead to gross errors when using the test results to estimate the potential corrosion problems and effects of corrosion inhibitor treatments in a crude oil production system. Corrosion tests simulating crude oil production systems ust include the specific produced crude oil in the test environment if the test is to produce valid results.

Efird, K.D.; Jasinski, R.J.

1989-02-01

103

Corrosion testing of carbon steel in aereated geothermal brine  

Energy Technology Data Exchange (ETDEWEB)

Two major problems are associated with the use of cooled geothermal water as coolant for the 5 MW(e) Pilot Power Plant at Raft River. They are: (1) a scaling potential owing to the chemical species present in solution, and (2) the corrosive nature of the geothermal water on carbon steel. A water treatment test program was established to reduce or eliminate these problems. Data show that scale can be prevented by a combination of dispersants and controlling the concentration of scaling species in the circulating water. Corrosion cannot be controlled without a pretreatment of tubing material. With the pretreatment, a protective gamma iron oxide film is laid down on the tube surface, that with proper corrosion inhibitor additives, significantly reduces both general and pitting corrosion. However, longer term testing is required to determine protection of pitting corrosion.

Suciu, D.F.; Wikoff, P.M.

1981-02-01

104

Corrosion of steel in ionic liquids  

Directory of Open Access Journals (Sweden)

Full Text Available The corrosion behavior of 1018 carbon steel alloy has been investigated by electrochemical techniques. The ionic liquids studied were 1-butyl-3-methylimidazolium chloride ([C4mim]Cl), 1 hexyl-3-methylimidazolium hexafluorophosphate ([C6mim]PF6) 1-octyl-3-methylimidazolium hexafluorophosphate ([C8mim]PF6), and 1-butyl-3-methylimidazolium bis-(trifluoromethanesulfonyl) imide ([C4mim][Tf2N]). Potentiodynamic polarization and Tafel plots were used to determine the corrosion behavior of the carbon steel. Results showed that corrosion resistance of 1018 carbon steel in ionic liquids is outstanding as indicated by the low corrosion rates obtained which ranged from 3-13 µm/yr. Anodic polarization curves showed active/passive corrosion behavior of the alloy in most of the ionic liquids tested. However, ionic liquids containing chloride ions were unable to form a passive region.

Arenas M.F.; Reddy R.G.

2003-01-01

105

Corrosion of Electroless Nickel-Coated Steel.  

Science.gov (United States)

The corrosion behavior of electroless nickel-coated steel has been investigated. The effectiveness of electroless nickel as a coating is strongly dependent on the film homogeneity, thickness, and phosphorous content. Defective electroless nickel coatings ...

J. F. McIntyre S. M. Hoover C. M. Dacres K. A. Musselman

1987-01-01

106

Development of novel protective high temperature coatings on heat exchanger steels and their corrosion resistance in simulated coal firing environment; Developpement de revetements pour les aciers d'echangeurs thermiques et amelioration de leur resistance a la corrosion en environnement simulant les fumees de combustion et de charbon  

Energy Technology Data Exchange (ETDEWEB)

Improving the efficiencies of thermal power plants requires an increase of the operating temperatures and thus of the corrosion resistance of heat exchanger materials. Therefore, the present study aimed at developing protective coatings using the pack cementation process. Two types of heat exchanger steels were investigated: a 17% Cr-13% Ni austenitic steel and three ferritic-martensitic steels with 9 (P91 and P92) and 12% Cr (HCM12A). The austenitic steel was successfully aluminized at 950 C. For the ferritic-martensitic steels, the pack cementation temperature was decreased down to 650 C, in order to maintain their initial microstructure. Two types of aluminides, made of Fe{sub 2}Al{sub 5} and FeAl, were developed. A mechanism of the coating formation at low temperature is proposed. Furthermore, combining the pack cementation with the conventional heat treatment of P91 allowed to take benefit of higher temperatures for the deposition of a two-step Cr+Al coating. The corrosion resistance of coated and uncoated steels is compared in simulated coal firing environment for durations up to 2000 h between 650 and 700 C. It is shown that the coatings offer a significant corrosion protection and, thus, an increase of the component lifetime. Finally, the performance of coated 9-12% Cr steels is no longer limited by corrosion but by interdiffusion between the coating and the substrate. (author)

Rohr, V.

2005-10-15

107

Atmospheric corrosion of mild steel. Pt. I. Rural and urban atmospheres  

International Nuclear Information System (INIS)

[en] This paper summarizes the results obtained in the MICAT project for mild steel specimens exposed for 1 to 4 years in 22 rural and urban atmospheres in the Ibero-American region. Test site characterization and chemical and morphological determination of the steel corrosion product layers (SCPLs) contributed to understanding the corrosion phenomena involved. It was observed how some climatological factors could affect steel corrosion rates and SCPL properties. Although the studied atmospheres were classified into different ISO groups, steel corrosion rates did not differ significantly between them. The only common characteristic of these atmospheres was an increase in SCPLs protectiveness with exposure time. (orig.)

2000-01-01

108

Corrosion of steel surfaces on machining equipment  

Energy Technology Data Exchange (ETDEWEB)

Corrosion was observed on the ways of various machine tools that were inactive for a short time. The corrosion resistance of various coolants, way oils, and spindle lubricants was determined on bare steel using the 5 percent salt spray test per ASTM-B 117. Inhibited versions of the coolants, way oils, and spindle lubricants were evaluated and reported in the paper.

Menke, J. [Army ARDEC, Davenport, IA (United States)

1998-12-31

109

Discussion: Corrosion of steel in cracked concrete  

Energy Technology Data Exchange (ETDEWEB)

The present work discusses Corrosion of Steel in Cracked Concrete'' by N.S. Berke, M.P. Dallaire, M.C. Hicks, and R.J. Hoopes, which was published in Corrosion 49, 11 (1993), pp. 934-943. The authors did not submit a reply. The paper by Berke, et al., discussed results based upon corrosion testing of cracked concrete beams. The aim of the study was to determine whether calcium nitrite (Ca[NO[sub 2

McDonald, D.B. (Wiss, Janney, Elstner Associates Inc., Northbrook, IL (United States))

1994-06-01

110

Corrosion of Steels in Steel Reinforced Concrete in Cassava Juice  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The corrosion of two types of construction steels, ST60Mn and RST37-2?, in a low cyanide concentration environment (cassava juice) and embedded in concrete had been studied. The ST60 Mn was found to be more corrosion resistant in both ordinary water and the cassava juice environment. The ...

G.O. Oluwadare; O. Agbaje

111

Corrosion of carbon steel under waste disposal conditions  

International Nuclear Information System (INIS)

The corrosion of carbon steel has been studied in the United Kingdom under granitic groundwater conditions, with pH between 5 and 10 and possibly substantial amounts of Cl-, SO42- and HCO3-/CO32-. Corrosion modes considered include uniform corrosion under both aerobic and anaerobic conditions; passive corrosion; localized attack in the form of pitting or crevice corrosion; and environmentally assisted cracking - hydrogen embrittlement or stress corrosion cracking. Studies of these processes are being carried out in order to predict the metal thicknesses required to give container lifetimes of 500 to 1000 years. A simple uniform corrosion model predicts a corrosion rate of around 13.4 ?m/a at 20C, rising to 69 ?m/a at 50C and 208 ?m/a at 90C. A radiation dose of 105 rad/h and a G-value of 2.8 for the production of oxidizing species would account for an increase in corrosion rate of 7 ?m/a. This model overestimates slightly the results actually achieved for experimental samples exposed for two years, the difference being due to a protective film formed on the samples. These corrosion rates predict that the container must be 227 mm thick to withstand uniform corrosion; however, they predict very high levels of hydrogen production. Conditions will be favourable for localized or pitting corrosion for about 125 years, leading to a maximum penetration of 160 mm. Since the exposure environment cannot be predicted precisely, one cannot state that stress corrosion cracking is impossible. Thus the container must be stress relieved. Other corrosion mechanisms such as microbial corrosion and hydrogen embrittlement are not considered significant

1990-01-01

112

Behavior and mechanism of corrosion protection for galvanized steels by self-healing effect of chromate coatings; Kurometo himaku no jiko hoshu sayo ni yoru aen mekki kozai no boshoku kyodo to sono kiko  

Energy Technology Data Exchange (ETDEWEB)

At present, most of steel materials are conducted with treatment for an aim of corrosion protection. Corrosion resistance of the chromate treated steel materials are thought for self-recovery action with chromate film to contribute. The self-recovery action of the chromate treated film is an action to control corrosion of exposed metal element portion such as not only chromate treated portion but also fractured portion of the chromate film. As this phenomenon has been presumed experientially so far, there was few examples elucidated experimentally. In this paper, the corrosion reaction resistance of the chromate treated zinc plated steels was obtained by presuming equivalent circuit, after immersing into NaCl aqueous solution, giving artificial defects onto the chromate film, and measuring time-elapsing change of AC impedance. And then, self-recovery mechanism was demonstrated by measuring a change on standing of corrosion current distribution using Scanning Vibrating Electrode Technique (SVET), further conducting surface analysis on self-recovery portion of the chromate film using X-ray Photoelectron Spectroscopy (XPS) for its model specimen. 15 refs., 9 figs.

Suda, A. [Nihon Parkerizing Co. Ltd., Kanagawa (Japan). Central Research Lab.; Asari, M. [Isuzu Motors Ltd., Tokyo (Japan)

1997-02-15

113

Field performance of sprayed zinc anodes in controlling corrosion of steel reinforced concrete  

Energy Technology Data Exchange (ETDEWEB)

The deterioration of concrete structures often results from the corrosion of their steel reinforcement. Cathodic protection (CP) is a proven means to stop rebar corrosion. One anode material gaining acceptance in the infrastructure corrosion fight is zinc thermal spray coating. This paper discusses an investigation of such CP systems.

Tinnea, J. [John S. Tinnea and Associates, Seattle, WA (United States)

1998-12-31

114

Corrosion fatigue of steel in concrete structures. Final report  

Energy Technology Data Exchange (ETDEWEB)

The basic objective of this research programme was to clarify to what extent the traditional alkaline protection is sufficient also under cyclic actions in chloride environments or under which conditions more protection efforts (coating, cathodic protection) would be required. As a measure of the efficiency of the protection the fatigue strength of the prestressing steel under simultaneous action of different corrosive environments has been investigated. Corrosion fatigue tests on 3 series of 3-point-loaded beams post-tensioned with a 7-wire monostrand tendon according to German standard specifications have been performed. The corrosive environment was produced for the beams of the first two series by wetting their surface with salt water in regular intervals. For the third series of beams chloride has been added to the concrete and the grouting mortar and the beams have been wetted with water at proper intervals. Constant amplitude load cycles have been applied.

Schaefer, R.; Jungwirth, D.; Windisch, A.

1988-01-01

115

Corrosion of two oxide-covered steels  

Science.gov (United States)

Determining the corrosive response of pipeline steel under laboratory immersion conditions can be difficult when an adequate reproduction of feild conditions is required. The difficulty is multiplied when testing an oxide-covered surface. Corrosion standards do not adequately cover testing oxide-covered steels. Methodology is developed to test the corrosive response of oxide-covered steels, especially pre-immersion surface oxides such as millscale. The methodology focuses on open-circuit potential monitoring, polarization, mass loss and surface examination. Procedures are recommended for specimen preparation, equipment to handle hostile media, test sequencing, specimen cleaning, and preparation for post-immersion examination. Long standing belief's regarding the interaction of millscale in the corrosive response of a steel originating from pre-1950's steel immersed in sea water that have propagated are: the presence of millscale causes pitting and scatter in corrosive testing results or is negligible due to quick removal. Results from A36 and X70 steels in dearated high chloride ion containing environments indicate that an adjustment of historical industry perspectives of millscale is required. Millscale does not cause pitting. Pitting is material/environment dependent. A material/environment that is prone to pitting will, at least initially, experience a concentration of the corrosion at breaks in the millscale. The presence of millscale does not ensure pitting will occur. Scatter in the corrosion parameters determined from mass loss and polarizations are not related to the presence or absence of millscale but due to a combination of testing methodology and material/environment. Removal of millscale is material/environment dependent requiring very acidic conditions to negate the interaction in the materials corrosive response. The presence of millscale can be enhanced by oxide growth during immersion.

Schwarz-Tonhauser, Melissa

116

Research on atmospheric corrosion of steel using synchrotron radiation  

International Nuclear Information System (INIS)

[en] Correlation between local structure around Cr in the protective rust layer on weathering steel and protective performance of the rust layer is presented as an example of corrosion research using synchrotron radiation which has recently been applied in various research fields as a useful tool. In addition, in situ observation of initial process of rust formation on steel is also mentioned. It was pointed out by considering the X-ray absorption fine structure spectra that the nanostructure of the protective rust layer on weathering steel primarily comprises of small Cr-goethite crystals containing surface adsorbed and/or intergranular CrOx3-2X complex anions. This CrOx3-2X explains the protective performance of the rust layer originated by dense aggregation of fine crystals with cation selectivity of the Cr-goethite. It is very advantageous to employ white X-rays for in situ observation of rusting process of a carbon steel covered with electrolyte thin films because rust structure might change very quickly. This in situ observation revealed the effect of ion species on the change in rust phase during wet/dry repeating. It can be said that application of synchrotron radiation on corrosion research is so useful to understand the nanostructure of surface oxides which closely relate to corrosion behavior of metals and alloys. (author)

2004-01-01

117

Characteristics of Corrosion Product Layer Formed on Weathering Steel Exposed to the Tropical Climate of Vietnam  

Directory of Open Access Journals (Sweden)

Full Text Available The weathering steel (Corten B) was exposed to out-door atmosphere of Hanoi (urban site) and Donghoi (marine site). The results showed the protective ability of corrosion product layer formed on weathering steel in the initial stage. The SEM-EDX analysis detected the presence of chromium and copper in the inner layers of corrosion product formed on weathering steel. These elements improved corrosion resistance of corrosion product layers. In addition, the dense ?-FeOOH phase were appeared early in corrosion product which is detected by X-ray diffraction and Micro Raman investigations. The results of polarization and EIS measurements also demonstrated the protectiveness of the corrosion product of weathering steel.

Le Thi Hong Lien; Hoang Lam Hong

2013-01-01

118

POLYETHERSULFONE COATING FOR MITIGATING CORROSION OF STEEL IN GEOTHERMAL ENVIRONMENT.  

Energy Technology Data Exchange (ETDEWEB)

Emphasis was directed toward evaluating the usefulness of a polyethersulfone (PES)-dissolved N-methyl pyrrolidone (NMP) solvent precursor as a low-temperature film-forming anti-corrosion coating for carbon steel in simulated geothermal environments at brine temperatures up to 300 C. A {approx} 75 {micro}m thick PES coating performed well in protecting the steel against corrosion in brine at 200 C. However, at {>=} 250 C, the PES underwent severe hydrothermal oxidation that caused the cleavage of sulfone- and ether-linkages, and the opening of phenyl rings. These, in turn, led to sulfone {yields} benzosulfonic acid and ether {yields} benzophenol-type oxidation derivative transformations, and the formation of carbonyl-attached open rings, thereby resulting in the incorporation of the functional groups, hydroxyl and carbonyl, into the coating. The presence of these functional groups raised concerns about the diminutions in water-shedding and water-repellent properties that are important properties of the anti-corrosion coatings; such changes were reflected in an enhancement of the magnitude of susceptibility of the coatings surfaces to moisture. Consequently, the disintegration of the PES structure by hydrothermal oxidation was detrimental to the maximum efficacy of the coating in protecting the steel against corrosion, allowing the corrosive electrolytes to infiltrate easily through it.

SUGAMA, T.

2005-06-01

119

Corrosion of steel tendons used in prestressed concrete pressure vessels  

International Nuclear Information System (INIS)

The purpose of this investigation was to determine the corrosion behavior of a high strength steel (ASTM A416-74 grade 270), typical of those used as tensioning tendons in prestressed concrete pressure vessels, in several corrosive environments and to demonstrate the protection afforded by coating the steel with either of two commercial petroleum-base greases or Portland Cement grout. In addition, the few reported incidents of prestressing steel failures in concrete pressure vessels used for containment of nuclear reactors are reviewed. The susceptibility of the steel to stress corrosion cracking and hydrogen embrittlement and its general corrosion rate were determined in several salt solutions. Wires coated with the greases and grout were soaked for long periods in the same solutions and changes in their mechanical properties were subsequently determined. All three coatings appeared to give essentially complete protection but small flaws in the grease coatings were detrimental; flaws or cracks less than 1 mm wide in the grout were without effect

1978-12-07

120

Corrosion of steel tendons used in prestressed concrete pressure vessels  

Energy Technology Data Exchange (ETDEWEB)

The corrosion behavior of a high-strength steel (Specifications for Uncoated Seven-Wire-Stress-Relieved Strand for Prestressed Concrete (ASTM A 416-74, Grade 270)), typical of those used as tensioning tendons in prestressed concrete pressure vessels was measured in several corrosive environments. The protection obtained by coating the steel with two commercial petroleum-base greases or with Portland cement grout was evaluated. The few reported incidents of prestressing steel failures in concrete pressure vessels used for containment of nuclear reactors were reviewed. The susceptibility of the steel to stress corrosion cracking and hydrogen embrittlement and its general corrosion rate were determined in several salt solutions. Wires coated with the greases and grout were soaked for long periods in the same solutions and changes in their mechanical properties were subsequently determined. All three coatings appeared to give essentially complete protection; however, flaws in the grease coatings could be detrimental, and flaws or cracks less than 1-mm-wide (0.04 in.) in the grout were without effect.

Griess, J.C.; Naus, D.J.

1980-01-01

 
 
 
 
121

Corrosion of steel tendons used in prestressed concrete pressure vessels  

International Nuclear Information System (INIS)

[en] The corrosion behavior of a high-strength steel [Specifications for Uncoated Seven-Wire-Stress-Relieved Strand for Prestressed Concrete (ASTM A 416-74, Grade 270)], typical of those used as tensioning tendons in prestressed concrete pressure vessels was measured in several corrosive environments. The protection obtained by coating the steel with two commercial petroleum-base greases or with Portland cement grout was evaluated. The few reported incidents of prestressing steel failures in concrete pressure vessels used for containment of nuclear reactors were reviewed. The susceptibility of the steel to stress corrosion cracking and hydrogen embrittlement and its general corrosion rate were determined in several salt solutions. Wires coated with the greases and grout were soaked for long periods in the same solutions and changes in their mechanical properties were subsequently determined. All three coatings appeared to give essentially complete protection; however, flaws in the grease coatings could be detrimental, and flaws or cracks less than 1-mm-wide (0.04 in.) in the grout were without effect

1980-01-01

122

Microbially influenced corrosion of carbon steels  

Energy Technology Data Exchange (ETDEWEB)

Microbially influenced corrosion of pipeline steels is an economically important problem. Microbes form tubercles which block fluid flow and can facilitate localized corrosion leading to through-wall penetrations. Microbes of diverse physiological types and metabolic potentialities have been recovered from fresh tubercles or under-deposit corrosion and have been characterized. In tests utilizing sterilizable flow-through systems containing pipeline steel coupons, corrosion rates determined by nondestructive electrochemical means have indicated that increasing the number of physiological types of microbes inoculated into the system generally increased the severity of the microbially influenced corrosion (MIC). This study reports the MIC of monocultures and combinations of monocultures in an aerobic fresh water system with low sulfate and an anaerobic saline system. In both the aerobic and anaerobic systems, the combination of microbes induced greater MIC responses than the monocultures. In tests involving a combination of microbes in both systems in which one member was a sulfate-reducing bacteria (SRB), the corrosion mechanism was different for the control and the monocultures. This difference was indicated by the phase shift in the electrochemical impedance spectra (EIS). The localization of corrosion, that in many cases is the hallmark of MIC, may be initiated by the inhomogeneities of supposedly smooth metal surfaces. The scanning vibrating electrode technique (SVET) demonstrated non-uniform current densities over carbon steel electrodes polished to a 600 grit finish suggesting pitting and repassivation of pits in sterile medium.

White, D.C.; Jack, R.F.; Dowling, N.J.E.; Franklin, M.J.; Nivens, D.E.; Brooks, S.; Mittelman, M.W.; Vass, A.A. (Tennessee Univ., Knoxville, TN (USA). Inst. for Applied Microbiology); Isaacs, H.S. (Brookhaven National Lab., Upton, NY (USA))

1990-01-01

123

Corrosion of mild steel under anaerobic biofilm  

Energy Technology Data Exchange (ETDEWEB)

Corrosion of mild steel under completely anaerobic conditions in the presence of a mixed population biofilm, including sulfate-reducing bacteria (SRB), has been studied in a continuous flow system. The closed channel flow reactor was continuously fed with low concentration substrate at different dilution rates that influenced biofilm accumulation. No direct correlation was observed between corrosion and SRB activity in the absence of ferrous iron. Furthermore, corrosion of mild steel in the SRB environment was determined by the nature of the metal and environmental conditions such as dissolved iron concentration. When formation of an iron sulfide film on mild steel was prevented before the biofilm accumulated, the metal surface retained its scratch lines after a 21-day experiment (SRB at 2.6 [times] 10[sup 9]/cm[sup 2]). However, when the iron sulfide film was formed before the accumulation of biofilm, visible localized corrosion appeared after 14 days and increased up to 21 days. Intergranular and pitting attack was found in the localized corrosion area. Inclusions (Al, Mn, and Fe) and grain boundary triple points were also found in the localized corrosion area. At high iron concentration (approximately 60 mg/l in the bulk water), all biogenic sulfide was precipitated and corrosion had significantly enhanced. Intergranular attack was found over the entire metal surface.

Lee, W.; Characklis, W.G. (Montana State Univ., Bozeman (United States))

1993-03-01

124

NBS Papers on Underground Corrosion of Steel Piling.  

Science.gov (United States)

The monograph is a collection of published papers on underground corrosion of steel piling. The papers describe corrosion of various types of steel piling exposed underground in the United States under climatic conditions ranging from semi-tropical to fri...

W. J. Schwerdtfeger M. Romanoff

1972-01-01

125

Kinetics and structural studies of the atmospheric corrosion of carbon steels in Panama  

Science.gov (United States)

The corrosion of a carbon steel was studied in different atmospheres at sites in the Republic of Panama. The weight loss (corrosion penetration) suffered by the carbon steel is related to time by a bilogarithmic law. Mössbauer spectroscopy indicated the rust was composed of non-stoichiometric magnetite (Fe3-xO4), maghemite (?-Fe2O3), goethite (?-FeOOH) of intermediate particle size, lepidocrocite (?-FeOOH) and superparamagnetic particles. Magnetite formation is related to the alternating dry--wet cycles. Goethite is related to corrosion penetration by a saturation type of behavior, following a Langmuir type of relationship. Goethite in rust protects steel against further atmospheric corrosion.

Jaén, Juan A.; de Villalaz, Mariela Sánchez; de Araque, Lilibeth; de Bósquez, Agnes

1997-09-01

126

Wechselstromkorrosion und kathodischer Schutz - Feldversuche. Abschlussbericht. (AC corrosion and cathodic protection - field experiments. Final report).  

Science.gov (United States)

The aim of the investigation is assessing the danger of corrosion of unalloyed steels by AC currents with the simultaneous effect of cathodic protection currents. This task was caused by cases of damage to cathodically protected pipelines, where an effect...

1992-01-01

127

Corrosion of Steels in Steel Reinforced Concrete in Cassava Juice  

Science.gov (United States)

The corrosion of two types of construction steels, ST60Mn and RST37-2?, in a low cyanide concentration environment (cassava juice) and embedded in concrete had been studied. The ST60 Mn was found to be more corrosion resistant in both ordinary water and the cassava juice environment. The cyanide in cassava juice does not attack the steel but it provides an environment of lower pH around the steel in the concrete which leads to breakdown of the passivating film provided by hydroxyl ions from cement. Other factors such as the curing time of the concrete also affect the corrosion rates of the steel in the concrete. The corrosion rate of the steel directly exposed to cassava juice i.e., steel not embedded in concrete is about twice that in concrete. Long exposure of concrete structure to cassava processing effluent might result in deterioration of such structures. Careful attention should therefore be paid to disposal of cassava processing effluents, especially in a country like Nigeria where such processing is now on the increase.

Oluwadare, G. O.; Agbaje, O.

128

Effects of anaerobe in sea bottom sediment on the corrosion of carbon steel  

Energy Technology Data Exchange (ETDEWEB)

The in-situ study of steel corrosion in sea bottom sediment (SBS) was carried out by Transplanting Burying Plate method (TBP method). It was found that the corrosion rate of steel in the sea bottom sediment with sulfate reducing bacteria (SRB) could be as high as ten times of that in sea bottom sediment without SRB. The experiments in simulated sea bottom sediments with different SRB contents by artificial culturing showed that the electrochemical behavior of steel in the sea bottom sediment with SRB was different from that without SRB. SRB altered the polarization behavior of steel significantly. The environment was acidified due to the activity of SRB and the corrosion of steel was accelerated. The corrosion of carbon steel in sea bottom sediment is anaerobic corrosion, and the main factor is anaerobe. There are SRB commonly in SBS, and the amount of SRB decreases along with the depth of sediment. Because of the asymmetry and variation of sea bottom sediment, the most dangerous corrosion breakage of steel in SBS is local corrosion caused by SRB. So the main countermeasure of corrosion protection of sea bottom steel facilities should be controlling of the corrosion caused by anaerobe. (Abstract Copyright [2004], Wiley Periodicals, Inc.)

Huang, Y.; Duan, J.; Ma, S. [Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071 (China)

2004-01-01

129

Lead/carbon steel galvanic corrosion evaluation  

Energy Technology Data Exchange (ETDEWEB)

In a study aimed to select a carbon steel for its possible use as a liner for a high level radioactive waste canister, galvanic corrosion tests of lead/carbon steel galvanic couples in groundwater and in seawater were performed at 75 C. Lead behaved anodically due to a current polarity inversion phenomenon, and therefore corroded preferentially. This polarity inversion is temperature dependent. Under the same conditions, commercial lead showed higher corrosion rates in groundwater than high purity lead. No current polarity inversion was detected in galvanic tests performed either in bentonite suspensions in groundwater or in seawater. (orig.).

Semino, C.J. [Comision Nacional de Energia Atomica, Buenos Aires (Argentina). Dept. de Materiales; Burkart, A.L. [Comision Nacional de Energia Atomica, Buenos Aires (Argentina). Dept. de Materiales; Garcia, M.E. [Comision Nacional de Energia Atomica, Buenos Aires (Argentina). Dept. de Materiales; Cassibba, R. [Comision Nacional de Energia Atomica, Buenos Aires (Argentina). Dept. de Materiales

1996-11-01

130

Corrosion Behavior of Low Alloy Steels Containing Manganese in Mixed Chloride Sulfate Solution  

Science.gov (United States)

The corrosion resistance of the low alloy steels was improved by the addition of Mn up to 2.0 wt pct due to grain refinement and the formation of a protective rust layer. On the other hand, the addition of 5.0 wt pct manganese decreased the corrosion resistance of low alloy steel due to the microstructural changes that hinder the formation of the protective rust layer.

Nam, Nguyen Dang; Kim, Min Jun; Kim, Jung Gu

2013-09-01

131

Corrosion of Steel in Concrete – Thermodynamical Aspects  

DEFF Research Database (Denmark)

The present understanding of selected corrosion phenomena in reinforced concrete is reviewed. Special emphasis is given to chloride induced corrosion. There is a general acceptance of the basic corrosion mechanism for steel in concrete. However different anodic reactions governing the subsequent formation and composition of corrosion products have been proposed. Suggested reactions, except half-cell reactions, are verified or rejected based on their Gibbs free energy, while the electrode potential is calculated for half-cell reactions. Corrosion products postulated to form are related to observations. A thermodynamically possible reaction mechanism for the formation of green rust in the presence of chlorides is proposed. Initial verification of the suggested mechanism is given based on experimental data from the literature and own observations.

Küter, Andre; MØller, Per

2004-01-01

132

Modeling of marine corrosion of steel specimens  

Energy Technology Data Exchange (ETDEWEB)

Phenomenological modeling of the long term general corrosion of mild and low alloy steel specimens under marine conditions is considered, using weight loss as a function of time. A conceptual model for immersion corrosion, tidal corrosion and atmospheric corrosion under marine conditions is proposed. The model uses accepted theories for short term surface corrosion and employs modern understanding of the action of bacterial colonization of the surfaces of specimens, including the development of anaerobic conditions. Kinetic, diffusion, nutrient and anaerobic components of the model are identified and mathematical descriptions given. The model is compared to some data available in the literature. Some observations are made about data requirements for further development of models of the type proposed.

Melchers, R.E. [Univ. of Newcastle, New South Wales (Australia). Dept. of Civil, Surveying and Environmental Engineering

1997-12-31

133

Metronidazole: A Corrosion Inhibitor for Mild Steel in Aqueous Environment  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english The inhibition efficiency (IE) of metronidazole (MZ)-Zn(II) system in controlling corrosion of mild steel in aqueous solution containing 60 ppm of Cl- ion has been evaluated by weight loss method. Weight loss study reveals that the formulation consisting of 140 ppm of MZ and 50 ppm of Zn(II) has 84% inhibition efficiency in controlling corrosion of mild steel immersed in aqueous solution containing 60 ppm of Cl- ion. Polarization study reveals that this system as a mixed (more) type of inhibitor controlling the cathodic and anodic reaction to an equal extent. AC impedance reveals that a protective film is formed on the metal surface. The FTIR spectra revealed that the protective film consists of Fe(II)-MZ complex.

Megalai, S.M.; Manjula, Y. P.; Manonmani, K.N.; Kavitha, N.; Baby, N.

2012-11-01

134

S-5U: An inhibitor of acid corrosion of steel  

Energy Technology Data Exchange (ETDEWEB)

The inhibitor S-5U, based on wastes from the chemical industry and easily available raw material, is an improved modification of the inhibitor S-5. The protective action of the inhibitor is investigated by the gravimetric method in solutions of various acids. The inhibitor of acid corrosion of steel can also be used to remove hardness salts from heat-exchange apparatus in nitric acid.

Uzlyuk, M.V.; Fedorov, Y.V.; Panfilova, Z.V.; Pinus, A.M.; Tolsykh, V.F.

1985-11-01

135

Corrosion studies on alpha tantalum and beta tantalum coated steel  

Science.gov (United States)

Tantalum coating by sputtering, one form of physical vapor deposition (PVD), has been investigated as a replacement for chromium coatings on gun bores to protect them from erosion and corrosion due to its high ductility and high corrosion resistance in aggressive environments. When deposited as a film on steel substrates by sputtering, either alpha-Ta, beta-Ta, or a mixture of both phases have been observed under varying deposition conditions. To evaluate corrosion behavior of Ta coatings, electrochemical impedance spectroscopy and potentiodynamic polarization were conducted as a function of coating thickness. The coating porosity was observed to decrease with increasing coating thickness and hence, coatings greater than 50 mum exhibited corrosion resistance consistent with the bulk phase. Substrate roughness appeared to have little to no effect on the coating duality with respect to corrosion performance for 50 mum alpha-Ta coatings. Coatings produced in full scale processes revealed that for Ta coating (<50 mum), the corrosion process was dominated by dissolution of the steel substrate through open pores, however, at the end of 5 days, coating degradation was not observed. In contrast, while open pores were not observed with the Cr coatings, the corrosion resistance decreased as a function of time under acidic conditions, resulting in dissolution and oxidation of Cr. Initially, however, the sputtered Cr coating exhibited improved corrosion resistance over the electrodeposited one, potentially due to its oxide film. The unique properties of tantalum oxide films produced from anodic oxidation and thermal oxidation demonstrates that the nanoscale oxide films formed exhibit an ordered local structure reflecting the very compact nature that enhances its corrosion resistance.

Maeng, Sung Min

136

Electrochemical study of corrosion inhibition of stainless steel in phosphoric medium  

Energy Technology Data Exchange (ETDEWEB)

The corrosion of metals represents a terrible waste of both natural resources and money, the failure of some stainless steel resulting from pitting corrosion is some times considered a technological problem, consequently, much effort has been expended in attempting to understand and overcome the corrosion therefore, many stainless steel/ environment combinations have been studied. The use of heterocyclic compounds as inhibitors is one of the most practical methods for protection against corrosion in acidic media. In continuation of our work on development of macrocyclic compounds as corrosion inhibitors we report in our study the corrosion inhibiting behaviour of organic compound Methoxy-2-Allyl-4 Phenol (MAP) containing coordinating and conjugation groups, at three forms (natural, polymerized and chemically treated) on the corrosion of stainless steel in phosphoric acid. This study focused on the comparison for corrosion inhibition proprieties of these different applications using potentiodynamic polarization, electrochemical impedance spectroscopy and SEM. The specimen was evaluated to determine change in his corrosion potential and resistance polarization; These MAP products have exhibited corrosion inhibition by maintaining a high resistance polarization (low corrosion rate) in each application. These results reveal that this compound is efficient inhibitor in all forms; the most inhibition efficiency is obtained with polymerized form. To further evaluate the test data, the steel surfaces were analyzed using scanning electron microscopy, SEM observations of surface treated concrete confirmed presence of inhibitor on the steel surfaces. (authors)

Hnini, K.; Chtaini, A. [Laboratoire d' Electrochimie et de Bio Corrosion, Faculte des Sciences et Techniques, Beni-Mellal (Morocco); Khouili, M.; Elbouadili, A. [Laboratoire de Chimie Organique et Analytique, Faculte des Sciences et Techniques, Beni-Mellal (Morocco)

2004-07-01

137

Microbially Influenced Corrosion of Stainless Steels  

Energy Technology Data Exchange (ETDEWEB)

Microbially Influenced Corrosion(MIC) is often a significant factor in controlling the long-term performance of most structural materials in industrial applications. This papers cover MIC mechanism and evaluation of stainless steels in soil and sea water environments. Papers also cover detection, monitoring and mitigation of MIC, biocides and treatments. (author). 28 refs., 2 tabs., 5 figs.

Lee, Yong Deuk; Ryu, Seung Ki; Kim Young Ho [POSCO Techanical Researh Laboratories, Pohang (Korea, Republic of)

1996-06-25

138

Protective film formation of carbon steel surfaces for corrosion and deposit control in Heavy Water Plant, Manuguru (Paper No. 1.1)  

International Nuclear Information System (INIS)

Heavy Water Plant, Manuguru based on H2S-H2O bi-thermal chemical exchange process employs carbon steel as major material of construction for towers and piping. Several different phases of iron sulphide form as a result of interaction between aqueous H2S and carbon steel. Development of a procedure for formation of stable film on carbon steel as a preconditioning step was carried out based on work done by Heavy Water Division and the experiences of HWP, Kota. Heavy Water Plant, Manuguru was designed for carrying protective film formation of entire exchange unit including vessels, tanks, pipings etc. under dynamic conditions. This paper describes the procedure followed for the protective film formation of carbon steel surfaces at HWP, Manuguru. (author). 2 refs., 3 tabs., 2 figs.

1992-01-01

139

Predicting corrosion of steel in crude oil production  

Energy Technology Data Exchange (ETDEWEB)

In this paper a technique that accurately predicts the produced water level in crude oil production causing accelerated corrosion of steel (defined as the corrosion rate break produced water level) and evaluates the requirement for corrosion inhibitor treatment is presented. The primary focus is preventative corrosion engineering in corrosion prediction and chemical treatment initiation to minimize cost of corrosion control while maximizing its effectiveness. The technique is particularly useful for new crude oil discoveries in which no specific corrosion data exist.

Efird, K.D. (Occidental International Exploration and Production Co., Bakersfield, CA (US))

1991-03-01

140

Reinforcement steel corrosion in passive state and by carbonation: Consideration of galvanic currents and interface steel - concrete defaults  

International Nuclear Information System (INIS)

This thesis aims to study the durability of nuclear waste deep storage structures. The work carried out is essentially an experimental study, and focuses on the corrosion of steel in the passive state with aerated or non-aerated conditions on the one hand, and the corrosion of steel in carbonated concrete during the propagation phase on the other hand. Indeed, the pore solution of concrete in contact with the metal is alkaline (pH between 12 and 13). Under these conditions, steel reinforced concrete remains passive by forming a stable and protective oxide layer (corrosion of steel in the passive state). This passive layer limits the steel corrosion rate at very low values (negligible on a short life time) but not null. For the nuclear waste storage structures due to a very long life time (up to several hundred years), this low corrosion rate can become a risk. Therefore, it is necessary to study the evolution of the oxide layer growth over time. The objectives of the thesis are to study the influence of the steel-concrete interface quality on reinforcement corrosion in passive and active state, and the possible occurrence of galvanic corrosion currents between different reinforcement steel areas. (author)

2010-01-01

 
 
 
 
141

Investigation on corrosion of steel structures for civil engineering at thermal power station. Karyoku hatsuden shisetsu ni okeru dobokuko kozobutsu no fushoku jittai chosa  

Energy Technology Data Exchange (ETDEWEB)

For establishing diagnosis technology of steel structures at thermal power station, collection and classification of corrosion data concerning steel pipe for pier, sheet pile for shore protection, tierod, were achieved with consideration on causes of corrosion and its rate. Thus, present situation of corrosion protection technology was summarized. For the study of corrosion, destructive and non-destructive tests were conducted, by using them, corrosion rate in ocean brine and in soil were investigated. As for evaluation methods of corrosion, acceralated test, exposure test, poralized resistance test, were conducted, together with appreciation of healthiness. Regarding protective technologies, electric protection, painted film, anti-corrosive materials, were summarized. 37 refs., 19 figs., 18 tabs.

1989-10-01

142

Improvement Corrosion Resistance of Low Carbon Steel by Using Natural Corrosion Inhibitor  

Directory of Open Access Journals (Sweden)

Full Text Available Carbon steel, the most widely used engineering material, despite its relatively limited corrosion resistance used in large tonnages in marine applications, nuclear powered transportation, chemical processing , petroleum production and refining, pipelines, mining, construction and metal-processing equipment. The main objective of the present work involved the study of the inhibiting properties of natural product as Spearmint plant extract as a safety and an environmentally friendly corrosion inhibitor for low carbon steel in (3.5% NaCl) solution. Results showed when the immersion model in (3.5% NaCl) solution that contains the inhibitor with concentration of (15% in volume), it's getting a decrease in lost weight , indicating a layer of adequate oxide on the surface of the steel, indicating that the amount of loss weight decrease with increasing concentration of inhibitor and this shows the damper on his ability to form a protective layer

Khadim F. Al-Sultani; Shaymaa Abbas Abdulsada

2013-01-01

143

Corrosion inhibition of reinforcing steel by using acrylic latex  

Energy Technology Data Exchange (ETDEWEB)

Acrylic latex was introduced into steel-reinforcing steel concrete as concrete admixtures or rebar coatings in order to prevent corrosion of steel reinforcements. The results showed that applying the latex by both methods took effect in different ways, while the latter was more noticeable. The corrosion prevention mechanism and the surface state of the steel rebar were also explored, based on which suggestions for enhancing the corrosion-resistant ability were made.

Wang, S.X.; Lin, W.W.; Ceng, S.A.; Zhang, J.Q. [Zhejiang Univ., Hangzhou (China)

1998-05-01

144

Corrosion performance of martensitic stainless steel seamless pipe for linepipe application  

Energy Technology Data Exchange (ETDEWEB)

The corrosion performance of two types of weldable martensitic stainless steel seamless pipe for pipeline application is investigated. 11Cr steel pipe developed for sweet environment gives better resistance to CO{sub 2} corrosion than the 13Cr martensitic stainless steel for OCTG. 12Cr steel pipe developed for light sour environment shows good SSC resistance in a mild sour environment and superior CO{sub 2} corrosion resistance at high temperature and high CO{sub 2} partial pressure condition. The suitable condition for the 11Cr steel pipe and the 12Cr steel pipe in sweet environment, and the critical pH and H{sub 2}S partial pressure for the 12Cr steel pipe welded joint in sour environment are clarified. Both welded joints have superior resistance to hydrogen embrittlement under the cathodic protection condition in sea water.

Kimura, Mitsuo; Miyata, Yukio; Toyooka, Takaaki; Murase, Fumio [Kawasaki Steel Corp., Handa, Aichi (Japan)

1999-11-01

145

Corrosion protection of equipment in recirculating water supply systems  

Energy Technology Data Exchange (ETDEWEB)

The metals in the condensers, coolers and heat exchangers of petroleum refineries and petrochemical plants are subject to corrosion, and this is responsible for forced shutdowns. This paper notes that the shortest service life is given by the carbon and silicon-manganese steels, the longest by the chrome-nickel steels and arsenic-alloyed brasses. It reports that a high level of protection is provided by the use of the inhibitor IKB-4V at the Industrial Association ''Novopolotsknefteorgsintez'' and a so-called complex corrosion retarder consisting of a mixture of zinc sulfate and orthophosphoric acid at the Novo-Ufa refinery. It also points out that the most desirable method for corrosion protection of cooling towers, from the standpoint of technical and economic justification, is the use of protective paint coatings. It urges scientific research and design organizations and also the plants of the petroleum refining and petrochemical industry to take a multipronged approach in solving problems in corrosion control. It is pointed out that protection by inhibitors must be combined with the use of paints and other types of organic and inorganic coatings, protection against salt deposition and biological overgrowth, and the rational use of corrosion-resistant materials of construction.

Teslya, B.M.; Burlov, V.V.; Shadrina, A.N.; Vyazhevich, A.V.

1983-01-01

146

Corrosion of two kinds of cast steels containing chromium in hot concentrated alkaline  

Directory of Open Access Journals (Sweden)

Full Text Available A typical hot concentrated alkaline corrosion environment exists in alumina metallurgical industry, so that steel materials with outstanding alkaline corrosion resistance are strongly demanded for its processing equipment. In this paper, the corrosion resistance of two kinds of martensitic cast steels containing chromium in static 303g/L NaOH alkaline solution at 85? was studied through polarization and potential-time curves, corrosion weight loss and corrosion morphology analysis. Experimental results showed that protection effect by passive film of cast steel containing Cr was temporary. The low carbon steel without Cr content also exhibited chemical passivity in the same solution. The corrosion mode of the tested Cr-containing cast steel was composed of active dissolving corrosion and caustic embrittlement cracking. Dissolving corrosion was the primary mechanism for the induced weight loss, while severe caustic embrittlement cracking was secondary. With the increase of chromium content in the cast steel, the tendency of the caustic embrittlement cracking decreased, while the active dissolving corrosion increased.

LI Wei; LIU Jun-quan; TU Xiao-hui3

2007-01-01

147

Probabilistic modeling of marine corrosion of steel specimens  

Energy Technology Data Exchange (ETDEWEB)

Structural reliability estimation for steel structures exposed to marine environments is of interest for ships hulls and for offshore structures. In such estimation, the rate, extent, localization and variability of expected corrosion is important, particularly for the tidal zone, where cathodic or coating protection systems may be absent or less than wholly effective. The reliability assessment should consider the time deterioration of the strength of the structure as well as the probabilistic nature of marine corrosion, given that (1) there is insufficient data for actual structures and (2) there are a number of variables influencing corrosion. This paper describes some results from current efforts to develop non-linear and piecewise-linear phenomenological models for the probabilistic description of the corrosion of steel under given marine immersion and tidal conditions. Further, using the available data, it is shown that the uncertainty in the expected deterioration effect for both immersion and tidal zone corrosion in marine environments can be described by a time dependent log normal distribution.

Melchers, R.E. [Univ. of Newcastle (Australia). Dept. of Civil Engineering and Surveying

1995-12-31

148

Influence of microalloying on the corrosion resistance of steel in saturated calcium hydroxide  

International Nuclear Information System (INIS)

The influence of microalloying vanadium or titanium on improving the corrosion resistance of mild steel in saturated calcium hydroxide solution was investigated. Potential-time, potentiodynamic polarization, and impedance measurement techniques were employed. The corrosion products have been examined by infrared and X-ray diffraction analysis and by scanning electron microscopy. It has been shown that the grain refining, due to microalloying, plays an important role in enhancing the corrosion resistance of steel. Scales of calcite and iron oxides on top of a protective oxide are formed on the investigated steels.

1996-01-01

149

Influence of microalloying on the corrosion resistance of steel in saturated calcium hydroxide  

Energy Technology Data Exchange (ETDEWEB)

The influence of microalloying vanadium or titanium on improving the corrosion resistance of mild steel in saturated calcium hydroxide solution was investigated. Potential-time, potentiodynamic polarization, and impedance measurement techniques were employed. The corrosion products have been examined by infrared and X-ray diffraction analysis and by scanning electron microscopy. It has been shown that the grain refining, due to microalloying, plays an important role in enhancing the corrosion resistance of steel. Scales of calcite and iron oxides on top of a protective oxide are formed on the investigated steels.

Hegazy, M.M. [Helwan Univ., Cairo (Egypt). Dept. of Chemistry; Eissa, M.M. [CMRDI, Cairo (Egypt). Steel Metallurgy and Ferroalloys Dept.

1996-06-01

150

Corrosion of stainless steels by sulphur dioxide and chlorine in atmospheric conditions  

Energy Technology Data Exchange (ETDEWEB)

This paper deals with the effect of sulphur dioxide and chlorine on stainless steels (AISI 304 and 321) under different atmospheric conditions. 70% RH value was found to be critical giving maximum corrosion. Potassium dichromate has been found to be a suitable passivating agent for protection against corrosion due to chlorine. (5 refs.)

Gupta, S.; Dhirendra, Dr.; Sanyal, B.; Pandey, G.N.

1982-10-01

151

The assessment of corrosion type and corrosion rate of carbon steel in compacted bentonite  

International Nuclear Information System (INIS)

[en] Carbon steel is one of the candidate materials for overpacks for high-level radioactive waste disposal in Japan. The estimation of corrosion allowance of carbon steel overpack needs to clarify the type of corrosion and the corrosion rate under repository conditions. The type of the corrosion occurring on overpacks depends on whether carbon steel is passivated or not. If carbon steel is passivated under repository conditions, localized corrosion such as pitting, crevice corrosion and stress corrosion cracking may occur under some conditions. On the other hand, if carbon steel is not passivated under repository conditions, general corrosion will occur. Passivation behavior and corrosion rate of carbon steel were investigated by electrochemical measurements under simulated repository conditions. The results of the measurements showed that carbon steel was hard to passivate in highly compacted bentonite. The immersion tests were carried out in compacted bentonite and average corrosion rates were measured from weight loss and the AC impedance of carbon steel specimens. The database of average corrosion rate were made from the data obtained by the weight loss technique. Based on the database of average corrosion rate in compacted bentonite, the relationship between average corrosion rates and test conditions were investigated. The average corrosion depth for 1000years was also estimated to be less than 5 mm. In order to simulate the accumulation of corrosion products after long term, the external current were supplied to carbon steel specimens. After the formation of corrosion products, corrosion rates were measured using AC impedance technique. The results of the measurements showed that the corrosion rate of carbon steel did not increase in the presence of corrosion products formed by external current supply. (author)

152

Corrosion protected reversing heat exchanger  

International Nuclear Information System (INIS)

A reversing heat exchanger of the plate and fin type having multiple aluminum parting sheets in a stacked arrangement with corrugated fins separating the sheets to form multiple flow paths, means for closing the ends of the sheets, an input manifold arrangement of headers for the warm end of of the exchanger and an output manifold arrangement for the cold end of the exchanger with the input air feed stream header and the waste gas exhaust header having an alloy of zinc and aluminum coated on the inside surface for providing corrosion protection to the stack

1984-01-01

153

Corrosion protected reversing heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

A reversing heat exchanger of the plate and fin type having multiple aluminum parting sheets in a stacked arrangement with corrugated fins separating the sheets to form multiple flow paths, means for closing the ends of the sheets, an input manifold arrangement of headers for the warm end of of the exchanger and an output manifold arrangement for the cold end of the exchanger with the input air feed stream header and the waste gas exhaust header having an alloy of zinc and aluminum coated on the inside surface for providing corrosion protection to the stack.

Zawierucha, R.

1984-09-25

154

Galvanic corrosion between carbon steel 1018 and Alloy 600 in crevice with boric acid solution  

International Nuclear Information System (INIS)

This work dealt with the evaluation of galvanic corrosion rate in a corrosion cell having annular gap of 0.5 mm between carbon steel 1018 and alloy 600 as a function of temperature and boron concentration. Temperature and boron concentration were ranged from 110 to 300 .deg. C and 2000?10000 ppm, respectively. After the operating temperature of the corrosion cell where the electrolyte was injected was attained at setting temperature, galvanic coupling was made and at the same time galvanic current was measured. The galvanic corrosion rate decreased with time, which was described by corrosion product such as protective film as well as boric acid deposit formed on the carbon steel with time. From the galvanic current obtained as a function of temperature and boron concentration, it was found that the galvanic corrosion rate decreased with temperature while the corrosion rate increased with boron concentration. The experimental results obtained from galvanic corrosion measurement were explained by adhesive property of corrosion product such as protective film, boric acid deposit formed on the carbon steel wall and dehydration of boric acid to be slightly soluble boric acid phase. Moreover the galvanic corrosion rate calculated using initial galvanic coupling current instead of steady state coupling current was remarked, which could give us relatively closer galvanic corrosion rate to real pressurized water reactor

2005-01-01

155

Galvanic corrosion between carbon steel 1018 and Alloy 600 in crevice with boric acid solution  

Energy Technology Data Exchange (ETDEWEB)

This work dealt with the evaluation of galvanic corrosion rate in a corrosion cell having annular gap of 0.5 mm between carbon steel 1018 and alloy 600 as a function of temperature and boron concentration. Temperature and boron concentration were ranged from 110 to 300 .deg. C and 2000{approx}10000 ppm, respectively. After the operating temperature of the corrosion cell where the electrolyte was injected was attained at setting temperature, galvanic coupling was made and at the same time galvanic current was measured. The galvanic corrosion rate decreased with time, which was described by corrosion product such as protective film as well as boric acid deposit formed on the carbon steel with time. From the galvanic current obtained as a function of temperature and boron concentration, it was found that the galvanic corrosion rate decreased with temperature while the corrosion rate increased with boron concentration. The experimental results obtained from galvanic corrosion measurement were explained by adhesive property of corrosion product such as protective film, boric acid deposit formed on the carbon steel wall and dehydration of boric acid to be slightly soluble boric acid phase. Moreover the galvanic corrosion rate calculated using initial galvanic coupling current instead of steady state coupling current was remarked, which could give us relatively closer galvanic corrosion rate to real pressurized water reactor

Kim, Dong Jin; Kim, Hong Pyo; Kim, Joung Soo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Machonald, Digby D. [The Pennsylvania State University, University Park (United States)

2005-06-15

156

Production, properties and application of steels resistant to atmospheric corrosion  

International Nuclear Information System (INIS)

[en] Steels, resistant to atmospheric corrosion, applied in the USSR and abroad, are reviewed. The influence of alloying elements (Cu, P, Cr, Si, Ni, Mo, Mn, As etc) upon resistance against atmospheric corrosion and mechanical properties of rolled steel is discussed. Technological properties, fields of the above steels application as well as the data on the range of product, are presented

1978-01-01

157

Real-time measurement of corrosion in steel cord belts  

Energy Technology Data Exchange (ETDEWEB)

Monitoring corrosion in steel cord belts started in 1979 in Australia with the development of the conveyor belt monitoring system known as 'cbm'. While corrosion monitoring is not widely used today, it still has some special applications which are described in this paper. In particular, long term corrosion and corrosion at rip detection loops can be detected with modern day corrosion monitoring systems. Commercially used non-destructive test (NDT) equipment, such as broken cable monitors, can be inaccurate when trying to identify corrosion from cable damage data. This paper discusses the necessity of corrosion monitoring as an essential part of damage evaluation in steel cord belts. (orig.)

Harrison, A.; Moore, K. [Conveyor Technologies Ltd., Aurora, CO (United States)

1999-12-01

158

Metallic nitrides for corrosion protection in marine environments: Theory compared to experimental results  

Energy Technology Data Exchange (ETDEWEB)

A theoretical and experimental study was conducted to predict and test the corrosion behavior of metallic nitride films on stainless steel. Theoretical prediction of corrosion resistance properties was conducted by the construction and interpretation of Pourbaix Diagrams for metallic nitrides. Electrochemical Impedance Spectroscopy (EIS) was then employed to determine whether the predicted corrosion protection in a marine environment was obtained. This study found that in most cases, the use of Pourbaix Diagrams to predict corrosion resistance on 304 stainless steel gave accurate results and is a useful technique for material selection of nitride/substrate combinations for corrosion resistance.

Giaimo, A.; Alias, M.N.; Brown, R. [Univ. of Rhode Island, Kingston, RI (United States)

1997-12-01

159

Microbial corrosion and cracking in steel. Assessment of soil corrosivity using an electrochemical soil corrosion probe  

Energy Technology Data Exchange (ETDEWEB)

An electrochemical soil corrosion probe has been designed, manufactured, and tested at five different locations in the field. The probe includes facilities for hydrogen permeation measurements, local soil resistivity measurements by the Wenner fourpoint method, and open circuit potential measurements on carbon steel- and high-alloyed (SMO-254) stainless steel electrodes. The carbon steel electrodes were arranged as two sets of three-electrode arrangements. Using these arrangements, electrochemical impedance spectroscopy (EIS), galvanostatic pulse (GP) measurements, and DC polarisation scans were applied for characterisation of the corrosion conditions present in the soil. (au) EFP-95. 21 refs.

Vendelbo Nielsen, L.

1998-08-01

160

Investigation of Corrosion and Cathodic Protection in Reinforced Concrete. I: Application of Electrochemical Techniques  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The electrochemical behavior of steel reinforcement in conditions of corrosion and cathodic protection was studied, using electrochemical impedance spectroscopy (EIS) and compared to reference (noncorroding) conditions. Polarization resistance (PR) method and potentiodynamic polarization (PDP) were ...

Koleva, D.A.; De Wit, J.H.W.; Van Breugel, K.; Lodhi, Z.F.; Van Westing, E.

 
 
 
 
161

Application of Electrochemical Impedance Spectroscopy in the Evaluation of Corrosion and Cathodic Protection in Reinforced Concrete  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The electrochemical behavior of steel reinforcement in conditions of corrosion and cathodic protection (CP) was studied, using electrochemical impedance spectroscopy (EIS) and compared to reference (non-corroding) conditions. Polarization resistance (PR) method and potentio-dynamic polarization (PDP...

Koleva, D.A.; Van Breugel, K.; De Wit, J.H.W.; Fraaij, A.L.A.; Boshkov, N.

162

Erosion-corrosion behavior and cathodic protection of alloys in seawater-sand slurries  

Science.gov (United States)

An experimental study was conducted on the erosion-corrosion behavior of three alloys in seawater-sand slurries. The idea explored was to select a steel, a copper alloy, and a titanium alloy, which should have good resistance to abrasive wear because of high hardness (within their alloy classes). Then cathodic pro-tection would be used to protect them from corrosion. The alloys studied were 4340 steel, silicon bronze, and titanium alloy Ti-6V-4Al. Limiting conditions for cathodic protection were derived from electro-chemical polarization measurements. From erosion-corrosion tests, it was found that erosive wear by sand dominated the metal loss rates of both silicon bronze and Ti-6V-4Al. For the 4340 steel, which was the hardest material, cathodic protection provided good erosion-corrosion resistance. Supplementary measurements showed that ductility loss due to cathodically charged hydrogen in the 4340 steel was neg-ligible under the experimental conditions.

Yang, J.; Swisher, J. H.

1993-12-01

163

Atmospheric corrosion of mild steel in Oman  

Science.gov (United States)

A systematic study has been made of the initial corrosion products which form on mild steel capons exposed near the coastal region of Oman and at some industrial areas. The phases and compositions of the products formed at different periods of exposure were examined by using Mossbauer spectroscopy (295 and 78 K) and X-ray diffraction (XRD) techniques. The results show that lepidocorcite and maghemite are early corrosion products and goethite starts to form after 2 months of metal exposure to the atmosphere. Akaganeite is an early corrosion product but it forms in marine environments only, which reflects the role of chlorine effect in the atmosphere. The 12 months coupons showed the presence of goethite, lepidocorcite and maghemite, but no akaganeite being seen in the products of one of the studied areas.

Gismelseed, Abbasher; Al-Harthi, S. H.; Elzain, M.; Al-Rawas, A. D.; Yousif, A.; Al-Saadi, S.; Al-Omari, I.; Widatallah, H.; Bouziane, K.

164

Atmospheric corrosion of mild steel in Oman  

International Nuclear Information System (INIS)

[en] A systematic study has been made of the initial corrosion products which form on mild steel capons exposed near the coastal region of Oman and at some industrial areas. The phases and compositions of the products formed at different periods of exposure were examined by using Moessbauer spectroscopy (295 and 78 K) and X-ray diffraction (XRD) techniques. The results show that lepidocorcite and maghemite are early corrosion products and goethite starts to form after 2 months of metal exposure to the atmosphere. Akaganeite is an early corrosion product but it forms in marine environments only, which reflects the role of chlorine effect in the atmosphere. The 12 months coupons showed the presence of goethite, lepidocorcite and maghemite, but no akaganeite being seen in the products of one of the studied areas.

2006-01-01

165

Concrete cover cracking with localized corrosion of reinforcing steel  

Energy Technology Data Exchange (ETDEWEB)

The critical amount of steel corrosion needed for concrete cover cracking of a reinforced concrete element was measured, focusing on cases where only a fraction of the steel bar length is corroding. The amount of corrosion needed to crack the concrete cover was found to range between 49 micrometre to 137 micrometre in specimens of localized corrosion. In contrast, in cases of uniform corrosion of comparable systems the corrosion needed to crack the concrete cover varied from 15 micrometre to 75 micrometer. Based on this and previous work on this problem, an empirical equation is proposed for the critical amount of steel corrosion as a function of specimen dimensions. The model proposed for estimating the critical amount of steel corrosion showed reasonable agreement between estimates of the work of corrosion expansion and the energy required to crack the concrete. 23 refs., 3 tabs., 8 figs.

Torres-Acosta, A. A.; Sagues, A. A. [South Florida Univ., Dept of Civil and Environmental Engineering, Tampa FL (United States)

2000-07-01

166

Corrosion of steel in concrete in cooling water walls. Report part 3 - Corrosion of steel in water saturated concrete  

International Nuclear Information System (INIS)

It is a well known fact that for concrete structures exposed to water the splash zone exhibit the greatest risk for corrosion on the reinforcement. Chloride ions are enriched and the supply of oxygen is good. Below the water table reported corrosion damages are few. The threshold for chloride content is in most cases exceeded but the propagation rate is low due to slow diffusion rate of oxygen in water saturated concrete. Despite this, ongoing corrosion of reinforcement has been observed in cooling water systems at the Swedish nuclear power plants. The aim of this project has been to identify and qualitatively quantify the importance of different possible mechanisms involved in corrosion of reinforcement in water saturated concrete. This has been achieved by collecting experiences, literature survey, modelling, theoretical calculations, experimental investigations as well as field measurements. The investigations have resulted in several new findings. The following have been concluded: In water saturated concrete, without the existence of macro cells, the reinforcement corrodes in an active state but with a very low rate. This active corrosion proceeds independently of the chloride content of the concrete. The corrosion rate is low even with thin concrete cover and most probably even if the concrete has been leached. Nor does high velocity of the cooling water create serious attacks. Inspections have unveiled attacks of reinforcement corrosion in the splash zone, in walls externally exposed to air and in the vicinity to pumps. In the splash zone the attacks occur above the water level. The absence of a macro cell resulting in increased corrosion on parts below the water line is of subordinate importance and is judged being without practical influence. The corrosion takes place where the environmental conditions are optimal. The same is valid for walls externally exposed to air. The macro cell is of subordinate importance. In the vicinity of pumps, observed corrosion, is probably caused by galvanic corrosion as a consequence of incomplete cathodic protection of stainless steel surfaces within the pumps. Single rebar's being isolated from the rest of the reinforcement can be exposed to stray current corrosion if they are located close to a cathodically protected structure having a high demand for protective current. Concrete structures of greater extent can be exposed to stray current interference caused by high voltage direct current transmission lines located in the neighbourhood. Future installations of cathodic protection in extended culverts should not imply connection of separate parts to each other. The risk of alternating current corrosion is judged to be minimal. If it was not for the corrosion observed on reinforcement on the Oeland Bridge and in Gothenburg harbour, which until now has not been explained, corrosion should be possible to exclude in other positions than the splash zone, walls externally exposed to air and in the vicinity to unprotected structures of stainless steel

2009-01-01

167

Corrosion Test of US Steels in Lead-Bismuth Eutectic (LBE) and Kinetic Modeling of Corrosion in LBE Systems  

International Nuclear Information System (INIS)

We present the LBE corrosion test results of several US steels, and a preliminary analysis using a kinetic model for corrosion in LBE systems. Tube and rod specimens of austenitic steels 316/316L, D9, ferritic/martensitic steels HT-9 and T- 410 and Russian martensitic steel EP823 were inserted in an LBE loop CU-1M at IPPE. The oxygen concentration in LBE was between 3-5x10-6 wt% and the flow velocity in the test sections was 1.9 m/s. The tests were performed simultaneously at 460 and 550 deg. C for 1000, 2000 and 3000 hours. Weight change, optical, SEM and X-ray analysis of the specimen performed, obtaining results on oxide film thickness, corrosion depth, microstructure and composition changes. Protective oxide films formed on the surfaces of all steels. The oxides on austenitic steels are thin compared to the oxides on ferritic/martensitic steels, which have pronounced double layer structure. T-410 specimens suffered local corrosion. Parallel to the experimental investigations, a kinetic model was developed for corrosion and corrosion product transport in oxygen controlled LBE systems. Our model incorporates the species distribution based on local thermodynamic equilibrium at the surface of structural materials into boundary conditions, and directly calculates mass transport through boundary layer diffusion and convection in the bulk flow. The model predicts drastic reduction of corrosion when oxygen in LBE is properly controlled. It also predicts complex profiles of corrosion and precipitation in flow loops that are dependent upon global conditions. This indicates that the straightforward test results may have limited applicable range if the configuration and conditions of the entire test loop are not carefully taken into account. (authors)

2002-01-01

168

Calculation of minimum cathodic protection potential of carbon steel in soil using cathodic polarization curve  

International Nuclear Information System (INIS)

Consideration is given to the simple method for calculating the minimal protective potential and corrosion rate of steel in soil using cathode curve and the value of free corrosion potential. The suggested electrochemical method for calculating corrosion rate at cathode polarization requires the minimal number of experimental data (cathode polarization curve and E cor value) and calculation procedure is very simple.

1994-01-01

169

Thin film corrosion protecting coatings for high temperature fuel cells  

Energy Technology Data Exchange (ETDEWEB)

One of the major problems in high temperature fuel cells (molten carbonate fuel cells and solid oxide fuel cells) is the corrosion of metallic components. A method to solve this problem was proposed. Stainless steel components are usually protected by coatings which tend to diffuse into the substrate. This results in reduced protection or even a complete loss of protection. It was suggested that a diffusion barrier applied between the coating and substrate could solve this problem. The corrosion of steel sheet material coated with a diffusion layer and a corrosion protecting layer was studied. Materials studied included the refractory metals molybdenum, tungsten, chromium nitride and titanium nitride. Auger electron spectroscopy (AES) depth profiles were described for samples coated with each of these materials as a diffusion barrier and with a nickel layer on top before diffusion. AES revealed a very low diffusion of components from the coatings to the substrate and vice versa. Metallographic cross sections also showed that the system prevents corrosion almost completely. 9 refs., 9 figs.

Wind, J.; Nitschke, F.; Meyer, M. [Daimler-Benz AG, Berlin (Germany). Forschung Technikumfeld

1997-12-31

170

Relationships between anodic polarization and corrosion of steel in concrete  

Energy Technology Data Exchange (ETDEWEB)

Corrosion of reinforcement in concrete is a topic of concern mainly because of the high cost of repair and rehabilitation of concrete structural elements. There is as yet no method of assessment that would enable the rapid and accurate prediction of the extent of corrosion of reinforcing steel in concrete on site. Half cell potential techniques commonly used in situ give only probabilistic information on corrosion activity. Research effort is thus needed in both investigating and developing methods to assess more accurately the corrosion characteristics of steel in concrete with an ultimate view of site application. Long-term investigations on chloride induced corrosion of steel reinforcement have been conducted on a series of concrete slab specimens to establish relationships between electrochemical data and chloride induced corrosion of steel reinforcement. Potentiodynamic anodic polarization procedures were used to monitor corrosion of steel reinforcement in concrete slab specimens over a period of four years. A statistically significant relationship between the area under the corrosion current and time relationship and the weight loss of steel reinforcement was established. Assessments of corrosion rates of steel in the concretes studied were thus verified. Reinforcement corrosion was found to be localized under the high chloride conditions occurring mainly in an area adjacent to the chloride source.

Baweja, D.; Sirivivantnanon, V. (CSIRO Div. of Building, North Ryde (Australia). Construction and Engineering); Roper, H. (Univ. of Sydney, Redfern (Australia). School of Civil and Mining Engineering)

1993-11-01

171

Protection of mild steel corrosion with Schiff bases in 0.5 M H{sub 2}SO{sub 4} solution  

Energy Technology Data Exchange (ETDEWEB)

Three new Schiff bases, viz., N,N'-ethylen-bis (salicylideneamino) [S{sub 1}], N,N'-isopropenyl-bis (salicylideneamino) [S{sub 2}], and N-acetylacetone imine, N'-(2-hydroxybenzophenone imine) ortho-phenyl en [S{sub 3}] have been investigated as corrosion inhibitors for mild steel in 0.5 M H{sub 2}SO{sub 4} using Tafel polarization and electrochemical impedance spectroscopy (Ei). The three Schiff bases function as good inhibitors reaching inhibition efficiencies of {approx}97-98% at 300 ppm concentration. The fraction of the metal surface covered by the inhibitor is found to increase with inhibitor concentration. Of the three Schiff bases, the S shows better efficiency than the other two Schiff bases. The adsorption of the inhibitor follows Langmuir isotherm. Thermodynamic calculations indicate the adsorption to be physical in nature.

Hosseini, M.G. [Electrochemistry Research Laboratory, Physical Chemistry Department, Chemistry Faculty, Tabriz University (Iran, Islamic Republic of)]. E-mail: mg-hosseini@tabrizu.ac.ir; Ehteshamzadeh, M. [Department of Materials Science and Engineering, Tarbiat Modarres University, Tehran (Iran, Islamic Republic of); Shahrabi, T. [Department of Materials Science and Engineering, Tarbiat Modarres University, Tehran (Iran, Islamic Republic of)

2007-03-01

172

Corrosion Protection of Electrically Conductive Surfaces  

Directory of Open Access Journals (Sweden)

Full Text Available The basic function of the electrically conductive surface of electrical contacts is electrical conduction. The electrical conductivity of contact materials can be largely reduced by corrosion and in order to avoid corrosion, protective coatings must be used. Another phenomenon that leads to increasing contact resistance is fretting corrosion. Fretting corrosion is the degradation mechanism of surface material, which causes increasing contact resistance. Fretting corrosion occurs when there is a relative movement between electrical contacts with surfaces of ignoble metal. Avoiding fretting corrosion is therefore extremely challenging in electronic devices with pluggable electrical connections. Gold is one of the most commonly used noble plating materials for high performance electrical contacts because of its high corrosion resistance and its good and stable electrical behavior. The authors have investigated different ways to minimize the consumption of gold for electrical contacts and to improve the performance of gold plating. Other plating materials often used for corrosion protection of electrically conductive surfaces are tin, nickel, silver and palladium. This paper will deal with properties and new research results of different plating materials in addition to other means used for corrosion protection of electrically conductive surfaces and the testing of corrosion resistance of electrically conductive surfaces.

Jian Song; Liangliang Wang; Andre Zibart; Christian Koch

2012-01-01

173

Influence of burnishing on stress corrosion cracking susceptibility of duplex steel  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: of the current study was to investigate the usability of burnishing-inducted surface enhancement method for improve the stress corrosion cracking resistance of duplex stainless steel.Design/methodology/approach: The surface layers upon round in cross section specimens were performed through burnishing treatment. Corrosion tests were performed with the use of Slow Strain Rate Test technique in inert (glycerin) and aggressive (boiling 35% MgCl2 solution) environments.Findings: It was shown that burnishing treatment increases corrosion resistance of the steel. Stress corrosion cracking resistance depends on the magnitude of cold work at surface layers. High level of cold work decreases corrosion resistance.Research limitations/implications: This study does not indicate the optimum stress level and stress distribution in surface layers for the best corrosion resistance. It is necessary to continue the research to determine burnishing parameters for demanded properties of duplex steel surface layers.Practical implications: The burnishing treatment can significantly improve stress corrosion resistance of specified parts of chemical installations working in the contact with aggressive media. Such parts as valve parts or propeller shafts can be successfully protected against corrosion attack.Originality/value: Burnishing surface enhancement for constructional parts made of duplex stainless steels exposed to corrosive environments has not been reported in literature. Application of this technology can increase life-time of chemical installation devices and improve their reliability.

J. ?abanowski; A. Ossowska

2006-01-01

174

Measurement of corrosion under insulation and effectiveness of protective coatings  

Energy Technology Data Exchange (ETDEWEB)

A laboratory cell set-up was designed and constructed for the simulation of corrosion under insulation (CUI) on a pipe section at elevated temperature. The CUI cell consisted of six carbon steel ring specimens separated by insulation spacers and held together by blind flanged pipe sections on both ends. Thermal insulation which was placed around the testing section provided the annular space to retain the test environment. The ring specimens were used as test electrodes in two separate electrochemical cells. One cell was used as the control while the other was used to test applied protective coatings. Corrosion measurements were made using both electrochemical polarization resistance and mass loss data under isothermal and cyclic wet/dry test conditions. The test cell was used to (1) successfully simulate CUI in the laboratory, (2) evaluate the corrosivity and different modes of corrosion observed with CUI and (3) evaluate proprietary coatings for minimizing CUI under simulated CUI conditions.

Abayarathna, D.; Ashbaugh, W.G.; Kane, R.D. [CLI International, Inc., Houston, TX (United States); McGowan, N. Heimann, B. [Elisha Technologies Co., Moberly, MO (United States)

1997-08-01

175

A study on the N-, S- and Cl-modified nano-TiO2 coatings for corrosion protection of stainless steel  

International Nuclear Information System (INIS)

Nano-titania coatings doped with anions of nitrogen, sulfur and chlorine have been supplied on the surface of 316L stainless steel by a sol-gel process and dip-coating technique. The measurements of XRD, SEM, ATR-IR, Raman and XPS were carried out to characterize the chemical composition and structure for the prepared samples. The corrosion performances of the coating in 0.5 M NaCl were evaluated by electrochemical impedance spectroscopy (EIS) and polarization measurements. According to the measurements of EIS and electrochemical polarization, the N-modified TiO2 nano-coatings show a highest corrosion resistance among the prepared coatings. It is revealed, from the SEM, XRD and Raman characterizations, that the surface of N-modified TiO2 nano-coatings are more compact and uniform, relatively well-crystallized and able to act as an optimal barrier layer to metallic substrates. The XPS analysis confirms the presence of low concentration of N element in two forms, atomic ?-N (interstitial state) and chemisorbed ?-N2 on the surface of TiO2 nano-coatings. It is suggested that the addition of nitrogen is beneficial to improve the compact structure and enhance the hydrophobic property.

2007-08-01

176

Effect of debonded interfaces on corrosion of mild steel composites in supercritical CO2-saturated brines  

Energy Technology Data Exchange (ETDEWEB)

The geologic sequestration of CO{sub 2} is a proposed method to limit greenhouse gas emissions and has been the subject of many studies in the last decade. Wellbore systems achieve isolation of the storage reservoir through a combination of steel (generally carbon steel) and Portland cement. CO{sub 2} leakage along the steel-cement interface has the potential to accelerate corrosion. We conduct experiments to assess the corrosion risk at cement-steel interface under in situ wellbore conditions. Wellbore interfaces were simulated by assemblies constructed of J55 mild steel and Portland class G (Epoxy was used in this study to separate) cement and corrosion was investigated in supercritical CO{sub 2} saturated brines, (NaCl = 1 wt%) at T = 50 C, pCO{sub 2} = 1200 psi with interface gap size = 100 {micro}m and {infinity} (open surface). The experiments were carried out in a high-pressure, 1.8 L autoclave. The corrosion kinetics were measured employing electrochemical techniques including linear polarization resistance and electrochemical impedance spectroscopy techniques. The corrosion scales were analyzed using secondary electron microscopy, back scattering electron microscopy, energy dispersive spectroscopy and x-ray diffraction. Corrosion rates decreased as time with or without interface gap. In this case corrosion rates are controlled by scale protectivity through the interface gap. Scaled steel corrosion rates were two orders of magnitude less compared with fresh steel. The corrosion scale is pseudo crystalline at the open interface. Well-crystallized scale was observed at interface gap sizes 100 {micro}m. All corrosion scales were composed of iron carbonates.

John, Han [Los Alamos National Laboratory; Carey, James W [Los Alamos National Laboratory; Zhang, Jinsuo [Los Alamos National Laboratory

2010-10-07

177

Diamond smoothing effect on chloride corrosion cracking resistance of Kh17N15 steel  

International Nuclear Information System (INIS)

[en] Results of investigation into effect of the surface plastic deformation of metal using diamond smothing method on resistance of Kh17N15 steel to chloride corrosion cracking are presented. Peculiarities of thin-wall article treatment, effect of smothing conditions and conditions of steel charging for electrochemical and corrosion behaviour in high parameter chloride-containing water, are discussed. Application perspective of diamond smothing to protect articles working under loads lower than the conventional yield strength against corrosion cracking, is shown

1992-01-01

178

Special features of corrosion of chrome-nickel-molybdenum steel in friction in electrolytes  

Energy Technology Data Exchange (ETDEWEB)

The authors use potentiometry along with chemical and mechanical methods to investigate the mutual effects of wear and electrochemical corrosion on the integrity of Steel-08KH21N6M2T under conditions of sliding friction and in electrolytes consisting of sulfuric acid, sodium sulfate and sodium hydroxide. They construct a mathematical model of the wear and corrosion kinetics which incorporates the surface properties of the steel and the current density and pH of the electrolyte and discuss possibilities for protecting the alloy from both wear and corrosion.

Lazarev, G.E.; Afanas' ev, K.I.

1987-01-01

179

Corrosion and corrosion protection of RE-Fe-B magnets  

International Nuclear Information System (INIS)

[en] The corrosion behavior of Nd-Fe-B magnets is addressed in this paper. It varies depending on the alloy composition, surface condition, and corrosion environment and temperature. The kinetics of corrosion of Nd-Fe-B magnets in deionized water at room temperature are usually a gradual weight decrease, while those in an autoclave environment are generally a two-step weight change: first, an incubation step; second, linear weight loss. The corrosion products in deionized water are mainly Fe (OH)2, while those in an autoclave are mainly Nd(OH)3. Magnets surface treated with H2CrO4, HF, H3PO4, or their combinations exhibit a significant improvement in corrosion resistance compared with untreated magnets. The mechanism of corrosion protection for Nd-Fe-B magnets by surface treatment with H2CrO4 is believed to be removal of the nucleation site for corrosion by chromic acid etch, and formation of a protective film on the surface by chromate conversion. The combination of surface treatment and alloying with elements such as Dy will further improve the corrosion resistance of the magnet

1989-01-01

180

Electrochemical protection of pointed metallic structures from atmospheric corrosion  

International Nuclear Information System (INIS)

[en] Efficiency of electrochemical protection (ECP) of steel against atmospheric corrosion under thin electrolyte films is investigated. It is shown that the zone of ECP action is restricted by a low conductivity of moisture films, occurring on metals under natural conditions. A method of increasing ECP efficiency by means of using electroconducting coatings applied to standard paint and varnish coatings, is proposed. 6 refs., 2 figs

1994-01-01

 
 
 
 
181

Investigation of corrosion behavior of Mg-steel laser-TIG hybrid lap joints  

Energy Technology Data Exchange (ETDEWEB)

Highlights: Black-Right-Pointing-Pointer Galvanic corrosion increases the corrosion rate of the Mg-steel joint. Black-Right-Pointing-Pointer Fe splashes lower the corrosion resistance of the joint greatly. Black-Right-Pointing-Pointer The effect of grain refinement on the corrosion behavior of the joint is slight. Black-Right-Pointing-Pointer Ni or Cu interlayer could not improve the corrosion resistance of fusion zone. Black-Right-Pointing-Pointer The arc-sprayed coating could enhance the reliability of weld joint. - Abstract: The paper investigates the corrosion behavior of the lap joint of AZ31 magnesium alloy to Q235 steel with salt solution immersion testing and electrochemical testing. It is demonstrated that grain refinement resulting from the welding process has little effect on the corrosion behavior of the lap joint. However, the cathodic phases formed in the welding process and the galvanic corrosion between magnesium alloy and steel decrease the corrosion resistance of the joint greatly. Besides, neither Cu nor Ni, as filler material, could improve the corrosion resistance of the joint, but the arc-sprayed Al coating acting as a protective layer could.

Liu Liming, E-mail: liulm@dlut.edu.cn [Key Laboratory of Liaoning Advanced Welding and Joining Technology, School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China); Xu Rongzheng [Key Laboratory of Liaoning Advanced Welding and Joining Technology, School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China)

2012-01-15

182

Improved corrosion protection of powered roof supports  

Energy Technology Data Exchange (ETDEWEB)

Corrosion damage to equipment has required British Coal to spend considerable sums of money on refurbishing. The corrosion protection currently applied during equipment manufacture is influenced more by initial costs than by total life cost. This paper describes a major corrosion project which was conducted to assess metallic, paint and plastic coatings for the protection of powered roof support components. The project involved evaluation of coatings in the laboratory and on coal face installations, estimating the total life costs and deciding upon the most suitable coatings for future use. About 16000 components were involved in the field trials: the costs and production schedules relating to the protective systems were thus representative of large scale use. Forty two protective coatings were used in the underground field trials, with varying degrees of success. The results enabled an improved corrosion protection scheme to be produced whose use should result in substantial savings to British Coal. 6 refs., 6 figs., 6 tabs.

Griffiths, J.R.; Talks, M.G.; Trudgeon, M.A.

1988-12-01

183

Evaluation of the susceptibility to pitting corrosion of structural steels, including steels with modified surface  

International Nuclear Information System (INIS)

Although the low alloy ferrite-perlite and bainite-martensite steels mostly undergo the general corrosion, pitting corrosion occurring under certain conditions jeopardizes the safety of installations, causing perforation of walls or initiation of crack. On the basis of electrochemical, corrosion and microscopic examinations, the conditions simulating typical industrial corrosion environments, containing Cl- ions have been selected, to which the parts of machines, devices and installation are subjected. The test parameters provide the preferential pitting corrosion without prevailing general corrosion, and provide the similar type of corrosion of different kinds of ferrite-perlite and bainite-martensite steels, including steels with modified surface layer. The proposed express method allows to evaluate the susceptibility to pitting corrosion and to evaluate the effect of surface modification on susceptibility to pitting corrosion in environments containing Cl- ions. The method may be applied for the proper selection of materials exploited under pitting corrosion conditions and for preparation of precorroded samples for mechanical testing. (author)

2001-01-01

184

Atmospheric Corrosion on Steel Studied by Conversion Electron Mössbauer Spectroscopy  

Science.gov (United States)

In order to investigate initial products on steel by atmospheric corrosion, conversion electron Mössbauer measurements were carried out at temperatures between 15 K and room temperature. From the results obtained at low temperatures, it was found that the corrosion products on steel consisted of ferrihydrite.

Nakanishi, Akio; Kobayashi, Takayuki

2004-12-01

185

Atmospheric Corrosion on Steel Studied by Conversion Electron Moessbauer Spectroscopy  

International Nuclear Information System (INIS)

[en] In order to investigate initial products on steel by atmospheric corrosion, conversion electron Moessbauer measurements were carried out at temperatures between 15 K and room temperature. From the results obtained at low temperatures, it was found that the corrosion products on steel consisted of ferrihydrite.

2004-01-01

186

Aminopyrimidine derivatives as inhibitors for corrosion of 1018 carbon steel in nitric acid solution  

Energy Technology Data Exchange (ETDEWEB)

The effect of some aminopyrimidine derivatives on the corrosion of 1018 carbon steel in 0.05 M HNO{sub 3} solution was studied using weight loss and polarization techniques. The percentage inhibition efficiency was found to increase with increasing concentration of inhibitor and with decreasing temperature. The addition of KI to aminopyrimidine derivatives enhanced the inhibition efficiency due to synergistic effect. The inhibitors are adsorbed on the steel surface according to Temkin isotherm. Some thermodynamic functions were computed and discussed. It was found that the aminopyrimidine derivatives provide a good protection to steel against pitting corrosion in chloride containing solutions.

Abdallah, M. [Chemistry Department, Faculty of Science, Benha University, Benha (Egypt)]. E-mail: metwally552@hotmail.com; Helal, E.A. [Corrosion Department, Badr El-Din Petroleum company (Egypt); Fouda, A.S. [Chemistry Department, Faculty of Science, Mansoura University, Mansoura 35516 (Egypt)]. E-mail: asfouda@yahoo.com

2006-07-15

187

Aminopyrimidine derivatives as inhibitors for corrosion of 1018 carbon steel in nitric acid solution  

International Nuclear Information System (INIS)

The effect of some aminopyrimidine derivatives on the corrosion of 1018 carbon steel in 0.05 M HNO3 solution was studied using weight loss and polarization techniques. The percentage inhibition efficiency was found to increase with increasing concentration of inhibitor and with decreasing temperature. The addition of KI to aminopyrimidine derivatives enhanced the inhibition efficiency due to synergistic effect. The inhibitors are adsorbed on the steel surface according to Temkin isotherm. Some thermodynamic functions were computed and discussed. It was found that the aminopyrimidine derivatives provide a good protection to steel against pitting corrosion in chloride containing solutions.

2006-01-01

188

Variables affecting mixed oxidant corrosion of stainless steels in gasifiers  

International Nuclear Information System (INIS)

This paper is the final installment of EPRI's project on corrosion in syngas coolers of integrated coal gasification combined cycle plant. In previous papers we explored the effect of chloride species on mixed oxidant corrosion of stainless steels (CORROSION 97, paper 134) and iron aluminides (CORROSION 98, paper 185). It was found that the amount of chloride species in the gas and in deposits largely determined the rate of corrosion. Armed with this understanding the effect of a few common process variables is explored in this paper. It was found that corrosion rates decline at higher temperatures when chloride-enhanced mixed oxidant corrosion occurs at lower temperatures, but corrosion rates increase with temperature for pure sulfidation/oxidation, as may be expected. System pressure was generally of secondary importance, but again higher corrosion rates were generally experienced at elevated pressure, when chloride-enhanced corrosion was predominant, especially at lower temperatures. A simulated temperature excursion below the syngas dewpoint had similar effects, and also caused chloride enhanced corrosion in 310 stainless steel, which usually does not show this type of corrosion, except when exposed to aqueous corrosion during downtime. A pleasant surprise was the almost complete lack of corrosion when H2S and HCl levels were reduced to those expected downstream from gasifiers using in-bed desulfurization. It would appear that 12Cr steels may be adequate here. This is being explored further. (orig.)

2000-01-01

189

Internal isotope dilution. [Electrochemical corrosion, low alloy steels  

Energy Technology Data Exchange (ETDEWEB)

A variant of the isotope dilution technique, the internal isotope dilution, is presented. It has been used for studying the corrosion of steel samples in aqueous HCl, H/sub 2/SO/sub 4/, and NaCl solutions. To this end, radioactive /sup 55/Fe/sup 3 +/ and /sup 59/Fe/sup 3 +/ ions were added to the corrosive solutions. Iron ions originating from the corrosion of the steel samples act as diluents. Reaction rate and activation energy of the corrosion of steel OL-32 have been calculated on the basis of the experimental results.

Cecal, A. (Polytechnisches Institut, Splai Bahlui (Romania). Fakultaet fuer Chemische Technologie)

1984-07-01

190

A study for localization of corrosion on carbon steel overpack  

International Nuclear Information System (INIS)

[en] Carbon steel is one of the candidate materials for overpacks for high level radioactive waste disposal in Japan. The estimation of corrosion allowance needs to clarify the localization of corrosion. One of the most extreme case of the localization under oxidizing condition at the initial stage of repository is considered to be localized corrosion such as pitting and crevice corrosion due to the break down of passive film formed on the metal surface. In this study, the critical condition for the initiation and the propagation behavior of pitting and crevice corrosion were assessed by the experimental study. The results of the electrochemical experiments in carbonate-chloride aqueous solution showed that carbon steel have high sensitivity for the pitting and crevice corrosion in passive region. The propagation behavior of pitting and crevice corrosion was studied by the immersion tests under aerated condition. The results of the immersion tests showed that the degree of localization became small and seemed to be like general corrosion in appearance as the localized corrosion propagate. The extreme value statistical analysis were applied to the corrosion depth measured in the immersion tests. Based on the analysis, it was concluded that the equation for maximum corrosion depth due to oxygen obtained in our previous study would give conservative assessment even in the assumption of propagation of pitting corrosion or crevice corrosion. The localization of corrosion for carbon steel under reducing condition after consumption of oxygen was also estimated. The external current was supplied to the carbon steel specimens in compacted bentonite to accelerate the corrosion and corrosion depth were measured for each specimens and extreme value statistical analysis were applied to the results. The pitting factor became small as the average corrosion depth became large. Assuming that the average corrosion depth in 1000 years is 5-10 mm, the pitting factor is estimated to be about 2. (author)

1999-01-01

191

Water corrosion test of oxide dispersion strengthened (ODS) steel claddings  

International Nuclear Information System (INIS)

As a part of feasibility study of ODS steel cladding, its water corrosion resistance was examined under water pool condition. Although addition of Cr is effective for preventing water corrosion, excessive Cr addition leads to embrittlement due to the Cr-rich ?' precipitate formation. In the ODS steel developed by the Japan Atomic Energy Agency (JAEA), the Cr content is controlled in 9Cr-ODS martensite and 12Cr-ODS ferrite. In this study, water corrosion test was conducted for these ODS steels, and their results were compared with that of conventional austenitic stainless steel and ferritic-martensitic stainless steel. Following results were obtained in this study. (1) Corrosion rate of 9Cr-ODS martensitic and 12Cr-ODS ferritic steel are significantly small and no pitting was observed. Thus, these ODS steels have superior resistance for water corrosion under the condition of 60degC and pH8-12. (2) It was showed that 9Cr-ODS martensitic steel and 12Cr-ODS ferritic steel have comparable water corrosion resistance to that of PNC316 and PNC-FMS at 60degC for 1,000h under varying pH of 8, 10. Water corrosion resistance of these alloys is slightly larger than that of PNC316 and PNC-FMS at pH12 without significant difference of appearance and uneven condition. (author)

2006-01-01

192

Corrosion of Steel in Concrete – Potential Monitoring and Electrochemical Impedance Spectroscopy during Corrosion Initiation and Propagation  

DEFF Research Database (Denmark)

A reinforced mortar specimen that allows potential measurements and electrochemical impedance spectroscopy (EIS) immediately after preparation was designed and tested. The specimen consists of a mortar cylinder with a central rebar and a concentric arrangement of embedded Ru/Ir activated titanium wires. The wires can act as both reference and counter electrode during EIS and, thus, no external electrode is required. The defined geometry solves reproducibility problems involved with application of an external reference electrode for EIS. Changes of the electromotive force (EMF) between rebar and titanium wires can be monitored immediately after preparation. The wire arrangement also allows investigation of local changes in the bulk mortar by EIS or by measuring the potential development of the titanium wires versus an external standard electrode. The specimen design was evaluated in an investigation on the effect of the steel quality and the steel surface properties on initiation and propagation of chloride-induced reinforcement corrosion. Besides untreated (as received) carbon rebars and stainless rebars, selected surface treatments and galvanization were investigated. The surface treatments included grit blasting, electrochemical and hydrochloric acid cleaning (HCl) as well as weathering. The results indicate that the investigated treatments of the carbon steel surface have no major effect on the initiation period, which was approximately 20 days under the actual conditions. The galvanized rebar appears to be protected throughout the experimental period to date (200 days), whereas active corrosion of the stainless steel appeared to be initiated after 100 days exposure.

Küter, Andre; Mason, Thomas O.

2005-01-01

193

Corrosion of steel in concrete in cooling water walls. Report part 2 - Effects of the relative humidity on chlorine-initiated corrosion of the reinforcing steel  

International Nuclear Information System (INIS)

Steel in concrete is protected against corrosion by the high pH value of the concrete. The passivity can however be broken if chloride ions penetrate into the concrete. It is presumed that a certain amount of chloride is needed to activate the steel. This value is called the threshold level. Even though many attempts have been performed no reliable value has been found. One of the reasons for this is probably that the threshold value is influenced by the humidity of the concrete. At very high humidity the transport of oxygen to the steel surface is slow and at low humidity the electrical resistance increases. The aim of this investigation has been to determine at what humidity the corrosion rate reaches its highest value. With this as a background new tests can be performed to predict the chloride threshold value. The results indicate that it most probably do exist a threshold value for each concrete quality. At chloride contents above the threshold value the steel looses its passivity. If severe corrosion takes place or not is however strongly dependent on the humidity of the concrete. In a close interval around 95 % relative humidity the steel is attacked by pitting corrosion when the threshold value is exceeded. At lower and higher humidity the passivity is incomplete and the corrosion rate in most cases marginal. Future investigations concerning chloride threshold values is recommended to be performed at a relative humidity of 95 % and by using reference samples according to proposed procedure.

2010-01-01

194

Corrosion behavior of duplex polyaniline/epoxy coating on mild steel in 3% NaCl  

Directory of Open Access Journals (Sweden)

Full Text Available The corrosion behavior and thermal stability of epoxy coatings electrodeposited on mild steel and on mild steel with electrochemically deposited polyaniline (PANI) film were investigated by electrochemical impedance spectroscopy (EIS) and thermo gravimetric analysis (TGA). The aim of the paper was to present new findings on the corrosion protection of mild steel by a duplex PANI/-epoxy coating in 3% NaCI solution and to determine the effect of thin PANI film on the protective properties of the coating. PANI film was deposited electrochemically on mild steel from an aqueous solution of 0.5 mol dm"3 sodium benzoate and 0.1 mol dm"3 aniline at a constant current density of 1.5 mA cm"2. Non-pigmented epoxy coatings on mild steel and on mild steel with PANI film were obtained by cathodic electrode position at constant voltage and stirring conditions. The resin concentration in the electrode position bath was 10 wt.% solid dispersion in water at pH 5.7. The applied voltage was 250 V, the temperature 26°C and the deposition time 3 min. It was shown that thin PANI film could be used to modify the surface of mild steel prior to epoxy coating deposition, due to the increased corrosion protection of a duplex PANI/epoxy coating comparing to an epoxy coating on mild steel in 3% NaCl solution.

Gvozdenovi? Milica M.; Grgur Branimir N.; Ka?arevi?-Popovi? Zorica M.; Miškovi?-Stankovi? Vesna B.

2005-01-01

195

Effect of chloride content of molten nitrate salt on corrosion of A516 carbon steel.  

Energy Technology Data Exchange (ETDEWEB)

The corrosion behavior of A516 carbon steel was evaluated to determine the effect of the dissolved chloride content in molten binary Solar Salt. Corrosion tests were conducted in a molten salt consisting of a 60-40 weight ratio of NaNO{sub 3} and KNO{sub 3} at 400{sup o}C and 450{sup o}C for up to 800 hours. Chloride concentrations of 0, 0.5 and 1.0 wt.% were investigated to determine the effect on corrosion of this impurity, which can be present in comparable amounts in commercial grades of the constituent salts. Corrosion rates were determined by descaled weight losses, corrosion morphology was examined by metallographic sectioning, and the types of corrosion products were determined by x-ray diffraction. Corrosion proceeded by uniform surface scaling and no pitting or intergranular corrosion was observed. Corrosion rates increased significantly as the concentration of dissolved chloride in the molten salt increased. The adherence of surface scales, and thus their protective properties, was degraded by dissolved chloride, fostering more rapid corrosion. Magnetite was the only corrosion product formed on the carbon steel specimens, regardless of chloride content or temperature.

Bradshaw, Robert W.; Clift, W. Miles

2010-11-01

196

Corrosion behaviour of stainless steels in flowing LBE at low and high oxygen concentration  

International Nuclear Information System (INIS)

The corrosion behaviours of austenitic steel AISI 316L and martensitic steel T91 were investigated in flowing lead-bismuth eutectic (LBE) at 400 deg. C. The tests were performed in the LECOR and CHEOPE III loops, which stood for the low oxygen concentration and high oxygen concentration in LBE, respectively. The results obtained shows that steels were affected by dissolution at the condition of low oxygen concentration (C[O2] = 10-8-10-10 wt%) and were oxidized at the condition of high oxygen concentration (C[O2] = 10-5-10-6 wt%). The oxide layers detected are able to protect the steels from dissolution in LBE. Under the test condition adopted, the austenitic steel behaved more resistant to corrosion induced by LBE than the martensitic steel.

2004-11-01

197

Stress corrosion cracking of stainless steel  

International Nuclear Information System (INIS)

[en] Nevertheless stress corrosion cracking (SCC) is already well-known phenomenon for materials researchers, especially for researchers and engineers on corrosion, cases at actual plants, especially at nuclear power plants, are successive, and on SCC of the primary cooling pipe stainless steel in BWRs constructed at middle of 1970s, SCC of BWRs in the world was potentiated. For its inspection and countermeasure, some problems formed on wide reduction of their plant operabilities and increase of exposed radiation doses. As a result of performing their countermeasures under cooperations of plant engineers and researchers, their essential solving methods seemed to be obtained for their material measures by reduction of carbon contents causing sensitivity occurrence of SCC, application of various relaxation measures to remained stress at welded portions, and adoption of improvement on water chemistry, but new SCC is potentiated at shrouds and recirculation pipes of SUS316 and SUS316NG with low carbon content of a key card of SCC resistant materials after 2001. Here was summarized some opinions on SCC of the low carbon stainless steel of a new phenomenon, as well as weighting on water chemistry. (G.K.)

2003-01-01

198

In-situ electrochemical study of corrosion of steel and aluminum/steel couples during cyclic corrosion test  

Energy Technology Data Exchange (ETDEWEB)

Use of aluminum alloys for automotive applications is growing steadily. Galvanic corrosion is a major concern for those alloys. Because of the predominate use of steels in the automotive industry, the majority of accelerated test procedures commonly accepted by the industry are designed for cosmetic corrosion and perforation of steels. SAE 52334 and Ford Arizona Proving Ground (Ford APG) tests are two examples. Adopting those tests for galvanic corrosion of Al alloys without any fundamental understanding of the process may lead to misleading results. In this paper, electrochemical studies were conducted to examine the acceleration effects of several parameters on different types of corrosion. Galvanic corrosion of aluminum 6111 alloy and cold rolled steel (Al/ CRS) couples and general corrosion of cold rolled steel substrates were studied.

Gao, G. [Ford Motor Co., Dearborn, MI (United States)

1998-12-31

199

A Novel Hydrazinecarbothioamide as a Potential Corrosion Inhibitor for Mild Steel in HCl  

Directory of Open Access Journals (Sweden)

Full Text Available 2-(1-methyl-4-((E)-(2-methylbenzylidene)amino)-2-phenyl-1H-pyrazol-3(2H)-ylidene)-hydrazineecarbothioamide (HCB) was synthesized as a corrosion inhibitor from the reaction of 4-aminoantipyrine, thiosemicarbazide and 2-methylbenzaldehyde. The corrosion inhibitory effects of HCB on mild steel in 1.0 M HCl were investigated using potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). The results showed that HCB inhibited mild steel corrosion in acidic solution and inhibition efficiency increased with an increase in the concentration of the inhibitor. The inhibition efficiency was up to 96.5% at 5.0 mM. Changes in the impedance parameters suggested that HCB adsorbed on the surface of mild steel, leading to the formation of a protective film. The novel corrosion inhibitor synthesized in the present study was characterized using Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) spectral data.

Ahmed A. Al-Amiery; Abdul Amir H. Kadhum; Abu Bakar Mohamad; Sutiana Junaedi

2013-01-01

200

Kinetics and structural studies of the atmospheric corrosion of carbon steels in Panama  

Energy Technology Data Exchange (ETDEWEB)

The corrosion of a carbon steel was studied in different atmospheres at sites in the Republic of Panama. The weight loss (corrosion penetration) suffered by the carbon steel is related to time by a bilogarithmic law. Moessbauer spectroscopy indicated the rust was composed of non-stoichiometric magnetite (Fe{sub 3-x}O{sub 4}), maghemite ({gamma}-Fe{sub 2}O{sub 3}), goethite ({alpha}-FeOOH) of intermediate particle size, lepidocrocite ({gamma}-FeOOH) and superparamagnetic particles. Magnetite formation is related to the alternating dry-wet cycles. Goethite is related to corrosion penetration by a saturation type of behavior, following a Langmuir type of relationship. Goethite in rust protects steel against further atmospheric corrosion.

Jaen, Juan A. [Universidad de Panama, Centro de Investigaciones con Tecnicas Nucleares (Panama); Sanchez de Villalaz, Mariela [Universidad Tecnologica de Panama, Laboratorio de Metalurgia (Panama); Araque, Lilibeth de [Universidad de Panama, Centro de Investigaciones con Tecnicas Nucleares (Panama); Bosquez, Agnes de [Universidad de Panama, Departamento de Quimica (Panama)

1997-09-15

 
 
 
 
201

Kinetics and structural studies of the atmospheric corrosion of carbon steels in Panama  

International Nuclear Information System (INIS)

[en] The corrosion of a carbon steel was studied in different atmospheres at sites in the Republic of Panama. The weight loss (corrosion penetration) suffered by the carbon steel is related to time by a bilogarithmic law. Moessbauer spectroscopy indicated the rust was composed of non-stoichiometric magnetite (Fe3-xO4), maghemite (?-Fe2O3), goethite (?-FeOOH) of intermediate particle size, lepidocrocite (?-FeOOH) and superparamagnetic particles. Magnetite formation is related to the alternating dry-wet cycles. Goethite is related to corrosion penetration by a saturation type of behavior, following a Langmuir type of relationship. Goethite in rust protects steel against further atmospheric corrosion

1997-01-01

202

The concept of protection potential applied to the corrosion of metallic orthopedic implants.  

UK PubMed Central (United Kingdom)

Cyclic polarization curves obtained for a cobalt-base casting alloy (similar to Vitallium Surgical Alloy) and for 316L stainless steel show that the cobalt-base alloy exhibits a high (noble) protection potential whereas the stainless steel exhibits a low (active) protection potential. It is suggested that the resistance to crevice corrosion of Vitallium Surgical Alloy results from its high value of protection potential whereas the susceptibility of 316L stainless to severe crevice corrosion results from its low value of protection potential.

Cahoon JR; Bandyopadhya R; Tennese L

1975-05-01

203

Cathodic protection of steel pipes and its modeling  

International Nuclear Information System (INIS)

Cathodic protection is a technique of reducing the corrosion rate of buried or immersed metallic structure by making the steady state or corrosion electrical potential of the metal sufficiently more electronegative. Experiments have been conducted with steel pipes lm in length immersed in various electrolytes and subjected to impressed cathodic protection. Potentials at different points within the length of the pipe were measured by standard electrodes. The potential distribution within the pipeline depend on impressed current applied, resistivity of electrolyte, resistance of coating and presence of coatings

1988-01-01

204

Materials corrosion and protection at high temperatures  

International Nuclear Information System (INIS)

[en] 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.)

2010-06-04

205

Polyelectrolyte-diffused zinc phosphate conversion coatings and polyacid coupling primers for corrosion protection of steel and aluminum, and alkali-catalyzed hydrolysis of polyimide-based materials: Final report  

Energy Technology Data Exchange (ETDEWEB)

Under US Army Research Office (ARO) sponsorship, Brookhaven National Laboratory (BNL) performed research on three topics: (1) polyelectrolyte-modified zinc phosphate (Zn/center dot/Ph) conversion coatings for the corrosion protection of steel, (2) water-soluble polyacid coupling primers for improving the corrosion resistance and adherence of polymeric paints, and (3) high-temperature lightweight polyimide material systems. In the first topic, it was found that insoluble crystalline zinc phosphate (Zn/center dot/Ph) conversion coatings can be produced on steel surfaces by immersing a surface-cleaned cold-rolled steel substrate into a BNL-developed phosphating solution containing three components, zinc orthophosphate dihydrate (Zn/sub 3/(PO/sub 4/)/sub 2/sup /minus////center dot/2H/sub 2/O), H/sub 3/PO/sub 4/, and water. The major phase in the conversion coating derived from this simple phosphating solution is the same zinc phosphate dihydrate as that used in the converting solution. Referring to the second topic, it was found that the poly(itaconic acid), p(IA), which contains two functional COOH groups located on the same backbone carbon, has potential for use as a water-soluble intermediate coupling primer for polymer adhesive/Al/sub 2/O/sub 3/ adherend joint systems. Emphasis in the third topic was placed on understanding the reaction processes and degradation mechanisms of PI polymers which occur at the interfaces between the PI and inorganic pigments in hydrothermal environments at /ge/150/degree/C.

Sugama, T.; Kukacka, L.E.; Carciello, N.R.; Warren, J.B.; Clayton, C.R.

1989-08-01

206

Corrosion behaviour of plastically deformed high-Mn austenitic steels  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: The aim of the work was the comparison of corrosion resistance in an aqueous sulfuric acid solution of two high-manganese austenitic steels of the 0.05C-25Mn-Al-Si-Nb-Ti type in a plastically deformed state.Design/methodology/approach: Investigations were carried out on specimens obtained from a thermo-mechanically rolled sheet and then plastically deformed through bending and immersed in corrosive solutions (1N H2SO4) for 100 hours. The mass decrement was calculated by the gravimetric method, whereas the character of corrosion damages was observed in metallographic investigations using light and scanning electron microscopes both in the polished and etched states.Findings: It was found that after the thermo-mechanical processing one steel is characterized by an austenitic structure with numerous annealing twins, whereas in the second steel lamellar martensitic phases in an austenitic matrix occur. The investigations showed that the examined high-manganese steels have very low corrosion resistance in normal H2SO4. Higher impact on the corrosion resistance than the phase composition has the chemical composition. The mass decrement of the steel with martensite plates is a bit higher than that witha single-phase austenitic matrix. The specimens were intensively dissolved due to general corrosion accompanying by pitting and hydrogen cracking.Research limitations/implications: To investigate in more detail the corrosion behaviour of high-manganese austenitic steels, the polarization tests and the analysis of corrosion products should be carried out.Practical implications: The obtained results can be used for searching the appropriate way of improving the corrosion resistance of high-strength high-manganese austenitic steels.Originality/value: The corrosion resistance of two types of advanced high-manganese austenitic steels with different initial structures was compared. Hydrogen impact in austenitic steels was discussed.

A. Grajcar; W. Krukiewicz; S. Ko?odziej

2010-01-01

207

On the corrosion resistance of 01Kh25 ferritic steel  

International Nuclear Information System (INIS)

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% H2SO4 is two order below 06KhN28MDT austenitic steel in presence of Cu2+ 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.

1989-01-01

208

Importance of Surface Preparation for Corrosion Protection of Automobiles  

Directory of Open Access Journals (Sweden)

Full Text Available An overview of science and technology of pretreatment process suitable for automotive finishing with cathodic electrodeposition primer is presented in details in this paper. Both the theoretical principles and practical aspects of tricationic phosphating process that are used in automotive industry are discussed in details. The characteristic features of phosphate coatings of both conventional high zinc phosphating formulations and modern tricationic phosphating formulations on steel surface are compared in details by SEM, EDX and XRD techniques. The corrosion protection of the phosphated and painted steel panels were evaluated by both salt spray test and electrochemical impedance spectroscopy (EIS). The analysis of impedance data in terms of pore resistance (Rpo), coating capacitance (Cc) and breakpoint frequency (fb) as a function of salt spray exposure time provides a clear insight into the mechanism of superior corrosion resistance provided by the modern tricationic phosphating formulations compared with conventional high zinc phosphating formulations.

Narayan Chandra Debnath

2013-01-01

209

Investigation of Carbon steel corrosion in water base drilling mud  

Directory of Open Access Journals (Sweden)

Full Text Available Carbon steel, the most widely used engineering material, accounts for approximately 85%, of the annual steel production worldwide. Despite its relatively limited corrosion resistance, carbon steel is used in large tonnages in marine applications, nuclear power and fossil fuel power plants, transportation, chemical processing, petroleum production and refining, pipelines, mining, construction and metal-processing equipment. This paper Investigate Carbon steel corrosion in water. The corrosion rate in production and casing pipes in water base drilling mud (packer fluid), different salt concentration (100gm/L , 150 gm/L , 200gm/L) have been used and different temperature (30co , 50 co , 70 co) have been investigated. Weight loss and polarization methods were applied. The results indicate that the corrosion rates decrease with the increasing of salt concentration while the corrosion rates increase with increasing of temperature

Fadhil Sarhan Kadhim

2011-01-01

210

Corrosion behavior of duplex stainless steel in sulphuric acid  

International Nuclear Information System (INIS)

Duplex stainless steels are alloyed and processed to develop microstructure of roughly equal amounts of ferrite and austenite. Duplex stainless steel constitute a new class of materials because they have balanced amounts of ferrite and austenite. Since they have high content of chromium and molybdenum present, thus they have good corrosion resistance. Their corrosion resistance is double to that of annealed austenitic stainless steels with regard to pitting, crevice corrosion, sulphide stress corrosion, and chloride stress corrosion environments. The corrosion behavior of duplex stainless steel in various concentrations of sulphuric acid was studied. The reactions were carried out by placing the steel specimen in a beaker containing a known concentration of sulphuric acid at room temperature for a definite period. Pits were initiated in duplex stainless steel specimen and the propagation of pits depends upon the concentration of the acid solution in which the sample is in contact. The weight loss for definite period of time were measured and corrosion rates were calculated in millimetres per year. The corrosion rates increases with an increase in acid concentration at room temperature. A comparison of the results obtained from various concentrations of sulphuric acid with the same concentrations of nitric acid is also discussed. (author)

2003-01-01

211

Sensitization-induced localized corrosion in austenitic stainless steels  

International Nuclear Information System (INIS)

[en] Sensitization-induced localized corrosion can be broadly classified into two categories, namely, intergranular corrosion (IGC) and intergranular stress corrosion cracking (IGSCC). These two forms of corrosion affect several grades of austenitic stainless steels and nickel based alloys, and are commonly observed in power, chemical and petrochemical industries. Majority of corrosion failures of critical austenitic stainless steel components in these industries can be attributed to IGC and IGSCC. It is therefore essential to monitor the extent and rate of these localized forms of corrosion periodically. This paper will discuss the following issues related to sensitization induced localized corrosion in austenitic stainless steels: low temperature sensitization (LTS) in austenitic stainless steels, modification to ASTM test for evaluation of IGC susceptibility in austenitic stainless steels and NDT methods (UT and ECT) for monitoring IGC and IGSCC in austenitic stainless steels. Irradiation-assisted stress corrosion cracking (IASCC), attributed to solute segregation (Si, P) and chromium depletion at grain boundaries induced by irradiation will also be discussed. (author)

2010-01-01

212

Experiences of corrosion and corrosion protection in seawater systems in the Nordic countries  

International Nuclear Information System (INIS)

[en] A summary is given of the experience of the corrosion resistance of pumps, heat exchangers, valves and pipings in different seawater cooling systems in Scandinavia, including power reactor cooling systems in Finland and Sweden. For pumps and heat exchangers the experience has been so extensive that a clear picture of today's standing can be given. Owing to scanty data concerning valves and pipes, the survey of the corrosion in these components is less well supported. Vertically extended centrifugal pumps are the pumps in general use in power plant cooling systems. To counteract corrosion on pump riser and pump casing having an organic surface coating, and on stainless steel shafts and impellers, these components should be provided with internal and external cathodic protection. For tube and plate type heat exchangers, titanium has proved to be the best material choice. Rubber-enclosed carbon steel pipings, or pipings having a thick coating of epoxy plastic, have shown very strong corrosion resistance in power plant seawater cooling systems. Valves in seawater systems have primarily been affected by corrosion due to poorly executed or damaged organic coating on cast iron. Different seawater-resistant bronzes (red bronze, tin bronze and aluminium bronze) are therefore preferable as valve materials

1985-01-01

213

Hot Corrosion Behavior of HVOF Sprayed Coatings on ASTM SA213-T11 Steel  

Science.gov (United States)

Cr3C2-NiCr, NiCr, WC-Co and Stellite-6 alloy coatings were sprayed on ASTM SA213-T11 steel using the HVOF process. Liquid petroleum gas was used as the fuel gas. Hot corrosion studies were conducted on the uncoated as well as HVOF sprayed specimens after exposure to molten salt at 900 °C under cyclic conditions. The thermo-gravimetric technique was used to establish the kinetics of corrosion. XRD, SEM/EDAX and EPMA techniques were used to analyze the corrosion products. All these overlay coatings showed a better resistance to hot corrosion as compared to that of uncoated steel. NiCr Coating was found to be most protective followed by the Cr3C2-NiCr coating. WC-Co coating was least effective to protect the substrate steel. It is concluded that the formation of Cr2O3, NiO, NiCr2O4, and CoO in the coatings may contribute to the development of a better hot-corrosion resistance. The uncoated steel suffered corrosion in the form of intense spalling and peeling of the scale, which may be due to the formation of unprotective Fe2O3 oxide scale.

Sidhu, H. S.; Sidhu, B. S.; Prakash, S.

2007-09-01

214

Effect of environment on corrosion characteristics of newly developed DMR-1700 structural steel  

Directory of Open Access Journals (Sweden)

Full Text Available The corrosion resistance of any metallic material depends on the environment to which it is exposed. DMR-1700 steel is a material for structural applications that has been recently developed at Defence Metallurgical Research Laboratory by changing the chemistry of alloying elements. Therefore, a detailed understanding of its corrosion characteristics under different environmental conditions is essential. In the present paper, we report the results of a systematic corrosion study that was carried out on the new steel to determine the effect of the environment on the protective nature of the oxide scale that forms on its surface under different environmental conditions. Furthermore, the oxide scale as well as the resistance to pitting and crevice corrosion were studied in various environments. The surface morphologies of the corroded steels were observed under a scanning electron microscope (SEM) to determine the nature of the corrosion. On the basis of studies by different techniques, DMR-1700 steel is recommended for the manufacture of components used in various systems in conjunction with the application of an appropriate protective coating to improve its resistivity to corrosion.

Injeti Gurrappa and Guntupalli Malakondaiah

2008-01-01

215

Mild corrosion behavior on sulphurized steel surface during friction  

Science.gov (United States)

After treatment by low temperature ion sulphuration, the solid lubrication sulphuration layers (FeS films) were produced on the AISI 1045 and stainless steel. A mass of corrosion peeling pits occurred on the worn scars of 1045 steel sulphuration layer after wear test, whereas none of them on the stainless steel one. AFM was used to observe the morphology of sulphuration layer, SEM equipped EDS was utilized to analyze the morphologies and compositions of worn scars. XPS and XRD were employed to detect the valence states of sulphuration layer and its worn scars, as well as the phase structures. The results showed that during friction, under the frictional heat, the sulfate radical with mild corrosion was produced, so that the 1045 steel without any anti-corrosion was corroded in some certain, meanwhile the stainless steel was not corroded depending on its excellent corrosion resistance.

Wang, Hai-Dou; Xu, Bin-Shi; Liu, Jia-Jun; Zhuang, Da-Ming; Zhang, Xian-Cheng; Wei, Shi-Cheng

2005-12-01

216

Electrochemical study of the crevice corrosion resistance of stainless steels: example of Cr-Mo ferritic steels  

International Nuclear Information System (INIS)

The measurement of stainless steel depassivating pH enables the crevice corrosion resistance to be evaluated. It is concluded that: Mo is more efficient than Cr; the classification of the stainless steel types is not the same for pitting and crevice corrosion resistance; crevice corrosion resistance of Cr-Mo ferritic steels is similar to that of Cr-Ni-Mo austenitic steels

1975-05-26

217

Role of nanophase oxides in short-term atmospheric corrosion of structural steels  

Science.gov (United States)

Systematic studies on the development of nanophase iron oxides in the corrosion products of carbon and weathering steel were performed to understand the role of nanophase oxides in short-term atmospheric corrosion. Similarities and/or differences between short-term and long-term atmospheric corrosion were established by studying carbon steel and weathering steel coupons exposed in mild marine environments for short-term and comparing it with previously established long-term data. Influence of substitutional elements, in particular chromium, in forming nanophase goethite was investigated. Crystallographic, magnetic and morphological properties of nanophase chromium substituted goethite have been characterized in order to understand the protective nature of chromium-substituted goethite in a naturally weathered steel surface. Spectroscopic investigation of the corrosion products of both carbon and weathering steel indicated that lepidocrocite and goethite were the predominant oxides to form following short-term exposures. The corrosion coatings were well layered for exposure times as early as 2 months. The layering was very similar to that observed on steel coupons exposed for more than 8 years. The outer layer was composed of lepidocrocite and occasionally goethite. The inner layer was mainly composed of nanophase goethite. The relative fraction of nanophase goethite was significantly higher in weathering steel compared to carbon steel at the end of six months of exposure. The data analysis also revealed that during the first two months of exposure weathering steel corrodes faster than carbon steel. However carbon steel corrodes more rapidly after 6 months of exposure. At the end of one year, the corrosion rate of carbon steel is higher than weathering steel. It is proposed that during the couple of months, nucleation of oxides is the dominant process in both carbon and weathering steel. At the end of six months, a considerable amount of nanophase goethite formed on carbon steel continues to grow into bigger crystals. On the other hand, in weathering steel the crystal growth of a significant fraction of initially formed nanophase goethite is inhibited. It is proposed that substitutional elements like chromium inhibit the crystal growth in weathering steel. The crystallographic and spectroscopic data for showed that with increasing chromium concentration, the crystallite size of synthetic goethite measured from X-ray diffraction and particle length of goethite measured from Mossbauer spectroscopy and Transmission Electron Microscopy, became smaller. (Abstract shortened by UMI.)

Balasubramanian, Rama

218

Corrosion Behaviour of Nickel Plated Low Carbon Steel in Tomato Fluid  

Directory of Open Access Journals (Sweden)

Full Text Available This research work investigated the corrosion resistance of nickel plated low carbon steel in tomato fluid. It simulated the effect of continuous use of the material in a tomato environment where corrosion products are left in place. Low carbon steel samples were nickel electroplated at 4V for 20, 25, 30 and 35 mins using Watts solution.The plated samples were then subjected to tomato fluid environment for for 30 days. The electrode potentials mV (SCE) were measured every day. Weight loss was determined at intervals of 5 days for the duration of the exposure period. The result showed corrosion attack on the nickel- plated steel, the severity decreasing with the increasing weight of nickel coating on substrate. The result showed that thinly plated low carbon steel generally did not have any advantage over unplated steel. The pH of the tomato solution which initially was acidic was observed to progress to neutrality after 4 days and then became alkaline at the end of the thirty days test (because of corrosion product contamination of the tomato)contributing to the reduced corrosion rates in the plated samples after 10 days. Un-plated steel was found to be unsuitable for the fabrication of tomato processing machinery without some form of surface treatment - thick nickel plating is suitable as a protective coating in this environment.

Oluleke OLUWOLE; Oluwadamilola OLAWALE

2010-01-01

219

Electrochemical Studies of Stainless Steel Corrosion in Peroxide Solutions  

Directory of Open Access Journals (Sweden)

Full Text Available Pollution control measures have resulted in replacement of chlorine by peroxide as bleaching chemical. Change of chemical affects corrosion aspects, the suitability of existing plant metallurgy and materials of construction of bleach plants. Accordingly long term immersion and electrochemical corrosion tests were conducted on stainless steel 304L, 316L, 2205 and 6% Mo and mild steel in peroxide solutions of pH 10. The materials were tested for uniform corrosion, pitting and crevice corrosion and attack around the weld area. Corrosion attack estimated from long term immersion tests is found in agreement, by and large, with that analyzed from electrochemical test. E-pH diagrams drawn for water-peroxide system have been used to understand the corrosivity of the peroxide media. An attempt has been made to suggest a suitable material of construction for handling the test media on the basis of degree of corrosion attack on them and their cost and the mechanical properties.

Ajay K. Singh; Vipin Chaudhary; A. Sharma

2012-01-01

220

Corrosion of vessel steel during its interaction with molten corium  

International Nuclear Information System (INIS)

[en] An experimental examination of the cooled vessel steel corrosion during the interaction with molten corium is presented. The experiments have been conducted on 'Rasplav-2' test facility and followed up with physico-chemical and metallographic analyses of melt samples and corium-specimen ingots. The results discussed in the first part of the paper have revealed specific corrosion mechanisms for air and inert atmosphere above the melt. Models have been proposed based on this information and approximate curves constructed for the estimation of the corrosion rate or corrosion depth of vessel steel in conditions simulated by the experiments

1885-01-00

 
 
 
 
221

Corrosion of vessel steel during its interaction with molten corium  

Energy Technology Data Exchange (ETDEWEB)

An experimental examination of the cooled vessel steel corrosion during the interaction with molten corium is presented. The experiments have been conducted on 'Rasplav-2' test facility and followed up with physico-chemical and metallographic analyses of melt samples and corium-specimen ingots. The results discussed in the first part of the paper have revealed specific corrosion mechanisms for air and inert atmosphere above the melt. Models have been proposed based on this information and approximate curves constructed for the estimation of the corrosion rate or corrosion depth of vessel steel in conditions simulated by the experiments.

Bechta, S.V. [Scientific Research Technological Institute (NITI), Sosnovy Bor of Leningrad Oblast 188540 (Russian Federation)]. E-mail: bechta@sbor.spb.su; Khabensky, V.B. [Scientific Research Technological Institute (NITI), Sosnovy Bor of Leningrad Oblast 188540 (Russian Federation); Vitol, S.A. [Scientific Research Technological Institute (NITI), Sosnovy Bor of Leningrad Oblast 188540 (Russian Federation); Krushinov, E.V. [Scientific Research Technological Institute (NITI), Sosnovy Bor of Leningrad Oblast 188540 (Russian Federation); Granovsky, V.S. [Scientific Research Technological Institute (NITI), Sosnovy Bor of Leningrad Oblast 188540 (Russian Federation); Lopukh, D.B. [SPb Electrotechnical University (SpbGETU), Professor Popov str., b.5/3, 197376 St. Petersburg (Russian Federation); Gusarov, V.V. [Institute of Silicate Chemistry of Russian Academy of Science (ISC of RAS), Odoevsky str., b. 24/2, 199155 St. Petersburg (Russian Federation); Martinov, A.P. [SPb Electrotechnical University (SpbGETU), Professor Popov str., b.5/3, 197376 St. Petersburg (Russian Federation); Martinov, V.V. [Scientific Research Technological Institute (NITI), Sosnovy Bor of Leningrad Oblast 188540 (Russian Federation); Fieg, G. [Forshungszentrum Karlsruhe (FZK), Institut fur Neutronenphysik and Reaktortechnik, Postfach 3640, D-78021 Karlsruhe (Germany); Tromm, W. [Forshungszentrum Karlsruhe (FZK), Institut fur Neutronenphysik and Reaktortechnik, Postfach 3640, D-78021 Karlsruhe (Germany); Bottomley, D. [Europaeische Kommission, General Direktion GFS, Institut fuer Transurane (ITU), Postfach 2340, 76125 Karlsruhe (Germany); Tuomisto, H. [Fortum Engineering Ltd. 00048 FORTUM, Rajatorpantie 8, Vantaa (Finland)

2006-07-15

222

Atmospheric corrosion of mild steel. Pt. II. Marine atmospheres  

International Nuclear Information System (INIS)

[en] This paper summarizes the results obtained in the MICAT project for mild steel specimens exposed for 1 to 4 years in 47 marine atmospheres in the Ibero-American region. All these atmospheres were characterized for climatology, pollution and corrosion rates according to ISO standards. Complementary morphological and chemical characterization of the steel corrosion product layers (SCPLs) formed in these atmospheres was carried out. The overall analysis of results contributes to understanding, in a systematic way, how atmospheric corrosivity categories can be correlated with corrosion mechanisms. Special aspects of the atmospheres, from pure to mixed marine, were considered. (orig.)

2000-01-01

223

Effects of cathodic protection on corrosion fatigue  

International Nuclear Information System (INIS)

The effects of cathodic protection on corrosion fatigue of alloys can vary widely, ranging from strongly beneficial to strongly detrimental. This paper provides a concise synopsis of the subject, based upon a review of selected literature. Attempts are made to discern important generalizations concerning the effects of various cathodic protection levels on crack initiation and crack propagation in ferrous and nonferrous alloy systems

1981-01-01

224

Corrosion protection of powered roof supports  

Energy Technology Data Exchange (ETDEWEB)

Various protective coatings were evaluated for use on powered roof supports by laboratory testing and by full scale field trials on three coal faces. 16000 components were specially treated for the underground trials and problems associated with provisioning were identified. Cost benefit analyses showed that improved corrosion protection could be cost-effective and a revised treatment schedule for supports is recommended.

1985-01-01

225

Corrosion-resistant Foamed Cements for Carbon Steels  

Energy Technology Data Exchange (ETDEWEB)

The cementitious material consisting of Secar #80, Class F fly ash, and sodium silicate designed as an alternative thermal-shock resistant cement for the Enhanced Geothermal System (EGS) wells was treated with cocamidopropyl dimethylamine oxide-based compound as foaming agent (FA) to prepare numerous air bubble-dispersed low density cement slurries of and #61603;1.3 g/cm3. Then, the foamed slurry was modified with acrylic emulsion (AE) as corrosion inhibitor. We detailed the positive effects of the acrylic polymer (AP) in this emulsion on the five different properties of the foamed cement: 1) The hydrothermal stability of the AP in 200 and #61616;C-autoclaved cements; 2) the hydrolysis-hydration reactions of the slurry at 85 and #61616;C; 3) the composition of crystalline phases assembled and the microstructure developed in autoclaved cements; 4) the mechanical behaviors of the autoclaved cements; and, 5) the corrosion mitigation of carbon steel (CS) by the polymer. For the first property, the hydrothermal-catalyzed acid-base interactions between the AP and cement resulted in Ca-or Na-complexed carboxylate derivatives, which led to the improvement of thermal stability of the AP. This interaction also stimulated the cement hydration reactions, enhancing the total heat evolved during cement’s curing. Addition of AP did not alter any of the crystalline phase compositions responsible for the strength of the cement. Furthermore, the AP-modified cement developed the porous microstructure with numerous defect-free cavities of disconnected voids. These effects together contributed to the improvement of compressive-strength and –toughness of the cured cement. AP modification of the cement also offered an improved protection of CS against brine-caused corrosion. There were three major factors governing the corrosion protection: 1) Reducing the extents of infiltration and transportation of corrosive electrolytes through the cement layer deposited on the underlying CS surfaces; 2) inhibiting the cathodic reactions at the corrosion site of CS; 3) extending the coverage of cement over CS surfaces; and, 4) improving the adherence of the cement to CS surfaces. Thus, the CS’s corrosion rate of 176 milli inch/per year (mpy) for 1 wt% FA-foamed cement without AP was considerably reduced to 69 mpy by adding only 2 wt% AP. Addition of AP at 10 wt% further reduced this rate to less than 10 mpy.

Sugama T.; Gill, S.; Pyatina, T., Muraca, A.; Keese, R.; Khan, A.; Bour, D.

2012-12-01

226

Cavitation corrosion of duplex stainless steel in seawater  

Energy Technology Data Exchange (ETDEWEB)

A laboratory study was conducted on the cavitation corrosion behavior of a commercial cast duplex stainless steel (DSS) in seawater using an ultrasonically-induced cavitation facility. Mass loss, free-corrosion potential, potentiodynamic polarization, and microscopic examinations were compared in the absence and presence of cavitation. The rate of mass loss was negligible in quiescent seawater. However, the rate was 0.64 mg/h-cm{sup 2} after testing for 11 h in the presence of cavitation. Cathodic protection (CP) reduced the rate of mass loss by 19%. Cavitation caused an active shift in the free-corrosion potential by {approximately}140 mV. During polarization in the absence and presence of cavitation, the alloy passivated spontaneously without an active-to-passive transition. Cavitation slightly increased the cathodic and anodic currents, shifted the corrosion potential in the noble direction by 75 mV, and decreased the breakdown potential by {approximately}50 mV. Under the free-corrosion condition, small cavities initiated in the ferrite matrix and at the ferrite-austenite boundaries. With the progress of cavitation, the attack concentrated in the austenite phase but spread to the ferrite phase and was associated with ductile tearing, cleavage-like facets, river patterns, and crystallographic steps at later stages. CP decreased the number of cavities slightly. Specimen cross sections revealed microcracks initiating from the ferrite matrix at the bottom of cavities. Crack propagation into the bulk of the material was impeded by the austenite islands and branched along parallel slip systems.

Al-Hashem, A.; Caceres, P.G.; Abdullah, A.; Shalaby, H.M. [Kuwait Inst. for Scientific Research, Safat (Kuwait)

1997-02-01

227

Role of FeS in protective action of iron corrosion inhibitors  

International Nuclear Information System (INIS)

Adsorption of hexanol on iron sulfide, sodium capronate and AB catamine was studied. Influence of FeS on the AB catamine protective action in the course of steel 10 corrosion in 1M solution of NaCl was considered. High adsorption specific capacity of FeS as regards surfactants was ascertained. Adsorption of the inhibitor by iron sulfide reduces its protective action during steel corrosion, although does not lead to its compolete loss, which indicates participation of colloid particles in the formation of protective film on metal

1992-01-01

228

Prediction of external corrosion for steel cylinders  

International Nuclear Information System (INIS)

The US Department of Energy (DOE) currently manages the UF6 Cylinder Program (the program). The program was formed to address the depleted-uranium hexafluoride (UF6) stored in approximately 50,000 carbon steel cylinders. The cylinders are located at three DOE sites: the K-25 site (K-25) at Oak Ridge, Tennessee; the Paducah Gaseous Diffusion Plant (PGDP) in Paducah, Kentucky, and the Portsmouth Gaseous Diffusion Plant (PORTS) in Portsmouth, Ohio. The System Requirements Document (SRD) (LMES 1996a) delineates the requirements of the program. The appropriate actions needed to fulfill these requirements are then specified within the System Engineering Management Plan (SEMP) (LMES 1996b). The report presented herein documents activities that in whole or in part satisfy specific requirements and actions stated in the UF6 Cylinder Program SRD and SEMP with respect to forecasting cylinder conditions. The wall thickness projections made in this report are based on the assumption that the corrosion trends noted will continue. Some activities planned may substantially reduce the rate of corrosion, in which case the results presented here are conservative. The results presented here are intended to supersede those presented previously, as the quality of several of the datasets has improved.

1997-01-01

229

Structure and corrosion resistance of oxides grown on maraging steel in steam at elevated temperatures  

Science.gov (United States)

The microstructure of oxides formed on 250 maraging steel in steam at elevated temperatures was established. The coating consisted of at least two sub-layers, an innermost layer of austenitic phase and a layer of magnetite Fe 3O 4. When low loads of steel were used, a third top layer of hematite Fe 2O 3 was found. The coating provides good protection against atmospheric corrosion, which was significantly better than phosphating.

Rezek, J.; Klein, I. E.; Yahalom, J.

1997-01-01

230

Corrosion fatigue behaviour of ion nitrided AISI 4140 steel  

Energy Technology Data Exchange (ETDEWEB)

Machine components suffer from corrosion degradation of fatigue characteristics and improvement can be attained by the application of a nitriding treatment, particularly to low alloy steels. In the present study, the effect of ion nitriding on corrosion fatigue performance of AISI 4140 steel has been investigated by conducting a series of rotary bending corrosion fatigue tests at 95 Hz, in 3% NaCl aqueous solution. Hourglass shaped, 4 mm diameter fatigue specimens were ion nitrided at 748 K for 1, 3, 8 and 16 h prior to the tests. It was observed that distinct fatigue limit behaviour of ion nitrided steel in air completely disappeared in corrosive environment besides severe degradation in fatigue characteristics. An improvement reaching to 60% in corrosion fatigue strength can be attained by successive ion nitriding practice based on a fatigue life of 10{sup 7} cycles. An attempt was made to establish an empirical relationship between corrosion fatigue strength and relative case depth, which considers the size of the ion nitrided specimen. It was also determined that a power relationship holds between corrosion fatigue strength and fatigue life of ion nitrided steel. The presence of white layer has resulted in additional improvement in corrosion fatigue resistance, and it was observed that corrosion fatigue cracks were initiated dominantly under the white layer by pit formation mechanism. (orig.)

Genel, K. [Sakarya Univ., Adapazari (Turkey). Mech. Eng. Dept.; Demirkol, M.; Guelmez, T. [Faculty of Mechanical Engineering, Istanbul Technical University, Guemuessuyu, 80191, Istanbul (Turkey)

2000-08-31

231

Corrosion fatigue behaviour of ion nitrided AISI 4140 steel  

International Nuclear Information System (INIS)

Machine components suffer from corrosion degradation of fatigue characteristics and improvement can be attained by the application of a nitriding treatment, particularly to low alloy steels. In the present study, the effect of ion nitriding on corrosion fatigue performance of AISI 4140 steel has been investigated by conducting a series of rotary bending corrosion fatigue tests at 95 Hz, in 3% NaCl aqueous solution. Hourglass shaped, 4 mm diameter fatigue specimens were ion nitrided at 748 K for 1, 3, 8 and 16 h prior to the tests. It was observed that distinct fatigue limit behaviour of ion nitrided steel in air completely disappeared in corrosive environment besides severe degradation in fatigue characteristics. An improvement reaching to 60% in corrosion fatigue strength can be attained by successive ion nitriding practice based on a fatigue life of 107 cycles. An attempt was made to establish an empirical relationship between corrosion fatigue strength and relative case depth, which considers the size of the ion nitrided specimen. It was also determined that a power relationship holds between corrosion fatigue strength and fatigue life of ion nitrided steel. The presence of white layer has resulted in additional improvement in corrosion fatigue resistance, and it was observed that corrosion fatigue cracks were initiated dominantly under the white layer by pit formation mechanism. (orig.)

2000-08-31

232

Corrosion investigation of coatings for surface protection of military hardware  

Energy Technology Data Exchange (ETDEWEB)

A product improvement program (PIP) for the surface finish of some steel military hardware has been recently initiated by the Navy. Presently the metal cleaning methods, interior and exterior surface finishes and corrosion protection requirements for such hardware are specified in MIL-P-18948. The coated hardware are stored in a warehouse structure for long durations. Because these storage places are not environmentally controlled (that is, no temperature or humidity control) the corrosion protection has not been adequate. The exterior surfaces of the hardware are coated with a corrosion inhibiting alkyd primer coating (TT-P-664) or a rust inhibiting lacquer primer coating (MIL-P-11414) to a thickness of 0.4 to 0.6 mils. The exterior color paint, (MIL-E-52891 or MIL-P11195), is applied to a thickness of 1.5 mils. The investigation of various coatings to replace the present system is an ongoing effort. The coatings have been examined from a corrosion protection vantage point and results have been correlated. The coatings were evaluated by exposing them to natural marine atmosphere and seawater wetdown tests. The coatings were also exposed to a 5.0% sodium chloride solution in a laboratory environmental salt fog chamber for 500 hours. Selected coatings were examined using Electrochemical Impedance Spectroscopy (EIS). The results obtained from field tests, salt fog, and EIS measurements are discussed.

Lindsey, N.; Vasanth, K.L. [Naval Surface Warfare Center, Silver Spring, MD (United States)

1996-10-01

233

Silica nanocontainers for active corrosion protection.  

UK PubMed Central (United Kingdom)

Novel self-healing protective coatings with nanocontainers of corrosion inhibitors open new opportunities for long-term anticorrosion protection of different metallic materials. In this paper a new type of functional nanoreservoir based on silica nanocapsules (SiNC) synthesized and loaded with corrosion inhibitor 2-mercaptobenzothiazole (MBT) in a one-stage process is reported for the first time. Unlike conventional mesoporous silica nanoparticles, SiNC possess an empty core and shell with gradual mesoporosity, arising from the particular conditions of the synthetic route adopted, which confers significant loading capacity and allows prolonged and stimuli-triggered release of the inhibiting species. The kinetics of inhibitor release was studied at different pH values and concentrations of NaCl. The results show a clear dependence of the release profiles on corrosion relevant triggers such as pH and Cl(-) concentration. When SiNC loaded with MBT are dispersed in NaCl solution, there is a significant decrease of the corrosion activity on aluminium alloy 2024. More importantly, when SiNC-MBT is added to a conventional water-based coating formulation, the modified coating hampers corrosion activity at the metal interface, better than in the case of direct addition of corrosion inhibitor. Furthermore, self-healing is observed before and after artificially inflicting defects in the modified coatings. As a result, the developed nanocontainers show high potential to be used in new generation of active protective coatings.

Maia F; Tedim J; Lisenkov AD; Salak AN; Zheludkevich ML; Ferreira MG

2012-02-01

234

Corrosion protection of equipment for potash removal of carbon dioxide from hydrogen  

Energy Technology Data Exchange (ETDEWEB)

An investigation has been conducted of the corrosion resistance of 08Kh22N6T, 08Kh21N6M2T, 06Kh17G17DAMB, 03Kh13AG20, and 08Kh18G8N2T steels for the purpose of selection of materials for equipment of the potash cleaning block. In addition to the determination of general corrosion resistance of the specimens, the possibility of the origin and occurrence of specific forms of corrosion damage including point corrosion, intergranular corrosion, and corrosion cracking was also recorded. The resistance to general corrosion in aqueous solutions of potash and carbon dioxide of steels economically alloyed with nickel is sufficiently high. The action of several inhibitors was tested to clarify the question of the possibility and effectiveness of inhibitor protection of carbon steel under conditions of potash cleaning. The most effective inhibitor was V/sub 2/O/sub 5/ (vanadium pentoxide). However, the addition of vanadium pentoxide does not provide reliable protection of carbon steel equipment. In potash cleaning, inhibitor protection is possible only with the observance of strict control over the addition of inhibitor.

Maksimova, G.F.; D' yakov, V.G.; Shigryaev, B.F.

1986-03-01

235

Tailored steel strip coatings for modern car body and corrosion concepts  

Energy Technology Data Exchange (ETDEWEB)

To offer customers cost advantages a new product family of zn-mg coated steel sheets - ze-mg - is under development at the surface technology center doc {sup registered} by means of physical vapor deposition of magnesium on already zinc coated steel sheet. the new zn-mg alloy coating allows to reduce the thickness of the metallic coating in the case of ze-mg 35/35 to about 3.5 {mu}m instead of 7.5 {mu}m for conventional zinc coated steel sheets while the level of corrosion protection is a comparable level. target is to achieve advantages with regard to further processing e.g. simplified laser welding of overlap joints. the current developments of new post treatments are focusing particularly on systems which offer improved environmental characteristics, better corrosion protection and enhanced forming properties. drylubes offer these properties. strip drawing tests and measurements of the deep drawing working range demonstrate improved tribological properties. drylubes permit heavy deep-drawing operations without any additional lubrication. spot lubricants are needed only in extremely critical areas. corrosion protection by metallic coatings can be further enhanced by organic coatings which are applied in a coil coating process. precoated steel sheet like weldable corrosion protection primer, preprimed and prefillered enable savings due to the elimination of mainly cost-intensive key process steps at Darmakers' and suppliers' paint process chain. these products can benefit of using ze-mg. (orig.)

Saemann, N.; Rogner, I.; Koenig, S. [DOC Dortmunder OberflaechenCentrum, Dortmund (Germany)

2005-07-01

236

Inhibition effect of phosphorus-based chemicals on corrosion of carbon steel in secondary-treated municipal wastewater.  

UK PubMed Central (United Kingdom)

Secondary-treated municipal wastewater (MWW) could supply a viable alternative water resource for cooling water systems. Inorganic salts in the concentrated cooling water pose a great challenge to corrosion control chemicals. In this study, the inhibition effect of 1-hydroxy ethylidene-1,1-diphosphonic acid (HEDP), trimethylene phosphonic acid (ATMP) and 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTCA) on corrosion of carbon steel in secondary-treated MWW was investigated by the means of potentiodynamic polarization and electrochemical impedance spectroscopy. The inhibition effect increased with increasing concentration of inhibitors. The corrosion rates of carbon steel were 1.5, 0.8, 0.2 and 0.5 mm a(-1) for blank, HEDP, ATMP and PBTCA samples at 50 mg L(-1), respectively. The phosphorus-based chemicals could adsorb onto the surface of the carbon steel electrode, form a coat of protective film and then protect the carbon steel from corrosion in the test solution.

Shen Z; Ren H; Xu K; Geng J; Ding L

2013-01-01

237

Uniform corrosion monitoring of carbon steel in concrete  

Science.gov (United States)

Corrosion in concrete can cause disastrous destructions of bridges and other constructions. Different methods of corrosion monitoring can be applied including electrochemical noise despite its disadvantageous limitations. Noise measurements enable continuous monitoring of corrosive conditions inside concrete and recognition when corrosion starts to make trouble there. Results of electrochemical noise measurements in concrete are presented. Polarization resistance of carbon steel is estimated by current and voltage noise measurements. Changes of factor 2-4 of the estimated polarization resistance are recognized during time of noise registration. The observed changes in uniform corrosion rate can be identified by electrochemical noise analysis. Limitations of the applied method of polarization resistance evaluation are considered and presented.

Smulko, Janusz M.; Darowicki, Kazimierz; Zielinski, Artur

2004-05-01

238

Corrosion by concentrated sulfuric acid in carbon steel pipes and tanks: state of the art  

Energy Technology Data Exchange (ETDEWEB)

PETROBRAS, allied to the policy of reduction of emission of pollutants, has been adjusting the processes of the new refineries to obtain products with lower sulfur content. Thus, the sulfur dioxide, extracted from the process gases of a new refinery to be built in the Northeast, will be used to produce sulfuric acid with concentration between (94-96) %. This acid will be stored in carbon steel tanks and transported through a buried 8-km carbon steel pipe from the refinery to a pier, where it will be loaded onto ships and sent to the consumer markets. Therefore, the corrosion resistance of carbon steel by concentrated acid will become a great concern for the mentioned storage and transportation. When the carbon steel comes into contact with concentrated sulfuric acid, there is an immediate acid attack with the formation of hydrogen gas and ferrous ions which, in turn, forms a protective layer of FeSO{sub 4} on the metallic surface. The durability of the tanks and pipes made of carbon steel will depend on the preservation of this protective layer. This work presents a review of the carbon steel corrosion in concentrated sulfuric acid and discusses the preventive methods against this corrosion, including anodic protection. (author)

Panossian, Zehbour; Almeida, Neusvaldo Lira de; Sousa, Raquel Maria Ferreira de [Instituto de Pesquisas Tecnologicas (IPT), Sao Paulo, SP (Brazil); Pimenta, Gutemberg de Souza [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil). Centro de Pesquisas e Desenvolvimento (CENPES); Marques, Leandro Bordalo Schmidt [PETROBRAS Engenharia, Rio de Janeiro, RJ (Brazil)

2009-07-01

239

Corrosion resistance of chromium-nickel steel containing rare earths  

International Nuclear Information System (INIS)

[en] 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

1983-01-01

240

Synthesis of the functional derivatives of thioglycolic acid and research of influence of structural factors on their protective properties at corrosion of steel  

International Nuclear Information System (INIS)

[en] Full text: Results of influence of structural factors investigation on protective properties of some mono-and di-replaced functional derivatives with general formulas HS-CH2COOH and R'-S-CH2-COOR, synthesized on the basis of thioglycolic acids (TGA) have been considered. It is established, that in biphasic sour system 0.04% water solution CH3COOH-kerosene, all the investigated compounds-both mono and di-replaced, process inhibitor properties. Influence of the nature, structure and lengths of radicals on efficiency of obtained compounds is also established. It is revealed, that among the investigated connections, bi-replaced derivatives of TGA: cyclohexyl propoxycarbonylmethyl sulphide and deputy ether butoxycarbonyymethyl this iconic acids are the most effective inhibitors. As well it is revealed, that all the mono-replaced derivatives of TGA, expect the compound with formula HS-CH2-COOCH2-OH, in biphasic neutral system 3% water solution NaCI- kerosene stimulate corrosion process St-3.It is established, that above-stated di-replaced derivatives TGA also process inhibitor properties in neutral system, however efficiency of these compounds turned to be much less, than in sour system

2007-01-01

 
 
 
 
241

Influence of alloying elements on corrosion resistance of low alloy steels in marine environment  

Energy Technology Data Exchange (ETDEWEB)

Most area of the earth is ocean. Therefore, exploitation of marine resources and utilization of marine space rapidly increase in recent years. Most of marine structures, such as wharfs, oil drilling platforms, coastal bridges, airports, etc. are mainly constructed by steel. It is therefore very important to develop marine corrosion resistant steels that do not require protection and are inexpensive. In this study, a series of low alloy steels were prepared by the method of experimental design as well as conventional design to study the effects of alloying elements on the marine corrosion resistance, under consideration of the requirement of mechanical properties. All steels were cyclically dipped to synthetic sea water in the laboratory for 7 weeks or exposed in the Taichung Harbor for more than 4 years. Both test results show similar tendency of the effects of alloying elements, but the effects of fouling on pitting were only observed in the latter. Addition of phosphorus and copper can improve the general corrosion resistance in atmospheric splash zone and titanium has the same effect in sea water. Molybdenum can improve the general corrosion resistance in both splash and tidal zones and pitting resistance in tidal and submerged zones. Due to enrichment of the alloying elements in the rust resulting in development of inner dense rust layer and change of rust composition, the anti-corrosion ability of most designed steels can be enhanced in marine environment. In addition, the corrosion resistance of most tested steels is superior to plain carbon steel (A-36) and weathering steel (Acr-Ten A) in Taichung Harbor.

Wei, F.I. [China Steel Corp., Kaohsiung (Taiwan, Province of China). Steel and Aluminum Research and Development Dept.

1995-09-01

242

Weathering steel: Five-year atmospheric corrosion performance  

Energy Technology Data Exchange (ETDEWEB)

In 1984, a research study was initiated to quantify the corrosion rates of weathering steel coupons. This report presents the results of long-term outdoor corrosion tests performed on A588 weathering steel in a variety of environments representative of those in which bridges are situated. Data were obtained over five years from approximately 50 coupons exposed at five separate sites in southern Ontario. The data are compared to findings from other jurisdictions.

Pianca, F.

1994-01-01

243

Corrosion under stress of AISI 304 steel in thiocyanate solutions  

International Nuclear Information System (INIS)

Corrosion susceptibility under stress of AISI 304 steel sensitized in a sodium thiocyanate solution has been studied and results were compared with those obtained with solutions of thiosulfate and tetrathionate. Sensitized steel type 304 is highly susceptible to corrosion when under intergranular stress (IGSCC) in thiocyanate solutions but the aggressiveness of this anion is less than that of the other sulphur anions studied (thiosulfate and tetrathionate). This work has been partly carried out in the Chemistry Department. (Author).

1989-01-01

244

Corrosion fatigue of surgical stainless steel in synthetic physiological solution.  

UK PubMed Central (United Kingdom)

Fatigue tests conducted both in air and synthetic physiological solution show that the fatigue strength of surgical stainless steel in synthetic physiological solution is about 10% lower than the strength in air for a given endurance level. It is proposed that surgical stainless steel which is normally passive in physiological solution suffers corrosion fatigue because of susceptibility to crevice corrosion which occurs at extrusions and intrusions (crevices) on the surface thereby shortening the crack initiation time and the fatigue life.

Cahoon JR; Holte RN

1981-03-01

245

Radiation effects on noble steel corrosion in nitric acid  

International Nuclear Information System (INIS)

The highgrade steel 1.4301 with 17% Cr and 8.5% Ni was preferably analyzed: the time-invariant rate of corrosion depends on the nitric acid concentration (?[HNO3]5/3) and the temperature (activation energy 63.1 kJ). Foreign salts (Ce4+, chromate, fluoride, J-, JO3-, JO4-) increase the corrosion rate only if the ions have either an oxidizing or complexing effect. Iodate ions decrease the corrosion rate. With ?- or ? radiation, a significant increase of the corrosion rate was not noticed in any case after eliminating experimental difficulties. The higher corrosion rate caused by oxidizing agents (Cr6+, Ce4+) is, however, decreased, since these compounds are also reduced by the reactive species occurring in water radiolysis. A mechanical damage of the passive layer of highgrade steel in the presence of nitric acid and foreign salts does not lead to an increased corrosion rate in subsequent total immersion tests. (orig./MM)

1989-01-01

246

Electrochemical methods for characterisation of thermal spray corrosion resistant stainless steel coatings  

International Nuclear Information System (INIS)

[en] The use of thermal spray stainless steel coatings for protection of low alloyed steels against different types of corrosion is limited due to high porosity levels and oxide inclusions. In this paper electrochemical methods like corrosion potential monitoring and cyclic voltammetry are reported to monitor the corrosion resistance of thermal spray coatings. The studied stainless steel AISI 316 coatings are deposited by arc spraying, plasma spraying or high velocity oxygen fuel (HVOF) spraying. The electrochemical tests are performed in a 0.5 M H2SO4 solution. It is found that none of the tested coatings had an electrochemical response equal to that of stainless steel alloy AISI 316. The results indicate that the HVOF coating has the highest corrosion resistance and the corrosion resistance of arc spray coatings can be improved by spraying in an inert argon atmosphere. The electrochemical response of the studied arc spray coatings is independent of substrate type (including the case of no substrate), indicating that the underlying alloy does not contribute to the corrosion process and only the coating itself is attacked. The HVOF coatings age rapidly in a 0.5 M H2SO4 solution. It is proposed that this is due to pore opening and pore widening. (orig.)

1998-01-01

247

Localized corrosion of steels in geothermal steam/brine mixtures  

Energy Technology Data Exchange (ETDEWEB)

Coupons of eight different carbon and chrome-moly alloy steels were exposed to high temperature, high salinity wellhead brine flow at a geothermal well in the Salton Sea Geothermal Field for periods of up to six months. The corrosion rate and corrosion attack morphology of each coupon was determined. Exposure time was a test variable and ranged from one month to six months. Test results indicate that carbon steels generally suffer high corrosion rates and are susceptible to severe localized attack which shows a mesa-canyon pattern. Chrome-moly alloy steels corrode at much lower rates and show an attack pattern of small shallow pits. With time, these pits grow mostly in the lateral direction. These results suggest that chrome-moly alloy steels offer significant improvement over carbon steels and that the disk-shaped pits are not likely to lead to rapid perforation.

McCright, R.D.; Frey, W.F.; Tardiff, G.E.

1980-05-29

248

Corrosion Protection Properties of 4-[(E)-[(2,4-Dihydroxy phenyl)methylidene] amino]-6-methyl-3-sulfanylidene-2,3,4,5-tetrahydro-1,2,4-triazin-5-one [DMSTT] Toward Mild Steel in Sulfuric Acid  

Science.gov (United States)

The inhibition of mild steel corrosion in aerated 0.5 N H2SO4 solution was investigated using potentiodynamic polarization studies (Tafel), linear polarization studies, electrochemical impedance spectroscopy studies, adsorption studies, and surface morphological studies. The effect of inhibitor concentration on corrosion rate, the effect of temperature, degree of surface coverage, adsorption kinetics, and surface morphology are investigated. The inhibition efficiency increased markedly with increase in the additive concentration and decreased slightly with increasing temperature. The presence of DMSTT decrease the double-layer capacitance and increase the charge transfer resistance. The value of activation energy ( E a) of metal corrosion, adsorption equilibrium constant ( K ads), and free energy of adsorption (? G ads) were calculated from the temperature dependence of corrosion current. The adsorption of inhibitor molecule on mild steel surface follow Langmuir isotherm. DMSTT offers excellent inhibition properties and acts as a mixed-type inhibitor.

John, Sam; Joseph, Abraham

2013-02-01

249

The Effect of Sour Gases and Some Anions on the Corrosion Behavior of Carbon Steel  

Directory of Open Access Journals (Sweden)

Full Text Available The effect of the presence of CO2 and H2S in the well water used in the petroleum plant on corrosion of carbon steel has been tested using impedance measurements. Carbon dioxide leads to decrease in the resistivity of the film developed on the metallic surface, while the effect of hydrogen sulfide is less pronounced. Scanning electron micrographs have shown that corrosion products cover only small part of metallic surface in water containing CO2. Studies under polarization conditions will allow concluding that the dissolved gases in the well water reduce the ability of the film to protect the metal against corrosion. The influence of the oxoanions and halide ions on the corrosion rate of steel has also been analyzed.

S.A. Salih; A.A. Mazhar; H. Mahanny

2004-01-01

250

Bacterial corrosion of mild steel under the condition of simultaneous formation of ferrous and sulphide ions  

Energy Technology Data Exchange (ETDEWEB)

Corrosion of mild steel in cultures of a Pseudomonas species under the condition of simultaneous formation of Fe(II) and S/sup 2-/ was initially inhibited by inhibiting the anodic reaction, but after long incubation the corrosion process was allowed to continue. When only S/sup 2-/ was produced, the initial corrosion rate increased for up to 60 h but later declined, probably due to a protective FeS film formed on the metal. Cathodic reactions were affected in a similar fashion as the anode. Extensive pitting corrosion was observed when the mild steel coupons were immersed in bacterial culture producing Fe(II) and S/sup 2-/, but not in the uninoculated control.

Obuekwe, C.O.; Westlake, D.W.S.; Plambeck, J.A.

1987-06-01

251

The Effect of Sour Gases and Some Anions on the Corrosion Behavior of Carbon Steel  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english The effect of the presence of CO2 and H2S in the well water used in the petroleum plant on corrosion of carbon steel has been tested using impedance measurements. Carbon dioxide leads to decrease in the resistivity of the film developed on the metallic surface, while the effect of hydrogen sulfide is less pronounced. Scanning electron micrographs have shown that corrosion products cover only small part of metallic surface in water containing CO2. Studies under polarizatio (more) n conditions will allow concluding that the dissolved gases in the well water reduce the ability of the film to protect the metal against corrosion. The influence of the oxoanions and halide ions on the corrosion rate of steel has also been analyzed.

Salih, S.A.; Mazhar, A.A.; Mahanny, H.

2004-01-01

252

Analysis of corrosion products of carbon steel in wet bentonite.  

Science.gov (United States)

As a part of evaluation of the long-term durability for the overpack containers for high-level radioactive waste, we have conducted corrosion tests for carbon steel in wet bentonite, a candidate buffer material. The corrosion rates were evaluated by weigh...

K. Osada T. Nagano S. Nakayama S. Muraoka

1992-01-01

253

Steel corrosion in anoxic mediums with high chloride concentrations  

International Nuclear Information System (INIS)

[en] Carbon steels are widely used in contact with chloride containing mediums, however most of the literature reports corrosion problems in solutions in contact with air, for example, sea water. There are other applications where the steel is in contact with freshwater in the absence of oxygen as is the case with materials for nuclear repositories or in petroleum production. These mediums can have varied composition but their corrosivity is usually related to the concentration of chlorides. There are no systematic studies in the literature about the influence of high chloride concentrations on the speed of steel corrosion for carbon steels in the absence of oxygen. Some work has been done using Raman and XPS spectroscopy, but these techniques have been carried out ex situ in samples submitted to the action of high chloride concentrations. This results in the appearance of corrosion products on the metal surface due to the oxidation of the surface from exposure to air before and during the use of these techniques, generating confusing and uncertain data. The lack of reliable data is due to the difficulty of applying these techniques in situ under very low oxygen conditions (less than 10 ppb) without allowing any air into the system. Since there are no studies in the literature about the influence of high concentrations of chloride on the corrosion speed of carbon steels in the absence of oxygen, this work aims to generate experimental data to evaluate the influence of high concentrations of this anion on the corrosion speed of steel under anoxic conditions. The corrosivity of each solution was evaluated using electrochemical techniques such as corrosion potential, corrosion speed, anodic and cathodic polarization curves, cyclic voltammetries and electrochemical impedance spectroscopy to study the oxidation-reduction processes that occur with specific temperature, pH and chloride concentration conditions. Concentrated solutions of sodium chloride (50,000, 100,000 and 180,000 ppm of Cl-) were used in the absence of oxygen (concentration less than 10 ppb) and at 40oC0C and pH=7.5. The material chosen for this study was AISI 1018 steel. The results show that the corrosion speed of the carbon steel decreases with the increase in chloride concentrations and the increase in the steel's exposure time to the corrosive medium. This suggests that a high concentration of Cl- anions in the medium will provoke the adsorption of matter on the metal surface forming a homogeneous barrier that impedes corrosion by simply blocking the active reaction sites

2008-01-01

254

Corrosion behaviour of unprotected and hot-dipped galvanized steel for fuel oil storage  

Energy Technology Data Exchange (ETDEWEB)

Investigations have been done with unprotected and galvanized steel under fuel oil storage conditions. By adding sodium chloride as corrosive agent and a commercial corrosion inhibitor conditions for localized corrosion of unprotected steel were simulated. Results show that no localized corrosion occurs with galvanized steel.

Kruse, C.L.

1984-04-01

255

Corrosion protection of metals by silane surface treatment  

Science.gov (United States)

The need for toxic chromate replacements in metal-finishing industries has prompted an intensive search for replacement technologies in recent years. Among the replacements that have been proposed, those that are based upon the use of organofunctional silanes rank very high in terms of performance, broad applicability as well as ease of application. This dissertation presents a four-part work: (1) structural characterization of silane films on metals, (2) mechanism studies of silane-treated metal systems, (3) development of water-based silane systems, and (4) measurements of other properties of silane films. In part 1, silane films, i.e., bis-[triethoxysilylpropyl]tetrasulfide (bis-sulfur silane) and bis-[trimethoxysilylpropyl]amine (bis-amino silane) were deposited on AA 2024-T3 and were characterized mainly using reflection-absorption Fourier-transform infrared spectroscopy (FTIR-RA) and electrochemical impedance spectroscopy (EIS) techniques. In part 2, the mechanistic study of corrosion protection of AA 2024-T3 by bis-sulfur silane film was carried out. In summation, the following two factors play critical roles in the corrosion protection of AA 2024-T3: (1) the formation of a highly crosslinked interfacial layer, and (2) high water resistance of silane films. The former inhibits corrosion in the following two ways: (1) blocking favorable sites for water adsorption by the formation of AlOSi bonds at the interface which effectively reduces the tendency of aqueous corrosion; and (2) bonding tightly to the metal and thus restricting transportation of the existing corrosion products away from their original sites which hinders pit growth. It should be noted that a high density of AlOSi bonds can be obtained employing bis-silanes rather than mono-silanes. A high water resistance makes water penetration difficult in silane films. This is essential for preventing AlOSi bonds from hydrolysis. In part 3, test results for newly-developed water-based silane systems were reported. The major advantage of these silane systems is that they are highly miscible with water, which makes them more industrially acceptable than alcohol-based silanes. Test results demonstrated that these silanes provide excellent corrosion protection as well as paint adhesion on a variety metals including, Al alloys, Zn-coated steels, carbon steels, and stainless steels. Part 4 reported several other properties of silane films, such as resistivity/conductivity, mechanical properties, and thermal stabilities of silane films. (Abstract shortened by UMI.)

Zhu, Danqing

256

Electrochemical and corrosion behavior of carbon steel in SULFIRAN process  

Energy Technology Data Exchange (ETDEWEB)

Corrosion behavior of carbon steel was evaluated in Fe-EDTA solution designed to be used in acid gas treatment process (SULFIRAN plant) in the temperature range between 35 deg. C and 45 deg. C. Electrochemical techniques, i.e. polarization curves and electrochemical impedance spectroscopy (EIS) were applied for laboratory evaluations. Linear polarization resistance (LPR) and weight loss techniques were used to determine the corrosion rate for pilot tests. In addition, several surface analysis techniques such as XRD, XRF, SEM and optical microscopy were employed to determine the corrosion morphology. Metallurgical and SEM investigations of the carbon steel corrosion showed corrosion-induced damages in SULFIRAN process. The corrosion demonstrated in the forms of severe uniform corrosion, wide shallow pits formation, under deposit corrosion, hydrogen micro-void formation, and hydrogen induced disbonding between the interfaces of the inclusion (MnS) and metal matrix. The corrosion rate of carbon steel alloy is predicted to be very high (>200 mils per year or mpy) in this process.

Neshati, J. [Corrosion Department, Research Institute of Petroleum Industry (RIPI), P.O. Box 18745-4163, Tehran (Iran, Islamic Republic of)], E-mail: Neshatyj@ripi.ir; Abedi, S. Sh. [Corrosion Department, Research Institute of Petroleum Industry (RIPI), P.O. Box 18745-4163, Tehran (Iran, Islamic Republic of); Forsat, Kh. [Engineering and Process Development Division, Research Institute of Petroleum Industry (RIPI), Tehran (Iran, Islamic Republic of); Jenab, M. Hosseini [Gas Science Department, Research Institute of Petroleum Industry (RIPI), Tehran (Iran, Islamic Republic of); Mirfendereski, S. [Corrosion Department, Research Institute of Petroleum Industry (RIPI), P.O. Box 18745-4163, Tehran (Iran, Islamic Republic of)

2009-05-15

257

Use of acoustic emission to detect localised corrosion under passive protection, illustrated with real examples  

Energy Technology Data Exchange (ETDEWEB)

After several years of research in laboratory, the ability to detect active corrosion by Acoustic Emission technique has been successfully proved. The benefit of using this technology has been recognised by chemical and petrochemical industry to detect stress corrosion cracking and pitting of stainless steel alloy. The purpose of this paper is to present an extension of this technique to coated low alloy carbon steel. In this case, the mechanism of corrosion is well-known uniform corrosion but the damage appears in restricted area where the passive protection is no more efficient. The goal is to make a diagnosis on the propagation of the localised corrosion or to verify the integrity of the corrosion protective layer on components during in service conditions. This need arises from un-predicted failures of industrial equipment due to fast propagation of corrosion damage, after the destruction of coating. This paper presents several situations where CORPAC technology has been applied, not only to detect and locate damage from corrosion, but also to validate repairs and evaluate the efficiency of corrosion protection. (authors)

Proust, Alain; Lenain, Jean-Claude [Euro Physical Acoustics SA, 27 Rue Magellan, 94373 Sucy-en-Brie Cedex (France)

2004-07-01

258

Experimental and theoretical studies of thiazoles as corrosion inhibitors for mild steel in sulphuric acid solution  

International Nuclear Information System (INIS)

Graphical abstract: The inhibition effect of 2-amino-5-mercapto-1,3,4-thiadiazole and 2-mercaptothiazoline on mild steel corrosion in 1.0 M H2SO4 was studied using electrochemical techniques. The effects of the presence of extra NH2 group and N atom in 2A5MT on the ability to act as corrosion inhibitors were investigated by theoretical calculations. Highlights: ? The inhibition effects of thiazoles on mild steel corrosion in 1.0 M H2SO4 were studied. ? It was shown that both thiazole compounds act as excellent corrosion inhibitors for mild steel. ? The high inhibition efficiency was attributed to the adsorption of the inhibitor molecules on the metal surface. ? Langmuir adsorption isotherm exhibited the best fit to the experimental data. ? Quantum chemical calculations show there is a correlation between inhibitive property and molecular parameters. - Abstract: The inhibition effects of 2-amino-5-mercapto-1,3,4-thiadiazole (2A5MT) and 2-mercaptothiazoline (2MT) on mild steel corrosion in 1.0 M H2SO4 were studied with potentiodynamic polarization, linear polarization resistance and electrochemical impedance spectroscopy techniques. It was shown that both 2A5MT and 2MT act as good corrosion inhibitors for mild steel protection. The high inhibition efficiencies were attributed to the simple blocking effect by adsorption of inhibitor molecules on the steel surface. The effects of the presence of extra NH2 group and N atom in 2A5MT on the ability to act as corrosion inhibitors were investigated by theoretical calculations.

2011-01-01

259

An electroactive co-polymer as corrosion inhibitor for steel in sulphuric acid medium  

International Nuclear Information System (INIS)

The corrosion behavior of mild steel in sulphuric acid solution containing various concentrations of a co-polymer formed between maleic anhydride and N-vinyl-2-pyrrolidone (VPMA) was investigated using weight-loss, polarization and electrochemical impedance techniques. The polymer acts as an effective corrosion inhibitor for steel in sulphuric acid medium. The inhibition process is attributed to the formation of an adsorbed film of co-polymer on the metal surface which protects the metal against corrosion. Scanning electron microscopy (SEM) studies of the metal surfaces confirmed the existence of an adsorbed film. The adsorption followed the Langmuir isotherm. The protection efficiency increased with increase in inhibitor concentration and decreased with increase in temperature and acid concentration. The thermodynamic functions of the adsorption and dissolution processes were evaluated.

2008-06-30

260

Electrochemical synthesis and corrosion behavior of thin polyaniline film on mild steel, copper and aluminum  

Directory of Open Access Journals (Sweden)

Full Text Available The electrochemical synthesis of polyaniline (PANI) on mild steel, aluminum and copper from the sodium benzoate solutions has been investigated. It has been shown that thin, highly adherent, polyaniline films on the investigated metals could be obtained by anodic oxidation with current densities in the range of 0.5 and 1.5 mA cm-2. The corrosion behavior of mild steel, aluminum and copper with polyaniline coating in 0.5 mol dm3 NaCl (pH 3) solutions, has been investigated by polarization technique. The corrosion current densities, porosity and protection efficiency was determined. It has been shown that polyaniline coating provided corrosion protection of all mentioned metals.

Elkais Ali Ramadan; Gvozdenovi? Milica M.; Jugovi? Branimir Z.; Trišovi? Tomislav Lj.; Maksimovi? Miodrag M.; Grgur Branimir N.

2011-01-01

 
 
 
 
261

Rusting Evolution of MnCuP Weathering Steel Submitted to Simulated Industrial Atmospheric Corrosion  

Science.gov (United States)

The rusting evolution of MnCuP weathering steel in a simulated industrial atmosphere as a function of corrosion duration was investigated by corrosion weight gain, scanning electron microscopy, X-ray diffraction, and electrochemical methods. The results indicate that the corrosion kinetics is related closely to the rust composition and electrochemical properties. The corrosion rate is higher during the first corrosion stage, and it is lower during the second corrosion stage. During the first corrosion stage, the rust layer is in low density, discontinuous, and loose, with a lower relative abundance of ?-FeOOH. During the second corrosion stage, a compact and protective inner rust layer forms with a higher relative abundance of ?-FeOOH, contributing to enhanced rust layer resistance. The rust initially enhances and then stabilizes the cathodic process, but the anodic process tends to be inhibited by the protective rust layer. Electrochemical impedance spectroscopy tests indicate that it is more scientific to evaluate the rust layer protective ability by charge transfer resistance.

Hao, Long; Zhang, Sixun; Dong, Junhua; Ke, Wei

2012-05-01

262

The use of a sacrificial zinc anode for cathodic protection of steel in reinforced concrete  

Energy Technology Data Exchange (ETDEWEB)

The problem of corrosion of the reinforcing steel in concrete is recognized as a worldwide problem. In particular, these is extensive corrosion in residential and commercial balconies in tropical, coastal areas of the US, especially in Florida. A system of cathodic protection of reinforcing steel in concrete utilizing a sacrificial zinc anode and ionically conductive adhesive is described. Installation and monitoring of two condominium balconies in south Florida will be described, including instant-off and depolarization measurements over 18 months.

Hartman, R.B.; Hillier, W.H. [3M Co., St. Paul, MN (United States)

1997-12-01

263

Corrosion fatigue of a superduplex stainless steel weldment  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Superduplex stainless steels have superior mechanical and corrosion properties compared to austenitic stainless steels such as the grade 300 series. This is a result of a microstructure consisting of roughly equal percentages of austenite (y) and ferrite (a) and negligible inclusion content. As a r...

Comer, Anthony John

264

Cathodic protection of steel by hot dip coating  

Energy Technology Data Exchange (ETDEWEB)

Anodic metal coatings on steel products form a barrier that is particularly effective against corrosive environments. This paper examines continuous and discontinuous (diffusion, e.g., sheradizing) hot dip coating techniques and their relative electrochemical and microstructural aspects. Attention is given to Zn and Al cathodic protection, in particular, uses of the alloy, Zn-55 %Al and the eutectic alloy, Zn-5% Al. Special applications are presented, as well as, the use of the steels which are highly adaptable to galvanizing. New plant techniques and the economic aspects of zinc coatings are also discussed.

Costa, A. (Galvan SpA, Milan (Italy))

1990-02-01

265

Hardfaced welded protective coatings for corrosion and wear stresses  

International Nuclear Information System (INIS)

As a rule, materials which resist even extremely high corrosion and wear stresses, are very expensive and/or difficult to work. For this reason many efforts are made to avoid massive types of construction, if possible, and only to provide the stressed surface with a suitable protective coating. An economically favourable alternative, which is particularly used for thick-walled components, is hardfacing welding. With this it is possible to use coated basic materials, eg: unalloyed steels as the sources of mechanical strength, and to coat the surface with different hardfacing welding processes according to the stresses on it. (orig.).

1992-01-01

266

Corrosion and hydrogen permeation of A216 Grade WCA steel in hydrothermal magnesium-containing brines  

International Nuclear Information System (INIS)

[en] Corrosion rates determined at 1 month in 150/degree/C brine increased with magnesium concentration. The structure of the corrosion product, as determined by x-ray diffraction, depended upon the magnesium concentration. In brines with less than 10,000 ppM magnesium, the primary corrosion product had a spinel structure characteristic of magnetite or magnesioferrite. In brines containing magnesium concentrations greater than 20,000 ppM, the primary corrosion product had the amakinite structure characteristic of a complex iron-magnesium hydroxide. The high corrosion rates observed in brines containing high magnesium concentrations suggest that the corrosion products having the amakinite structure is less protective than corrosion products having the spinel structure. Corrosion rates in high-magnesium (inclusion) brine determined over a 6-month test duration were essentially constant. Hydrogen permeation rates observed in exposing mild steel to high-Mg/sup 2/plus// brine at 150/degree/C could be potentially damaging to a mild steel waste package container. The rate of hydrogen permeation was proportional to the brine flow rate in the autoclave. Thiourea additions to the brine increased the hydrogen permeation rate; sulfate and bromide ion additions did not. The maximum gaseous hydrogen pressure attainable is not known (based on 3Fe /plus/ 4H2O /plus/ Fe(sub 3)O /plus/ 4H2, would be /approximately/900 atmospheres), and the dependence of permeation rate on temperature is not known. 8 refs., 13 figs., 3 tabs

1988-03-09

267

Corrosion protective coating for metallic materials  

Energy Technology Data Exchange (ETDEWEB)

Corrosion protective coatings for metallic materials, particularly aluminum and aluminum alloys, produced with simple, low-cost equipment and materials other than toxic metals or metal salts, or metal cyanides. The metallic material is cleaned, degreased, and deoxidized, the surface is converted to a substantially alkaline condition, and the surface is chemically sealed with inorganic metal compounds.

Buchheit, Rudolph G. (Albuquerque, NM); Martinez, Michael A. (Albuquerque, NM)

1998-01-01

268

Chloride corrosion of reinforcement and cathodic protection; Betoniteraesten kloridikorroosio ja katodinen suojaus  

Energy Technology Data Exchange (ETDEWEB)

Chloride corrosion of steel in concrete may result in shortening of the service life or a premature, expensive renovation or even failure of the renovation, unless the factors of chloride corrosion are known. It is nowadays impossible to remove chlorides from concrete reliably without cutting out chloride contamined concrete layer. However, after the renovation concrete may often contain chlorides so much that corrosion of steel will start and the service life will shorten. The expected service life can be gained by renovating the structure so both the threshold value of chloride content (the value after corrosion starts) and speed of the corrosion process are taken into account in the plans. The other renovating method is cathodic protection to stop corrosion. In the beginning of the report, chloride corrosion of steel in concrete (not in cold climate) is given on the base of the literature references and experience of renovations. Influence of binding material of concrete to threshold value and to continuation of corrosion process are presented. The proposal to the binding material quality and the minimum content of binding material are given. The end of the report presents the prerequisites to cathodic protection and designing principles.

Meuronen, A.; Westerlund, E.

1992-03-01

269

Chloride corrosion of reinforcement and cathodic protection. Betoniteraesten kloridikorroosio ja katodinen suojaus  

Energy Technology Data Exchange (ETDEWEB)

Chloride corrosion of steel in concrete may result in shortening of the service life or a premature, expensive renovation or even failure of the renovation, unless the factors of chloride corrosion are known. It is nowadays impossible to remove chlorides from concrete reliably without cutting out chloride contamined concrete layer. However, after the renovation concrete may often contain chlorides so much that corrosion of steel will start and the service life will shorten. The expected service life can be gained by renovating the structure so both the threshold value of chloride content (the value after corrosion starts) and speed of the corrosion process are taken into account in the plans. The other renovating method is cathodic protection to stop corrosion. In the beginning of the report, chloride corrosion of steel in concrete (not in cold climate) is given on the base of the literature references and experience of renovations. Influence of binding material of concrete to threshold value and to continuation of corrosion process are presented. The proposal to the binding material quality and the minimum content of binding material are given. The end of the report presents the prerequisites to cathodic protection and designing principles.

Meuronen, A.; Westerlund, E.

1992-03-01

270

Ranitidine Drugs as Non-Toxic Corrosion Inhibitors for Mild Steel in Hydrochloric Acid Medium  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english Expired ranitidine was tested as a corrosion inhibitor for mild steel in 1 M HCl using different techniques: weight loss, potentiodynamic polarization, open circuit potential and electrochemical impedance spectroscopy. The polarization resistance (Rp) value increased with increase in the concentration of the inhibitor. Results obtained revealed that ranitidine performed excellently as a corrosion inhibitor for mild steel in this medium at 303 K. The protection efficiency (more) increased with increasing inhibitor concentration. The maximum protection efficiency of 90% has been obtained at 400 ppm. On the other hand, the efficiency decreases with increasing temperature. The adsorption of the inhibitor on the mild steel surface followed Langmuir adsorption isotherm model. The activation and thermodynamic parameters of dissolution and adsorption were calculated and discussed. The negative value of ?Gads (-40 kJ mol-1) indicates spontaneous chemical adsorption. Results obtained from polarization, EIS and weight loss measurements are in good agreement with each other.

Abdel Hameed, R.S.

2011-01-01

271

Atmospheric corrosion of carbon steel resulting from short term exposures  

Energy Technology Data Exchange (ETDEWEB)

The study of corrosion products from short term atmospheric exposures of carbon steel, is very important to understand the processes that lead to corrosion of steels, and ultimately improve the performance of such steel in highly corrosive environments. Many regions along the Gulf of Mexico have extremely corrosive environments due to high mean annual temperature, humidity, time-of-wetness and every high atmospheric pollutants. The process the formation of corrosion products resulting from short term exposure of carbon steel, both as a function of environmental conditions and exposure time, has been investigated. Two sets of coupons were exposed at marine and marine locations, in Campeche, Mexico. Each set was exposed between 1 and 12 months to study the corrosion as a function of time. During the exposure periods, the relative humidity, rainfall, mean temperature, wind speed and wind direction were monitored along with the chloride and sulfur dioxide concentrations in the air. The corroded coupons were analyzed by Moessbauer, Raman, Infrared spectroscopies and X-ray diffraction in order to completely identify the oxides and map their location in the corrosion coating. Scattering and transmission Moessbauer analysis showed some layering of the oxides with lepidocrocite and akaganeite closer to the surface. The fraction of akaganeite phase increased at sites with higher chloride concentrations. A detailed analysis on the development of the oxide phases as a function of exposure time and environmental conditions will be presented. (Author)

Balasubramanian, R.; Cook, D.C.; Perez, T.; Reyes, J. [Department of Physics, Old Dominion University, Norfolk, VA 23529 (United States)

1998-12-31

272

Nitrogen addition and localized corrosion behaviour of austenitic stainless steels  

International Nuclear Information System (INIS)

[en] Nitrogen as an alloying element has been reported to improve the localized corrosion resistance, particularly pitting, crevice and intergranular corrosion of austenitic stainless steels in chloride containing aqueous environments. The authors highlight the corrosion behaviour of nitrogen-alloyed (up to 0.56 wt%) austenitic stainless steels and compared the studies carried out by several groups. The influence of various metallurgical variables including cold working, thermal ageing, grain size and surface treatment on the pitting corrosion behaviour of the nitrogen-alloyed austenitic stainless steels is addressed. The mechanism by which nitrogen enhanced the corrosion resistance is elucidated with the help of results obtained using electrochemical and surface analytical techniques. The role of nitrogen on the formation of passive films and the semiconducting nature of passive film with nitrogen addition, are discussed to understand the corrosion resistance offered by the passive films with increasing nitrogen addition. The differences in the localized corrosion behaviour between various nitrogen alloyed stainless steels are highlighted. (author)

2010-01-01

273

Early corrosion detection in structural carbon steels using electromagnetic sensors  

Science.gov (United States)

The capability and sensitivity of an electromagnetic (EM) sensor to be used as a non destructive evaluation (NDE) technique to detect and monitor corrosion in structural steels has been evaluated. Three structural carbon steels: AISI 1018, AISI 1045, and Stress Proof, were used for the study. The effect of corrosion on the magnetic properties of the steels was evaluated. Correlation curves and equations relating mass loss due to corrosion at early stages and magnetic property are presented. Based on the results it is established that the EM sensor has the potential to be used as a reliable NDE tool to detect corrosion at early stages based on the variation in magnetic saturation. These results are used to estimate and monitor the degree of damage in terms of mass loss.

Rumiche, F.; Indacochea, J. E.; Wang, M. L.

2006-04-01

274

Corrosion of steel H piles in decomposed granite  

Energy Technology Data Exchange (ETDEWEB)

To study the corrosion of steel H piles in a completely decomposed granite, piles were exposed by excavation 22 years after their installation. The thickness of the pile sections was measured. The average corrosion rate of the steel piles was estimated to be 0.011 mm/year, and the maximum corrosion rate was estimated to be 0.015--0.018 mm/year. The rates are low. The results confirm the conclusions derived from tests done in places with temperate climate that steel piles installed in undisturbed, native soils undergo little corrosion. Thus, such conclusions are also applicable to the completely decomposed granite in a place like Singapore with high year-round temperatures ranging from 25 to 35 C.

Wong, I.H. [Mitic Associates, Cashew Heights (Singapore); Law, K.H. [Land Transportation Authority, Singapore (Singapore)

1999-06-01

275

Peroxy molybdates preparation, characterization and mild steel corrosion inhibition  

International Nuclear Information System (INIS)

[en] Six peroxyl molybdates were prepared by varying pH (5,6 and 7) and ratio between hydrogen peroxide and molybdate (2:1 and 1:1). These were characterized as mono-, di-mixed and polymerized peroxy molybdates. The best corrosion inhibition of mild steel in simulated cooling water (SCW) was obtained by di peroxy molybdate. This shows the beneficial effect of per oxo group addition to molybdate. Other peroxy molybdates did not show improved corrosion inhibition compared to the molybdate. This was due to decomposition of these peroxy molybdates before reaching the mild steel surface. With citric acid, peroxy molybdates provided highly improved corrosion inhibition of mild steel in SCW and the result was obtained with monomeric mono peroxy molybdates. These results as well as the mechanisms of corrosion inhibition were discussed. (author)

1997-01-01

276

Flow accelerated corrosion and erosion-corrosion of RAFM steel in liquid breeders  

International Nuclear Information System (INIS)

Corrosion experiments for RAFM, JLF-1 steel (Fe-9Cr-2W-0.1C) in three types of liquid breeders (i.e. Li, Pb-17Li and Flinak) were performed at 600 oC. The influence of the different experimental parameters, such as a flowing condition, an exposure time and a geometric condition, on the corrosion behavior was investigated. The present study focused on the evaluation of the weight loss of the corroded specimen by the corrosion model based on mass transfer. The dissolution of the metal elements from the steel was accelerated by the fluids. An erosion-corrosion of the steel was caused by the peeling off of the corroded steel surface in the flowing liquid breeders.

2010-10-01

277

Flow accelerated corrosion and erosion-corrosion of RAFM steel in liquid breeders  

Energy Technology Data Exchange (ETDEWEB)

Corrosion experiments for RAFM, JLF-1 steel (Fe-9Cr-2W-0.1C) in three types of liquid breeders (i.e. Li, Pb-17Li and Flinak) were performed at 600 {sup o}C. The influence of the different experimental parameters, such as a flowing condition, an exposure time and a geometric condition, on the corrosion behavior was investigated. The present study focused on the evaluation of the weight loss of the corroded specimen by the corrosion model based on mass transfer. The dissolution of the metal elements from the steel was accelerated by the fluids. An erosion-corrosion of the steel was caused by the peeling off of the corroded steel surface in the flowing liquid breeders.

Kondo, Masatoshi, E-mail: kondo.masatoshi@nifs.ac.jp [National Institute for Fusion Science, Toki (Japan); Muroga, Takeo; Sagara, Akio [National Institute for Fusion Science, Toki (Japan); Valentyn, Tsisar [Physico-Mechanical Institute of National Academy of Sciences of Ukraine, Lviv (Ukraine); Suzuki, Akihiro; Terai, Takayuki [University of Tokyo, Tokyo (Japan); Takahashi, Minoru [Tokyo Institute of Technology, Tokyo (Japan); Fujii, Naoki [Biko chemical company, Kobe, 658-0013 (Japan); Yokoyama, Yukihiro; Miyamoto, Hiroshi; Nakamura, Eiji [Santoku cooperation, Kobe, 673-0443 (Japan)

2011-10-15

278

Corrosion protection for silver reflectors  

Energy Technology Data Exchange (ETDEWEB)

A method of protecting silver reflectors from damage caused by contact with gaseous substances which are often present in the atmosphere and a silver reflector which is so protected. The inventive method comprises at least partially coating a reflector with a metal oxide such as aluminum oxide to a thickness of 15 .ANG. or less.

Arendt, Paul N. (Los Alamos, NM); Scott, Marion L. (Los Alamos, NM)

1991-12-31

279

Steam corrosion resistance of new 12% Cr ferritic boiler steels  

Energy Technology Data Exchange (ETDEWEB)

A new 12%Cr steel integrating good creep properties, fabricability and corrosion resistance up to 650 C is being developed. For each step of this development, long term oxidation tests (about 6000 h and 8000 h) were made in pure water vapour in the temperature range 600-650 C. The laboratory and industrial heats were tested in comparison with two 12%Cr steels (X20CrMoV12-1), a 9%Cr steel (T91) and a fined grain austenitic stainless steel (TP347FG). Corrosion damage was measured using mass losses obtained after a reducing descaling process. Weight loss and metallographic results confirm the good corrosion resistance in steam of the new steel, VM12, and show either 2 different corrosion mechanisms or the same mechanism but with 2 different spreading rates: for the VM12, one X20 heat and TP347 steels, the time required for the whole surface of the samples being covered with corrosion products is definitely longer than for the other 9-12% Cr. (orig.)

Lepingle, V.; Louis, G. [Ecole des Mines de Douai, Douai (France); Petelot, D. [Centre de Recherche Vallourec, Aulnoye Aymeries (France); Lefebvre, B.; Vandenberghe, B. [Vallourec and Mannesmann Tubes, St Saulve (France)

2004-07-01

280

Poly(o-phenylenediamine) as an inhibitor of mild steel corrosion in HCl solution  

International Nuclear Information System (INIS)

The inhibition properties of the electro-prepared P(o-phenylenediamine), P(oPD), on the corrosion rate of mild steel (MS) in HCl solutions have been investigated under different experimental conditions using weight loss and potentiodynamic polarization techniques. The data obtained from the two techniques are comparable and showed that the presence of P(oPD) in the acid solutions suppresses the corrosion rate of MS indicating that the polymer acts as corrosion inhibitor. The inhibition efficiency (IE%) of the polymer enhances with increasing its concentration and decreases with an increase in temperature. The inhibition occurs through adsorption and formation of barrier film on the metal surface which separates the metal from direct contact with the corrosive medium and hence protects the metal against the corrosion. Langmuir isotherm fits well with the experimental data. Thermodynamic parameters for both dissolution and adsorption processes were determined.

2010-09-01

 
 
 
 
281

Marine bacteria and localized corrosion on polymer coated steel: Cause and effect  

Energy Technology Data Exchange (ETDEWEB)

Diagnosis of microbiologically influenced corrosion on iron-containing substrata exposed in marine environments cannot be based solely on spatial relationships between large accumulations of bacterial cells and iron corrosion products. Field experiments were designed to evaluate the relationship between marine bacteria and localized corrosion on coated mild steel. In all cases, the distribution of bacteria was strongly influenced by the presence of iron corrosion products independent of coating combinations. In the presence of cathodic protection, coating defects were filled with calcareous deposits and few bacterial cells. Results demonstrate that bacteria are preferentially attracted to iron corrosion products in coating defects and that attraction is more influential than topography in determining the spatial distribution of bacterial cells.

Little, B.J.; Ray, R.; Ray, P. [Naval Research Lab., Stennis Space Center, MS (United States); Jones-Meehan, J. [Naval Research Lab., Washington, DC (United States); Lee, C.C.; Mansfeld, F.; Wagner, A. [Univ. of Southern California, Los Angeles, CA (United States). Dept. of Materials Science

1999-11-01

282

Effect of environmental variables on localized corrosion of carbon steel  

International Nuclear Information System (INIS)

Environmental conditions under which localized corrosion of carbon steel could take place in simulated groundwater were examined. Using specimens with crevices, it was determined that at potentials above the repassivation potential, the ratio of the chloride concentration to the total carbonate concentration, solution pH, and solution temperature played critical roles in establishing conditions that promote localized corrosion, as well as in influencing the rate of propagation. preoxidation in air at 200 C for short times improved the resistance to localized corrosion, but was detrimental for longer times. Monitoring of the open-circuit potential of samples with crevices in air-saturated, alkaline (pH 11) solutions revealed that the repassivation potential could be exceeded and localized corrosion can occur under free corrosion conditions. Factors important to the use of carbon steel as a construction material for high-level radioactive water disposal containers were discussed.

2000-01-01

283

Recent Research and Development in Solving Atmospheric Corrosion Problems of Steel Industries in Japan  

International Nuclear Information System (INIS)

[en] A rust layer, so called 'protective' rust layer, on a weathering low-alloy steel has strong protective ability for atmospheric corrosion of the steel. We have recently found through a large number of spectroscopic studies including Moessbauer spectroscopy that the protective rust layer forms after long-term phase transformation. The phase and structure of the rust definitely control the protective ability of the rust layer. From this recent knowledge, some new technologies have been developed. One is the surface-treatment technique that provides a possibility for obtaining the protective rust layer in a relatively short period even in the severe environments such as in marine and chloride (de-icing salts) containing environments. Others are based on selection of effective alloying elements for steel materials. These are particularly important for application in areas where protective rust layer formation may be hindered or prevented. In this paper, we mention recent progress in research and development on rusting protection by rust for atmospheric corrosion of steels in Japan.

2002-01-01

284

Corrosion in lithium-stainless steel thermal-convection systems  

International Nuclear Information System (INIS)

The corrosion of types 304L and 316 austenitic stainless steel by flowing lithium was studied in thermal-convection loops operated at 500 to 6500C. Both weight and compositional changes were measured on specimens distributed throughout each loop and were combined with metallographic examinations to evaluate the corrosion processes. The corrosion rate and mass transfer characteristics did not significantly differ between the two austenitic stainless steels. Addition of 500 or 1700 wt ppM N to purified lithium did not increase the dissolution rate or change the attack mode of type 316 stainless steel. Adding 5 wt % Al to the lithium reduced the weight loss of this steel by a factor of 5 relative to a pure lithium-thermal-convection loop

1980-04-24

285

Corrosion in lithium-stainless steel thermal-convection systems  

Energy Technology Data Exchange (ETDEWEB)

The corrosion of types 304L and 316 austenitic stainless steel by flowing lithium was studied in thermal-convection loops operated at 500 to 650/sup 0/C. Both weight and compositional changes were measured on specimens distributed throughout each loop and were combined with metallographic examinations to evaluate the corrosion processes. The corrosion rate and mass transfer characteristics did not significantly differ between the two austenitic stainless steels. Addition of 500 or 1700 wt ppM N to purified lithium did not increase the dissolution rate or change the attack mode of type 316 stainless steel. Adding 5 wt % Al to the lithium reduced the weight loss of this steel by a factor of 5 relative to a pure lithium-thermal-convection loop.

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

1980-01-01

286

Investigation of Fecraly Coating on Corrosion Behaviour of Mild Steel  

Directory of Open Access Journals (Sweden)

Full Text Available Steel has found wide application in hot rolling equipments in the steel industry and the oil rig structures in sea water. These equipments are frequently subjected to corrosive and temperature condition which causes severe damage to them, hence the need to develop steel suitable to withstand these conditions in terms of surface treatment. This research work investigates the effect of FeCrAlY coating on mild steel under high temperature and aggressive environment. Iron based coatings are used due to low cost among other properties such as good corrosion resistance, ease of machining and high ductility when compared to hard metals.Thermal spraying of the specimens was carried out using high velocity oxygen fuel (HVOF). Corrosion test was carried out on both coated and uncoated samples. All samples were subjected to the same high temperature treatment for oxidation test.

Joseph B. AGBOOLA

2009-01-01

287

Corrosion resistance of high strength modified 13Cr steel  

Energy Technology Data Exchange (ETDEWEB)

A new 13Cr martensitic stainless steel (0.025C-13Cr-Ni-Mo) with excellent resistance to CO{sub 2} corrosion and good resistance to SSC is developed and its application limit in oil and gas environments is clarified. The CO{sub 2} corrosion rate of the 13Cr steels with Ni and Mo is less than 0.3 mm/yr at 180 C (356 F) in 20% NaCl. It is less than that of the conventional 13Cr steel (0.2C-13Cr). The corrosion rate of the steel slightly decreases with the increase in Mo and Ni content. The SSC resistance improves with the increase in Mo content. The critical partial pressure of H{sub 2}S for the 2% Mo steel is greater than 0.005 MPa at the pH value of 3.5. The effects of Ni and Cu on SSC are not distinctive for this kind of steel. These results depends on the hydrogen permeability. The critical H{sub 2}S partial pressure for the 110 grade steel is the same as that of the 95 grade steel at the pH values of 4.5 and 3.0, and is slightly lower at the pH values between 3.0 and 4.5. The new 13Cr steel proves to have excellent properties in the sweet and slightly sour environment.

Kimura, Mitsuo; Miyata, Yukio; Yamane, Yasuyoshi; Toyooka, Takaaki; Nakano, Yoshifumi [Kawasaki Steel Corp., Handa, Aichi (Japan). Technical Research Labs.; Murase, Fumio [Kawasaki Steel Corp., Handa, Aichi (Japan). Chita Works

1997-08-01

288

The selection of reagents for inhibition of carbonic acid corrosion of steel under salt precipitation the conditions  

Energy Technology Data Exchange (ETDEWEB)

Inhibition against carbonic acid corrosion of steel was investigated under conditions of salt precipitation. The data on 34 corrosion inhibitors showed that reagents could be classified into two groups according to the nature of their action. For the first group, the corrosion rate at a given inhibitor concentration in the inhibited synthetic stratal water of a Samotlorskii petroleum deposit (previously named residual corrosion rate, RCR) was found to be constant and independent of the critical corrosion rate. Inhibitors of the second group demonstrated a constant protective effect. Out of the 34 inhibitors, 18 were related to the first group, and four to the second. The other need additional investigation. The critical corrosion rate, the residual corrosion rate (for the first group), and the value of the protective effect (for the second group) must be considered when one selects an inhibitor for certain conditions.

Markin, A.N.

1994-01-01

289

Desenvolvimento e uso do compósito de Nb2O5|Cu como revestimento aplicado por aspersão térmica sobre o aço AISI 1020 para proteção contra a corrosão pelo solo em estruturas enterradas Development of Nb2O5|Cu composite as AISI 1020 steel thermal spray coating for protection against corrosion by soil in buried structures  

Directory of Open Access Journals (Sweden)

Full Text Available An Nb2O|Cu corrosion-resistant coating was developed and applied onto AISI 1020 steel substrate by Powder Flame Spray. A galvanostatic electrochemical technique was employed, with and without ohmic drop, in four different soils (two corrosively aggressive and two less aggressive). Behavior of coatings in different soils was compared using a cathodic hydrogen reduction reaction (equilibrium potential, overvoltage and exchange current density) focusing on the effect of ohmic drop. Results allow recommendation of Nb2O5|Cu composite for use in buried structure protection.

Oscar Regis Junior; José Maurílio da Silva; Kleber Franke Portella; Ramon Sigifredo Cortes Paredes

2012-01-01

290

Desenvolvimento e uso do compósito de Nb2O5|Cu como revestimento aplicado por aspersão térmica sobre o aço AISI 1020 para proteção contra a corrosão pelo solo em estruturas enterradas/ Development of Nb2O5|Cu composite as AISI 1020 steel thermal spray coating for protection against corrosion by soil in buried structures  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english An Nb2O|Cu corrosion-resistant coating was developed and applied onto AISI 1020 steel substrate by Powder Flame Spray. A galvanostatic electrochemical technique was employed, with and without ohmic drop, in four different soils (two corrosively aggressive and two less aggressive). Behavior of coatings in different soils was compared using a cathodic hydrogen reduction reaction (equilibrium potential, overvoltage and exchange current density) focusing on the effect of ohmic drop. Results allow recommendation of Nb2O5|Cu composite for use in buried structure protection.

Regis Junior, Oscar; Silva, José Maurílio da; Portella, Kleber Franke; Paredes, Ramon Sigifredo Cortes

2012-01-01

291

Development of Nb{sub 2}O{sub 5}|Cu composite as AISI 1020 steel thermal spray coating for protection against corrosion by soil in buried structures; Desenvolvimento e uso do composito de Nb{sub 2}O{sub 5}|Cu como revestimento aplicado por aspersao termica sobre o aco AISI 1020 para protecao contra a corrosao pelo solo em estruturas enterradas  

Energy Technology Data Exchange (ETDEWEB)

An Nb{sub 2}O|Cu corrosion-resistant coating was developed and applied onto AISI 1020 steel substrate by Powder Flame Spray. A galvanostatic electrochemical technique was employed, with and without ohmic drop, in four different soils (two corrosively aggressive and two less aggressive). Behavior of coatings in different soils was compared using a cathodic hydrogen reduction reaction (equilibrium potential, overvoltage and exchange current density) focusing on the effect of ohmic drop. Results allow recommendation of Nb{sub 2}O{sub 5}|Cu composite for use in buried structure protection. (author)

Regis Junior, Oscar [Universidade Tecnologica Federal do Parana, Ponta Grossa, PR (Brazil). Dept. de Mecanica; Silva, Jose Maurilio da; Portella, Kleber Franke [Instituto de Tecnologia para o Desenvolvimento, Curitiba, PR (Brazil). Dept. de Pesquisa em Engenharia Civil; Paredes, Ramon Sigifredo Cortes, E-mail: regis@utfpr.edu.br [Universidade Federal do Parana, Curitiba, PR (Brazil). Dept. de Mecanica

2012-07-01

292

Materials corrosion and protection at high temperatures; Corrosion et protection des materiaux a haute temperature  

Energy Technology Data Exchange (ETDEWEB)

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.)

Balbaud, F.; Desgranges, Clara; Martinelli, Laure; Rouillard, Fabien [CEA-Saclay, DEN, DPC, SCCME, Laboratoire d' Etude de la Corrosion Non Aqueuse, 91191 Gif-sur-Yvette Cedex (France); Duhamel, Cecile [Mines ParisTech, Centre des materiaux UMR-CNRS 7633, BP 87, 91003 Evry Cedex (France); Marchetti, Loic; Perrin, Stephane [CEA, Laboratoire d' Etude de la Corrosion Aqueuse (France); Molins, Regine [Mines ParisTech, Direction de la Recherche, 60 Bvd Saint Michel, 75272 Paris Cedex 06 (France); Chevalier, S.; Heintz, O. [Laboratoire interdisciplinaire Carnot de Bourgogne, UMR 5209 CNRS, Univ. de Bourgogne, Dijon (France); David, N.; Fiorani, J.M.; Vilasi, M. [Institut Jean Lamour, UMR 7198, Univ. Henri Poincare Nancy-1 - CNRS, 54506 Vandoeuvre-les-Nancy (France); Wouters, Y.; Galerie, A. [SIMAP UMR CNRS 5266, Grenoble-INP/UJF, 1130 rue de la Piscine BP 75, 38402 Saint-Martin-d' Heres Cedex (France); Mangelinck, D. [IM2NP, UMR6242, CNRS, Univ. Paul Cezanne, Case 142, Faculte de Saint Jerome, 13397 Marseille Cedex 20 (France); Viguier, B.; Monceau, D. [Univ. de Toulouse, Institut Carnot CIRIMAT, INP-ENSIACET, 4 allee Emile Monso, BP 44362, 31030 Toulouse Cedex 4 (France); Soustelle, M. [Ecole nationale superieure des mines, Saint Etienne (France); Pijolat, M. [Centre Spin, Ecole des mines de Saint Etienne (France); Favergeon, J.; Brancherie, D.; Moulin, G.; Dawi, K. [Laboratoire Roberval, UTC (France); Wolski, K.; Barnier, V. [Centre SMS, EMSE, UMR 5146, LCG, Univ. de Lyon, 158 Cours Fauriel, 42023 Saint Etienne (France); Rebillat, F. [LCTS, Univ. de Bordeaux (France); Lavigne, O. [Onera, Dep. Materiaux et Structures Metalliques, BP 72, 29 av. de la Division Leclerc, 92322 Chatillon (France); Brossard, J.M. [Dep. energetique et procedes, Veolia Environnement Recherche et Innovation, Limay (France); Ropital, F. [IFP Energies Nouvelles, BP 3, 69360 Solaize (France); Mougin, J. [CEA-Liten, 17 rue des Martyrs, 38054 Grenoble Cedex 9 (France)

2011-07-01

293

Corrosion protection and finishing of automobiles  

International Nuclear Information System (INIS)

finishing of automobiles is an important aspect. There have been considerable reductions of weight in automobiles by the use of composites components replacing heavy metallic components. Fenders previously based on metal have been replaced with plastic and painted with the same colour shade as of the metallic body, this has eps for proper adhesion of the paints on the plastic fender to avoid chipping off the paint form it. This paper discusses the necessary processes required for finishing of an automobile along with the corrosion protection measures. Automobiles contains a variety of engineering materials, engine main body fuel tanks connecting rods heat radiators and other mechanical parts are made from different types of engineering alloys having varying chemical compositions. Other parts like dashboard, front panel and other are made from composites. The main body made from cold roll ed steel having various contours 'c' it due to the different designs is the potential site for corrosion attack, The main body is exposed to the hostile environment through out its life period. An automobile is given a particular finish with a view to counter the hostile environments as they are not limited for plying in a limiting conditions and are taken to different weather conditions in one day thus facing severe stresses and strain. Thus it is essential that an automobile before rolling 'out of the assembly line should properly corrosion resistant and aesthetically pleasant also. Finishing for automobiles being very specialized, the main requirement being maximum durability with minimum numbers of coats baked, at the fastest possible schedule. High gloss and range of good eye catching colours being important to increase sales appeal. In the near past the car finishes were based on alkyd-amino resins baking materials and force drying lacquers, which have excellent appearance originally and maintain it on aging. The finishing system for the synthetic baking type may consist of one primer coat and a double finish coat. The two finishing coats are applied one immediately after the other, and both are baked simultaneously. An alternate system is to apply a red iron oxide epoxy primer followed by a gray epoxy primer and to bake the two coats at 200 degree C for about 35 minutes. The dry film thickness is about is about 1.5 mils. This coating is wet sanded, washed, and dried then top-coated with a double (wet-on-wet) coat of alkyd-amino resin enamel. The enamel is baked at 120 degree C for about 35 minutes. The lacquer system consists of one prime coat followed by several coats of lacquer finish. Number of coats depending on the price range of the car. All the efforts are made to make the metal surface as smooth as possible and free from rough places due to spot wielding and filing. This means a minimum of sanding on the primer, thus saving in labour cost but also makes possible less pigment in the primer resulting in better hold-out of the finish. However, the primer must be hard enough to sand easily, because rubbery primers tare slow sanding and tend to show scratch marks from the sand paper. All metal surfaces are given a passivating treatment before application of the primer. (author)

2005-01-01

294

Investigation on corrosion of titanium/steel brazed joint  

Energy Technology Data Exchange (ETDEWEB)

Furnace vacuum brazing has been employed to join commercially pure titanium alloy and low carbon steel using a silver-based filler metal with a composition of Ag-Cu34-Ti2 (wt%). Three different brazing temperatures (850 C, 880 C, 930 C) and two holding times (5 and 15 min) were applied and evaluated. The corrosion behavior of the joints in 0.1 M sulfuric acid was investigated using immersion and electrochemical tests. Measurements of corrosion potential, corrosion current density, corrosion rate, polarization resistance, weight loss, and morphology of corrosion attack were used in this study. The results indicated that a severe corrosion attack at the interfacial area of the steel side took place. Despite the difference in corrosion rate values obtained by electrochemical and weight loss measurements, the trend of the results was identical to a large extent. The corrosion resistance of the joint showed a general tendency to increase with an increasing brazing temperature and holding time. Therefore, the joints produced at a temperature of 930 C and a holding time of 15 min produced the best result concerning the corrosion behavior. (orig.)

Elrefaey, A.; Wojarski, L.; Tillmann, W. [TU Dortmund (Germany). Lehrstuhl fuer Werkstofftechnologie

2010-11-15

295

Localized weld metal corrosion in stainless steel water tanks  

Energy Technology Data Exchange (ETDEWEB)

The rapidly developed leaks within the TFC and TFD tanks (LLNL groundwater treatment facilities) were caused by localized corrosion within the resolidified weld metal. The corrosion was initiated by the severe oxidation of the backsides of the welds which left the exposed surfaces in a condition highly susceptible to aqueous corrosion. The propagation of surface corrosion through the thickness of the welds occurred by localized corrosive attack. This localized attack was promoted by the presence of shielded aqueous environments provided by crevices at the root of the partial penetration welds. In addition to rapid corrosion of oxidized surfaces, calcium carbonate precipitation provided an additional source of physical shielding from the bulk tank environment. Qualification testing of alternate weld procedures showed that corrosion damage can be prevented in 304L stainless steel GTA welds by welding from both sides while preventing oxidation of the tank interior through the use of an inert backing gas such as argon. Corrosion resistance was also satisfactory in GMA welds in which oxidized surfaces were postweld cleaned by wire brushing and chemically passivated in nitric acid. Further improvements in corrosion resistance are expected from a Mo-containing grade of stainless steel such as type 316L, although test results were similar for type 304L sheet welded with type 308L filler metal and type 316L sheet welded with type 316L filler metal.

Strum, M.J.

1995-05-25

296

Study on the Corrosion Inhibition Characteristics of Carbon Steel by Sodium Phosphate and Sodium Nitrite  

International Nuclear Information System (INIS)

Sodium nitrite is widely used as one of the popular corrosion inhibitors for the protection of ferrous metal in closed cooling water system, such as a diesel engine and a chiller. The optimum treatment conditions are studied through laboratory tests using linear polarization resistance (LPR) technique. Corrosion rate of the carbon steel electrode could be maintained less than 2.5x10-3 mmpy in the test condition of 500 ppm as NO2-, 200 ppm as CT, 70 .deg. C and pH 6.8. The pH control is confirmed not to be an important factor in the protection of carbon steel by sodium nitrite inhibitor. The addition of tolyltriazole was needed for the protection of the copper alloy in the sodium nitrite treatment system

2010-01-01

297

Study on the Corrosion Inhibition Characteristics of Carbon Steel by Sodium Phosphate and Sodium Nitrite  

Energy Technology Data Exchange (ETDEWEB)

Sodium nitrite is widely used as one of the popular corrosion inhibitors for the protection of ferrous metal in closed cooling water system, such as a diesel engine and a chiller. The optimum treatment conditions are studied through laboratory tests using linear polarization resistance (LPR) technique. Corrosion rate of the carbon steel electrode could be maintained less than 2.5x10{sup -3} mmpy in the test condition of 500 ppm as NO{sub 2}{sup -}, 200 ppm as CT, 70 .deg. C and pH 6.8. The pH control is confirmed not to be an important factor in the protection of carbon steel by sodium nitrite inhibitor. The addition of tolyltriazole was needed for the protection of the copper alloy in the sodium nitrite treatment system.

Moon, Jeon Soo; Lee, Jae Kun [Green Growth Laboratory, Korea Electric Power Research Institute, Daejeon (Korea, Republic of)

2010-06-15

298

Relationship between atmospheric Corrosion of carbon steel and air quality  

Energy Technology Data Exchange (ETDEWEB)

This study has been conducted to examine the relationship between atmospheric corrosion of steel and atmospheric environment factors including acid rain. Mild carbon steel test panels were exposed in the atmosphere at ten sites in Tokyo and Yamanashi Prefecture from 1970 to 1990. In the late 1960s and early 1970s, the levels of SO2, SO4[sup 2-] and suspended particulate matter in the air were considerably high, but their levels had rapidly declined until the late 1970s. Corrosion rates of low carbon steel in the air decreased in the same tendency. The difference of corrosion rates almost coincided with concentration of air pollutants such as SO2, suspended particulate matter, NOx and sea salt. Annual rates of steel corrosion were influenced more by rain than air pollutants. The most effective component in the rain water was H[sup +] and the next most was SO4[sup 2-]. The relationship between corrosion rate and the air pollutant concentrations were confirmed by using statistical analysis of multiple regression and correlation. The most effective atmospheric factors to the corrosion rates were concentration of rain components such as H[sup +], SO4[sup 2-], NO3[sup -] and NH4[sup +]. 18 refs., 5 figs., 7 tabs.

Komeiji, T.; Aoki, K. (The Tokyo Metropolitan Research Inst. for Environmental Protection, Tokyo (Japan)); Kadoi, M. (Nihon Univ., Tokyo (Japan)); Sakamoto, K. (Saitama Univ., Saitama (Japan))

1994-05-15

299

Erosion-corrosion of a carbon steel elbow in CO{sub 2} environment  

Energy Technology Data Exchange (ETDEWEB)

It is well known that for many conditions erosion-corrosion can produce much higher wall penetration rates than erosion or corrosion acting alone. While flow velocity generally is believed to be an important factor in erosion-corrosion, more needs to be learned about how flow conditions influence erosion-corrosion. Toward this end, a flow loop was used to study erosion-corrosion of carbon steel elbows in a CO{sub 2} environment with sand entrained in the flowing liquid. Three typical behaviors were found. At low velocities a protective iron carbonate scale formed over all surfaces of the elbow, and corrosion rates were very low. At high velocities, impingement on elbow surfaces by sand particles entrained in the flow prevented protective scales from forming anywhere in the elbow. Corrosion rates for this case were high and uniform over the entire surface. At intermediate velocities, Protective scales formed over all of the elbow surface except at very localized points where the impinging sand particles prevented scale formation. Deep pits formed at these points and wall penetration rates were extremely high. These conditions are very damaging but can be avoided, if recognized in advance, by reducing or increasing the flow velocities. A computational model for predicting sand erosion in piping systems was used to simulate the experiments to explain the three observed behaviors and to predict conditions defining the boundaries between them.

Shadley, J.R.; Shirazi, S.A.; Dayalan, E.; Ismail, M.; Rybicki, E.F. [Univ. of Tulsa, OK (United States)

1995-10-01

300

Intergranular stress corrosion sensitivity in stabilized stainless steels  

International Nuclear Information System (INIS)

[en] Stabilized stainless steels are used in ASEA-ATOM BWR's in a number of forged and casted components, viz. valve housings. Samples of steels that are Ti-stabilized have been analyzed for carbon, and then CERT-tested for intergranular stress corrosion (IGSCC). The steels tested are Sandvik 8R30 and VEW A700. The medium was water with 8 ppm O2 and at 286 degreeC, and a feed conductivity of less than 0.1?Scm-1. The tests show that the zone near welds in these stabilized steels which in strongly oxidizing acids are sensitive to knife line attack, are also in BWR systems sensitive to IGSCC. This type of corrosion can be inhibited by minimizing the carbon content of the steels. (Aa)

1984-01-01

 
 
 
 
301

Oil field chemicals synergistic effects on the corrosion rate of L-80 steel in sea and formation waters  

Energy Technology Data Exchange (ETDEWEB)

The corrosion rate of tubular grade L-80 carbon steel under downhole conditions of a northern oil field of Kuwait was investigated. This was done using the injection seawater, formation water and a 50:50 mixture of both waters in the presence of commercially available corrosion inhibitor, scale inhibitor, and biocide products separately and in combination with each other. The main objective of this study was to investigate the effect of the corrosion inhibitor and its interaction with the scale inhibitor and the biocide, as seen in the corrosion rate of L80 carbon steel. This was done using the manufacturers' recommended dosage levels of the corrosion inhibitor, scale inhibitor and biocide. The corrosion rates were measured by linear polarization. Tests were conducted using the rotating cylinder electrode method with rotational speeds of 1000 and 2000 rpm at 80 deg. C. The seawater results indicated that the corrosion-scale inhibitor and biocide-scale inhibitor combinations provided the best protection at both rotation speeds. In formation water, the effects of rotation speed were more apparent with higher corrosion rates of L-80 carbon steel accompanying higher shear forces. In the 50: 50 mix waters and the formation water, the corrosion-scale inhibitors-biocide combination provided the best protection at both rotational speeds under downhole conditions of a northern oil field of Kuwait. (authors)

Al Hashem, A.; Carew, J. [Petroleum Research and Studies Center, Kuwait Institute for Scientific Research, P.O. Box 24885, 13109 Safat Kuwait (Kuwait); Al-Borno, A. [Charter Coating Service (2000) Ltd., no 6, 4604, 13 Street N.E., Calgary, AB T2E 6P1 (Canada)

2004-07-01

302

Corrosion of steel tanks in liquid nuclear wastes  

International Nuclear Information System (INIS)

The objective of this work is to understand how solution chemistry would impact on the corrosion of waste storage steel tanks at the Hanford Site. Future tank waste operations are expected to process wastes that are more dilute with respect to some current corrosion inhibiting waste constituents. Assessment of corrosion damage and of the influence of exposure time and electrolyte composition, using simulated (non-radioactive) wastes, of the double-shell tank wall carbon steel alloys is being conducted in a statistically designed long-term immersion experiment. Corrosion rates at different times of immersion were determined using both weight-loss determinations and electrochemical impedance spectroscopy measurements. Localized corrosion susceptibility was assessed using short-term cyclic potentiodynamic polarization curves. The results presented in this paper correspond to electrochemical and weight-loss measurements of the immersed coupons during the first year of immersion from a two year immersion plan. A good correlation was obtained between electrochemical measurements, weight-loss determinations and visual observations. Very low general corrosion rates (-1) were estimated using EIS measurements, indicating that general corrosion rate of the steel in contact with liquid wastes would no be a cause of tank failure even for these out-of-chemistry limit wastes. (author)

2005-01-01

303

Analysis of corrosion products of carbon steel in wet bentonite  

International Nuclear Information System (INIS)

As a part of evaluation of the long-term durability for the overpack containers for high-level radioactive waste, we have conducted corrosion tests for carbon steel in wet bentonite, a candidate buffer material. The corrosion rates were evaluated by weight difference of carbon steel and corrosion products were analyzed by Fourier transform infrared spectroscopy (FT-IR) and colorimetry. At 40degC, the corrosion rate of carbon steel in wet bentonite was smaller than that in pure water. At 95degC, however, the corrosion rate in wet bentonite was much higher than that in pure water. This high corrosion rate in wet bentonite at 95degC was considered to result from evaporation of moisture in bentonite in contact with the metal. This evaporation led to dryness and then to shrinkage of the bentonite, which generated ununiform contact of the metal with bentonite. Probably, this ununiform contact promoted the local corrosion. The locally corroded parts of specimen in wet bentonite at 95degC were analyzed by Fourier transform infrared microspectroscopy (micro-FT-IR), and lepidocrocite ?-FeO(OH) was found as well as goethite ?-FeO(OH). In wet bentonite at 95degC, hematite ?-Fe2O3 was identified by means of colorimetry. (author)

1992-01-01

304

Corrosion of mild steel in simulated cesium elution process solutions  

Energy Technology Data Exchange (ETDEWEB)

The West Valley Support Project is being conducted to meet technology needs for the West Valley Demonstration Project and to provide support to the site cleanup and stabilization activities, which involves removing residual Cs in Tank 8D-1 after waste retrieval. In-tank oxalic acid elution of Cs-loaded zeolite is being evaluated. The work reported here involved evaluating the potential for increased corrosion of Tank 8D-1 during Cs elution, because oxalic acid is corrosive to carbon steel. This included corrosion tests with mild steel (A516 Grade 55) at 27-50 C with 4 and 8 wt% oxalic acid, for 2, 4, and 6 days. Results agreed with Sept. 1995 tests at 50 C for 1-3 weeks. Corrosion rate of A516 Grade 55 mild steel in oxalic acid is quite high (about 150 mils/y or 3.8 mm/y). Corrosion increased three- or fourfold going from 27 to 50 C. Although the tests resulted in a very rough surface appearance, indicating potential for localized corrosion, eg, pitting and crevice corrosion, the exposure times used were apparently too short to initiate pitting.

Elmore, M.R.

1996-09-01

305

Corrosion of mild steel in simulated cesium elution process solutions  

International Nuclear Information System (INIS)

The West Valley Support Project is being conducted to meet technology needs for the West Valley Demonstration Project and to provide support to the site cleanup and stabilization activities, which involves removing residual Cs in Tank 8D-1 after waste retrieval. In-tank oxalic acid elution of Cs-loaded zeolite is being evaluated. The work reported here involved evaluating the potential for increased corrosion of Tank 8D-1 during Cs elution, because oxalic acid is corrosive to carbon steel. This included corrosion tests with mild steel (A516 Grade 55) at 27-50 C with 4 and 8 wt% oxalic acid, for 2, 4, and 6 days. Results agreed with Sept. 1995 tests at 50 C for 1-3 weeks. Corrosion rate of A516 Grade 55 mild steel in oxalic acid is quite high (about 150 mils/y or 3.8 mm/y). Corrosion increased three- or fourfold going from 27 to 50 C. Although the tests resulted in a very rough surface appearance, indicating potential for localized corrosion, eg, pitting and crevice corrosion, the exposure times used were apparently too short to initiate pitting.

1996-01-01

306

Bacterial corrosion in marine sediments: influence of cathodic protection  

International Nuclear Information System (INIS)

[en] In order to protect offshore structures from marine corrosion, cathodic protection is widely applied via sacrificial anodes (for example zinc or aluminium) or impressed current. In aerated seawater, steel is considered to be protected when a potential of -8050 mV/Cu.CuSO4 is achieved. In many cases, however this potential must be lowered, due to the activity of microorganisms and more specially sulfate-reducing bacteria (SRB). SRB are obligate anaerobes using sulphate as electron acceptor with resultant production of sulphide. Some of them are also able to use hydrogen as energy source, causing cathodic depolarization of steel surfaces. An experiment was performed to analyze the relation between SRB activity and use of different cathodic potentials applied to mild steel samples in marine sediments. Analytical techniques employed included lipid bio-markers and electrochemical methods. Results indicated an evolution of the bacterial community structure both on the steel and in the sediment, as a function of time and potential. The results also show that cathodically produced hydrogen promotes the growth of SRB (author)[fr] La duree de vie des structures metalliques immergees en milieu marin est souvent liee a la mise en place d'une protection cathodique par courant impose ou anodes sacrificielles. Cependant, ce type de protection induit la formation de quantites non negligeables d'hydrogene susceptible d'etre utilise comme source d'energie par certains microorganismes tels les bacteries sulfato-reductrices. Une experience a ete realisee dans le but d'etudier les relations possibles entre differents potentiels de protection, la croissance de bacteries sulfato-reductrices, et la corrosion d'aciers doux places dans des sediments marins a temperature ambiante (10 deg. C) et a temperature plus elevee (35 deg. C). Des analyses, chimiques, biochimiques et microbiologiques ainsi que des mesures electrochimiques (densite de courant cathodique, diagrammes d'impedance...) ont ete realisees sur des periodes d'exposition de 0 a 3 mois et pour des potentiels imposes de -800, -900, -1000, et 1100 mV/Ag.AgCl. Les resultats obtenus indiquent une evolution de la structure de la population bacterienne dans les premiers millimetres de sediments au dessus des echantillons. Cette evolution bacterienne et principalement le developpement de bacteries sulfato-reductrices resultant de la production d'hydrogene cathodique a l'interface metal-sediment peut remettre en cause les criteres de protection cathodique habituellement preconises et un potentiel de -900 mV/Ag.AgCl apparait ainsi comme suffisant pour proteger les structures metalliques placees dans un tel environnement. (auteur)

1988-01-01

307

Ni-W coatings electrodeposited on carbon steel: Chemical composition, mechanical properties and corrosion resistance  

Energy Technology Data Exchange (ETDEWEB)

Highlights: > Hard, ductile and adherent nanostructured Ni-W coatings on carbon steel. > New procedures for achieving deposits by current pulse techniques. > Current pulse frequency was the dominant factor to define coating characteristics. > Ni-W coatings protect the carbon steel from corrosion induced by sulphate anions. - Abstract: Hard, ductile and adherent nanostructured Ni-W coatings were electrodeposited on carbon steel from electrolyte solutions containing sodium tungstate, nickel sulfate and sodium citrate, using different current pulse programs. Current pulse frequency was the dominant factor to define chemical composition, grain size, thickness and hardness. According to the electrodeposition conditions the deposited coatings showed 15-30 at% W, the grain size ranged from 65 to 140 nm, and the hardness varied from 650 to 850 Hv. Tungsten carbide also present in the coating contributed to its hardness. The corrosion resistance of the Ni-W coated steel was tested by potentiodynamic polarization in a neutral medium containing sulphate ions. The Ni-W coating protected the carbon steel from localized corrosion induced by sulphate anions.

Arganaraz, M.P. Quiroga; Ribotta, S.B. [INQUINOA-CONICET, Instituto de Quimica Fisica, Facultad de Bioquimica, Quimica y Farmacia, Universidad Nacional de Tucuman, Ayacucho 471, (4000) San Miguel de Tucuman (Argentina); Folquer, M.E., E-mail: mefolquer@fbqf.unt.edu.ar [INQUINOA-CONICET, Instituto de Quimica Fisica, Facultad de Bioquimica, Quimica y Farmacia, Universidad Nacional de Tucuman, Ayacucho 471, (4000) San Miguel de Tucuman (Argentina); Gassa, L.M.; Benitez, G.; Vela, M.E.; Salvarezza, R.C. [Instituto de Investigaciones Fisicoquimicas Teoricas y Aplicadas (INIFTA), Universidad Nacional de La Plata-CONICET, Suc. 4, C.C. 16, (1900) La Plata (Argentina)

2011-07-01

308

Ni-W coatings electrodeposited on carbon steel: Chemical composition, mechanical properties and corrosion resistance  

International Nuclear Information System (INIS)

[en] Highlights: ? Hard, ductile and adherent nanostructured Ni-W coatings on carbon steel. ? New procedures for achieving deposits by current pulse techniques. ? Current pulse frequency was the dominant factor to define coating characteristics. ? Ni-W coatings protect the carbon steel from corrosion induced by sulphate anions. - Abstract: Hard, ductile and adherent nanostructured Ni-W coatings were electrodeposited on carbon steel from electrolyte solutions containing sodium tungstate, nickel sulfate and sodium citrate, using different current pulse programs. Current pulse frequency was the dominant factor to define chemical composition, grain size, thickness and hardness. According to the electrodeposition conditions the deposited coatings showed 15-30 at% W, the grain size ranged from 65 to 140 nm, and the hardness varied from 650 to 850 Hv. Tungsten carbide also present in the coating contributed to its hardness. The corrosion resistance of the Ni-W coated steel was tested by potentiodynamic polarization in a neutral medium containing sulphate ions. The Ni-W coating protected the carbon steel from localized corrosion induced by sulphate anions.

2011-07-01

309

Corrosion protection for silver reflectors  

Energy Technology Data Exchange (ETDEWEB)

This patent describes a method of protecting a silver reflector from damage caused by contact with gaseous substances. It comprises: at least partially coating the reflector to a thickness of 15 [Angstrom] or less with a substance selected from a group containing aluminum oxide, magnesium oxide, titanium dioxide, silicon dioxide, yttrium oxide, hafnium oxide, zirconium oxide, and praseodymium oxide.

Arendt, P.N.; Scott, M.L.

1991-12-31

310

Corrosion resistant steel with high coefficient of thermal neutron absorption  

International Nuclear Information System (INIS)

[en] A new corrosion resistant chromium steel with high content (up to 1.8 mass%) of natural boron was developed. The steel is designated for manufacture of fuel assembly jackets and shields absorbing thermal neutrons. It differs from foreign analogues by higher boron content and by the absence of scarce nickel in its composition. The steel tubes were tested in aqueous solution of boric acid at temperatures of 20 to 100 deg C for 500, 1000, 2000 and 3000 h. Data on neutron absorption for sheets and tubes are presented in comparison with German steel type Boron 304. 2 refs.; 2 tabs

1992-01-01

311

Strain Aging of X100 Steel in Service and the Enhanced Susceptibility of Pipelines to Stress Corrosion Cracking  

Science.gov (United States)

In this study, experimental tests were performed to investigate the strain aging behavior of X100 pipeline steel in service and the resulting enhancement of susceptibility of pipelines to stress corrosion cracking (SCC). Results demonstrated that an immediate rise in temperature during coating application could result in strain aging of X100 steel, as indicated by increasing strength and decreasing elongation as well as the presence of Lüders strain during yielding. The aged steel is associated with an enhanced cracking susceptibility under cathodic protection potentials. It is believed that strain aging is able to enhance hydrogen evolution and the further permeation into steel, resulting in hydrogen-induced SCC of the steel.

Liang, Guangchuan; Peng, Xingyu; Juan, E. San; Cheng, Y. Frank

2013-08-01

312

Corrosion testing of stainless steel-zirconium metal waste form  

International Nuclear Information System (INIS)

[en] Stainless steel-zirconium (SS-Zr) alloys are being considered as waste forms for the disposition of metallic waste generated during the electrometallurgical treatment of spent nuclear fuel. The waste forms contain irradiated cladding hulls, components of the alloy fuel, noble metal fission products, and actinide elements. The baseline waste form is a stainless steel-15 wt% zirconium (SS-15Zr) alloy. This article presents microstructure and some of the corrosion studies being conducted on the waste form alloys. Electrochemical corrosion, immersion corrosion, and vapor hydration tests have been performed on various alloy compositions to evaluate corrosion behavior and resistance to selective leaching of simulated fission products. The SS-Zr waste forms are successful at the immobilization and retention of fission products and show potential for acceptance as high-level nuclear waste forms

1998-12-04

313

Electrochemical Corrosion Testing of Borated Stainless Steel Alloys  

Energy Technology Data Exchange (ETDEWEB)

The Department of Energy Office of Civilian Radioactive Waste Management has specified borated stainless steel manufactured to the requirements of ASTM A 887-89, Grade A, UNS S30464, to be the material used for the fabrication of the fuel basket internals of the preliminary transportation, aging, and disposal canister system preliminary design. The long-term corrosion resistance performance of this class of borated materials must be verified when exposed to expected YMP repository conditions after a waste package breach. Electrochemical corrosion tests were performed on crevice corrosion coupons of Type 304 B4 and Type 304 B5 borated stainless steels exposed to single postulated in-package chemistry at 60°C. The results show low corrosion rates for the test period

lister, tedd e; Mizia, Ronald E

2007-09-01

314

78 FR 15376 - Determinations: Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea  

Science.gov (United States)

...Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea On the basis of the record...corrosion-resistant carbon steel flat products from Germany and Korea would not be likely to lead...Corrosion-Resistant Carbon Steel Flat Products from Germany and Korea: Investigation Nos....

2013-03-11

315

Mangrove tannins and their flavanoid monomers as alternative steel corrosion inhibitors in acidic medium  

International Nuclear Information System (INIS)

The inhibitive behaviour on steel of flavanoid monomers that constitute mangrove tannins namely catechin, epicatechin, epigallocatechin and epicatechingallate was investigated in an aerated HCl solution via electrochemical methods. The monomers were found to be mainly cathodic inhibitors and the inhibition efficiency was dependent on concentration. To explain the adsorptive behaviour of the molecules on the steel surface, a semiempirical approach involving quantum chemical calculations using HyperChem 6.0 was undertaken. The HOMO electronic density of the molecule was used to explain the inhibiting mechanism. The most probable adsorption centers were found in the vicinity of the phenolic groups. In a second part, the use of mangrove tannin, extracted from the mangrove barks as steel corrosion inhibitors in acidic media was investigated and its inhibitive efficiency was compared with that of commercial mimosa, quebracho and chestnut tannins. The inhibitive performance of mangrove tannins was comparable to the other tannins investigated, indicating their potential in corrosion protection

2007-01-01

316

Mangrove tannins and their flavanoid monomers as alternative steel corrosion inhibitors in acidic medium  

Energy Technology Data Exchange (ETDEWEB)

The inhibitive behaviour on steel of flavanoid monomers that constitute mangrove tannins namely catechin, epicatechin, epigallocatechin and epicatechingallate was investigated in an aerated HCl solution via electrochemical methods. The monomers were found to be mainly cathodic inhibitors and the inhibition efficiency was dependent on concentration. To explain the adsorptive behaviour of the molecules on the steel surface, a semiempirical approach involving quantum chemical calculations using HyperChem 6.0 was undertaken. The HOMO electronic density of the molecule was used to explain the inhibiting mechanism. The most probable adsorption centers were found in the vicinity of the phenolic groups. In a second part, the use of mangrove tannin, extracted from the mangrove barks as steel corrosion inhibitors in acidic media was investigated and its inhibitive efficiency was compared with that of commercial mimosa, quebracho and chestnut tannins. The inhibitive performance of mangrove tannins was comparable to the other tannins investigated, indicating their potential in corrosion protection.

Rahim, Afidah A. [School of Chemical Sciences, University Sains Malaysia, 11800 Penang (Malaysia)]. E-mail: afidah@usm.my; Rocca, E. [Laboratoire de Chimie du Solide Mineral, Universite Henri Poincare, Nancy I BP 239, 54506 Vandoeuvre Les Nancy (France); Steinmetz, J. [Laboratoire de Chimie du Solide Mineral, Universite Henri Poincare, Nancy I BP 239, 54506 Vandoeuvre Les Nancy (France); Kassim, M.J. [School of Chemical Sciences, University Sains Malaysia, 11800 Penang (Malaysia); Adnan, R. [School of Chemical Sciences, University Sains Malaysia, 11800 Penang (Malaysia); Sani Ibrahim, M. [School of Chemical Sciences, University Sains Malaysia, 11800 Penang (Malaysia)

2007-02-15

317

Vanadin - corrosion protection and corrosion acceleration in steam-generating furnaces  

International Nuclear Information System (INIS)

The vanadium/oxygen system is complex as all of the transitions from the metal phase to the pentoxide are diffuse. No defined phases can be expected in practice. The transition from quadrivalent to pentavalent vanadium occurs easily for oxides and vanadates and is accompanied by lattice expansion. Molten vanadates may lose oxygen on cooling - recognized by the occurence of spitting. The destructive effect of vanadates is based on their solubility for slags and glasses; this is supported by the cleaving effect of vanadium according to the spacing-position theory of Endell-Hellbruegge. The dissolution of protective oxide films, immediate reformation of oxides and so on, leads to a 'catastrophic corrosion'. Only by diluting vanadium rich oil ash with high melting components can vanadium corrosion be reduced in steam generating furnaces. The recovery of vanadium from the walls of oil fired steam generators may be of interest. On the other hand V2O5 has shown its usefulness in protecting refractory building material such as silicon carbide from corrosion. Vanadium is also used to alloy austenitic steel. (orig.)

1976-01-01

318

Corrosion behavior of stainless steels simulating radiation-induced segregation  

International Nuclear Information System (INIS)

[en] Effect of chemical composition caused by radiation-induced segregation on corrosion behavior was examined using the experimental alloys simulating the chemical composition at/near grain boundaries of irradiated austenitic stainless steels. The corrosion behavior of the experimental alloys seemed to be dependent mainly on the concentration of Cr. However some effects of Ni and Si content were observed on the anodic dissolution in a sulfuric acid solution. Some differences were observed on the electrochemical properties of anodic polarization behavior against the alloys those had the chemical composition of thermally-sensitized austenitic stainless steel. (author)

2004-01-01

319

Electrochemical and weight-loss study of carbon steel corrosion  

International Nuclear Information System (INIS)

The Point Lepreau Generating Station (PLGS) will undergo an 18 month refurbishment project beginning in April, 2008. During this time, most of the carbon steel piping in the primary loop will be drained of water and dried. However, some water will remain during the shutdown due to the lack of drains in some lower points in the piping system. As a result, it is necessary to examine the effect of corrosion during the refurbishment. This study examined the effect of several variables on the corrosion rate of clean carbon steel. Specifically, the effect of oxygen in the system and the presence of chloride ions were evaluated. Corrosion rates were determined using both a weight-loss technique and electrochemical methods. The experiment was conducted at room temperature. The corrosion products from the experiment were analyzed using a Raman microscope. The results of the weight-loss measurements show that the corrosion rate of polished carbon steel is independent of both the presence of oxygen and chloride ions. The electrochemical method failed to yield meaningful results due to the lack of clearly interpretable data and the inherent subjectivity in the analysis. Lepidocricite was found to be the main corrosion product using the Raman microscope. (author)

2007-01-01

320

Electrochemical and weight-loss study of carbon steel corrosion  

Energy Technology Data Exchange (ETDEWEB)

The Point Lepreau Generating Station (PLGS) will undergo and 18 month refurbishment project beginning in April, 2008. During this time, most of the carbon steel piping in the primary loop will be drained of water and dried. However, some water will remain during the shutdown due to the lack of drains in some lower points in the piping system. As a result, it is necessary to examine the effect of corrosion during the refurbishment. This study examined the effect of several variables on the corrosion rate of clean carbon steel. Specifically, the effect of oxygen in the system and the presence of chloride ions were evaluated. Corrosion rates were determined using both a weight-loss technique and electro-chemical methods. The experiment was conducted at room temperature. The corrosion products from the experiment were analyzed using a Raman microscope. The results of the weight-loss measurements show that the corrosion rate of polished carbon steel is independent of both the presence of oxygen and chloride ions. The electrochemical method failed to yield meaningful results due to the lack of clearly interpretable data and the inherent subjectivity in the analysis. Lepidocricite was found to be the main corrosion product using the Raman microscope. (author)

Thomas, V.J.; Olive, R.P. [Univ. of New Brunswick, Fredericton, New Brunswick (Canada)

2007-09-15

 
 
 
 
321

Electrochemical and weight-loss study of carbon steel corrosion  

International Nuclear Information System (INIS)

The Point Lepreau Generating Station (PLGS) will undergo and 18 month refurbishment project beginning in April, 2008. During this time, most of the carbon steel piping in the primary loop will be drained of water and dried. However, some water will remain during the shutdown due to the lack of drains in some lower points in the piping system. As a result, it is necessary to examine the effect of corrosion during the refurbishment. This study examined the effect of several variables on the corrosion rate of clean carbon steel. Specifically, the effect of oxygen in the system and the presence of chloride ions were evaluated. Corrosion rates were determined using both a weight-loss technique and electro-chemical methods. The experiment was conducted at room temperature. The corrosion products from the experiment were analyzed using a Raman microscope. The results of the weight-loss measurements show that the corrosion rate of polished carbon steel is independent of both the presence of oxygen and chloride ions. The electrochemical method failed to yield meaningful results due to the lack of clearly interpretable data and the inherent subjectivity in the analysis. Lepidocricite was found to be the main corrosion product using the Raman microscope. (author)

2007-01-01

322

Sulfide stress corrosion cracking resistance of low Cr steel  

Energy Technology Data Exchange (ETDEWEB)

The sulfide stress corrosion cracking resistance of low Cr steels was investigated to clarify the application limit in sour environment. The SSC threshold stress of the 0.5% Cr pipe was 95% SMYS which is the same as the Cr-free one. The SSC critical hardness of the 0.5% Cr pipe was about Hv 250 in the 3,000 ppm H{sub 2}S solution and increased with the decrease in H{sub 2}S content. The KISSC value of the 0.5% Cr pipe was nearly equal to the Cr-free one. The SSC resistance of the 0.5% Cr pipe was same as the sour resistant Cr-free pipe. The hydrogen permeation rate of the Cr bearing steel was slightly lower than that of the Cr-free steel. This fact is attributed to the difference in corrosion film created on the corrosion surface. The linepipe steel with the Cr content of 0.5% proved to have sulfide stress corrosion cracking resistance as large as the sour resistant linepipe steel.

Kimura, Mitsuo; Kataoka, Yoshihiro; Nakano, Yoshifumi [Kawasaki Steel Corp., Handa, Aichi (Japan). Research Labs.

1996-08-01

323

Testing the corrosion resistance of stainless steels during the fermentation of probiotic drink.  

UK PubMed Central (United Kingdom)

BACKGROUND: Over recent years, food producers have devoted much attention to the production of safe foods. Simultaneously, using advanced process technologies, it has been necessary to carefully select materials for use in process equipment. Milk and its products are exposed to metal surfaces from the time they are processed, through the various stages of handling and manufacture, to the packaging of the finished products for market. The selection of suitable materials for daily use in the dairy industry cannot be governed solely by their price and mechanical properties but must also take into consideration their influence on the quality of milk products. RESULTS: This paper presents the results of testing the corrosion resistance of three stainless steels during the fermentation of a specific probiotic drink, kefir. Experiments were conducted using preliminarily activated kefir grains as a starter culture. Corrosion resistance was studied using a gravimetric and two electrochemical methods. The two steels showing the best corrosion performance differed mainly in their Mo and Nb contents. CONCLUSION: The results indicated that Nb played the most protective role against corrosion during kefir fermentation, since the steel containing Nb but no Mo showed the lowest corrosion rate.

Pe?ar D; Slemnik M; Goršek A

2011-05-01

324

The study of corrosion behavior of laser induced surface improvement (LISI) on steel and aluminum substrates  

Energy Technology Data Exchange (ETDEWEB)

Laser Induced Surface Improvement (LISI) is a new process developed by University of Tennessee Space Institute (UTSI) which employs lasers to melt precursor coatings and portions of the substrate to form a durable corrosion resistant surface. The LISI surface can be tailored to yield a composition that provides minimum impact to the base substrate material while giving good corrosion characteristics. The LISI surface treatment of tungsten carbide was applied on 7075 and 6061 aluminum alloys. The LISI treatment uses a chromium/nickel mixture and a stainless steel type mixture (pseudo stainless steel of 18 wt% chromium, 8 wt% nickel and a trace amount of manganese and silicon) on steel alloy 1010. The corrosion characteristics of these samples were determined in 3.5 wt% NaCl aqueous solution using linear polarization resistance technique. Potentiodynamic scans were run to determine the corrosion rates and optical microscopy was used to examine pitting characteristics of the different surface coatings. The effectiveness of the LISI modified surfaces to protect both steel and aluminum substrates is discussed.

Lindsey, N.; Vasanth, K.L.

1999-07-01

325

Corrosion rate of ferritic ODS stainless steels in a supercritical water environment  

Energy Technology Data Exchange (ETDEWEB)

Full text of publication follows: The corrosion behavior of several ODS (Oxide Dispersion Strengthened) steels (Fe-xCryAl-zW-Y{sub 2}O{sub 3}) were studied. A corrosion experiment was performed up to 1000 hrs in 510 deg. C and 25 MPa pure water environments. The dissolved oxygen content was controlled by exposing the test solution to laboratory air at the start of the test. The weight gain of each sample was used to estimate the amount of corrosion assuming dissolution rates to be small. Low angle X-ray diffraction method was applied for characterizing the surface oxide resulting from corrosion reactions. further, the cross section area was observed by FESEM-EPMA to reveal the morphology and composition of the oxide. The weight gain increased with time and after a certain time, it reached a steady state. Using the weight gain data, we estimated the corrosion rate defined as the ratio of weight gain and the test interval. The corrosion rate decreased with time, which reflected that the oxide film became protective for all the ODS steels. From XRD and FESEM-EPMA studies, the oxide layers were examined to be Cr rich spinel at the early test period and to become Cr oxide (Cr{sub 2}O{sub 3}) after a certain time due to phase transformation. The Cr oxide formation inhibited further corrosion, reaching the steady state. No exclusive aluminum oxide layer was formed in the test condition. Nonetheless, the summation of Cr and Al content represented the corrosion resistance of ODS steels. (authors)

Lee, S.G.; Kasada, R.; Kimura, A.; Cho, H.S. [Kyoto Univ., lnstitute of Advanced Energy (Japan); Lee, J.H. [Kyoto Univ., Graduate School of Energy Science (Japan)

2007-07-01

326

Corrosion rate of ferritic ODS stainless steels in a supercritical water environment  

International Nuclear Information System (INIS)

Full text of publication follows: The corrosion behavior of several ODS (Oxide Dispersion Strengthened) steels (Fe-xCryAl-zW-Y2O3) were studied. A corrosion experiment was performed up to 1000 hrs in 510 deg. C and 25 MPa pure water environments. The dissolved oxygen content was controlled by exposing the test solution to laboratory air at the start of the test. The weight gain of each sample was used to estimate the amount of corrosion assuming dissolution rates to be small. Low angle X-ray diffraction method was applied for characterizing the surface oxide resulting from corrosion reactions. further, the cross section area was observed by FESEM-EPMA to reveal the morphology and composition of the oxide. The weight gain increased with time and after a certain time, it reached a steady state. Using the weight gain data, we estimated the corrosion rate defined as the ratio of weight gain and the test interval. The corrosion rate decreased with time, which reflected that the oxide film became protective for all the ODS steels. From XRD and FESEM-EPMA studies, the oxide layers were examined to be Cr rich spinel at the early test period and to become Cr oxide (Cr2O3) after a certain time due to phase transformation. The Cr oxide formation inhibited further corrosion, reaching the steady state. No exclusive aluminum oxide layer was formed in the test condition. Nonetheless, the summation of Cr and Al content represented the corrosion resistance of ODS steels. (authors)

2007-01-01

327

Pipeline corrosion and cathodic protection. Third ed  

Energy Technology Data Exchange (ETDEWEB)

This update of Marshall Parker's classic text contains the latest ''hands on'' information available for taking measurements and making the calculations necessary for cathodic protection of buried pipe lines. Essentially a practical field manual, it is a simple and direct introduction to the fundamentals of a complex subject. Contents are: soil resistivity surveys; potential surveys; line currents, current requirement surveys, rectifier systems for coated lines; ground bed design and installation, galvanic anodes on coated lines, hot spot protection, bond protection; stray current electrolysis, interference; operation and maintenance; coating inspection and testing; fundamentals of underground corrosion; basic principles of cathodic protection; tables of properties and metals; and attenuation equations.

Parker, M.E.; Peattie, E.G.

1984-01-01

328

The methodology of determining the corrosion of steel structures  

Directory of Open Access Journals (Sweden)

Full Text Available The problems of determining the corrosive wear of steel structures are considered. The results of applying ultrasonic method to determine the remaining profile of the structure are described. The main advantages and disadvantages of ultrasonic thickness meters comparing to mechanical devices are given. Low reliability of the method based on evaluating the thickness of the corrosion oxides is substantiated. The problems of determining the original section of the elements are outlined. The algorithm for determining the corrosive wear is developed. An example of its application on a real object is shown.

S.D. Fedotov; A.V. Ulybin; N.N. Shabrov

2013-01-01

329

Biopolymer Corrosion Inhibition of Mild Steel: Electrochemical/Moessbauer Results  

International Nuclear Information System (INIS)

Metallic corrosion is the destructive attack of a metal by its environment. Organic inhibitors, amongst others, adsorb directly onto the surface of the metal and can thus inhibit corrosion. Chitosan, tri-methyl chitosan and dodecyl amine hydrochloride were studied with a view to assessing their potential use as adsorption inhibitors for mild steel in acid chloride and sulphate solutions. The inhibition efficiency was studied successfully by potentiostatic polarisation (Tafel plots), Moessbauer spectroscopy (CEMS and transmission) and corrosion experiments in static acidified electrolytes. Inhibition efficiencies ranged from 20 to 93%. The chemical compositions of the corrosion products were determined by means of Moessbauer spectroscopy, which identified iron hydroxides as the main corrosion products forming in the presence of the inhibitors.

2002-01-01

330

Erosion-corrosion of a carbon steel elbow in a carbon dioxide environment  

Energy Technology Data Exchange (ETDEWEB)

For many conditions, erosion-corrosion can produce higher wall penetration rates than erosion or corrosion alone. While flow velocity generally is believed to be an important factor, more information is needed on the influence of flow conditions. A flow loop was used to study erosion-corrosion of carbon steel elbows in a carbon dioxide environment with sand entrained in the flowing liquid. Three typical behaviors were found. At low velocities, a protective iron carbonate scale formed over all surfaces of the elbow, and corrosion rates were very low. At high velocities, impingement in elbow surfaces by sand particles entrained in the flow prevented protective scales from forming in the elbow. Corrosion rates were high and uniform over the entire surface. Corrosion rates were high and uniform over the entire surface. At intermediate velocities, protective scales formed over all of the elbow surface except at very localized points, where impinging sand particles prevented scale formation. Deep pits formed at these points, and wall penetration rates were extremely high. These conditions are damaging but can be avoided by reducing or increasing flow velocities. A computational model for prediction of sand erosion in piping systems was used to simulate experiments to explain the three observed behaviors and predict conditions defining boundaries between them.

Shadley, J.R.; Shirazi, S.A.; Dayalan, E.; Ismail, M.; Rybicki, E.F. [Univ. of Tulsa, OK (United States)

1996-09-01

331

Ductility of reinforcing steel with different degrees of corrosion and the 'equivalent steel' criterion  

Digital Repository Infrastructure Vision for European Research (DRIVER)

One of the most significant effects of reinforcing steel corrosion on reinforced concrete structures is the decline in the ductility-related properties of the steel. Such properties condition the behaviour of reinforced concrete structures and must be taken into account when re-engineering corroded...

Fernández Cánovas, M.; Cobo Escamilla, A.; Moreno Fernández, E.

332

Electrochemical Studies of Stainless Steel Corrosion in Peroxide Solutions  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english Pollution control measures have resulted in replacement of chlorine by peroxide as bleaching chemical. Change of chemical affects corrosion aspects, the suitability of existing plant metallurgy and materials of construction of bleach plants. Accordingly long term immersion and electrochemical corrosion tests were conducted on stainless steel 304L, 316L, 2205 and 6% Mo and mild steel in peroxide solutions of pH 10. The materials were tested for uniform corrosion, pitting a (more) nd crevice corrosion and attack around the weld area. Corrosion attack estimated from long term immersion tests is found in agreement, by and large, with that analyzed from electrochemical test. E-pH diagrams drawn for water-peroxide system have been used to understand the corrosivity of the peroxide media. An attempt has been made to suggest a suitable material of construction for handling the test media on the basis of degree of corrosion attack on them and their cost and the mechanical properties.

Singh, Ajay K.; Chaudhary, Vipin; Sharma, A.

2012-03-01

333

Corrosion resistance of zinc-magnesium coated steel  

International Nuclear Information System (INIS)

A significant body of work exists in the literature concerning the corrosion behaviour of zinc-magnesium coated steel (ZMG), describing its enhanced corrosion resistance when compared to conventional zinc-coated steel. This paper begins with a review of the literature and identifies key themes in the reported mechanisms for the attractive properties of this material. This is followed by an experimental programme where ZMG was subjected to an automotive laboratory corrosion test using acidified NaCl solution. A 3-fold increase in time to red rust compared to conventional zinc coatings was measured. X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy were used to characterize the corrosion products formed. The corrosion products detected on ZMG included simonkolleite (Zn5Cl2(OH)8 . H2O), possibly modified by magnesium uptake, magnesium hydroxide (Mg(OH)2) and a hydroxy carbonate species. It is proposed that the oxygen reduction activity at the (zinc) cathodes is reduced by precipitation of alkali-resistant Mg(OH)2, which is gradually converted to more soluble hydroxy carbonates by uptake of atmospheric carbon dioxide. This lowers the surface pH sufficiently to allow thermodynamically for general precipitation of insoluble simonkolleite over the corroding surface thereby retarding the overall corrosion reactions, leaving only small traces of magnesium corrosion products behind. Such a mechanism is consistent with the experimental findings reported in the literature

2007-01-01

334

Effect of carbon content and tempering structures on the electrochemical and corrosion properties of carbon steels  

International Nuclear Information System (INIS)

The effect of carbon content, hardening structures and internal stresses occuring in the result of carbonic steel heat treatment on their electrochemical and corrosion properties is investigated. The corrosion rate is shown to be increased in 6% H2SO4 and 3% NaCl with the increase of carbon content and in respect to internal stresses arising in the result of heat treatment, in transition from perlite, to sorbite, troostite- and martensite. The inhibitor protection is most effective in the case of perlite-ferrite structure; the effectiveness of the inhibitor protection decreases in transition to highly resistant structures. The electrochemical properties of steels also depend on carbon content and hardening structures

1982-01-01

335

Diffusion-coupled active dissolution in the localized corrosion of stainless steels  

Energy Technology Data Exchange (ETDEWEB)

The authors have examined the anodic dissolution of stainless steels in environments relevant to localized corrosion in neutral chloride solutions. There is a maximum active dissolution rate, for a given potential, which is not associated with the most concentrated localized environment. This observation seems to be significant with respect to the stability of localized corrosion in these alloys. Results of this kind are capable of explaining the existence of a critical pit solution, a protection potential against pitting, multiple steady states, low frequency electrochemical noise and differences between open circuit and potentiostatic behavior.

Newman, R.C.; Isaacs, H.S.

1983-07-01

336

Mechanical properties of oxides formed by anaerobic corrosion of steel  

International Nuclear Information System (INIS)

[en] In Sweden, it is proposed that spent nuclear fuel should be encapsulated in sealed cylindrical canisters for disposal in a geologic repository. The canisters would consist of a thick ferrous inner container and a copper overpack. If mechanical failure of the copper overpack occurred, allowing water to enter, there would be a build up of ferrous corrosion product, which could induce stresses in the outer copper canister. This paper describes an apparatus, the 'stress cell', which was designed to measure the expansion caused by the anaerobic corrosion of steel under compressive loads. The apparatus consisted of a stack of steel and copper discs, which were immersed in simulated anoxic groundwater. A system of levers amplified the change in height of the stack, and the displacement was measured using sensitive transducers. Three cells were set up; two contained alternate mild steel and copper discs, and the third, a control cell, consisted of alternate stainless steel and copper discs. A slight contraction of the control cell was observed but no expansion was measured in the mild steel - copper cells. In parallel, coupons of mild steel and cast iron were corroded in anoxic, artificial groundwater at 50 deg C and 80 deg C for several months. The coupons were examined by atomic force microscopy (AFM) to determine the mechanical properties and the structure of the corrosion product films, and X-ray photoelectron spectroscopy (XPS) to identify the chemical composition of the film. Copyright (2001) Material Research Society

2001-01-01

337

A liquid aluminum corrosion resistance surface on steel substrate  

Energy Technology Data Exchange (ETDEWEB)

The process of hot dipping pure aluminum on a steel substrate followed by oxidation was studied to form a surface layer of aluminum oxide resistant to the corrosion of aluminum melt. The thickness of the pure aluminum layer on the steel substrate is reduced with the increase in temperature and time in initial aluminizing, and the thickness of the aluminum layer does not increase with time at given temperature when identical temperature and complete wetting occur between liquid aluminum and the substrate surface. The thickness of the Fe-Al intermetallic layer on the steel base is increased with increasing bath temperature and time. Based on the experimental data and the mathematics model developed by the study, a maximum exists in the thickness of the Fe-Al intermetallic at certain dipping temperature. X-ray diffraction (XRD) and energy dispersive X-ray (EDX) analysis reveals that the top portion of the steel substrate is composed of a thin layer of {alpha}-Al{sub 2}O{sub 3}, followed by a thinner layer of FeAl{sub 3}, and then a much thicker one of Fe{sub 2}Al{sub 5} on the steel base side. In addition, there is a carbon enrichment zone in diffusion front. The aluminum oxide surface formed on the steel substrate is in perfect condition after corrosion test in liquid aluminum at 750 deg. C for 240 h, showing extremely good resistance to aluminum melt corrosion.

Wang Deqing; Shi Ziyuan; Zou Longjiang

2003-05-31

338

Crevice corrosion control for stainless steel using radiation-induced surface activation  

International Nuclear Information System (INIS)

When a semiconductor film is irradiated by ?-rays, excited electrons are transferred to a base metal in contact with the film, resulting in cathodic-anodic reactions and surface activation of the metal oxide film. The authors first produced radiation-induced surface activation (RISA) in 2000 and have used it in the development of a new corrosion protection method. This report describes a corrosion mitigation technique based on RISA to prevent crevice corrosion in stainless steel, using low-intensity radiation. Experimental results show that an electrode potential of -100 mV vs. Ag/AgCl was produced and maintained on TiO2-coated SUS304 stainless steel specimens immersed in artificial seawater and in close contact with a small, sealed 60Co source (external irradiation) or activated by neutron irradiation to become self-exciting, with no corrosion observed for more than 7 days. In contrast, the potential of a specimen without a radiation source decreased to less than -280 mV vs. Ag/AgCl and crevice corrosion occurred beneath the O-ring within a few days. The corrosion control mechanism was explored by measurement of dissolved oxygen and iron ions in the solution. (author)

2009-01-01

339

Properties of bacterial corrosion of stainless steel and its inhibition by protamine coating.  

Science.gov (United States)

We investigated characteristics of the corrosion of stainless steel specimens by bacteria and the effects of using antimicrobial coating on the surface for inhibiting corrosion. Bacillus sp. 2-A and Staphylococcus sp. 2-1 cells adhered tightly to a stainless steel SUS304 specimen, formed a microcolony or biofilm, and had highly corrosive activities. Microbially influenced corrosion (MC) was observed under or around adhering cells. However, dead cells were markedly less active than viable cells not only in corroding the specimen but also in adhering to its surface. The culture supernatant was not able to induce the corrosion of SUS304 effectively. A protamine coating on the specimen killed bacterial cells only on its surface, interfered with cell adhesion, and inhibited MC. From these results, adhesion of viable cells to the surface of a SUS304 specimen led to the outbreak of MC. Protamine was also found to be an effective substance tested for protecting the specimen from both cell adhesion and surface MC. We suggest that a protamine coating can be applied as a convenient and inexpensive corrosion prevention method. PMID:17408005

Matsumura, Yoshinobu; Yamada, Kaoru; Takahashi, Mitsuo; Kikuchi, Yasushi; Tsuchido, Tetsuaki

2007-03-01

340

Cathodic protection of AISI 316 stainless steel in hot concentrated nitric acid  

International Nuclear Information System (INIS)

Experiments have been mounted in order to investigate a cathodic protection scheme for AISI 316 stainless steel in hot concentrated nitric acid. Weight loss tests of the heat treated material were carried out in order to establish the effect of metallurgical factors on its behaviour in hot concentrated nitric acid. In order to study the characteristics of the cathodic protection scheme, local action anodic kinetics of the as-received and the sensitized stainless steel were determined in the above corrosive medium. Anodic polarization curves of the as-received and sensitized stainless steel, produced in hot concentrated sulfuric acid, contributed to the better understanding of the parameters concerning this protection scheme. It has been found that an as-received AISI 316 stainless steel can be protected in hot concentrated nitric acid. In order to achieve successful protection for the sensitized AISI 316 stainless steel, depleted austenite phases have to be eliminated in this material by adequate solution heat treatment. (author)

1980-01-01

 
 
 
 
341

Corrosion behaviour of highly alloyed stainless steels in mixed chloride and fluoride aqueous solutions  

Energy Technology Data Exchange (ETDEWEB)

Laboratory weight loss and cyclic potentiodynamic polarization corrosion tests were performed on two types of corrosion resistant alloys, a duplex alloy (ferritic-austenitic stainless steel) and two austenitic stainless steels, in mixtures of chloride (3000, 9000 and 15000 ppm) and fluoride (4800 and 15000 ppm) ions at pH 3. Two temperatures were tested, 60 and 70 C. The electrochemical results indicate that the duplex stainless steel presents high corrosion resistance. Weight loss results show low corrosion rates of the two types of stainless steels after 60 days exposure. Some pits-crevices were found under the corrosion crust deposits on the duplex stainless steel. (orig.)

Bastidas, J.M. [Centro Nacional de Investigaciones Metalurgicas, Madrid (Spain); Fosca, C. [Universidad Complutense de Madrid (Spain). Dept. de Ciencia de Materiales; Chico, B. [Centro Nacional de Investigaciones Metalurgicas, Madrid (Spain); Otero, E. [Universidad Complutense de Madrid (Spain). Dept. de Ciencia de Materiales

1997-04-01

342

Corrosion Inhibition and Adsorption of Anthocleista Djalonesis Leaf Extract on the Acid Corrosion of Mild Steel  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english Aqueous extracts of the leaves of Anthocleista djalonesis (AD) have been investigated as non toxic corrosion inhibitors for mild steel in acidic environments (1 M HCl and 0.5 M H2SO4, respectively). Corrosion rates were evaluated at 30 °C using the weight loss, electrochemical impedance spectroscopy and potentiodynamic polarization techniques. AD extract was found to inhibit mild steel corrosion in both acidic media via adsorption of the extract organic matter on the met (more) al/solution interface. Polarization data indicate that the extract functioned via a mixed inhibition mechanism, affecting both the cathodic and anodic partial reactions of the corrosion process. Molecular dynamics (MD) simulations were performed to illustrate the adsorption process of some specific components of the extract.

Ogukwe, C.E.; Akalezi, C.O.; Chidiebere, M. A.; Oguzie, K.L.; Iheabunike, Z.O.; Oguziea, E.E.

2012-05-01

343

Corrosion Inhibition and Adsorption of Anthocleista Djalonesis Leaf Extract on the Acid Corrosion of Mild Steel  

Directory of Open Access Journals (Sweden)

Full Text Available Aqueous extracts of the leaves of Anthocleista djalonesis (AD) have been investigated as non toxic corrosion inhibitors for mild steel in acidic environments (1 M HCl and 0.5 M H2SO4, respectively). Corrosion rates were evaluated at 30 °C using the weight loss, electrochemical impedance spectroscopy and potentiodynamic polarization techniques. AD extract was found to inhibit mild steel corrosion in both acidic media via adsorption of the extract organic matter on the metal/solution interface. Polarization data indicate that the extract functioned via a mixed inhibition mechanism, affecting both the cathodic and anodic partial reactions of the corrosion process. Molecular dynamics (MD) simulations were performed to illustrate the adsorption process of some specific components of the extract.

C.E. Ogukwe; C.O. Akalezi; M. A. Chidiebere; K.L. Oguzie; Z.O. Iheabunike; E.E. Oguziea

2012-01-01

344

Hydrogen effect on intergranular corrosion of stainless austenitic steels  

International Nuclear Information System (INIS)

Experimental investigation of the effect of grain-boundary microstructural peculiarities and hydrogen on intergranular corrosion (IGC) rate and sensitivity to IGC of 0Kh16N15M3B and O6Kh18N10T stainless austenitic steels is conducted. It is shown that grain-boundary separation in combination with hydrogen increases IGC rate and broadens the temperature range, in which stainless steel is susceptible to IGC. Determining effect of hydrogen interaction with grain-boundary precipitations on stainless steel tendency to IGC is noted

1985-01-01

345

Cesium corrosion process in Fe-Cr steel  

Science.gov (United States)

A cesium corrosion out-pile test was performed to Fe-Cr steel in a simulated fuel pin environment. In order to specify the corrosion products, the corroded area was analyzed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). A cesium corrosion process in Fe-Cr steel was successfully developed proceeding from both experimental results and thermochemical consideration. The corroded area was mainly formed by Fe layer and Fe depleted oxidized layer. The Fe depleted oxidized layer was formed by Cr0.5Fe0.5 and Cr2O3. The presumed main corrosion reactions were 2Cr+23O?CrO(?G=-894.1kJ/mol) and CrC+46Cs+46O?23CsCrO+6C(?G=-25018.1kJ/mol). Factors of these reactions are chromium, carbon, oxygen and cesium. Therefore, cesium corrosion progression must be dependent on the chromium content, carbon content in the steel, the supply rate of oxygen and temperature which correlated with the diffusion rate of cesium and oxygen into the specimen.

Sasaki, K.; Tanigaki, T.; Matsuyama, M.; Fukumoto, K.; Uno, M.

2013-10-01

346

Chlorine induced corrosion of steels in fossil fuel power plants  

Energy Technology Data Exchange (ETDEWEB)

The corrosion of steels in power plants (coal combustion, waste incineration) is mainly due to condensed chlorides in the ash deposited on the boiler tubes. These chlorides are stabilized by HCl in the combustion gas. In the case of coal as a fuel, chlorine is present as chloride minerals in the raw material which is converted to HCl during the combustion process. Corrosion of steels in chlorine containing environments occurs by the active oxidation mechanism, which is a self-sustaining accelerated oxidation process, catalyzed by chlorine. This study shows that solid chlorides react with the oxide scale of the steels to form chlorine, which initiates active oxidation. In order to prevent chlorine induced corrosion, the deposition of chlorides on the tubes within the coal ash must be avoided. This is possible by the presence of SO{sub 2}, which is present in the combustion gas, converting the chlorides to sulfates in the gas phase. The paper presents an example of a failure case in a coal fired plant in Germany. In this plant, chlorine induced corrosion was observed after effective removal of SO{sub 2} by additions of CaO. From thermodynamic calculations it can be shown that a certain amount of SO{sub 2} is necessary in order to avoid deposition of chlorides and to prevent corrosion.

Spiegel, M.; Grabke, H.J. [Max-Planck-Institut fuer Eisenforschung GmbH, Dusseldorf (Germany)

1998-12-31

347

Experimental investigation into corrosion of steels types 20 and 12 Kh1MF in desalinizated water by the weight and electrochemical methods  

International Nuclear Information System (INIS)

[en] The results of studying corrosion of steels 20 and 12Kh1MF under neutral-oxygen and ammonium water chemistry are analyzed. It is shown that chemical corrosion rate exceeds greatly electrochemical corrosion rate and nears it with O2 concentration increase up to 175 mkg/kg due to protective film formation. Iron participating in protective film formation can cause pipeline local corrosion of specific type at the same time. The results of corrosion tests realized by different methods under different conditions are compared

1992-01-01

348

Stainless steel corrosion by molten nitrates : analysis and lessons learned.  

Energy Technology Data Exchange (ETDEWEB)

A secondary containment vessel, made of stainless 316, failed due to severe nitrate salt corrosion. Corrosion was in the form of pitting was observed during high temperature, chemical stability experiments. Optical microscopy, scanning electron microscopy and energy dispersive spectroscopy were all used to diagnose the cause of the failure. Failure was caused by potassium oxide that crept into the gap between the primary vessel (alumina) and the stainless steel vessel. Molten nitrate solar salt (89% KNO{sub 3}, 11% NaNO{sub 3} by weight) was used during chemical stability experiments, with an oxygen cover gas, at a salt temperature of 350-700 C. Nitrate salt was primarily contained in an alumina vessel; however salt crept into the gap between the alumina and 316 stainless steel. Corrosion occurred over a period of approximately 2000 hours, with the end result of full wall penetration through the stainless steel vessel; see Figures 1 and 2 for images of the corrosion damage to the vessel. Wall thickness was 0.0625 inches, which, based on previous data, should have been adequate to avoid corrosion-induced failure while in direct contact with salt temperature at 677 C (0.081-inch/year). Salt temperatures exceeding 650 C lasted for approximately 14 days. However, previous corrosion data was performed with air as the cover gas. High temperature combined with an oxygen cover gas obviously drove corrosion rates to a much higher value. Corrosion resulted in the form of uniform pitting. Based on SEM and EDS data, pits contained primarily potassium oxide and potassium chromate, reinforcing the link between oxides and severe corrosion. In addition to the pitting corrosion, a large blister formed on the side wall, which was mainly composed of potassium, chromium and oxygen. All data indicated that corrosion initiated internally and moved outward. There was no evidence of intergranular corrosion nor were there any indication of fast pathways along grain boundaries. Much of the pitting occurred near welds; however this was the hottest region in the chamber. Pitting was observed up to two inches above the weld, indicating independence from weld effects.

Kruizenga, Alan Michael

2011-09-01

349

Chartek, fire and corrosion proof protection  

Energy Technology Data Exchange (ETDEWEB)

Born from the special products used for the heat shield of the American space capsules, over the last twenty years Chartek has been used for many applications in protecting structures against fire and corrosion, particularly in the areas of hydrocarbons (platforms, refineries), the petro-chemical and Liquefied Petroleum Gases industries (stationary tanks, train cars and tank-truks). Chartek is a coating made of compact epoxy resins reinforced with a metallic netting to improve mechanical resistance. As one of the six passive protection products, it has been tested in its third version, Chartek III, in the framework of the GASAFE program for passive prevention and protection against fire. This research program is managed by the french grouping GESIP (Petroleum Industry Study Group). 2 Photos.

1992-12-01

350

Chloride induced stress corrosion in stainless steel - some case studies  

Energy Technology Data Exchange (ETDEWEB)

Two cases of failure of stainless steel pipelines due to stress corrosion in fertilizer plants are discussed. In both the cases, chloride was the causative agent. In the first case the presence of chloride was due to its carry-over with superheated steam, while in the other it was from the brazing flux.

Verma, K.M.; Verma, S.C.; Sinha, A.K.

1983-01-01

351

Ambient temperature stress-corrosion cracking of sensitized stainless steels  

International Nuclear Information System (INIS)

Stress-corrosion cracking of sensitized Type 304 steel in low temperature borated water has been observed. The probable role of low levels of chloride ions or sulfur-containing ions is described, including the relationship of the phenomenon to polythionic acid cracking. The mechanism of the sulfur-induced cracking and its usefulness as a test for sensitization are outlined

1982-03-26

352

Corrosion rate measurements of steel in carbonated concrete  

Energy Technology Data Exchange (ETDEWEB)

The polarization resistance of steel bars in concrete after exposure to several environments, as measured by the potential step method, was compared to the actual mass losses of the bars. Each test sample consist of two steel bars embedded in concrete blocks, which were carbonated and exposed to one of several environments, outdoors, indoors, underground, in tunnel, or in water, for one year. Electrochemical measurements of these samples by using the potential step method were carried out at least once a week. The polarization resistance data thus obtained were changed into corrosion currents and mass losses. These calculated mass losses were compared with the actual mass losses of the rods. In some cases, such as indoors, outdoors or in tunnel, the corrosion rate of steel is determined by the amount of water in the concrete. In other cases, such as underground or in water, the oxygen supply determines the corrosion rate. This work demonstrate that in former condition, the potential step method can be use to measure the corrosion rate of steel easily and quickly.

Saito, H.; Miyata, Y.; Takazawa, H.; Takai, K.; Yamauchi, G. [Nippon Telegraph and Telephone Corp., Musashino, Tokyo (Japan)

1995-12-01

353

Oscillation and chaos in pitting corrosion of steel  

Energy Technology Data Exchange (ETDEWEB)

The potential and current oscillations during pitting corrosion of steel in NaCl solution were studied. Detailed analysis using numerical diagnostics developed to characterize complex time series clearly shows that the irregularity in these time series corresponds to deterministic chaos, rather than to random noise. The chaotic oscillations were characterized by power spectral densities, phase space and Lyapunov exponents.

Hernandez, M.A.; Rodriguez, F.J. [Univ. Nacional Autonoma Mexico (Mexico). Dipt. Ingenieria Metalurgica; Garcia, E. [Inst. Mexicano del Petroleo (Mexico); Boerio, F.J. [Univ. of Cincinnati, OH (United States). Dept. of Materials Science and Engineering

1999-11-01

354

Microgalvanic corrosion of laser-welded HSLA steels  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Laser welding of galvanized high strength low alloy (HSLA) steels leads to the evaporation of zinc at the weld and the formation of a heat-affected-zone (HAZ). High heat input due to welding generates macro galvanic coupling between the weld and the parent metal as well as micro galvanic corrosion a...

Looi, Y.-M.

355

AFM study of steel corrosion in aqueous solutions in concrete  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Early corrosion stages are studied in carbon steel by means of a solution simulating that contained in concrete pores. Non-carbonated solution contains 5% NaCl. The atomic force microscopy (AFM) technique is used to study material performance after different immersion times (up to 48 h). Obtained da...

Díaz-Benito, B.; Velasco, F.; Guzmán, S.; Calabrés, R.

356

Corrosion resistance properties of sintered duplex stainless steel  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: of this paper was to examine the corrosion resistance of duplex stainless steels using electrochemical methods in 1M NaCl solution. The influence of powder mixes preparation and cooling cycle after sintering on corrosion properties was evaluated.Design/methodology/approach: In presented study duplex stainless steels were obtained through powder metallurgy starting from austenitic, martensitic base powders by controlled addition of alloying elements, such as Cr, Ni, Mo and Cu. In the studies behind the preparation of mixes, Schaeffler’s diagram was taken into consideration. Prepared mixes have been compacted at 800 MPa and sintered in a vacuum furnace with argon backfilling at 1260°C for 1 h. After sintering two different cooling cycles were applied: rapid cooling with an average cooling rate of 245 °C/min and slow cooling of 5 °C/min in argon atmosphere. Produced duplex stainless steels have been studied by scanning and optical microscopy and EDS chemical analysis of microstructure components. Corrosion properties have been studied through electrochemical methods in 1M NaCl water solutionFindings: According to achieved results, it was affirmed that applied sintering method as well as powder mixes preparation allows for manufacturing the sintered duplex steels with good corrosion properties which depends on austenite/ferrite ratio in the microstructure and elements partitioning between phases. Corrosion resistance of sintered stainless steels is strictly connected with the density and the pore morphology present in the microstructure too. The highest resistance to pitting corrosion in 1M NaCl solution was achieved for composition with approximate balance of ferrite and austenite in the microstructure.Research limitations/implications: According to the powders characteristic, the applied fast cooling rate seems to be a good compromise for corrosion properties and microstructures, nevertheless further tests should be carried out in order to examine different cooling rates.Originality/value: The use of elemental powders added to a stainless steel base showed its potentialities, in terms of fair compressibility and final sintered density. In addition a good microstructural homogeneity and first of all corrosion resistance was achieved, also working with cycles possible for industries.

L.A. Dobrza?ski; Z. Brytan; M. Actis Grande; M. Rosso

2006-01-01

357

Corrosion fatigue of stiffened steel tubular T and Y joints  

Energy Technology Data Exchange (ETDEWEB)

Detailed experimental investigations have been taken up to study the corrosion fatigue behavior of steel tubular joints used in offshore structures under constant amplitude and random loading with respect to tropical seawater environment for which there is lack of data. As part of this study, corrosion fatigue tests were conducted on two unstiffened and nine internally ring stiffened welded steel tubular T and Y joints under constant amplitude axial brace loading at 0.2 Hz frequency. Seawater characteristics, corrosion rate an fatigue crack initiation and propagation were monitored during the tests. Hot spot stress range and stress ratio were varied for the specimens. The results of the study are discussed in this paper.

Ramachandra Murthy, D.S.; Madhava Rao, A.G.; Raghava, G.; Gandhi, P. [Structural Engineering Research Centre, Madras (India); Pant, P.K.; Anto, P.F.; Samant, A.K. [Oil and Natural Gas Commission, Panvel (India)

1994-12-31

358

Corrosion behavior of stainless steel-zirconium alloy waste forms  

Energy Technology Data Exchange (ETDEWEB)

Stainless steel-zirconium (SS-Zr) alloys are being considered as waste forms for the disposal of metallic waste generated during the electrometallurgical treatment of spent nuclear fuel. The baseline waste form for spent fuels from the EBR-11 reactor is a stainless steel-15 wt.% zirconium (SS-15Zr) alloy. This article briefly reviews the microstructure of various SS-Zr waste form alloys and presents results of immersion corrosion and electrochemical corrosion tests performed on these alloys. The electrochemical tests show that the corrosion behavior of SS-Zr alloys is comparable to those of other alloys being considered for the Yucca Mountain geologic repository. The immersion tests demonstrate that the SS-Zr alloys are resistant to selective leaching of fission product elements and, hence, suitable as candidates for high-level nuclear waste forms.

Abraham, D.P.; Simpson, L.J.; DeVries, M.J.; Callahan, D.E.

1999-07-01

359

New findings on intergranular corrosion mechanism of stabilized stainless steels  

Energy Technology Data Exchange (ETDEWEB)

Number of different sets of stabilized both ferritic and austenitic stainless steels with various alloying elements were evaluated to verify new findings on the intergranular corrosion mechanism. The intergranular segregation and precipitation were analyzed by using a transmission electron microscopy with an energy dispersive X-ray spectroscopy and a laser assisted three-dimensional atom probe. On the basis of the current result, it is newly proposed that the intergranular corrosion occurring in the stabilized both ferritic and austenitic stainless steels is induced by Cr-depletion due to segregation of un-reacted Cr atoms around carbides of stabilizer elements (Ti or Nb) along the grain boundary, but not due to formation of Cr-carbide. A prevention method for this type of intergranular corrosion is also suggested after critical evaluation on the effect of Cr, C, and Ni.

Kim, Jeong Kil [Pohang University of Science and Technology (POSTECH), Graduate Institute of Ferrous Technology, Pohang, 790-784 (Korea, Republic of); POSCO Technical Research Laboratories, Pohang, 790-704 (Korea, Republic of); Kim, Yeong Ho [POSCO Technical Research Laboratories, Pohang, 790-704 (Korea, Republic of); Lee, Bong Ho [National Center for Nanomaterials Technology, Pohang, 790-784 (Korea, Republic of); Kim, Kyoo Young, E-mail: kykim@postech.ac.k [Pohang University of Science and Technology (POSTECH), Graduate Institute of Ferrous Technology, Pohang, 790-784 (Korea, Republic of)

2011-01-15

360

Corrosion behavior of stainless steel-zirconium alloy waste forms  

International Nuclear Information System (INIS)

[en] Stainless steel-zirconium (SS-Zr) alloys are being considered as waste forms for the disposal of metallic waste generated during the electrometallurgical treatment of spent nuclear fuel. The baseline waste form for spent fuels from the EBR-II reactor is a stainless steel-15 wt.% zirconium (SS-15Zr) alloy. This article briefly reviews the microstructure of various SS-Zr waste form alloys and presents results of immersion corrosion and electrochemical corrosion tests performed on these alloys. The electrochemical tests show that the corrosion behavior of SS-Zr alloys is comparable to those of other alloys being considered for the Yucca Mountain geologic repository. The immersion tests demonstrate that the SS-Zr alloys are resistant to selective leaching of fission product elements and, hence, suitable as candidates for high-level nuclear waste forms

1999-01-01

 
 
 
 
361

Possibility of estimating hydrogen corrosion in steel using Barkhausen effect  

International Nuclear Information System (INIS)

[en] Potentialities of the method of the Barkhausen effect to determine the availability and degree of development of hydrogen corrosion in the structural steels St. 10 and 12MKh have been investigated. Results are presented. Dependences of mechanical characteristics and relative change of stress of the Barkhausen noises on the exposure time in the hydrogen atmosphere at high temperatures and pressures are presented. A conclusion is made on the applicability of the mentioned method for the proximate estimation of the duration of the hydrogen corrosion incubation period. It is shown possible to increase the method sensitivity to changes in steel as a result of hydrogen corrosion using harmonic analysis of the Barkhausen envelope

1989-01-01

362

Corrosion Behavior of Chemically Deposited Single and Bi-layered Conducting Polymer Coatings on Mild Steel  

Directory of Open Access Journals (Sweden)

Full Text Available The emeraldine base (EB) was synthesized by chemically oxidative polymerization using ammonium persulphate as an oxidant in hydrochloride aqueous medium. The polymer was chemically deposited on mild steel specimens using tetra methyl urea (TMU) as solvent through solvent evaporation method. The coating of polypyrrole (PPy) on carbon steel was deposited by chemical polymerization. A bi-layered polymer coating comprising of inner coat of PPy with top coat of EB (PPy/EB) was also deposited on mild steel following identical procedure. The deposited EB, PPy and PPy/EB coatings were characterized by Fourier Transform Infrared (FTIR) Spectroscopy and Scanning Electron Microscopy (SEM). The anticorrosive properties of single and bi-layered coatings was investigated in major corrosive environments such as 0.1 M HCl, 5% NaCl solution, artificial seawater, distilled water, tap water and open atmosphere by conducting various corrosion tests which include: immersion test, open circuit potential measurements, potentiodynamic polarization measurements, and atmospheric exposure test. The results of immersion tests showed that the PPy/EB coating gave best protection in all media under investigation, the protection efficiency being in the range of 72 to 79% after 30 days of immersion. The result of OCP measurements showed significant positive shift in the corrosion potential for single as well as bi-layered coatings in all corrosive medium under investigation; the bi-layered coating showing more positive corrosion potential. The potentiodynamic polarization studies also confirmed lower corrosion rates for PPy/EB coating than the single polymer coatings.

M Mobin; Nelofar Tanveer

2011-01-01

363

Corrosion Behavior of Chemically Deposited Single and Bi-layered Conducting Polymer Coatings on Mild Steel  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english The emeraldine base (EB) was synthesized by chemically oxidative polymerization using ammonium persulphate as an oxidant in hydrochloride aqueous medium. The polymer was chemically deposited on mild steel specimens using tetra methyl urea (TMU) as solvent through solvent evaporation method. The coating of polypyrrole (PPy) on carbon steel was deposited by chemical polymerization. A bi-layered polymer coating comprising of inner coat of PPy with top coat of EB (PPy/EB) was (more) also deposited on mild steel following identical procedure. The deposited EB, PPy and PPy/EB coatings were characterized by Fourier Transform Infrared (FTIR) Spectroscopy and Scanning Electron Microscopy (SEM). The anticorrosive properties of single and bi-layered coatings was investigated in major corrosive environments such as 0.1 M HCl, 5% NaCl solution, artificial seawater, distilled water, tap water and open atmosphere by conducting various corrosion tests which include: immersion test, open circuit potential measurements, potentiodynamic polarization measurements, and atmospheric exposure test. The results of immersion tests showed that the PPy/EB coating gave best protection in all media under investigation, the protection efficiency being in the range of 72 to 79% after 30 days of immersion. The result of OCP measurements showed significant positive shift in the corrosion potential for single as well as bi-layered coatings in all corrosive medium under investigation; the bi-layered coating showing more positive corrosion potential. The potentiodynamic polarization studies also confirmed lower corrosion rates for PPy/EB coating than the single polymer coatings.

Mobin, M; Tanveer, Nelofar

2011-07-01

364

Effect of impurities on the corrosion behavior of CO2 transmission pipeline steel in supercritical CO2-water environments.  

UK PubMed Central (United Kingdom)

The corrosion property of carbon steel was evaluated using an autoclave under CO(2)-saturated water phase and water-saturated CO(2) phase with impurities (O(2) and SO(2)) at 80 bar CO(2) and 50 °C to simulate the condition of CO(2) transmission pipeline in the carbon capture and storage (CCS) applications. The results showed that the corrosion rate of carbon steel in CO(2)-saturated water was very high and it increased with adding O(2) in the system due to the inhibition effect of O(2) on the formation of protective FeCO(3). It is noteworthy that corrosion took place in the water-saturated CO(2) phase under supercritical condition when no free water is present. The addition of O(2) increased the corrosion rates of carbon steel in water-saturated CO(2) phase. The addition of 0.8 bar SO(2) (1%) in the gas phase dramatically increased the corrosion rate of carbon steel from 0.38 to 5.6 mm/y. This then increased to more than 7 mm/y with addition of both O(2) and SO(2). SO(2) can promote the formation of iron sulfite hydrate (FeSO(3)·3H(2)O) on the steel surface which is less protective than iron carbonate (FeCO(3)), and it is further oxidized to become FeSO(4) and FeOOH when O(2) is present with SO(2) in the CO(2)-rich phase. The corrosion rates of 13Cr steel were very low compared with carbon steel in CO(2)-saturated water environments with O(2), whereas it was as high as carbon steel in a water-saturated CO(2) phase with O(2) and SO(2).

Choi YS; Nesic S; Young D

2010-12-01

365

Corrosion inhibition of carbon steel in 0.5 M NaCl aqueous solution by humid air plasma treatment  

Science.gov (United States)

Carbon steel (C75) is exposed to highly reactive species such as hydroxyl radicals OH created by a gliding arc discharge (GAD) in humid air at atmospheric pressure. The protective properties of carbon steel treated by GAD are studied versus different treatment times (t) and for an immersion in corroding 0.5 M sodium chloride solution during 24 h. Evolutions of corrosion rate are studied using weight loss measurements and electrochemical methods, e.g., electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization. The results obtained by GAD treatment show that the corrosion rate of steel decreases with the ennoblement of the corrosion potential and the decrease of the corrosion current density. This indicates that the plasma treatment acts as an anodic type inhibitor and suggests the formation of a protective layer. EIS measurements confirm the presence of this film: the charge transfer resistance (Rct) increases with GAD treatment time, leading to a corrosion inhibition efficiency around 73% for a treatment time equal to 60 min. This confirms the importance of the plasma effect. The gliding arc discharge is a clean and efficient technology for the surface treatment of carbon steel; it improves the anticorrosion properties of steel in aggressive environments, forming a resistant and insulating barrier.

Ghali, Noureddine; Addou, Ahmed; Mutel, Brigitte; Benstaali, Baghdad; Bentiss, Fouad; Brisset, Jean-Louis

2013-02-01

366

Biocidal effect of cathodic protection on bacterial viability in biofilm attached to carbon steel.  

Science.gov (United States)

Biofilm formed on carbon steel by various species of bacterial cells causes serious problems such as corrosion of steel, choking of flow in the pipe, deterioration of the heat-transfer efficiency, and so on. Cathodic protection is known to be a reliable method for protecting carbon steel from corrosion. However, the initial attachment of bacteria to the surface and the effects of cathodic protection on bacterial viability in the biofilm have not been clarified. In this study, cathodic protection was applied to an artificial biofilm containing Pseudomonas aeruginosa (PAO1), a biofilm constituent, on carbon steel. The aims of this study were to evaluate the inhibition effect of cathodic protection on biofilm formation and to reveal the inhibition mechanisms. The viability of PAO1 in artificial biofilm of 5 mm thickness on cathodically protected steel decreased to 1% of the initial cell concentration. Analysis of pH distribution in the artificial biofilm by pH microelectrode revealed that pH in proximity to carbon steel increased to approximately 11 after cathodic protection for 5 h. Moreover, 99% of region in the artificial biofilm was under the pH conditions of over nine. A simulation of pH profile was shown to correspond to experimental values. These results indicate cells in the artificial biofilm were killed or damaged by cathodic protection due to pH increase. PMID:17163515

Miyanaga, Kazuhiko; Terashi, Ryosuke; Kawai, Hirofumi; Unno, Hajime; Tanji, Yasunori

2007-07-01

367

Biocidal effect of cathodic protection on bacterial viability in biofilm attached to carbon steel.  

UK PubMed Central (United Kingdom)

Biofilm formed on carbon steel by various species of bacterial cells causes serious problems such as corrosion of steel, choking of flow in the pipe, deterioration of the heat-transfer efficiency, and so on. Cathodic protection is known to be a reliable method for protecting carbon steel from corrosion. However, the initial attachment of bacteria to the surface and the effects of cathodic protection on bacterial viability in the biofilm have not been clarified. In this study, cathodic protection was applied to an artificial biofilm containing Pseudomonas aeruginosa (PAO1), a biofilm constituent, on carbon steel. The aims of this study were to evaluate the inhibition effect of cathodic protection on biofilm formation and to reveal the inhibition mechanisms. The viability of PAO1 in artificial biofilm of 5 mm thickness on cathodically protected steel decreased to 1% of the initial cell concentration. Analysis of pH distribution in the artificial biofilm by pH microelectrode revealed that pH in proximity to carbon steel increased to approximately 11 after cathodic protection for 5 h. Moreover, 99% of region in the artificial biofilm was under the pH conditions of over nine. A simulation of pH profile was shown to correspond to experimental values. These results indicate cells in the artificial biofilm were killed or damaged by cathodic protection due to pH increase.

Miyanaga K; Terashi R; Kawai H; Unno H; Tanji Y

2007-07-01

368

Rhenium Uptake as Analogue 96Tc by Steel Corrosion Products  

Energy Technology Data Exchange (ETDEWEB)

Static batch experiments were used to examine the sorption of dissolved perrhenate [Re(VII)], as a surrogate for pertechnetate [Tc(VII)], on corrosion products of A-516 carbon steel coupons contacted with synthetic groundwater or dilute water. After 109 days of contact time, the concentration of dissolved Re(VII) in the synthetic groundwater matrix decreased by approximately 26%; the dilute water matrix experienced a 99% decrease in dissolved Re(VII) over the same time period. Bulk x-ray diffraction (XRD) results for the corroded steel coupons showed that the corrosion products consisted primarily of maghemite, lepidocrocite, and goethite. Analyses of the coupons by scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) indicated that Re was present with the morphologically complex assemblages of Fe oxide/hydroxide corrosion products for samples spiked with the highest dissolved Re(VII) concentration (1.0 mmol/L) used for these experiments. Analyses of corroded steel coupons contacted with solutions containing 1.0 mmol/L Re(VII) by synchrotron-based methods confirmed the presence of Re sorbed with the corrosion product on the steel coupons. Analyses showed that the Re sorbed on these corroded coupons was in the +7 oxidation state, suggesting that the Re(VII) uptake mechanism did not involve reduction of Re to a lower oxidation state, such as +4. The results of our studies using Re(VII) as an analogue for {sup 99}Tc(VII) suggest that {sup 99}Tc(VII) would also be sorbed with steel corrosion products and that the inventory of {sup 99}Tc(VII) released from breached waste packages would be lower than what is now conservatively estimated.

K.M. Krupka, C.F. Brown, H. Todd Schaef, S. M. Heald, M. M. Valenta, B. W. Arey

2006-04-30

369

Corrosion protection of a commercial NdFeB magnet by phosphating  

Energy Technology Data Exchange (ETDEWEB)

NdFeB magnets are susceptible to corrosion in normal working environments and are therefore protected against corrosion with coatings of epoxies, electrodeposited nickel, etc. Eventual failure of these coatings expose the surface of the magnet to corrosion. Hence, protection of magnets prior to the application of coatings is one way of overcoming the corrosion problems associated with coating failures. Phosphating is a well known process to protect carbon steels and other ferrous alloys in general, and is often used as a pretreatment before the application of coatings. This study reports the experimental work carried out to obtain a corrosion inhibiting layer directly on NdFeB magnet surfaces, that is also structurally coherent with the substrate. The electrochemical characteristics of the surface layer on the bare magnet surface, obtained by immersion in a solution of 0.15 M NaH{sub 2}PO{sub 4} and acidified with H{sub 2}SO{sub 4}, was determined. The corrosion resistance of the layer was tested in a solution of 1%(wt) NaCl plus 5 mM H{sub 2}SO{sub 4} with pH of 2.9, by electrochemical impedance spectroscopy (EIS) and cyclic polarization tests. The results indicated that NdFeB magnets can be protected in fairly aggressive media by a phosphate layer. Anodic polarization measurements indicated breakdown of the phosphate layer and corrosion of the magnet, only at an overpotential of approximately 400 mV. (orig.)

Saliba-Silva, A.M.; Costa, I. [IPEN, Inst. de Pesquisas Energeticas e Nucleares, Cidade Univ., Sao Paulo, SP (Brazil)

2001-07-01

370

An update of corrosion inhibitors for mild steel exposed to 32-0-0 UAN solution  

Energy Technology Data Exchange (ETDEWEB)

This is a continuation of corrosion studies on the effectiveness of commercial and newly-developed corrosion inhibitors for use with mild steel exposed to urea-ammonium nitrate (UAN) solution. This paper provides updated information on five newly-developed corrosion inhibitors. Tests were conducted with mild steel exposed to 32-0-0 UAN solution containing each corrosion inhibitor at ambient temperature and under static conditions. Real-time corrosion of the test specimens was monitored using AC impedance techniques. Corrosion performance of the inhibitors was evaluated based on comparison of the corrosion rate of specimens exposed to 32-0-0 UAN solution with and without a corrosion inhibitor.

Nguyen, D.T.; Nichols, D.E. [Tennessee Valley Authority, Muscle Shoals, AL (United States); Lohry, E.J. [Nutra-Flo Co., Sioux City, IA (United States)

1994-10-01

371

Preliminary investigations on the corrosivity of PUSPATI's tap water toward different types of steel  

International Nuclear Information System (INIS)

The corrosivity of tap water toward three types of steel has been investigated. It was found that galvanised steels and stainless steels do not experience any significant weight loss after being immersed in tap water for 15 to 30 days. Mild steel, on the other hand, was found to lose 0.34% of its weight after an immersion of 15 days and 0.46% of its weight after 30 days immersion. Water analysis indicates that during the immersion, significant amounts of Fe3+ ions were transferred from the metal surface into the solution. Results of the hardness measurement also suggest that CaCo3 scales which are loosely adhered to the surface of the metal have been formed. However, such layers are of no protective value and were removed during the cleaning of the specimen. (author)

1983-01-01

372

Corrosion of carbon steel in brine solutions of crude oil  

Energy Technology Data Exchange (ETDEWEB)

In Albania, CO{sub 2}/H{sub 2}S corrosion in oil and gas production environments represent one of the most important areas of corrosion. Pipelines used for transmission of natural gas and crude oil tank are exposed to the action of the contaminating agents diluted in liquid water. CO{sub 2} and H{sub 2}S are the contaminants that worries the most to the pipeline operator, mainly due to the variety of damages (localized corrosion, cracking and hydrogen embrittlement among others) they may cause. Considerable work had been done to define effects of CO{sub 2} and H{sub 2}S on corrosion rates in the world. However, little effort has been spent on the subject of CO{sub 2} contaminated with small amount of H{sub 2}S. Research has put more light on the effect of temperature, pH, flow and other parameters that have an impact on corrosion process. Efforts have been made towards learning about the corrosion processes in the complex systems CO{sub 2} / H{sub 2}S / H{sub 2}O. This is basically due to the incomplete knowledge of the synergistic relationship between CO{sub 2} and H{sub 2}S. Low cost carbon steel is generally used as construction material in these facilities. This is why the corrosion coupons used throughout this investigation were from the same carbon steel. This work was developed using weight loss experiments of samples in natural brine solutions of crude oil. Tests are performed at 20 deg. C and 60 deg. C without and with stirring of solutions. Some of the tests are realized in natural brine solutions saturated with CO{sub 2}, H{sub 2}S and CO{sub 2}/H{sub 2}S. The following conclusions can be drawn from the present work: 1. Corrosion rate increases approximately 2 times when temperature increases from 20 deg. C to 60 deg. C; 2. Flow increases corrosion rate and influences changing the morphology of corrosion from local to uniform; 3. H{sub 2}S, CO{sub 2} strongly effects increasing the corrosion rate of carbon steel. (authors)

Gace, Zana; Llabani, Alberta [University of Tirana, Faculty of Natural Sciences, Tirana (Albania)

2004-07-01

373

Management of Corrosion  

Energy Technology Data Exchange (ETDEWEB)

Papers submitted for AGARD Lecture Series No. 141 (Management of Corrosion), concerning the management of corrosion in the aerospace field, are presented. Among the subjects covered are the superiority of corrosion resistance of low alloy steel containing 0.5 wt% copper over plain carbon steel, some theoretical aspects of corrosion and practical implications for aircraft, the effect of the microenvironment on corrosion, corrosion protection by means of various coatings, the special susceptibility of aircraft components to corrosion, aircraft corrosion preventive measures, experimental methods used to monitor corrosion, and the effect of road salt and a marine environment on thin-gage metals used in vehicle and aircraft manufacture.

1985-05-01

374

Corrosion of low carbon steel in clay and sea sediments  

International Nuclear Information System (INIS)

A serie of corrosion test have been conducted putting in contact mild steel samples with clay and two types of sea sediments. The test have been performed at 30, 50 and 900C up to a maximum duration time of 220 days. As the tests were performed in a closed system, most of the corrosion arrived in anoxic conditions. After an initial stabilization period corrosion weight losses increase linearly with time. The long term corrosion rate in presence of carbonaceous sediments is significantly higher than that obtained in clay or clay rich sediments. An analysis of the ion diffused in the porous media has shown that all the iron which is corroded in the anoxic condition is released in a soluble form. 11 refs

1986-01-01

375

Appearance and corrosion of stainless steels in the atmosphere  

International Nuclear Information System (INIS)

The resistance of 38 types of stainless steels (SSs) to degradation in the atmosphere was directly related to alloy chromium and molybdenum contents by spectrocolorimetric measurements and a visual rating system. Only AISI 410 exhibited any signs of corrosion in a semi-rural environment. Significant corrosion product staining occurred on all non-molybdenum-bearing stainless grades that had been exposed for 2 to 15 y at the 250-m lot on Kure Beach, NC. Stainless grades that had been sensitized by an autogenous welding operation were susceptible to preferential corrosion at weld and heat-affected zone surfaces when exposed to the coastal environment. Galvanic attack and corrosion product staining was observed for certain dissimilar metal couples between AISI 304 and various nonferrous metals. Photometric technology provided an efficient, reliable, and quantitative test technique that was superior to conventional methods for evaluating the relative performance of SS in the atmosphere.

1988-01-01

376

Methanogen population in a marine biofilm corrosive to mild steel.  

UK PubMed Central (United Kingdom)

This study was conducted to analyze the methanogen population in a corrosive marine biofilm based on 16S rDNA analysis, using a PCR-cloning-sequencing approach. There were 80 methanogen clones developed from the PCR-amplified DNA extracted from the biofilm on the mild steel surface. All clones were categorized into one of five operational taxonomy units (OTUs). Two OTUs (comprising 57 clones) were affiliated with the acetotrophic Methanosaeta genus; the remaining three OTUs (23 clones) were affiliated with the hydrogenotrophic genera of Methanogenium, Methanoplanus and Methanocalculus. The hydrogenotrophic methanogens could directly cause metal corrosion through cathodic depolarization, whereas the acetotrophic methanogens grew syntrophically with corrosion-causing sulfate-reducing bacteria, as observed by fluorescent in situ hybridization, and thus contribute indirectly to metal corrosion.

Zhang T; Fang HH; Ko BC

2003-11-01

377

Corrosion failures of austenitic stainless steel piping  

Energy Technology Data Exchange (ETDEWEB)

The safe and efficient operation of many chemical/industrial systems requires the continued integrity of the process piping; this is achieved through a complex series of interactions influenced by design, fabrication, construction, operation, inspection and lay-up requirements. Potential material-enviroment interactions are frequently, if evaluated at all, relegated to secondary considerations. This tendency virtually assures corrosion induced degradation of the process piping systems. Pitting, crevice attack, stress cracking, microbiologically influenced corrosion, intergranular attack and corrosion fatigue have caused leaks, cracks, failures and shutdown of numerous process systems. This paper uses the lessons learned from failure analysis to emphasize the importance of an integrated material program to system success. The necessity of continuing evaluation if also emphasized through examples of failures which were associated with materials-environment interactions caused by slight alterations of processes and/or systems.

Louthan, M.R. Jr.

1993-10-01

378

Long-term atmospheric corrosion of mild steel  

International Nuclear Information System (INIS)

[en] Research highlights: ? Atmospheric corrosion rate stabilises after the first 4-6 years of exposure. ? Great compaction of the rust layers in rural and urban atmospheres. ? Corrosion (in rural and urban) deviates from common behaviour of bilogarithmic law. ? Typical structures of lepidocrocite, goethite and akaganeite are identified. ? Formation of hematite (industrial atmosphere) and ferrihydrite (marine atmosphere). - Abstract: A great deal of information is available on the atmospheric corrosion of mild steel in the short, mid and even long term, but studies of the structure and morphology of corrosion layers are less abundant and generally deal with those formed in just a few years. The present study assesses the structure and morphology of corrosion product layers formed on mild steel after 13 years of exposure in five Spanish atmospheres of different types: rural, urban, industrial and marine (mild and severe). The corrosion layers have been characterised by X-ray diffraction (XRD) and scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS). Long-term corrosion is seen to be more severe in the industrial and marine atmospheres, and less so in the rural and urban atmospheres. In all cases the corrosion rate is seen to decrease with exposure time, stabilising after the first 4-6 years of exposure. The most relevant aspects to be noted are (a) the great compaction of the rust layers formed in the rural and urban atmospheres, (b) the formation of hematite and ferrihydrite phases (not commonly found) in the industrial and marine atmospheres, respectively and (c) identification of the typical morphological structures of lepidocrocite (sandy crystals and flowery plates), goethite (cotton balls structures) and akaganeite (cotton balls structures and cigar-shaped crystals).

2011-01-01

379

Advanced zinc phosphate conversion and pre-ceramic polymetallosiloxane coatings for corrosion protection of steel and aluminum, and characteristics of polyphenyletheretherketone-based materials. Final report  

Energy Technology Data Exchange (ETDEWEB)

Anhydrous zinc phosphate (Zn{center_dot}Ph) coatings deposited by immersing the steel in transition Co, Ni, and Mn cation-incorporated phosphating solutions were investigated. Two features for the anhydrous 340C-heated (Zn{center_dot}Ph) were addressed; one was to determine if electron trapping of adsorbed CO{sup 2+} and Ni{sup 2+} ions acts to inhibit the cathodic reaction on the (Zn{center_dot}Ph), and the second was to determine the less susceptibility of the {alpha}-Zn{sub 3}(PO{sub 4}){sub 2} phase to alkali-induced dissolution. The factors governing film-forming of pre-ceramic polymetallosiloxane (PMS) coatings for Al substrates were investigated. Four factors were important in obtaining a good film: (1) formation of organopolymetallosiloxane at sintering temperatures of 150C; (2) pyrolytic conversion at 350C into an amorphous PMS network structure in which the Si-O-M linkage were moderately enhanced; (3) noncrystalline phases; and (4) formation of interfacial oxane bond between PMS and Al oxide. Formation of well-crystallized polyphenyletheretherketone (PEEK) in vicinity of silica aggregates was found in the molted body made in N{sub 2}. Crystalline PEEK contributed to thermal and hydrothermal stabilities of mortar specimens at temperatures up to 200C, and resistance in 5 wt % H{sub 2}SO{sub 4} solution at 80C.

Sugama, T.; Carciello, N.R.

1992-07-01

380

Laboratory evaluation of ozone as a corrosion inhibitor for carbon steel, copper, and galvanized steel in cooling water  

Energy Technology Data Exchange (ETDEWEB)

An experimental study has been made to evaluate ozone as a corrosion inhibitor for use in cooling water systems. Corrosion of AISI 1010 carbon steel, CDA 122 copper, and hot-dipped galvanized steel in soft and hard water containing 0 to 0.1 ppm of ozone was examined at 90 F over a range of water velocity of 0.5--9.5 ft/s. The mechanism of ozone affecting metal corrosion was studied with an electrochemical polarization technique and the change in the chemical composition of test water during the corrosion tests. It was found that in soft water corrosion of carbon steel was inhibited by ozone. The corrosion rate of carbon steel in soft water was: 22--60 mpy without ozone and 14--27 mpy in the presence of 0.1 ppm of ozone. Pitting corrosion occurred on all carbon steel coupons in soft water; ozone decreased pit density, pit size and pit depth. In hard water, corrosion of carbon steel was accelerated by ozone. Uniform corrosion occurred on all carbon steel coupons in hard water. The extent of corrosion acceleration by ozone decreased with increasing water velocity; at a high velocity of 9.5 ft/s the corrosion rates of carbon steel with and without ozone became approximately the same at 20 mpy. Corrosion of copper in both soft and hard water was accelerated by ozone. In the presence of 0.1 ppm ozone, the corrosion rate of copper was: 0.6--1.5 mpy in soft water, and 0.8--1.4 mpy in hard water. Corrosion of galvanized steel in both soft and hard water was inhibited by ozone. The inhibition efficiency increased with increasing water velocity.

Gan, F. [Wuhan Univ. (China); Chin, D.T. [