WorldWideScience

Sample records for micro-gravimetric corrosion studies

  1. Electrochemical and micro-gravimetric corrosion studies on spent fuel provide relevant source term data for a repository performance assessment

    International Nuclear Information System (INIS)

    Wegen, Detlef H.; Bottomley, Paul D. W.; Glatz, Jean-Paul

    2004-01-01

    Various electrochemical methods (corrosion potential monitoring, AC impedance analysis and electrochemical noise monitoring) were used in the investigation of UO 2 samples: natural and doped with two different levels of 238 Pu (0.1 and 10 wt%) simulating the increasing α-intensities seen with time in the repository. The results were compared and were able to show the intense, but also the very local nature of the radiolysis and to demonstrate that corrosion rates were proportional to α-radiolysis and hence the 238 Pu content; the corrosion rates were in accordance with earlier work at ITU. By contrast it was seen that the redox potentials only gave information as to the bulk solution that did not reflect the true conditions at the electrode interface that were driving the corrosion processes of UO 2 dissolution in groundwaters. The study shows how electrochemical techniques can provide vital information on the corrosion mechanism at the UO 2 /solution interface

  2. Critical Study of Corrosion Damaged Concrete Structures

    OpenAIRE

    Sallehuddin Shah Ayop; John Cairns

    2013-01-01

    Corrosion of steel reinforcement in concrete is one of the major problems with respect to the durability of reinforced concrete structures. The degradation of the structure strength due to reinforcement corrosion decreases its design life. This paper presents the literature study on the influence of the corrosion on concrete structure starting from the mechanism of the corrosion until the deterioration stage and the structural effects of corrosion on concrete structures.

  3. 219-S CORROSION STUDY

    International Nuclear Information System (INIS)

    DIVINE, J.R.; PARSONS, G.L.

    2008-01-01

    A minor leak was detected in a drain line for Hood 2B located in the 222-S Laboratory. The line transfers radioactive waste, spent analytical standards, and chemicals used in various analytical procedures. Details are in the report provided by David Comstock, 2B NDE June 2008, work package LAB-WO-07-2012. Including the noted leak, the 222-S Laboratory has experienced two drain line leaks in approximately the last two years of operation. As a consequence, CH2M HILL Hanford Group, Inc. (CH2M HILL) requested the support of ChemMet, Ltd., PC (ChemMet) at the Hanford Site 222-S Laboratory. The corrosion expertise from ChemMet was required prior to preparation of a compatibility assessment for the 222-S Laboratory waste transfer system to assure the expected life of the piping system is extended as much as practicable. The system includes piping within the 222-S Laboratory and the 219-S Waste Storage and Transfer Facility and Operations Process. The ChemMet support was required for an assessment by 222-S staff to analyze what improvements to operational activities may be implemented to extend the tank/piping system life. This assessment will include a summary of the various material types, age, and locations throughout the facility. The assessment will also include a discussion of materials that are safe for drain line disposal on a regular basis, materials that are safe for disposal on a case-by-case basis including specific additional requirements such as flushing, neutralization to a specific pH, and materials prohibited from disposal. The assessment shall include adequate information for 222-S Laboratory personnel to make informed decisions in the future disposal of specific material types by discussing types of compatibility of system materials and potential wastes. The assessment is expected to contain some listing of acceptable waste materials but is not anticipated to be a complete or comprehensive list. Finally the assessment will encompass a brief discussion of

  4. Corrosion studies on PREPP waste form

    International Nuclear Information System (INIS)

    Welch, J.M.; Neilson, R.M. Jr.

    1984-05-01

    Deformation or Failure Test and Accelerated Corrosion Test procedures were conducted to investigate the effect of formulation variables on the corrosion of oversize waste in Process Experimental Pilot Plant (PREPP) concrete waste forms. The Deformation or Failure Test did not indicate substantial waste form swelling from corrosion. The presence or absence of corrosion inhibitor was the most significant factor relative to measured half-cell potentials identified in the Accelerated Corrosion Test. However, corrosion inhibitor was determined to be only marginally beneficial. While this study produced no evidence that corrosion is of sufficient magnitude to produce serious degradation of PREPP waste forms, the need for corrosion rate testing is suggested. 11 references, 4 figures, 8 tables

  5. Current status of studies on nodular corrosion

    International Nuclear Information System (INIS)

    Yasuda, Takayoshi; Kawasaki, Satoru; Echigoya, Hironori; Kinoshita, Yutaka; Kubota, Hiroyuki; Konishi, Takao; Yamanaka, Tuneyasu.

    1993-01-01

    The studies on nodular corrosion formed on the outer surface of BWR fuel cladding tubes were reviewed. Main factors affecting the corrosion behavior were material and environmental conditions and combined effect. The effects of such material conditions as fabrication process, alloy elements, texture and surface treatment and environmental factors as neutron irradiation, thermo-hydrodynamic, water chemistry, purity of the coolant and contact with foreign metals on the corrosion phenomena were surveyed. Out-of-reactor corrosion test methods and models for the corrosion mechanism were also reviewed. Suppression of the accumulated annealing temperature during tube reduction process improved the nodular corrosion resistance of Zircaloys. Improved resistance for the nodular corrosion was reported for the unirradiated Zircaloys with some additives. Detailed irradiation test under the BWR conditions is needed to confirm the trend. Concerning the environmental factors, boiling on the cladding surface due to heat flux reduces the nodular corrosion susceptibility, while oxidizing radical generated from dissolved oxygen accelerates the corrosion. Concerning corrosion mechanisms, importance of such phenomena as the depleted zone of alloying elements in zirconium matrix, reduction of H + to H 2 in oxide layer, electrochemical property of precipitates, crystallographic anisotropy of oxidation rates were revealed. (author) 59 refs

  6. Long-term corrosion studies

    International Nuclear Information System (INIS)

    Gdowski, G.

    1998-01-01

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

  7. Glove corrosive liquid immersion and permeability study

    International Nuclear Information System (INIS)

    Middleton, H.W.

    1977-01-01

    The Occupational Safety and Health Administration's requirement for protective equipment for personnel working with chemical hazards resulted in a study of gloves used in work with corrosive liquids. Gloves of different materials and weights were tested using ASTM methods, in various corrosive liquids. Results show the best material for gloves used for different lengths of time in the liquids

  8. Corrosion process studies in a nuclear waste container

    International Nuclear Information System (INIS)

    Guasp, Ruben A.; Lanzani, Liliana A.; Coronel, Pascual; Bruzzoni, Pablo; Semino, Carlos J.

    1999-01-01

    Latest results on corrosion behavior studies on high activity nuclear waste container are reported. Corrosion evaluation on lead base alloys and modeling to predict carbon steel external container cover generalized corrosion, are the main issues of these studies. (author)

  9. Numerical Study of Corrosion Crack Opening

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle; Frandsen, Henrik Lund; Svensson, Staffan

    2008-01-01

    is proportional. More recently, the constant of proportionality, the so-called crack-corrosion index, has been studied further with respect to its dependence on the diameter of the reinforcement and the concrete cover. In the present paper the above-mentioned work is presented and extended with more realistic 3D......-models of the cracked concrete beam. The crack-corrosion index is evaluated for a variation of different parameters, i.e. bar diameter, concrete cover, crack length and type of corrosion product. This paper is an extended version of a paper by Thoft-Christensen et al. (2005) presented at the IFIP WG 7.5 Conference...... for the corrosion crack opening. Experiments and theoretical analysis by a numerical method, FEM, support that the relation between the reduction of the reinforcement bar diameter due to corrosion and the corresponding increase in crack width for a given time interval, measured on the surface of a concrete specimen...

  10. Task E container corrosion studies: Annual report

    International Nuclear Information System (INIS)

    Bunnell, L.R.; Doremus, L.A.; Topping, J.B.; Duncan, D.R.

    1994-06-01

    The Pacific Northwest Laboratory is conducting the Solid Waste Technology Support Program (SWTSP) for Westinghouse Hanford Company (WHC). Task E is the Container Corrosion Study Portion of the SWTSP that will perform testing to provide defensible data on the corrosion of low-carbon steel, as used in drums to contain chemical and radioactive wastes at the Hanford Site. A second objective of Task E is to provide and test practical alternative materials that have higher corrosion resistance than low-carbon steel. The scope of work for fiscal year (FY) 1993 included initial testing of mild steel specimens buried in Hanford soils or exposed to atmospheric corrosion in metal storage sheds. During FY 1993, progress was made in three areas of Task E. First, exposure of test materials began at the Soil Corrosion Test Site where low-carbon steel specimens were placed in the soil in five test shafts at depths of 9 m (30 ft). Second, the corrosion measurement of low-carbon steel in the soil of two solid waste trenches continued. The total exposure time is ∼ 500 days. Third, an atmospheric corrosion test of low-carbon steel was put initiated in a metal shed (Building 2401-W) in the 200 West Area. This annual report describes the Task E efforts and provides a current status

  11. Corrosion

    Science.gov (United States)

    Slabaugh, W. H.

    1974-01-01

    Presents some materials for use in demonstration and experimentation of corrosion processes, including corrosion stimulation and inhibition. Indicates that basic concepts of electrochemistry, crystal structure, and kinetics can be extended to practical chemistry through corrosion explanation. (CC)

  12. Pitting corrosion of copper. Further model studies

    International Nuclear Information System (INIS)

    Taxen, C.

    2002-08-01

    The work presented in this report is a continuation and expansion of a previous study. The aim of the work is to provide background information about pitting corrosion of copper for a safety analysis of copper canisters for final deposition of radioactive waste. A mathematical model for the propagation of corrosion pits is used to estimate the conditions required for stationary propagation of a localised anodic corrosion process. The model uses equilibrium data for copper and its corrosion products and parameters for the aqueous mass transport of dissolved species. In the present work we have, in the model, used a more extensive set of aqueous and solid compounds and equilibrium data from a different source. The potential dependence of pitting in waters with different compositions is studied in greater detail. More waters have been studied and single parameter variations in the composition of the water have been studied over wider ranges of concentration. The conclusions drawn in the previous study are not contradicted by the present results. However, the combined effect of potential and water composition on the possibility of pitting corrosion is more complex than was realised. In the previous study we found what seemed to be a continuous aggravation of a pitting situation by increasing potentials. The present results indicate that pitting corrosion can take place only over a certain potential range and that there is an upper potential limit for pitting as well as a lower. A sensitivity analysis indicates that the model gives meaningful predictions of the minimum pitting potential also when relatively large errors in the input parameters are allowed for

  13. Study of niobium corrosion in alkaline medium

    International Nuclear Information System (INIS)

    Almeida, S.H. de.

    1987-01-01

    A comparative study of niobium electrochemical behaviour in NaOH and KOH solution, with concentrations between 0,5 and 6,1M is presented. The studies were done through electrochemicals assays, consisting in the corrosion potential and anodic and cathodic polarization curves, complemented by loss of mass experiments. The niobium anodic behaviour in alkaline medium is characterized by passivation occurrence, with a stable film formation. The Na oH solution in alkaline medium are more corrosible to niobium than the KOH solution. The loss of mass assays showed that the corrosion velocit is more dependente of hydroxide concentration in KOH medium than the NaOH medium. (C.G.C.) [pt

  14. Corrosion Studies of Wrought and Cast NASA-23 Alloy

    Science.gov (United States)

    Danford, M. D.

    1997-01-01

    Corrosion studies were carried out for wrought and cast NASA-23 alloy using electrochemical methods. The scanning reference electrode technique (SRET), the polarization resistance technique (PR), and the electrochemical impedance spectroscopy (EIS) were employed. These studies corroborate the findings of stress corrosion studies performed earlier, in that the material is highly resistant to corrosion.

  15. Chemical treatment of zinc surface and its corrosion inhibition studies

    Indian Academy of Sciences (India)

    WINTEC

    Department of PG Studies and Research in Chemistry, School of Chemical Sciences, Kuvempu University, ... cations and is mainly used for the corrosion protection of ... provide a greater resistance to corrosion, but when exposed to humid ...

  16. Corrosion Study Using Electrochemical Impedance Spectroscopy

    Science.gov (United States)

    Farooq, Muhammad Umar

    2003-01-01

    Corrosion is a common phenomenon. It is the destructive result of chemical reaction between a metal or metal alloy and its environment. Stainless steel tubing is used at Kennedy Space Center for various supply lines which service the orbiter. The launch pads are also made of stainless steel. The environment at the launch site has very high chloride content due to the proximity to the Atlantic Ocean. Also, during a launch, the exhaust products in the solid rocket boosters include concentrated hydrogen chloride. The purpose of this project was to study various alloys by Electrochemical Impedance Spectroscopy in corrosive environments similar to the launch sites. This report includes data and analysis of the measurements for 304L, 254SMO and AL-6XN in primarily neutral 3.55% NaCl. One set of data for 304L in neutral 3.55%NaCl + 0.1N HCl is also included.

  17. Risk Based Corrosion Studies at SRS

    International Nuclear Information System (INIS)

    Hoffman, E.

    2010-01-01

    TYPE I and II (ASTM 285-B) - Experienced stress corrosion cracking (SCC), 2 have been closed; 22 scheduled for closure by 2017, and No active leak sites today. TYPE III (ASTM A516-70 and A537 Class I) - Post-fabrication relief of weld residual stresses, Improved resistance to SCC and brittle fracture, No leakage history, and Receives new waste. The objectives are to utilize statistical methods to reduce conservatism in current chemistry control program; and express nitrite inhibitor limits in terms of pitting risk on waste tank steel. Conclusions are: (1) A statistically designed experimental study has been undertaken to improve the effectiveness of the minimum nitrite concentrations to inhibit pitting corrosion; (2) Mixture/amount model supports that pitting depends on the ratio of aggressive to inhibitive anions, as well as the concentration of each species; (3) Secondary aggressive species, Cl - and SO 4 2- , significantly effect the corrosion response; and (4) Results support the reduction of the chemistry control nitrite inhibitor concentrations in the regime of 0.8-1.0 M nitrate.

  18. Model boiler studies on deposition and corrosion

    International Nuclear Information System (INIS)

    Balakrishnan, P.V.; McVey, E.G.

    1977-09-01

    Deposit formation was studied in a model boiler, with sea-water injections to simulate the in-leakage which could occur from sea-water cooled condensers. When All Volatile Treatment (AVT) was used for chemistry control the deposits consisted of the sea-water salts and corrosion products. With sodium phosphate added to the boiler water, the deposits also contained the phosphates derived from the sea-water salts. The deposits were formed in layers of differing compositions. There was no significant corrosion of the Fe-Ni-Cr alloy boiler tube under deposits, either on the open area of the tube or in crevices. However, carbon steel that formed a crevice around the tube was corroded severely when the boiler water did not contain phosphate. The observed corrosion of carbon steel was caused by the presence of acidic, highly concentrated chloride solution produced from the sea-water within the crevice. Results of theoretical calculations of the composition of the concentrated solution are presented. (author)

  19. A study on stress corrosion cracking of explosive plugged part

    International Nuclear Information System (INIS)

    Kaga, Seiichi; Fujii, Katsuhiro; Yamamoto, Yoshiaki; Sakuma, Koosuke; Hibi, Seiji; Morimoto, Hiroyoshi.

    1986-01-01

    Studies on the stress corrosion cracking of explosive plugged part are conducted. SUS 304 stainless steel is used as testing material. The distribution of residual stress in plug and tube plate after plugging is obtained. The effect of residual stress on the stress corrosion cracking is studied. Residual stress in tube plate near the plug is compressive and stress corrosion cracking dose not occur in the tube plate there, and it occurs on the inner surface of plug because of residual tensile stress in axial direction of the plug. Stress corrosion test in MgCl 2 solution under constant load is conducted. The susceptibility to stress corrosion cracking of the explosive bonded boundary is lower than that of base metal because of greater resistance to plastic deformation. Stress corrosion test in high temperature and high pressure pure water is also conducted by means of static type of autoclave but stress corrosion cracking does not occur under the testing condition used. (author)

  20. Study on influence of native oxide and corrosion products on atmospheric corrosion of pure Al

    International Nuclear Information System (INIS)

    Liu, Yanjie; Wang, Zhenyao; Ke, Wei

    2014-01-01

    Highlights: •Corrosion products layer is only formed in coastal atmosphere. •In coastal atmosphere, rate controlling step is diffusion process. •In rural atmosphere, rate controlling step is charge transfer process. •Pitting area increases greatly in coastal site, but slightly in rural site. -- Abstract: Effects of native oxide and corrosion products on atmospheric corrosion of aluminium in rural and coastal sites were studied by electrochemical impedance spectroscopy (EIS), open-circuit potential (OCP) and scanning electron microscope (SEM) techniques after outdoor exposure. In the rural atmosphere, only the compact, adhesive native oxide layer exists, and the rate controlling step is diffusion process, while in the coastal atmosphere, another loose, inadhesive corrosion products layer exists, and a charge transfer process controls the corrosion process. The pitting area in the coastal atmosphere increases over time more obviously than that in the rural atmosphere

  1. Aqueous corrosion study on U-Zr alloy

    International Nuclear Information System (INIS)

    Pal, Titas; Venkatesan, V.; Kumar, Pradeep; Khan, K.B.; Kumar, Arun

    2009-01-01

    In low power or research reactor, U-Zr alloy is a potential candidate for dispersion fuel. Moreover, Zirconium has a low thermal-neutron cross section and uranium alloyed with Zr has excellent corrosion resistance and dimensional stability during thermal cycling. In the present study aqueous corrosion behavior of U-Zr alloy samples was studied in autoclave at 200 deg C temperature. Corrosion rate was determined from weight loss with time. (author)

  2. The study on corrosion resistance of decorative satin nickel plating

    Directory of Open Access Journals (Sweden)

    LU Wenya

    2012-10-01

    Full Text Available This study examined the corrosion resistance of satin nickel plating on conductive plastic.The electrochemical tests were to analyze the corrosion behavior of satin nickel plating with different processes in 3.5% NaCl solution.The results show that,because the satin nickel plating has an organic film on its surface due to process characteristics,the film results in different corrosion resistance.By increasing satin additive dosage,the nickel plating chroma decreases,the microsurface of the plating becomes rough,and the corrosion resistance is followed by decrease.

  3. Corrosion study in molten fluoride salt

    International Nuclear Information System (INIS)

    Keny, S.J.; Kumbhar, A.G.; Rangarajan, S.; Gupta, V.K.; Maheshwari, N.K.; Vijayan, P.K.

    2013-01-01

    Corrosion behaviors of two alloys viz. Inconel 625 and Inconel 617 were tested in molten fluoride salts of lithium, sodium and potassium (FLiNaK) in the temperature range of 550-750 ℃ in a nickel lined Inconel vessel. Electrochemical polarization (Tafel plot) technique was used for this purpose. For both alloys, the corrosion rate was found to increase sharply beyond 650 ℃ . At 600 ℃ , Inconel 625 showed a decreasing trend in the corrosion rate over a period of 24 hours, probably due to changes in the surface conditions. After fifteen days, re-testing of Inconel 625 in the same melt showed an increase in the corrosion rate. Inconel 625 was found to be more corrosion resistant than Inconel 617. (author)

  4. Studying the causes for corrosive destruction of water conduits

    Energy Technology Data Exchange (ETDEWEB)

    Azamatova, F I; Kulinichev, G P; Porubov, I S

    1979-01-01

    Pipes from different oil and gas production administrations were selected for X-ray and metallographic studies of the cause of corrosive destruction. The chemical composition and mechanical properties of the pipe material are presented in tables. The phase composition of the corrosion products was studied by X-rays. The complex structure of the layer made up of the corrosion products was taken into consideration. The studies were conducted in an X-ray diffraction chamber. The obtained results are presented in a table. The metallographic studies showed that a significant corrosive damage of the materials of water conduits occurs as a result of the development of local corrosion processes, caused by the substantive heterogeneity of the structure of the metal, related to the nonuniform distribution of the pearlite because of carbon liquidation.

  5. Application of Moessbauer spectroscopy to study corrosion

    International Nuclear Information System (INIS)

    Ramshesh, V.; Ravichandran, K.; Venkateswarlu, K.S.

    1976-01-01

    The system components in a nuclear power station include steel, stainless steel and various alloys such as Monel, Inconel, Stellite etc. Usually water/heavy water used as the coolant flows at high temperatures and pressures. Under such conditions the interaction of system components with the coolant produces a host of corrosion products. The deposition of such products is essential. This report attempts to review the salient features of identification of such corrosion products using Moessbauer spectroscopy. (author)

  6. Study of stress corrosion cracking initiation of high alloy materials

    Energy Technology Data Exchange (ETDEWEB)

    Blahetova, Marie; Cihal, Vladimir; Lasek, Stanislav [Department of Materials Engineering, VSB - Technical University of Ostrava, tr. 17. listopadu 15, 708 33 Ostrava - Poruba (Czech Republic)

    2004-07-01

    The stainless steels and related alloys with sufficient resistance to a general corrosion can be susceptible to a localized corrosion (pitting, cracking, intergranular corrosion) in certain environment under specific conditions. The Drop Evaporation Test (DET) was developed for study of stainless materials resistance to stress corrosion cracking (SCC) at elevated temperatures 100 - 300 deg. C under constant external load using a chloride containing water solution. In the contribution the initiation and propagation of short cracks as well as pits were observed during the test. The crack initiation and/or propagation can be influenced by the cyclic thermal stresses, when the diluted water solution drops cool down the hot sample. The coordinates measurement of microscopic pits and sharp corrosion crack tips by the travelling microscope method allowed to derive the crack growth lengths and rates of short cracks. (authors)

  7. Study of stress corrosion cracking initiation of high alloy materials

    International Nuclear Information System (INIS)

    Blahetova, Marie; Cihal, Vladimir; Lasek, Stanislav

    2004-01-01

    The stainless steels and related alloys with sufficient resistance to a general corrosion can be susceptible to a localized corrosion (pitting, cracking, intergranular corrosion) in certain environment under specific conditions. The Drop Evaporation Test (DET) was developed for study of stainless materials resistance to stress corrosion cracking (SCC) at elevated temperatures 100 - 300 deg. C under constant external load using a chloride containing water solution. In the contribution the initiation and propagation of short cracks as well as pits were observed during the test. The crack initiation and/or propagation can be influenced by the cyclic thermal stresses, when the diluted water solution drops cool down the hot sample. The coordinates measurement of microscopic pits and sharp corrosion crack tips by the travelling microscope method allowed to derive the crack growth lengths and rates of short cracks. (authors)

  8. Ontario Hydro studies on copper corrosion under waste disposal conditions

    International Nuclear Information System (INIS)

    Lam, K.W.

    1990-01-01

    The corrosion rate of copper is generally greater in aerated solutions containing sulphide; also, in the presence of sulphide there is the fear that pitting may occur. Experiments have been carried out to study the corrosion of copper in deaerated groundwater/bentonite slurries with and without added sulphide for exposure periods from two months to one year. The groundwater contains 6500 ppm of chloride and 1000 ppm of sulphate. Tests were also performed in the presence of a 150 rad/h radiation field. In deaerated slurries at 75C the corrosion rate is less than 2 μm/a. With one addition of 10 mg/l sulphide, the rate increases by a factor of ten. With daily sulphide additions to deaerated solutions the corrosion rate initially falls but then rises and stabilizes after 15 days. In aerated solutions the corrosion increases over the first 25 days and then stabilizes. The corrosion rate of copper reached a steady value in 15 to 30 days. Rates are higher in aerated solutions, but the effect of adding sulphide is not so marked in aerated solutions as in unaerated solutions. The highest corrosion rate, less than 150 μm/a, was observed in aerated slurries saturated with sulphide. For deaerated solutions in the absence of sulphide the corrosion rate increases with temperature, but in aerated solutions the rate decreases. For solutions containing added sulphide the influence of temperature is negligible. The effect of a radiation field may be beneficial; in the presence of a radiation field the corrosion rate is less than 20 μm/a. After descaling the coupons showed a high density of irregularly shaped pits both in the presence and absence of sulphide, resulting from intergranular attack. The pitting factor for the highest corrosion rate is around 15

  9. Corrosion of orthodontic brackets in different spices: in vitro study.

    Science.gov (United States)

    Chaturvedi, T P

    2014-01-01

    Moist environment in the mouth varies and causes variable amounts of corrosion of dental materials. This is of concern particularly when metallic implants, metallic fillings, orthodontic appliances are placed in the hostile electrolytic environment in the human mouth. Components of diet rich in salt and spices are important factors influencing the corrosion of metallic appliances placed in the oral cavity. To study in vitro corrosion of orthodontic metallic brackets immersed in solutions of salt and spices in artificial saliva. Orthodontic brackets were used for corrosion studies in artificial saliva, salt, and spices using electrochemical technique and surface analysis. Electrochemical studies using different parameters were done in solutions of artificial saliva containing salt and spices. Photomicrographs from the optical microscope were also obtained. RESULTS of corrosion studies have clearly demonstrated that certain spices such as turmeric and coriander are effective in reducing corrosion, whereas salt and red chili have been found to enhance it. Surface analysis of small pits present on the surface of the as-received bracket will initiate corrosion which leads to more pitting.

  10. Corrosion Compatibility Studies on Inconel-600 in NP Decontamination Solution

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sang Yoon; Jung, Jun Young; Won, Huijun; Choi, Wangkyu; Moon, Jeikwon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-05-15

    It is well known that corrosion and contamination process in the primary cooling circuit of nuclear reactors are essentially interrelated: the contaminant isotopes are mostly corrosion products activated in the reactor core, and the contamination takes place on the out-core of Inconel-600 surface. This radionuclide uptake takes place up to the inner oxide layer and oxide/metal interface. So, it is necessary to remove inner oxide layer as well as outer oxide layer for excellent decontamination effects. The outer oxide layers are composed of Fe{sub 3}O{sub 4} and NiFe{sub 2}O{sub 4}. On the other hand, the inner oxide layers are composed of Cr{sub 2}O{sub 3}, (Ni{sub 1-x}Ni{sub x})(Cr{sub 1-y}Fe{sub y}){sub 2}O{sub 4}, and FeCr{sub 2}O{sub 4}. Because of chromium in the trivalent oxidation state which is difficult to dissolve, the oxide layer has an excellent protectiveness and become hard to be decontaminated. Alkaline permanganate (AP) or nitric permanganate (NP) oxidative phase has been used to dissolve the chromium-rich oxide. A disadvantage of AP process is the generation of a large volume of secondary waste. On the other hand, that of NP process is the high corrosion rate for Ni-base alloys. Therefore, for the safe use of oxidative phase in PWR system decontamination, it is necessary to reformulate the NP chemicals for decrease of corrosion rate. This study describes the corrosion compatibility on Inconel-600 and type 304 stainless steel in NP decontamination solution for PWR applications. To evaluate the general corrosion properties, weight change of NP treated specimens was measured. NP treated specimen surface was observed using optical microscope (OM) and scanning electron microscopy (SEM) for the evaluation of the localized corrosion. The effect of additives on the corrosion of the specimens was also evaluated. This study describes the corrosion compatibility on Inconel-600 and type 304 stainless steel in NP decontamination solution for PWR applications

  11. Corrosion Compatibility Studies on Inconel-600 in NP Decontamination Solution

    International Nuclear Information System (INIS)

    Park, Sang Yoon; Jung, Jun Young; Won, Huijun; Choi, Wangkyu; Moon, Jeikwon

    2013-01-01

    It is well known that corrosion and contamination process in the primary cooling circuit of nuclear reactors are essentially interrelated: the contaminant isotopes are mostly corrosion products activated in the reactor core, and the contamination takes place on the out-core of Inconel-600 surface. This radionuclide uptake takes place up to the inner oxide layer and oxide/metal interface. So, it is necessary to remove inner oxide layer as well as outer oxide layer for excellent decontamination effects. The outer oxide layers are composed of Fe 3 O 4 and NiFe 2 O 4 . On the other hand, the inner oxide layers are composed of Cr 2 O 3 , (Ni 1-x Ni x )(Cr 1-y Fe y ) 2 O 4 , and FeCr 2 O 4 . Because of chromium in the trivalent oxidation state which is difficult to dissolve, the oxide layer has an excellent protectiveness and become hard to be decontaminated. Alkaline permanganate (AP) or nitric permanganate (NP) oxidative phase has been used to dissolve the chromium-rich oxide. A disadvantage of AP process is the generation of a large volume of secondary waste. On the other hand, that of NP process is the high corrosion rate for Ni-base alloys. Therefore, for the safe use of oxidative phase in PWR system decontamination, it is necessary to reformulate the NP chemicals for decrease of corrosion rate. This study describes the corrosion compatibility on Inconel-600 and type 304 stainless steel in NP decontamination solution for PWR applications. To evaluate the general corrosion properties, weight change of NP treated specimens was measured. NP treated specimen surface was observed using optical microscope (OM) and scanning electron microscopy (SEM) for the evaluation of the localized corrosion. The effect of additives on the corrosion of the specimens was also evaluated. This study describes the corrosion compatibility on Inconel-600 and type 304 stainless steel in NP decontamination solution for PWR applications. It is revealed that Inconel-600 specimen is more

  12. Study on corrosion of thermal power plant condenser tubes

    Energy Technology Data Exchange (ETDEWEB)

    Mohammadi, Abdolreza Rashidi; Zhaam, Ali Akbar [Niroo Research Institute, end of Poonak Bakhtari blvd., Shahrak Ghods, Tehran (Iran)

    2004-07-01

    The aim of this investigation is to study kinds of corrosion mechanisms in thermal power plant condenser tubes. Condenser is a shell and tube heat exchanger in which cooling water flows through its tubes. While the steam from low pressure turbine passes within condenser tubes, it is condensed by cooling water. The exhausted steam from low pressure turbine is condensed on external surface of condenser tubes and heat is transferred to cooling water which flow into tubes. Tubes composition is usually copper-based alloys, stainless steel or titanium. Annual damages due to corrosion cause much cost for replacement and repairing metallic equipment and installations in electric power industry. Because of existence of different contaminants in water and steam cycle, condenser tubes surfaces are exposed to corrosion. Contaminants like oxygen, carbon dioxide, chloride ion and ammonia in water and steam cycle originate several damages such as pitting and crevice corrosion, erosion, galvanic attack, SCC, condensed corrosion, de-alloying in thermal power plant condenser. The paper first states how corrosion damage takes place in condensers and then introduces types of usual alloys used in condensers and also their corrosion behavior. In continuation, a brief explanation is presented about kinds of condenser failures due to corrosion. Then, causes and locations of different mechanisms of corrosion events on condenser tubes and effects of different parameters such as composition, temperature, chloride and sulfide ion concentration, pH, water velocity and biological precipitation are examined and finally protection methods are indicated. Also some photos of tubes specimens related to power plants are studied and described in each case of mentioned mechanisms. (authors)

  13. The study on corrosion resistance of decorative satin nickel plating

    OpenAIRE

    LU Wenya; CHENG Xianhua

    2012-01-01

    This study examined the corrosion resistance of satin nickel plating on conductive plastic.The electrochemical tests were to analyze the corrosion behavior of satin nickel plating with different processes in 3.5% NaCl solution.The results show that,because the satin nickel plating has an organic film on its surface due to process characteristics,the film results in different corrosion resistance.By increasing satin additive dosage,the nickel plating chroma decreases,the microsurface of the p...

  14. Corrosion and impedance studies on magnesium alloy in oxalate solution

    International Nuclear Information System (INIS)

    Fekry, A.M.; Tammam, Riham H.

    2011-01-01

    Highlights: → Corrosion behavior of AZ91E alloy was investigated in 0.1 M Na 2 C 2 O 4 containing different additives as Br - , Cl - or Silicate. → The corrosion rate of 0.1 M oxalate solution containing silicate ion is lower than the blank (0.1 M Na 2 C 2 O 4 ). This was confirmed by scanning electron microscope (SEM) observations. → For the other added ions Br - or Cl - , the corrosion rate is higher than the blank. - Abstract: Corrosion behavior of AZ91E alloy was investigated in oxalate solution using potentiodynamic polarization and electrochemical impedance measurements (EIS). The effect of oxalate concentration was studied, where the corrosion rate increases with increasing oxalate concentration. The effect of added ions (Br - , Cl - or SiO 3 2- ) on the electrochemical behavior of magnesium alloy in 0.1 M Na 2 C 2 O 4 solution at 298 K, was investigated. It was found that the corrosion rate of 0.1 M oxalate solution containing silicate ion is lower than the blank (0.1 M Na 2 C 2 O 4 ). This was confirmed by scanning electron microscope (SEM) observations. However, for the other added ions Br - or Cl - , the corrosion rate is higher than the blank.

  15. Corrosion and impedance studies on magnesium alloy in oxalate solution

    Energy Technology Data Exchange (ETDEWEB)

    Fekry, A.M., E-mail: hham4@hotmail.com [Chemistry Department, Faculty of Science, Cairo University, Gamaa Street, Giza 12613 (Egypt); Tammam, Riham H. [Chemistry Department, Faculty of Science, Cairo University, Gamaa Street, Giza 12613 (Egypt)

    2011-06-15

    Highlights: > Corrosion behavior of AZ91E alloy was investigated in 0.1 M Na{sub 2}C{sub 2}O{sub 4} containing different additives as Br{sup -}, Cl{sup -} or Silicate. > The corrosion rate of 0.1 M oxalate solution containing silicate ion is lower than the blank (0.1 M Na{sub 2}C{sub 2}O{sub 4}). This was confirmed by scanning electron microscope (SEM) observations. > For the other added ions Br{sup -} or Cl{sup -}, the corrosion rate is higher than the blank. - Abstract: Corrosion behavior of AZ91E alloy was investigated in oxalate solution using potentiodynamic polarization and electrochemical impedance measurements (EIS). The effect of oxalate concentration was studied, where the corrosion rate increases with increasing oxalate concentration. The effect of added ions (Br{sup -}, Cl{sup -} or SiO{sub 3}{sup 2-}) on the electrochemical behavior of magnesium alloy in 0.1 M Na{sub 2}C{sub 2}O{sub 4} solution at 298 K, was investigated. It was found that the corrosion rate of 0.1 M oxalate solution containing silicate ion is lower than the blank (0.1 M Na{sub 2}C{sub 2}O{sub 4}). This was confirmed by scanning electron microscope (SEM) observations. However, for the other added ions Br{sup -} or Cl{sup -}, the corrosion rate is higher than the blank.

  16. Task E container corrosion studies: Annual report. Revision 1

    International Nuclear Information System (INIS)

    Bunnell, L.R.; Doremus, L.A.; Topping, J.B.; Duncan, D.R.

    1994-06-01

    The Pacific Northwest Laboratory is conducting the Solid Waste Technology Support Program (SWTSP) for Westinghouse Hanford Company (WHC). Task E is the Container Corrosion Study Portion of the SWTSP that will perform testing to provide defensible data on the corrosion of low-carbon steel, as used in drums to contain chemical and radioactive wastes at the Hanford Site. A second objective of Task E is to provide and test practical alternative materials that have higher corrosion resistance than low-carbon steel. The scope of work for fiscal year (FY) 1993 included initial testing of mild steel specimens buried in Hanford soils or exposed to atmospheric corrosion in metal storage sheds. During FY 1993, progress was made in three areas of Task E. First, exposure of test materials began at the Soil Corrosion Test Site where low-carbon steel specimens were placed in the soil in five test shafts at depths of 9 m (30 ft). Second, the corrosion measurement of low-carbon steel in the soil of two solid waste trenches continued. The total exposure time is ∼ 500 days. Third, an atmospheric corrosion test of low-carbon steel was initiated in a metal shed (Building 2401-W) in the 200 West Area. This annual report describes the Task E efforts and provides a current status

  17. COPPER PITTING CORROSION: A CASE STUDY

    Science.gov (United States)

    Localized or pitting corrosion of copper pipes used in household drinking-water plumbing is a problem for many water utilities and their customers. Extreme attack can lead to pinhole water leaks that may result in water damage, mold growth, and costly repairs. Water quality has b...

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

    International Nuclear Information System (INIS)

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

    2006-12-01

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

  19. Study of corrosion in aluminium using neutron radiography technique

    International Nuclear Information System (INIS)

    Islam, M.N.; Alam, M.K.; Saklayen, M.A.; Ahsan, M.H.; Islam, S.M.A.; Zaman, M.A.

    2000-01-01

    Neutron radiography technique has been adopted for detection of corrosion in aluminium by filling artificially made holes on aluminium slab with Al(OH) 3 . The contrast between the optical densities of corrosion products and aluminium slab was assessed from the densitometric measurements. Variation of optical density difference with sample thickness has also been studied. The results confirm that approximately 0.039 mm thick corrosion products having diameter 10 mm can easily be detected in 2 cm thick aluminium slab. The linear attenuation coefficient of Al(OH) 3 has been obtained as 0.9447. From the present investigation it is confirmed that film neutron radiography (NR) technique is helpful for investigation of Al(OH) 3 type corrosion product in aluminium. (author)

  20. Atomic level characterization in corrosion studies

    Science.gov (United States)

    Marcus, Philippe; Maurice, Vincent

    2017-06-01

    Atomic level characterization brings fundamental insight into the mechanisms of self-protection against corrosion of metals and alloys by oxide passive films and into how localized corrosion is initiated on passivated metal surfaces. This is illustrated in this overview with selected data obtained at the subnanometre, i.e. atomic or molecular, scale and also at the nanometre scale on single-crystal copper, nickel, chromium and stainless steel surfaces passivated in well-controlled conditions and analysed in situ and/or ex situ by scanning tunnelling microscopy/spectroscopy and atomic force microscopy. A selected example of corrosion modelling by ab initio density functional theory is also presented. The discussed aspects include the surface reconstruction induced by hydroxide adsorption and formation of two-dimensional (hydr)oxide precursors, the atomic structure, orientation and surface hydroxylation of three-dimensional ultrathin oxide passive films, the effect of grain boundaries in polycrystalline passive films acting as preferential sites of passivity breakdown, the differences in local electronic properties measured at grain boundaries of passive films and the role of step edges at the exposed surface of oxide grains on the dissolution of the passive film. This article is part of the themed issue 'The challenges of hydrogen and metals'.

  1. TREATMENT TANK CORROSION STUDIES FOR THE ENHANCED CHEMICAL CLEANING PROCESS

    Energy Technology Data Exchange (ETDEWEB)

    Wiersma, B.

    2011-08-24

    Radioactive waste is stored in high level waste tanks on the Savannah River Site (SRS). Savannah River Remediation (SRR) is aggressively seeking to close the non-compliant Type I and II waste tanks. The removal of sludge (i.e., metal oxide) heels from the tank is the final stage in the waste removal process. The Enhanced Chemical Cleaning (ECC) process is being developed and investigated by SRR to aid in Savannah River Site (SRS) High-Level Waste (HLW) as an option for sludge heel removal. Corrosion rate data for carbon steel exposed to the ECC treatment tank environment was obtained to evaluate the degree of corrosion that occurs. These tests were also designed to determine the effect of various environmental variables such as temperature, agitation and sludge slurry type on the corrosion behavior of carbon steel. Coupon tests were performed to estimate the corrosion rate during the ECC process, as well as determine any susceptibility to localized corrosion. Electrochemical studies were performed to develop a better understanding of the corrosion mechanism. The tests were performed in 1 wt.% and 2.5 wt.% oxalic acid with HM and PUREX sludge simulants. The following results and conclusions were made based on this testing: (1) In 1 wt.% oxalic acid with a sludge simulant, carbon steel corroded at a rate of less than 25 mpy within the temperature and agitation levels of the test. No susceptibility to localized corrosion was observed. (2) In 2.5 wt.% oxalic acid with a sludge simulant, the carbon steel corrosion rates ranged between 15 and 88 mpy. The most severe corrosion was observed at 75 C in the HM/2.5 wt.% oxalic acid simulant. Pitting and general corrosion increased with the agitation level at this condition. No pitting and lower general corrosion rates were observed with the PUREX/2.5 wt.% oxalic acid simulant. The electrochemical and coupon tests both indicated that carbon steel is more susceptible to localized corrosion in the HM/oxalic acid environment than

  2. Treatment Tank Corrosion Studies For The Enhanced Chemical Cleaning Process

    International Nuclear Information System (INIS)

    Wiersma, B.

    2011-01-01

    Radioactive waste is stored in high level waste tanks on the Savannah River Site (SRS). Savannah River Remediation (SRR) is aggressively seeking to close the non-compliant Type I and II waste tanks. The removal of sludge (i.e., metal oxide) heels from the tank is the final stage in the waste removal process. The Enhanced Chemical Cleaning (ECC) process is being developed and investigated by SRR to aid in Savannah River Site (SRS) High-Level Waste (HLW) as an option for sludge heel removal. Corrosion rate data for carbon steel exposed to the ECC treatment tank environment was obtained to evaluate the degree of corrosion that occurs. These tests were also designed to determine the effect of various environmental variables such as temperature, agitation and sludge slurry type on the corrosion behavior of carbon steel. Coupon tests were performed to estimate the corrosion rate during the ECC process, as well as determine any susceptibility to localized corrosion. Electrochemical studies were performed to develop a better understanding of the corrosion mechanism. The tests were performed in 1 wt.% and 2.5 wt.% oxalic acid with HM and PUREX sludge simulants. The following results and conclusions were made based on this testing: (1) In 1 wt.% oxalic acid with a sludge simulant, carbon steel corroded at a rate of less than 25 mpy within the temperature and agitation levels of the test. No susceptibility to localized corrosion was observed. (2) In 2.5 wt.% oxalic acid with a sludge simulant, the carbon steel corrosion rates ranged between 15 and 88 mpy. The most severe corrosion was observed at 75 C in the HM/2.5 wt.% oxalic acid simulant. Pitting and general corrosion increased with the agitation level at this condition. No pitting and lower general corrosion rates were observed with the PUREX/2.5 wt.% oxalic acid simulant. The electrochemical and coupon tests both indicated that carbon steel is more susceptible to localized corrosion in the HM/oxalic acid environment than

  3. Pitting corrosion of copper. An equilibrium - mass transport study

    International Nuclear Information System (INIS)

    Taxen, C.

    2002-08-01

    A mathematical model for the propagation of corrosion pits is described and used to calculate the potentials below which copper is immune to pitting. The model uses equilibrium data and diffusion coefficients and calculates the stationary concentration profiles of 26 aqueous species from the bulk water outside a corrosion pit to the site of the metal dissolution. Precipitation of oxides and salts of copper is considered. Studied conditions include water compositions from tap waters to seawater at the temperatures 25 deg C and 75 deg C. Carbonate and sulphate are aggressive towards copper because of complex formation with divalent copper. Carbonate is less aggressive in a corrosion pit than outside at the pH of the bulk. Carbonate carries acidity out from the pit, favours oxide formation and may prevent the initiation of acidic corrosion pits. The concentration profiles are used to estimate the maximum propagation rates for a corrosion pit. A high potential is found to be the most important factor for the rate of propagation. The levels of potential copper can sustain, as corrosion potentials are discussed in terms of the stability of cuprous oxide as a cathode material for oxygen reduction relative to non-conducting cupric phases

  4. Pitting corrosion of copper. An equilibrium - mass transport study

    Energy Technology Data Exchange (ETDEWEB)

    Taxen, C. [Swedish Corrosion Inst., Stockholm (Sweden)

    2002-08-01

    A mathematical model for the propagation of corrosion pits is described and used to calculate the potentials below which copper is immune to pitting. The model uses equilibrium data and diffusion coefficients and calculates the stationary concentration profiles of 26 aqueous species from the bulk water outside a corrosion pit to the site of the metal dissolution. Precipitation of oxides and salts of copper is considered. Studied conditions include water compositions from tap waters to seawater at the temperatures 25 deg C and 75 deg C. Carbonate and sulphate are aggressive towards copper because of complex formation with divalent copper. Carbonate is less aggressive in a corrosion pit than outside at the pH of the bulk. Carbonate carries acidity out from the pit, favours oxide formation and may prevent the initiation of acidic corrosion pits. The concentration profiles are used to estimate the maximum propagation rates for a corrosion pit. A high potential is found to be the most important factor for the rate of propagation. The levels of potential copper can sustain, as corrosion potentials are discussed in terms of the stability of cuprous oxide as a cathode material for oxygen reduction relative to non-conducting cupric phases.

  5. Electrochemical and weight-loss study of carbon steel corrosion

    International Nuclear Information System (INIS)

    Thomas, V.J.; Olive, R.P.

    2007-01-01

    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)

  6. Effect of zinc injection on BWR fuel cladding corrosion. Pt. 1. Study on an accelerated corrosion condition to evaluate corrosion resistance of zircaloy-2 fuel cladding

    International Nuclear Information System (INIS)

    Kawamura, Hirotaka; Kanbe, Hiromu; Furuya, Masahiro

    2002-01-01

    Japanese BWR utilities have a plan to apply zinc injection to the primary coolant in order to reduce radioactivity accumulation on the structure. Prior to applying the zinc injection to BWR plants, it is necessary to evaluate the effect of zinc injection on corrosion resistance of fuel cladding. The objective of this report was to examine the accelerated corrosion condition for evaluation of BWR fuel cladding corrosion resistance under non-irradiated conditions, as the first step of a zinc injection evaluation study. A heat transfer corrosion test facility, in which a two phase flow condition could be achieved, was designed and constructed. The effects of heat flux, void fraction and solution temperature on BWR fuel cladding corrosion resistance were quantitatively investigated. The main findings were as follows. (1) In situ measurements using high speed camera and a void sensor together with one dimensional two phase flow analysis results showed that a two phase flow simulated BWR core condition can be obtained in the corrosion test facility. (2) The heat transfer corrosion test results showed that the thickness of the zirconium oxide layer increased with increasing solution temperature and was independent of heat flux and void fraction. The corrosion accelerating factor was about 2.5 times in the case of a temperature increase from 288degC to 350degC. (author)

  7. Study on Corrosion-induced Crack Initiation and Propagation of Sustaining Loaded RCbeams

    Science.gov (United States)

    Zhong, X. P.; Li, Y.; Yuan, C. B.; Yang, Z.; Chen, Y.

    2018-05-01

    For 13 pieces of reinforced concrete beams with HRB500 steel bars under long-term sustained loads, at time of corrosion-induced initial crack of concrete, and corrosion-induced crack widths of 0.3mm and 1mm, corrosion of steel bars and time-varying behavior of corrosion-induced crack width were studied by the ECWD (Electro-osmosis - constant Current – Wet and Dry cycles) accelerated corrosion method. The results show that when cover thickness was between 30 and 50mm,corrosion rates of steel bars were between 0.8% and 1.7% at time of corrosion-induced crack, and decreased with increasing concrete cover thickness; when corrosion-induced crack width was 0.3mm, the corrosion rate decreased with increasing steel bar diameter, and increased with increasing cover thickness; its corrosion rate varied between 0.98% and 4.54%; when corrosion-induced crack width reached 1mm, corrosion rate of steel bars was between 4% and 4.5%; when corrosion rate of steel bars was within 5%, the maximum and average corrosion-induced crack and corrosion rate of steel bars had a good linear relationship. The calculation model predicting the maximum and average width of corrosion-induced crack is given in this paper.

  8. Corrosion in waste-fired boilers: A thermodynamic study

    DEFF Research Database (Denmark)

    Becidan, Michael; Sørum, Lars; Frandsen, Flemming

    2009-01-01

    A twofold study using thermodynamic equilibrium calculations was carried out to study corrosion in MSW incinerators. Corrosion was associated with the amount of alkalis and trace metals gaseous chlorides. Firstly, a two-level factorial experimental design combined with a data analysis were used...... to determine the main and interaction effects for various alkalis and trace metals gaseous chlorides responses. The factors studied were Na, K, S and Cl concentrations. The results provided a picture of the controlling parameters and insight about the processes taking place. Secondly, the efficiency of two...

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

    Science.gov (United States)

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

    2017-01-01

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

  10. ELECTROCHEMICAL CORROSION STUDY VIA LINEAR POLARIZATION IN PEAS CAN

    Directory of Open Access Journals (Sweden)

    I. M. Costa

    2016-09-01

    Full Text Available The aim of this work is to study the corrosion of tinplate can for peas. Firstly, the characterization of canning solution was made. The values of pH, conductivity, Brix, viscosity, density and content of Fe were, respectively, 5.88; 32.6 mS/cm; 6.6%; 3,42cP; 1.026 g/ml; 12.05 mg/kg. The corrosion rate in the cans was determined by linear polarization technique. The electrodes with and without varnish were analyzed in the first and fifth day of the experiment for the 3 parts of the can. The corrosion rate increased significantly when the coating was removed and the body showed a higher corrosion rate, reaching 1.7 mm/year in the absence of varnish. The microstructure of the samples was evaluated by scanning electron microscopy (SEM coupled with energy dispersive spectroscopy (EDS. The increase of iron on the surface, evidenced by energy dispersive spectroscopy (EDS may have contributed to the corrosion in the samples without varnish.

  11. Corrosion cracking

    International Nuclear Information System (INIS)

    Goel, V.S.

    1985-01-01

    This book presents the papers given at a conference on alloy corrosion cracking. Topics considered at the conference included the effect of niobium addition on intergranular stress corrosion cracking, corrosion-fatigue cracking in fossil-fueled-boilers, fracture toughness, fracture modes, hydrogen-induced thresholds, electrochemical and hydrogen permeation studies, the effect of seawater on fatigue crack propagation of wells for offshore structures, the corrosion fatigue of carbon steels in seawater, and stress corrosion cracking and the mechanical strength of alloy 600

  12. An X-ray diffraction study of corrosion products from low carbon steel

    International Nuclear Information System (INIS)

    Morales, A. L.

    2003-01-01

    It was found in earlier work a decrease in the corrosion rate from low carbon steel when it was subjected to the action of a combined pollutant concentration (SO 4 ''2-=10''-4 M+Cl=1.5x 10''-3 M). It was also found that large magnetic content of the rust was related to higher corrosion rates. In the present study corrosion products are further analyzed by means of X-ray diffraction to account for composition changes during the corrosion process. it is found that lepidocrocite and goethite are the dominant components for the short-term corrosion in all batches considered while for log-term corrosion lepidocrite and goethite dominates if the corrosion rates is low and magnetite dominates if the corrosion rate is high. The mechanism for decreasing the corrosion rate is related to the inhibition of magnetite production at this particular concentration. (Author) 15 refs

  13. An electrochemical study of the corrosion behavior of primer coated 2219-T87 aluminum

    Science.gov (United States)

    Danford, M. D.; Higgins, R. H.

    1985-01-01

    The corrosion behavior for 2219-T87 aluminum coated with various primers, including those used for the external tank and solid rocket boosters of the Space Shuttle Transportation System, were investigated using electrochemical techniques. Corrosion potential time, polarization resistance time, electrical resistance time, and corrosion rate time measurements were all investigated. It was found that electrical resistance time and corrosion rate time measurement were most useful for studying the corrosion behavior of painted aluminum. Electrical resistance time determination give useful information concerning the porosity of paint films, while corrosion rate time curves give important information concerning overall corrosion rates and corrosion mechanisms. In general, the corrosion rate time curves all exhibited at least one peak during the 30 day test period, which was attributed, according to the proposed mechanisms, to the onset of the hydrogen evolution reaction and the beginning of destruction of the protective properties of the paint film.

  14. Prompt gamma analysis of chlorine in concrete for corrosion study

    Energy Technology Data Exchange (ETDEWEB)

    Naqvi, A.A. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)]. E-mail: aanaqvi@kfupm.edu.sa; Nagadi, M.M. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Al-Amoudi, O.S.B. [Department of Civil Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)

    2006-02-15

    Measurement of chlorine in concrete is very important for studying of corrosion of reinforcing steel in concrete. Corrosion of reinforcing steel is primarily ascribed to the penetration of chloride ions to the steel surface. Preventive measures for avoiding concrete structure reinforcement corrosion requires monitoring the chloride ion concentration in concrete so that its concentration does not exceed a threshold limit to initiate reinforcement concrete corrosion. An accelerator based prompt gamma neutron activation analysis (PGNAA) setup has been developed for non-destructive analysis of elemental composition of concrete samples. The setup has been used to measure chlorine concentration in concrete samples over a 1-3 wt% concentration range. Although a strong interference has been observed between the chlorine {gamma}-rays and calcium {gamma}-rays from concrete, the chlorine concentration in concrete samples has been successfully measured using the 1.164 and 7.643 MeV chlorine {gamma}-rays. The experimental data were compared with the results of the Monte Carlo simulations. An excellent agreement has been achieved between the experimental data and results of Monte Carlo simulations. The study has demonstrated the successful use of the accelerator-based PGNAA setup in non-destructive analysis of chlorine in concrete samples.

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

    International Nuclear Information System (INIS)

    BOOMER, K.D.

    2007-01-01

    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

  16. Corrosion studies on casing steel in CO2 storage environments

    NARCIS (Netherlands)

    Zhang, X.; Zevenbergen, J.F.; Benedictus, T.

    2013-01-01

    The corrosion behavior of casing steel N80 in brine plus CO2 was studied in autoclave to simulate the CO2 storage environment. The brine solution used in the study contained 130 g/l NaCl, 22.2 g/l CaCl2 and 4 g/l MgCl2. The CO2 was charged in the autoclave at different pressures (60, 80 and 100 bar)

  17. An Influence Study of Hydrogen Evolution Characteristics on the Negative Strap Corrosion of Lead Acid Battery

    Directory of Open Access Journals (Sweden)

    Zhong Guobin

    2015-01-01

    Full Text Available Negative strap corrosion is an important reason for the failure of valve regulated lead acid battery. This paper selected the Pb-Sb alloy material and Pb-Sn alloy material, made an investigation on the negative corrosion resistance and hydrogen evolution of these two alloy materials by scanning electron microscope analysis, metallographic analysis, chemical study and linear sweep voltammetry, and discussed the influence of lead alloy hydrogen evolution on the negative strap corrosion. The results showed that the hydrogen evolution reaction rates of the alloys had an impact on the corrosion areas with the maximum thickness of the alloys and the depth of corrosion layers. Greater hydrogen evolution reaction rate can lead to shorter distance between the corrosion area with the maximum thickness and the liquid level; whereas the greater corrosion layer thickness can bring aggravated risk of negative strap corrosion failure.

  18. Laser Raman Spectroscopy in studies of corrosion and electrocatalysis

    International Nuclear Information System (INIS)

    Melendres, C.A.

    1988-01-01

    Laser Raman Spectroscopy (LRS) has become an important tool for the in-situ structural study of electrochemical systems and processes in recent years. Following a brief introduction of the experimental techniques involved in applying LRS to electrochemical systems, we survey the literature for examples of studies in the inhibition of electrode reactions by surface films (e.g., corrosion and passivation phenomena) as well as the acceleration of reactions by electro-sorbates (electrocatalysis). We deal mostly with both normal and resonance Raman effects on fairly thick surface films in contrast to surface-enhanced Raman investigations of monolayer adsorbates, which is covered in another lecture. Laser Raman spectroelectrochemical studies of corrosion and film formation on such metals as Pb, Ag, Fe, Ni, Co, Cr, Au, stainless steel, etc. in various solution conditions are discussed. Further extension of the technique to studies in high-temperature and high-pressure aqueous environments is demonstrated. Results of studies of the structure of corrosion inhibitors are also presented. As applications of the LRS technique in the area of electrocatalysis, we cite studies of the structure of transition metal macrocyclic compounds, i.e., phthalocyanines and porphyrins, used for catalysis of the oxygen reduction reaction. 104 refs., 20 figs

  19. The present and future on surface analysis for corrosion study

    International Nuclear Information System (INIS)

    Ohtsuka, Toshiaki

    2015-01-01

    Surface analysis for corrosion study was reviewed. For the study, the in-situ analysis was desired to describe the real feature. Light i.e., electromagnetic wave from gamma rays to infrared light has been used for the in-situ measurement of the corroded surface, although various ideas should be introduced for the study. For the application of the electromagnetic waves, a suitable window material and a suitable distance between the window and specimen surface depending on the properties of the wave must be selected. Electron spectroscopy including X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES) is not applicable for the in-situ study and, however, it is very available for the corrosion study from the following points; elemental analysis, state analysis of the element, and microscopic analysis. In future, the tip enhance Raman scattering (TERS) for which the scanning probe microscopy (SPM) is combined with the surface enhanced Raman scattering (SERS) may be useful for the in-situ corrosion study. (author)

  20. Study of biofilm influenced corrosion on cast iron pipes in reclaimed water

    International Nuclear Information System (INIS)

    Zhang, Haiya; Tian, Yimei; Wan, Jianmei; Zhao, Peng

    2015-01-01

    Highlights: • Compared to sterile water, biofilm in reclaimed water promoted corrosion process significantly. • Corrosion rate was accelerated by the biofilm in the first 7 days but was inhibited afterwards. • There was an inverse correlation between the biofilm thickness and general corrosion rate. • Corrosion process was influenced by bacteria, EPS and corrosion products comprehensively. • The corrosion process can be divided into three different stages in our study. - Abstract: Biofilm influenced corrosion on cast iron pipes in reclaimed water was systemically studied using the weight loss method and electrochemical impedance spectroscopy (EIS). The results demonstrated that compared to sterile water, the existence of the biofilm in reclaimed water promoted the corrosion process significantly. The characteristics of biofilm on cast iron coupons were examined by the surface profiler, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The bacterial counts in the biofilm were determined using the standard plate count method and the most probable number (MPN). The results demonstrated that the corrosion process was influenced by the settled bacteria, EPS, and corrosion products in the biofilm comprehensively. But, the corrosion mechanisms were different with respect to time and could be divided into three stages in our study. Furthermore, several corresponding corrosion mechanisms were proposed for different immersion times.

  1. Study of biofilm influenced corrosion on cast iron pipes in reclaimed water

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Haiya, E-mail: flying850612@126.com; Tian, Yimei, E-mail: ymtian_2000@126.com; Wan, Jianmei, E-mail: 563926510@qq.com; Zhao, Peng, E-mail: zhpeng@tju.edu.cn

    2015-12-01

    Highlights: • Compared to sterile water, biofilm in reclaimed water promoted corrosion process significantly. • Corrosion rate was accelerated by the biofilm in the first 7 days but was inhibited afterwards. • There was an inverse correlation between the biofilm thickness and general corrosion rate. • Corrosion process was influenced by bacteria, EPS and corrosion products comprehensively. • The corrosion process can be divided into three different stages in our study. - Abstract: Biofilm influenced corrosion on cast iron pipes in reclaimed water was systemically studied using the weight loss method and electrochemical impedance spectroscopy (EIS). The results demonstrated that compared to sterile water, the existence of the biofilm in reclaimed water promoted the corrosion process significantly. The characteristics of biofilm on cast iron coupons were examined by the surface profiler, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The bacterial counts in the biofilm were determined using the standard plate count method and the most probable number (MPN). The results demonstrated that the corrosion process was influenced by the settled bacteria, EPS, and corrosion products in the biofilm comprehensively. But, the corrosion mechanisms were different with respect to time and could be divided into three stages in our study. Furthermore, several corresponding corrosion mechanisms were proposed for different immersion times.

  2. A study of microbial population dynamics associated with corrosion rates influenced by corrosion control materials

    NARCIS (Netherlands)

    Chang, Yu Jie; Hung, Chun Hsiung; Lee, Jyh Wei; Chang, Yi Tang; Lin, Fen Yu; Chuang, Chun Jie

    2015-01-01

    This research aims to analyze the variations of microbial community structure under anaerobic corrosive conditions, using molecular fingerprinting method. The effect of adding various materials to the environment on the corrosion mechanism has been discussed. In the initial experiment,

  3. Modern techniques for studying biofilm-influenced corrosion

    International Nuclear Information System (INIS)

    Beech, I.B.

    1998-01-01

    In natural and made-made environments the presence of biofilms on surfaces of metals and their alloys influences electrochemistry at the biofilm/substratum interface, enhancing or inhibiting corrosion reactions. Due to the complexity of the biocorrosion phenomenon a range of techniques is commonly employed to study mechanisms involved. In addition to traditional methods of corrosion investigation such as electrochemical measurements and light and scanning electron microscopy observations coupled with energy dispersive X-ray analysis (EDXA) and X-ray diffraction (XRD). Modern techniques of surface science proved to be very useful in elucidating biofilm/metal interactions. Recent applications of Environmental Scanning Electron Microscopy (ESEM), Atomic Force Microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) to biocorrosion studies allowed better understanding of the biologically influenced metal deterioration process. The scope and promise of these latter techniques will be discussed and their use illustrated on practical examples. (Author)

  4. Corrosion and Corrosion-Fatigue Behavior of 7075 Aluminum Alloys Studied by In Situ X-Ray Tomography

    Science.gov (United States)

    Stannard, Tyler

    7XXX Aluminum alloys have high strength to weight ratio and low cost. They are used in many critical structural applications including automotive and aerospace components. These applications frequently subject the alloys to static and cyclic loading in service. Additionally, the alloys are often subjected to aggressive corrosive environments such as saltwater spray. These chemical and mechanical exposures have been known to cause premature failure in critical applications. Hence, the microstructural behavior of the alloys under combined chemical attack and mechanical loading must be characterized further. Most studies to date have analyzed the microstructure of the 7XXX alloys using two dimensional (2D) techniques. While 2D studies yield valuable insights about the properties of the alloys, they do not provide sufficiently accurate results because the microstructure is three dimensional and hence its response to external stimuli is also three dimensional (3D). Relevant features of the alloys include the grains, subgrains, intermetallic inclusion particles, and intermetallic precipitate particles. The effects of microstructural features on corrosion pitting and corrosion fatigue of aluminum alloys has primarily been studied using 2D techniques such as scanning electron microscopy (SEM) surface analysis along with post-mortem SEM fracture surface analysis to estimate the corrosion pit size and fatigue crack initiation site. These studies often limited the corrosion-fatigue testing to samples in air or specialized solutions, because samples tested in NaCl solution typically have fracture surfaces covered in corrosion product. Recent technological advancements allow observation of the microstructure, corrosion and crack behavior of aluminum alloys in solution in three dimensions over time (4D). In situ synchrotron X-Ray microtomography was used to analyze the corrosion and cracking behavior of the alloy in four dimensions to elucidate crack initiation at corrosion pits

  5. Studies on plant extracts as corrosion inhibitors for mild steel in air saturated water

    International Nuclear Information System (INIS)

    Mohamad Daud; Abdul Razak Daud; Zainal Abidin Sidi

    1988-01-01

    The effectiveness in inhibiting corrosion by garlic, soya bean, and tobacco extracts and their combinations in air saturated water at ambient temperature were studied by using electrochemical corrosion test. The range of inhibitor concentration studied was from 0.1 to 1.0 g/l. The variations of corrosion potential and corrosion current density was recorded and the results showed that the extracts have inhibitive properties in the corrosion of mild stee. The effectiveness of the inhibitors is in the following order: extract mixture > tobacco > garlic > soya bean extracts. (author)

  6. FEBEX Project Post-mortem Analysis: Corrosion Study

    International Nuclear Information System (INIS)

    Madina, V.; Azkarate, I.

    2004-01-01

    The partial dismantling of the FEBEX in situ test was carried out during de summer of 2002, following 5 years of continuous heating. The operation included the demolition of the concrete plug and the removal of the section of the test corresponding to the first heater. A large number of samples from all types of materials have been taken during the dismantling for subsequent analysis. Part of the samples collected were devoted to the analysis of the corrosion processes occurred during the first operational phase of the test. These samples comprised corrosion coupons from different metals installed for that purpose, sensors retrieved during the dismantling that were found severely corroded and bentonite in contact with those sensors. In addition, a corrosion study was performed on the heater extracted and on one section of liner surrounding it. All the analyses were carried out by the Fundacion INASMET (Spain). This report describes, in detail the studies carried out the different materials and the obtained results, as well as the drawn conclusions. (Author)

  7. Corrosion cast study of the canine hepatic veins.

    Science.gov (United States)

    Uršič, M; Vrecl, M; Fazarinc, G

    2014-11-01

    This study presents a detailed description of the distribution, diameters and drainage patterns of hepatic veins on the basis of the corrosion cast analysis in 18 dogs. We classified the hepatic veins in three main groups: the right hepatic veins of the caudate process and right lateral liver lobe, the middle hepatic veins of the right medial and quadrate lobes and the left hepatic veins of both left liver lobes and the papillary process. The corrosion cast study showed that the number of the veins in the Nomina Anatomica Veterinaria and most anatomical textbooks is underestimated. The number of various-sized hepatic veins of the right liver division ranged from 3 to 5 and included 1 to 4 veins from the caudate process and 2 to 4 veins from the right lateral liver lobe. Generally, in all corrosion casts, one middle-sized vein from the right part of the right medial lobe, which emptied separately in the caudal vena cava, was established. The other vein was a large-sized vein from the remainder of the central division, which frequently joined the common left hepatic vein from the left liver lobes. The common left hepatic vein was the largest of all the aforementioned hepatic veins.

  8. FEBEX Project Post-mortem Analysis: Corrosion Study

    Energy Technology Data Exchange (ETDEWEB)

    Madina, V.; Azkarate, I.

    2004-07-01

    The partial dismantling of the FEBEX in situ test was carried out during de summer of 2002, following 5 years of continuous heating. The operation included the demolition of the concrete plug and the removal of the section of the test corresponding to the first heater. A large number of samples from all types of materials have been taken during the dismantling for subsequent analysis. Part of the samples collected were devoted to the analysis of the corrosion processes occurred during the first operational phase of the test. These samples comprised corrosion coupons from different metals installed for that purpose, sensors retrieved during the dismantling that were found severely corroded and bentonite in contact with those sensors. In addition, a corrosion study was performed on the heater extracted and on one section of liner surrounding it. All the analyses were carried out by the Fundacion INASMET (Spain). This report describes, in detail the studies carried out the different materials and the obtained results, as well as the drawn conclusions. (Author)

  9. Electrochemical study of stress corrosion cracking of copper alloys

    International Nuclear Information System (INIS)

    Malki, Brahim

    1999-01-01

    This work deals with the electrochemical study of stress corrosion of copper alloys in aqueous environment. Selective dissolution and electrochemical oxidation are two key-points of the stress corrosion of these alloys. The first part of this thesis treats of these aspects applied to Cu-Au alloys. Measurements have been performed using classical electrochemical techniques (in potentio-dynamic, potentio-static and galvano-static modes). The conditions of occurrence of an electrochemical noise is analysed using signal processing techniques. The impact on the behavior of Cu 3 Au are discussed. In the second part, the stress corrosion problem is addressed in the case of surface oxide film formation, in particular for Cu-Zn alloys. We have found useful to extend this study to mechanical stress oxidation mechanisms in the presence of an oscillating potential electrochemical system. The aim is to examine the influence of these new electrochemical conditions (galvano-static mode) on the behavior of stressed brass. Finally, the potential distribution at crack tip is calculated in order to compare the different observations [fr

  10. Corrosion studies on HGW-canister materials for marine disposal

    International Nuclear Information System (INIS)

    Taylor, K.J.; Bland, I.D.; Marsh, G.P.

    1984-07-01

    A combination of mathematical modelling and experimental studies has been used to investigate and assess the long term corrosion behaviour of heat generating waste canister/ overpack materials under conditions relevant to deep ocean disposal. Preliminary operation of the model, using improved electrochemical kinetic data from the experimental programme, has indicated that the general corrosion rate of carbon steel at 90 deg C will be 57 μm yr -1 which is equivalent to a metal loss of 57 mm in 1000 years. This prediction compares favourably with the results from long term tests, which are also in progress, for plain and electron beam welded carbon steel specimens embedded in marine sediment at 90 deg C under active dissolution conditions. Tests with γ-radiation at a dose rate of 1.5 x 10 5 R h -1 have shown that the pH of seawater falls to 3.7 after 5000 hours exposure causing a significant increase in the corrosion rate of carbon steel from 50 to 80 μm yr -1 . Further work is in progress to investigate the mechanism of this acidification and whether it also occurs at the more realistic lower radiation dose rates. (author)

  11. Corrosion study for a radioactive waste vitrification facility

    International Nuclear Information System (INIS)

    Imrich, K.J.; Jenkins, C.F.

    1993-01-01

    A corrosion monitoring program was setup in a scale demonstration melter system to evaluate the performance of materials selected for use in the Defense Waste Processing Facility (DWPF) at the DOE's Savannah River Site. The system is a 1/10 scale prototypic version of the DWPF. In DWPF, high activity radioactive waste will be vitrified and encapsulated for long term storage. During this study twenty-six different alloys, including DWPF reference materials of construction and alternate higher alloy materials, were subjected to process conditions and environments characteristic of the DWPF except for radioactivity. The materials were exposed to low pH, elevated temperature (to 1200 degree C) environments containing abrasive slurries, molten glass, mercury, halides and sulfides. General corrosion rates, pitting susceptibility and stress corrosion cracking of the materials were investigated. Extensive data were obtained for many of the reference materials. Performance in the Feed Preparation System was very good, whereas coupons from the Quencher Inlet region of the Melter Off-Gas System experienced localized attack

  12. Hot corrosion studies on nickel-based alloys containing silicon

    International Nuclear Information System (INIS)

    Kerr, T.W.; Simkovich, G.

    1976-01-01

    Alloys of Ni--Cr, Ni--Si and Ni--Cr--Si were oxidized and ''hot corroded'' in pure oxygen at 1000 0 C. In the oxidation experiments it was found that small amounts of either chromium or silicon in nickel increased the oxidation rates in comparison to pure nickel in accord with Wagner's parabolic oxidation theory. At high concentrations of the alloying elements the oxidation rates decreased due to the formation of oxide phases other than nickel oxide in the scale. Hot corrosion experiments were conducted on both binary and ternary alloys by oxidizing samples coated with 1.0 mg/cm 2 of Na 2 SO 4 in oxygen at 1000 0 C. In general it was found that high chromium and high silicon alloys displayed excellent resistance to the hot corrosion process gaining or losing less than 0.5 mg/cm 2 in 1800 min at temperature. Microprobe and x-ray diffraction studies of the alloy and the scale indicate that amorphous SiO 2 probably formed to aid in retarding both the oxidation and the hot corrosion process

  13. A study on corrosive behavior of spring steel by shot-peening process

    International Nuclear Information System (INIS)

    An, Jae Pil; Park, Keyung Dong

    2004-01-01

    In this study, the influence of shot peening on the corrosion was investigated on spring steel immersed in 3.5% NaCl. The immersion test was performed on the two kinds of specimens. Corrosion potential, polarization curve, residual stress and etc. were investigated from experimental results. From test results, the effect of shot peening on the corrosion was evaluated. In case of corrosion potential, shot peened specimen shows more activated negative direction as compared with parent metal. Surface of specimen, which is treated with the shot peened, is placed as more activated state against inner base metal. It can cause the anti-corrosion effect on the base metal

  14. Electrochemical study of corrosion inhibition of stainless steel in phosphoric medium

    Energy Technology Data Exchange (ETDEWEB)

    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

    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)

  15. Corrosion studies of austenitic and duplex stainless steels in aqueous lithium bromide solution at different temperatures

    International Nuclear Information System (INIS)

    Igual Munoz, A.; Garcia Anton, J.; Lopez Nuevalos, S.; Guinon, J.L.; Perez Herranz, V.

    2004-01-01

    The corrosion behavior of three stainless steels EN 14311, EN 14429 (austenitic stainless steels) and EN 14462 (duplex stainless steel) was studied in a commercial LiBr solution (850 g/l LiBr solution containing chromate as inhibitor) at different temperatures (25, 50, 75 and 85 deg C) by electrochemical methods. Open circuit potentials shifted towards more active values as temperature increased, while corrosion potentials presented the opposite tendency. The most resistant alloys to general corrosion were EN 14429 and EN 14462 because they had the lowest corrosion current for all temperatures. In all the cases corrosion current increases with temperature. Pitting corrosion resistance is improved by the EN 14462, which presented the highest pitting potential, and the lowest passivation current for the whole range of temperatures studied. The duplex alloy also presents the worst repassivation behavior (in terms of the narrowest difference between corrosion potential and pitting potential); it does not repassivate from 50 deg C

  16. Studies on broad spectrum corrosion resistant oxide coatings

    Indian Academy of Sciences (India)

    Unknown

    Corrosion resistant coating materials and their application ... technology demand such corrosion resistant coatings having a ... mill additives used are as follows: China clay, 3⋅0–10⋅0; .... stage involves modification in processing of the deve-.

  17. Corrosion of steel in cracked concrete: a microscale study

    NARCIS (Netherlands)

    Pacheco, J.; Savija, B.; Schlangen, E.; Polder, R.B.

    2014-01-01

    The influence of concrete cracking upon reinforcement corrosion is complex. Cracks allow fast penetration of chlorides, potentially leading to a shorter initiation period of reinforcement corrosion. Structural regulations control acceptable crack width values based on the exposure class of the

  18. Experimental Study on Rebar Corrosion Using the Galvanic Sensor Combined with the Electronic Resistance Technique

    Science.gov (United States)

    Xu, Yunze; Li, Kaiqiang; Liu, Liang; Yang, Lujia; Wang, Xiaona; Huang, Yi

    2016-01-01

    In this paper, a new kind of carbon steel (CS) and stainless steel (SS) galvanic sensor system was developed for the study of rebar corrosion in different pore solution conditions. Through the special design of the CS and SS electronic coupons, the electronic resistance (ER) method and zero resistance ammeter (ZRA) technique were used simultaneously for the measurement of both the galvanic current and the corrosion depth. The corrosion processes in different solution conditions were also studied by linear polarization resistance (LPR) and the measurements of polarization curves. The test result shows that the galvanic current noise can provide detailed information of the corrosion processes. When localized corrosion occurs, the corrosion rate measured by the ER method is lower than the real corrosion rate. However, the value measured by the LPR method is higher than the real corrosion rate. The galvanic current and the corrosion current measured by the LPR method shows linear correlation in chloride-containing saturated Ca(OH)2 solution. The relationship between the corrosion current differences measured by the CS electronic coupons and the galvanic current between the CS and SS electronic coupons can also be used to evaluate the localized corrosion in reinforced concrete. PMID:27618054

  19. Experimental Study on Rebar Corrosion Using the Galvanic Sensor Combined with the Electronic Resistance Technique

    Directory of Open Access Journals (Sweden)

    Yunze Xu

    2016-09-01

    Full Text Available In this paper, a new kind of carbon steel (CS and stainless steel (SS galvanic sensor system was developed for the study of rebar corrosion in different pore solution conditions. Through the special design of the CS and SS electronic coupons, the electronic resistance (ER method and zero resistance ammeter (ZRA technique were used simultaneously for the measurement of both the galvanic current and the corrosion depth. The corrosion processes in different solution conditions were also studied by linear polarization resistance (LPR and the measurements of polarization curves. The test result shows that the galvanic current noise can provide detailed information of the corrosion processes. When localized corrosion occurs, the corrosion rate measured by the ER method is lower than the real corrosion rate. However, the value measured by the LPR method is higher than the real corrosion rate. The galvanic current and the corrosion current measured by the LPR method shows linear correlation in chloride-containing saturated Ca(OH2 solution. The relationship between the corrosion current differences measured by the CS electronic coupons and the galvanic current between the CS and SS electronic coupons can also be used to evaluate the localized corrosion in reinforced concrete.

  20. Autoradiographic study of corrosion of refractories

    International Nuclear Information System (INIS)

    Lisenenkova, S.B.; Kucheryavyi, M.N.; Bursteva, T.A.

    1988-01-01

    A comparative study was made of the character of the interaction between a container-glass melt consisting of sodium calcium silicate and refractories in various furnace sections using an autoradiographic method. Static tests were conducted on specimens of the following refractories: chrome-aluminum-zircon, Bakor 41, corundum, a high alumina refractory, and a refractory based on tin dioxide. The specimens were activated by calcium 45. Autoradiography and photomicrography indicated that an intrinsic feature of all refractories was that calcium from the melt penetrated the refractories along the weak link; for fused-cast refractories, the glass phase; and for sintered refractories, through the binder and cracks

  1. Study on corrosion products from ear piercing studs

    International Nuclear Information System (INIS)

    Rogero, Sizue O.; Costa, Isolda; Saiki, Mitiko

    2000-01-01

    In this work instrumental neutron activation analysis was applied to analyse elemental composition of commercial gold coated ear piercing substrate and metals present in their corrosion products. The cytotoxic effect was also verified in these corrosion product extracts, probably, due to the lixiviation of Ni present in high quantity in their substrates. The analysis of gold coated ear piercing surfaces by scanning electron microscopy before and after the corrosion test showed coating defects and the occurrence of corrosion process. (author)

  2. Study on Corrosion of Materials by Fluoric Acid and Silicofluoric Acid

    International Nuclear Information System (INIS)

    Park, Kun You; Kwon, Yeong Soo; Kuk, Myung Ho; Kim, Myun Sup

    1986-01-01

    The corrosion properties of 304 Stainless steel, Cupro-nickel, NiCrMo alloy in hydrofluoric acid and silicofluoric acid has been studied. The corrosion resistance of NiCrMo alloy and Cupro-nickel in hydrofluoric acid or mixed acid of hydrofluoric and sulfuric acid is excellent. Because of lower corrosion resistance of 304 Stainless steel, it would not be used for these corrosion resistant materials. The corrosion activation energy of 304 Stainless steel, Cupro-nickel and NiCrMo alloy in 40% HF solution are 42.7, 58.9 and 89.7 kJ/mol, respectively. By these values, it is assumed that the corrosion rate determining step is the chemical reaction on surface of metals. In the plastics, Teflon and polychloro tetrafluoroethylene are most excellent for corrosion resistance in hydrofluoric acid

  3. Moessbauer spectroscopy study of iron corrosion underneath painting system

    International Nuclear Information System (INIS)

    Nigam, R.K.; Hajela, B.P.; Sengupta, S.; Srivastava, B.C.; Gupta, K.N.

    1986-01-01

    The effect of pigments on the development of corrosion products between the painting system and metal surface when exposed to marine environments has been discussed. The pigments studied were: red mud zinc chromate, zinc chromate, red oxide zinc phosphate, manganese phosphate barium chromate and basic lead silico chromate. Moessbauer spectroscopy revealed that the upper rust layer in all the cases consisted of γ-Fe 2 O 3 , γ-FeOOH and α-FeOOH. The lower rust layer immediately in contact with the metal surface consisted of an asymmetrical doublet due to γ-FeOOH. (Auth.)

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

    International Nuclear Information System (INIS)

    Poineau, Frederic; Tamalis, Dimitri

    2016-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-08-01

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

  6. Flow-induced corrosion of absorbable magnesium alloy: In-situ and real-time electrochemical study.

    Science.gov (United States)

    Wang, Juan; Jang, Yongseok; Wan, Guojiang; Giridharan, Venkataraman; Song, Guang-Ling; Xu, Zhigang; Koo, Youngmi; Qi, Pengkai; Sankar, Jagannathan; Huang, Nan; Yun, Yeoheung

    2016-03-01

    An in-situ and real-time electrochemical study in a vascular bioreactor was designed to analyze corrosion mechanism of magnesium alloy (MgZnCa) under mimetic hydrodynamic conditions. Effect of hydrodynamics on corrosion kinetics, types, rates and products was analyzed. Flow-induced shear stress (FISS) accelerated mass and electron transfer, leading to an increase in uniform and localized corrosions. FISS increased the thickness of uniform corrosion layer, but filiform corrosion decreased this layer resistance at high FISS conditions. FISS also increased the removal rate of localized corrosion products. Impedance-estimated and linear polarization-measured polarization resistances provided a consistent correlation to corrosion rate calculated by computed tomography.

  7. In situ AFM study of pitting corrosion and corrosion under strain on a 304L stainless steel

    International Nuclear Information System (INIS)

    Martin, F.A.; Cousty, J.; Masson, J-L.; Bataillon, C.

    2004-01-01

    Our study is centred on surface localised corrosion under strain of a standard stainless steel (304L). The interest we take in these corrosion phenomena is led by the general misunderstanding of its primary initiation steps. The goal of this study is to determine precisely the relationships between local geometrical defects (grain boundaries, dislocation lines, etc) or chemical defects (inclusions) with the preferential sites of corrosion on the strained material. By combining three techniques at the same time: Atomic Force Microscopy, an electrochemical cell and a traction plate, we can observe in situ the effect of localised stress and deformation on the sample surface exposed to a corrosive solution. We managed to build an original set-up compatible with all the requirements of these three different techniques. Furthermore, we prepared the surface of our sample as flat as possible to decrease at maximum the topographical noise in order to observe the smallest defect on the surface. By using a colloidal suspension of SiO 2 , we obtained surfaces with a typical corrugation (RMS) of about 1 A for areas of at least 1 μm 2 . Our experimental study has been organised in two primary investigations: - In situ study of the morphology evolution of the surface under a corrosive chloride solution (borate buffer with NaCl salt). The influence of time, NaCl concentration, and potential was investigated; - In situ exploration of a 304L strained surface. It revealed the first stages of the surface plastic evolutions like activation of sliding dislocations, materialized by parallel steps of about 2 nm high in the same grain. The secondary sliding plane systems were also noticeable for higher deformation rates. Recent results concerning in situ AFM observation of corroded surfaces under strain in a chloride media will be presented. (authors)

  8. In situ AFM study of pitting corrosion and corrosion under strain on a 304L stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Martin, F.A. [CEA de Saclay, DRECAM/SPCSI, 91191 Gif-sur-Yvette cedex (France); Cousty, J.; Masson, J-L. [CEA de Saclay, DRECAM/SPCSI, 91191 Gif-sur-Yvette cedex (France); Bataillon, C. [CEA de Saclay, DEN/DPC/LECA, 91191 Gif-sur-Yvette cedex (France)

    2004-07-01

    Our study is centred on surface localised corrosion under strain of a standard stainless steel (304L). The interest we take in these corrosion phenomena is led by the general misunderstanding of its primary initiation steps. The goal of this study is to determine precisely the relationships between local geometrical defects (grain boundaries, dislocation lines, etc) or chemical defects (inclusions) with the preferential sites of corrosion on the strained material. By combining three techniques at the same time: Atomic Force Microscopy, an electrochemical cell and a traction plate, we can observe in situ the effect of localised stress and deformation on the sample surface exposed to a corrosive solution. We managed to build an original set-up compatible with all the requirements of these three different techniques. Furthermore, we prepared the surface of our sample as flat as possible to decrease at maximum the topographical noise in order to observe the smallest defect on the surface. By using a colloidal suspension of SiO{sub 2}, we obtained surfaces with a typical corrugation (RMS) of about 1 A for areas of at least 1 {mu}m{sup 2}. Our experimental study has been organised in two primary investigations: - In situ study of the morphology evolution of the surface under a corrosive chloride solution (borate buffer with NaCl salt). The influence of time, NaCl concentration, and potential was investigated; - In situ exploration of a 304L strained surface. It revealed the first stages of the surface plastic evolutions like activation of sliding dislocations, materialized by parallel steps of about 2 nm high in the same grain. The secondary sliding plane systems were also noticeable for higher deformation rates. Recent results concerning in situ AFM observation of corroded surfaces under strain in a chloride media will be presented. (authors)

  9. Nuclear risk reduction study. The study of structure corrosion caused by sea salt aerosols

    International Nuclear Information System (INIS)

    Nakayasu, Fumio

    2008-01-01

    Present all nuclear power plants in Fukui prefecture are located at the bay side of Japan Sea coast. New facilities may be planed to be at ocean side. The sea salt corrosion at the ocean side should be larger than it at the bay side. We have the salt damage experimental yard at Awara sea coast and at Fukui city (about 15km from coast) for the corrosion comparison study between Japan Sea coast and inland. We confirm the amounts of sea salt aerosol vary among the season and year. The weight loss of specimen inside of shelter without filter is higher than both of sheltered with filter and inland specimen. The weight loss of specimen inside of shelter with filter is almost same as it of inland specimen. We confirmed the filter which we used is sufficient capability to prevent corrosion. We confirmed the corrosion rate of both opened specimen and sheltered specimen without filter increased after some periods. (author)

  10. Study on corrosion of carbon steel in DEA aqueous solutions

    Science.gov (United States)

    Yang, Jun Han; Xie, Jia Lin; Zhang, Li

    2018-02-01

    Corrosion of carbon steel in the CO2 capture process using diethanolamine (DEA) aqueous solutions was investigated. The effects of the mass concentrations of DEA, solution temperature and CO2 loading on the corrosion rate of carbon steel were demonstrated. The experimental results provided comprehensive information on the appropriate concentration range of DEA aqueous solutions under which low corrosion of carbon steel can be achieved.

  11. Nondestructive study of corrosion by the analysis of diffused light

    Science.gov (United States)

    Hogert, Elsa N.; Landau, Monica R.; Marengo, Jose A.; Ruiz Gale, Maria F.; Gaggioli, Nestor G.; Paiva, Raul D., Jr.; Soga, Diogo; Muramatsu, Mikiya

    1999-07-01

    This work describes the application of mean intensity diffusion analysis to detect and analyze metallic corrosion phenomena. We present some new results in the characterization of the corrosion process using a model based in electroerosion phenomena. Valuable information is provided about surface microrelief changes, which is also useful for numerous engineering applications. The quality of our results supports the idea that this technique can contribute to a better analysis of corrosion processes, in particular in real time.

  12. Corrosion products study of alcohol by Mossbauer spectroscopy

    International Nuclear Information System (INIS)

    Velazquez, R.; Gil de Larre, M.

    1995-01-01

    Simulated corrosion essays in alcohol is presented and corrosion products of storage tanks (CAPASA) were analyzed. The analysis by Mossbauer absortion and transmission spectroscopy shows the formation of hematite substratum in the rust of the storage tanks of carburetant and burning alcohol. In the sample of corrosion with strong rum shows the formation of lepidocrocite and with destilled water besides of lepidocrocite, magnetite (Fe3 O4) is detected

  13. A comparative study of accelerated tests to simulate atmospheric corrosion

    International Nuclear Information System (INIS)

    Assis, Sergio Luiz de

    2000-01-01

    In this study, specimens coated with five organic coating systems were exposed to accelerated tests for periods up to 2000 hours, and also to weathering for two years and six months. The accelerated tests consisted of the salt spray test, according to ASTM B-117; Prohesion (ASTM G 85-98 annex 5A); Prohesion combined with cyclic exposure to UV-A radiation and condensation; 'Prohchuva' a test described by ASTM G 85-98 using a salt spray with composition that simulated the acid rain of Sao Paulo, but one thousand times more concentrated, and 'Prohchuva' combined with cyclic exposure to UV-A radiation and condensation. The coated specimens were exposed with and without incision to expose the substrate. The onset and progress of corrosion at and of the exposed metallic surface, besides coating degradation, were followed by visual observation, and photographs were taken. The coating systems were classified according to the extent of corrosion protection given to the substrate, using a method based on ASTM standards D-610, D-714, D-1654 and D-3359. The rankings of the coatings obtained from accelerated tests and weathering were compared and contrasted with classification of the same systems obtained from literature, for specimens exposed to an industrial atmosphere. Coating degradation was strongly dependent on the test, and could be attributed to differences in test conditions. The best correlation between accelerated test and weathering was found for the test Prohesion alternated with cycles of exposure to UV-A radiation and condensation. (author)

  14. Laboratory studies of galvanic corrosion. I. Two-metal couples

    International Nuclear Information System (INIS)

    Mansfeld, F.; Kenkel, J.V.

    1975-01-01

    Galvanic interaction of stainless steel 304L, Ni 270, Cu, Ti--6Al--4V, Sn, 4130 steel, Cd, and Zn has been studied in 3.5 percent NaCl using galvanic current and weight loss measurements in 24-hour tests. Galvanic couples of 4130 steel and one of the Al alloys 1100, 2024, 2219, 6061, and 7075 have also been evaluated in tap water and distilled water. Galvanic current data can be used to assess both the effect of different dissimilar cathode materials as well as the relative susceptibility to galvanic corrosion of anode materials. For 3.5 percent NaCl, it has been found that the effect of the cathode material decreases in the order Cu greater than Ni greater than stainless steel greater than Ti--6Al--4V, while the relative susceptibility of anode materials decreases in the order Sn greater than Zn greater than 4130 steel greater than Cd. An analysis of data in various electrolytes shows that coupling of 4130 steel to Al alloys leads to cathodic protection of the steel in 3.5 percent NaCl, but to accelerated corrosion in tap water and distilled water. (U.S.)

  15. Morphological study of silver corrosion in highly aggressive sulfur environments

    DEFF Research Database (Denmark)

    Minzari, Daniel; Jellesen, Morten Stendahl; Møller, Per

    2011-01-01

    A silicone coated power module, having silver conducting lines, showed severe corrosion, after prolonged use as part of an electronic device in a pig farm environment, where sulfur containing corrosive gasses are known to exist in high amounts. Permeation of sulfur gasses and humidity through...... the silicone coating to the interface has resulted in three corrosion types namely: uniform corrosion, conductive anodic filament type of Ag2S growth, and silver migration with subsequent formation of sulfur compounds. Detailed morphological investigation of new and corroded power modules was carried out...

  16. Hydrofluoric Acid Corrosion Study of High-Alloy Materials

    International Nuclear Information System (INIS)

    Osborne, P.E.

    2002-01-01

    A corrosion study involving high-alloy materials and concentrated hydrofluoric acid (HF) was conducted in support of the Molten Salt Reactor Experiment Conversion Project (CP). The purpose of the test was to obtain a greater understanding of the corrosion rates of materials of construction currently used in the CP vs those of proposed replacement parts. Results of the study will help formulate a change-out schedule for CP parts. The CP will convert slightly less than 40 kg of 233 U from a gas (UF 6 ) sorbed on sodium fluoride pellets to a more stable oxide (U 3 O 8 ). One by-product of the conversion is the formation of concentrated HF. Six moles of highly corrosive HF are produced for each mole of UF 6 converted. This acid is particularly corrosive to most metals, elastomers, and silica-containing materials. A common impurity found in 233 U is 232 U. This impurity isotope has several daughters that make the handling of the 233 U difficult. Traps of 233 U may have radiation fields of up to 400 R at contact, a situation that makes the process of changing valves or working on the CP more challenging. It is also for this reason that a comprehensive part change-out schedule must be established. Laboratory experiments involving the repeated transfer of HF through 1/2-in. metal tubing and valves have proven difficult due to the corrosivity of the HF upon contact with all wetted parts. Each batch of HF is approximately 1.5 L of 33 wt% HF and is transferred most often as a vapor under vacuum and at temperatures of up to 250 C. Materials used in the HF side of the CP include Hastelloy C-276 and Monel 400 tubing, Haynes 230 and alloy C-276 vessels, and alloy 400 valve bodies with Inconel (alloy 600) bellows. The chemical compositions of the metals discussed in this report are displayed in Table 1. Of particular concern are the almost 30 vendor-supplied UG valves that have the potential for exposure to HF. These valves have been proven to have a finite life due to failure

  17. Hydrofluoric Acid Corrosion Study of High-Alloy Materials

    Energy Technology Data Exchange (ETDEWEB)

    Osborne, P.E.

    2002-09-11

    A corrosion study involving high-alloy materials and concentrated hydrofluoric acid (HF) was conducted in support of the Molten Salt Reactor Experiment Conversion Project (CP). The purpose of the test was to obtain a greater understanding of the corrosion rates of materials of construction currently used in the CP vs those of proposed replacement parts. Results of the study will help formulate a change-out schedule for CP parts. The CP will convert slightly less than 40 kg of {sup 233}U from a gas (UF{sub 6}) sorbed on sodium fluoride pellets to a more stable oxide (U{sub 3}O{sub 8}). One by-product of the conversion is the formation of concentrated HF. Six moles of highly corrosive HF are produced for each mole of UF{sub 6} converted. This acid is particularly corrosive to most metals, elastomers, and silica-containing materials. A common impurity found in {sup 233}U is {sup 232}U. This impurity isotope has several daughters that make the handling of the {sup 233}U difficult. Traps of {sup 233}U may have radiation fields of up to 400 R at contact, a situation that makes the process of changing valves or working on the CP more challenging. It is also for this reason that a comprehensive part change-out schedule must be established. Laboratory experiments involving the repeated transfer of HF through 1/2-in. metal tubing and valves have proven difficult due to the corrosivity of the HF upon contact with all wetted parts. Each batch of HF is approximately 1.5 L of 33 wt% HF and is transferred most often as a vapor under vacuum and at temperatures of up to 250 C. Materials used in the HF side of the CP include Hastelloy C-276 and Monel 400 tubing, Haynes 230 and alloy C-276 vessels, and alloy 400 valve bodies with Inconel (alloy 600) bellows. The chemical compositions of the metals discussed in this report are displayed in Table 1. Of particular concern are the almost 30 vendor-supplied UG valves that have the potential for exposure to HF. These valves have been

  18. Study of corrosion-erosion behaviour of stainless alloys in industrial phosphoric acid medium

    International Nuclear Information System (INIS)

    Guenbour, Abdellah; Hajji, Mohamed-Adil; Jallouli, El Miloudi; Bachir, Ali Ben

    2006-01-01

    The corrosion and corrosion-abrasion resistance of some stainless steels in industrial phosphoric acid 30% P 2 O 5 has been studied using electrochemical techniques. The corrosion rate of materials increases with the increase of temperature. Alloys which contain chromium, molybdenum and nitrogen in sufficient quantities present the best behaviour. In the abrasion-corrosion conditions, the experimental device set up allowed to follow continually samples electrochemical behaviour. Under dynamic conditions and without solid particles, the increase of acid projection speed has no effect on the alloys corrosion behaviour. The adding of abrasive leads to a general increase of corrosion rate and to a decrease of material resistance. Under these conditions, materials attack is controlled by synergistic effect between the abrasion and the impurities. The cast 30% Cr shows good resistance according to his high chromium content

  19. Study of corrosion-erosion behaviour of stainless alloys in industrial phosphoric acid medium

    Energy Technology Data Exchange (ETDEWEB)

    Guenbour, Abdellah [Laboratory of Electrochemistry-Corrosion, Av. Ibn Batouta, BP1014-Faculty of Science, Rabat (Morocco)]. E-mail: guenbour@fsr.ac.ma; Hajji, Mohamed-Adil [Group Corrosion and Protection of Materials, ENIM, Rabat (Morocco); Jallouli, El Miloudi [Group Corrosion and Protection of Materials, ENIM, Rabat (Morocco); Bachir, Ali Ben [Laboratory of Electrochemistry-Corrosion, Av. Ibn Batouta, BP1014-Faculty of Science, Rabat (Morocco)

    2006-12-30

    The corrosion and corrosion-abrasion resistance of some stainless steels in industrial phosphoric acid 30% P{sub 2}O{sub 5} has been studied using electrochemical techniques. The corrosion rate of materials increases with the increase of temperature. Alloys which contain chromium, molybdenum and nitrogen in sufficient quantities present the best behaviour. In the abrasion-corrosion conditions, the experimental device set up allowed to follow continually samples electrochemical behaviour. Under dynamic conditions and without solid particles, the increase of acid projection speed has no effect on the alloys corrosion behaviour. The adding of abrasive leads to a general increase of corrosion rate and to a decrease of material resistance. Under these conditions, materials attack is controlled by synergistic effect between the abrasion and the impurities. The cast 30% Cr shows good resistance according to his high chromium content.

  20. Statistical Study of Corrosion Types in Constructions in South Region of Rio De Janeiro – Brazil

    Directory of Open Access Journals (Sweden)

    Carolina Lacerda da Cruz

    2016-05-01

    Full Text Available Some of the most difficult and troubling problems encountered in construction are those caused by corrosive processes. The corrosion processes are constituted by some material degradation, generally metallic material, by means of chemical or electrochemical actions of environment in which the material are and can or cannot be combined with mechanical stress. Corrosion is present in the materials in general. Their deterioration is caused by such physical-chemical interaction between the material and the corrosive environment where it causes major problems in several activities. In order to prevent material losses, anticorrosive techniques are used which include coatings, medium modification techniques, anodic and cathodic protection, and corrosion inhibitors such as the organic compounds use. This article analyses the statistical study of corrosion types in construction in south region of Rio de Janeiro, Brazil.

  1. Grain boundary defects initiation at the outer surface of dissimilar welds: corrosion mechanism studies

    International Nuclear Information System (INIS)

    De Bouvier, O.; Yrieix, B.

    1995-11-01

    Dissimilar welds located on the primary coolant system of the French PWR I plants exhibit grain boundary defects in the true austenitic zones of the first buttering layer. If grain boundaries reach the interface, they can extend to the martensitic band. Those defects are filled with compact oxides. In addition, the ferritic base metal presents some pits along the interface. Nowadays, three mechanisms are proposed to explain the initiation of those defects: stress corrosion cracking, intergranular corrosion and high temperature intergranular oxidation. This paper is dealing with the study of the mechanisms involved in the corrosion phenomenon. Intergranular corrosion tests performed on different materials show that only the first buttering layer, even with some δ ferrite, is sensitized. The results of stress corrosion cracking tests in water solutions show that intergranular cracking is possible on a bulk material representative of the first buttering layer. It is unlikely on actual dissimilar welds where the ferritic base metal protects the first austenitic layer by galvanic coupling. Therefore, the stress corrosion cracking assumption cannot explain the initiation of the defects in aqueous environment. The results of the investigations and of the corrosion studies led to the conclusion that the atmosphere could be the only possible aggressive environment. This conclusion is based on natural atmospheric exposure and accelerated corrosion tests carried out with SO 2 additions in controlled atmosphere. They both induce a severe intergranular corrosion on true sensitized austenitic materials. This corrosion studies cannot conclude definitively on the causes of the defect initiation on field, but they show that the atmospheric corrosion could produce intergranular attacks in the pure austenitic zones of the first buttering layer of the dissimilar welds and that this corrosion is stress assisted. (author). 1 ref., 6 figs., 4 tabs

  2. Study of corrosion behavior of carbon steel under seawater film using the wire beam electrode method

    International Nuclear Information System (INIS)

    Liu, Zaijian; Wang, Wei; Wang, Jia; Peng, Xin; Wang, Yanhua; Zhang, Penghui; Wang, Haijie; Gao, Congjie

    2014-01-01

    Corrosion behavior of carbon steel under seawater film with various thickness was investigated by the wire beam electrode (WBE) method. It was found that the corrosion rate of carbon steel increased significantly under thin seawater film than it was immersed in seawater. The current variation under seawater film indicated that the thickness of diffusion layer of oxygen was about 500 μm, and the maximal current appeared around 40 μm, at which corrosion rate transited from cathodic control to anodic control. The results suggest that WBE method is helpful to study the corrosion process under thin electrolyte film

  3. Study of Plant Cordia Dichotoma as Green Corrosion Inhibitor for Mild Steel in Different Acid Media

    Directory of Open Access Journals (Sweden)

    R. Khandelwal

    2011-01-01

    Full Text Available The corrosion inhibition of mild steel using extracts of Cordia dichotoma in different acid media was investigated by mass loss and thermometric methods. The experiments were carried out at 299±0.2 K in presence of different concentrations of dry fruit, leaves and stem extracts of Cordia dichotoma. The results reveal that the alcoholic extracts of Cordia dichotoma is a better corrosion inhibitor than that of toxic chemicals. The fruit extract is more potent than leaves and stem extracts to inhibit the corrosion rate. The study seeks to investigate the possibility of using extracts of Cordia dichotoma as a green corrosion inhibitor for mild steel.

  4. Radiochemical studies on corrosion products of oral biomaterials

    International Nuclear Information System (INIS)

    Madbouly, H.A.Abdallah

    1998-01-01

    The work given in this thesis deals with a radioactive tracer study of the sorption of the corrosion products of dental amalgams and antimony on human teeth, porcelain and acrylic materials, used as dental restorative material. Sorption was investigated in presence of water and liquids commonly intaken by man; namely tea with or without sugar, soluble coffee ( Nescaffee) with or without sugar and/or milk, red tea (karkadeh or hibiscus) with or without sugar and chicken soup. The radioactive isotopes of Ag, Sn, Zn (amalgam components) and antimony were prepared by their irradiation in the nuclear reactor; 110m Ag, 113 Sn, 65 Zn and 124 Sb were thereby produced. The percent uptake of each studied element was evaluated from the depletion of radioactivity of the corresponding radioactive tracer in the given medium containing a tooth (human or artificial)

  5. Moessbauer effect study on the corrosion of an oil refinery

    International Nuclear Information System (INIS)

    Da Costa, M.I. Jr.; Kunrath, J.I.; Moro, J.T.; Englert, G.; Comparsi, L.U.; Mueller, I.L.

    1994-01-01

    Metallic coupons are placed in strategical points of an oil refining plant in order to control the amount of corrosion produced by amine stripping of H 2 S from liquefied oil and combustible gases. This paper reports some of the results obtained by CEMS and transmission Moessbauer spectroscopy for the corrosion products formed on such coupons. (orig.)

  6. The study of epoxy polyamide and polyvinyl resins as corrosion ...

    African Journals Online (AJOL)

    The corrosion resistance of two commonly used protective coatings (epoxy polyamide and polyvinyl resins) in the Niger Delta area of Nigeria has been assessed. The coatings on low carbon steel were subjected to varying conditions of pH, temperature and exposure time and the corrosion rates calculated. At a pH of 2, 3, 4, ...

  7. Experimental and quantum chemical studies on corrosion inhibition ...

    Indian Academy of Sciences (India)

    Abstract. The corrosion inhibition effect of fluconazole (FLU) was investigated on steel in 1 M hydrochloric acid solution. Weight loss measurements and atomic force microscope analysis were utilized to investigate the corrosion inhibition properties and film formation behaviour of FLU. Quantum chemical approach was also ...

  8. Experimental and quantum chemical studies on corrosion inhibition

    Indian Academy of Sciences (India)

    The corrosion inhibition effect of fluconazole (FLU) was investigated on steel in 1 M hydrochloric acid solution. Weight loss measurements and atomic force microscope analysis were utilized to investigate the corrosion inhibition properties and film formation behaviour of FLU. Quantum chemical approach was also used to ...

  9. Corrosion Analysis of TiCN Coated Al-7075 Alloy for Marine Applications: A Case Study

    Science.gov (United States)

    Srinath, M. K.; Ganesha Prasad, M. S.

    2018-05-01

    Corrosion is one of the most important marine difficulties that cause long term problems, occurring in ships and submarines surrounded by a corrosive environment when coupled with chemical, temperature and stress related conditions. Corrosion of marine parts could lead to severe disasters. Coatings and heat treatment in a very effective way could be used to protect the aluminium parts against corrosion. The present case study focuses on the corrosion and microstructural properties of TiCN coatings fabricated on Al-7075 aluminium alloy substrate by using Physical Vapour Deposition technique. Corrosion properties of specimen's heat treated at 500 °C at durations of 1, 4, 8 and 12 h were tested through salt spray test. According to D-1193, ASTM standard, corrosion resistance of coated and heat treated Al-7075 samples were investigated in solution kept at 95 °F with a pH of 6.5-7.2, with 5 sections of NaCl to 95 sections of type IV water. The specimen's heat treated for 1 h showed positive corrosion resistance, while the specimens treated for longer durations had the opposite effect. The microstructures of the salt spray tested coatings were investigated by scanning electron microscope. X-ray diffraction tests were conducted on specimens to determine the atomic and molecular structure of the surface crystals and the unit cell dimensions. The corrosion mechanisms of the coated specimens under the heat treated conditions have been explored.

  10. Study on metal material corrosion behavior of packaging of cement solidified form

    International Nuclear Information System (INIS)

    He Zhouguo; Lin Meiqiong; Fan Xianhua

    1997-01-01

    The corrosion behavior of A3 carbon steel is studied by the specimens that are exposed to atmosphere, embedded in cement solidified form or immersed in corrosion liquid. The corrosion rate is determined by mass change of the specimens. In order to compare the corrosion resistant performance of various coatings, the specimens painted with various material such as epoxide resin, propionic acid resin, propane ether resin and Ti-white paint are tested. The results of the tests show that corrosion rate of A3 carbon steel is less than 10 -3 mm·a -1 in the atmosphere and the cement solidified from, less than 0.1 mm·a -1 in the corrosion liquids, and pH value in the corrosion liquids also affect the corrosion rate of A3 carbon steel. The corrosion resistant performance of Ti-white paint is better than that of other paints. So, A3 carbon steel as packaging material can meet the requirements during storage

  11. Laboratory study of reinforcement protection with corrosion inhibitors

    International Nuclear Information System (INIS)

    Stefanescu, D.; Mihalache, M.; Mogosan, S.

    2013-01-01

    Concrete is a durable material and its performance as part of the containment function in NPPs has been good. However, experience shows that degradation of the reinforced concrete structures caused by the corrosion of the reinforcing steel represents more than 80% of all damages in the world. Much effort has been made to develop a corrosion inhibition process to prolong the life of existing structures and minimize corrosion damages in new structures. Migrating Corrosion Inhibitor technology was developed to protect the embedded steel rebar/concrete structure. These inhibitors can be incorporated as an admixture or can be surface impregnated on existing concrete structures. The effectiveness of two inhibitors (ethanolamine and diethanolamine) mixed in the reinforced concrete was evaluated by gravimetric measurements. The corrosion behavior of the steel rebar and the inhibiting effects of the amino alcohol chemistry in an aggressive environment were monitored using electrochemical measurements and scanning electron microscopy (SEM) investigations. (authors)

  12. Contribution to the study of uranium dioxide aqueous corrosion mechanisms

    International Nuclear Information System (INIS)

    Gallien, J.-P.

    1994-01-01

    The corrosion of uranium dioxide by a synthetical ground water has been studied in order to understand the behaviour of nuclear fuels in the hypothesis of a direct storage. An original leaching unit has been carried out in order to control the parameters occurring in the oxidation-dissolution of the uranium dioxide and to condition the leachate (in particular the temperature and the partial pressure of the carbon dioxide). A ground water in equilibrium with the geological enveloping site has been reconstituted from data acquired on the site. The influence of two parameters has been followed: the carbon dioxide carbon pressure and the redox potential. Each experiment has been carried out at 96 C during one month and the time-history of the solutions and of the solids has been studied. In oxidizing conditions, the uranium concentration in solution has been controlled by an U(VI) complex (one oxide, one hydroxide or a carbonate). The possibility of a control by an U(IV) complex (as coffinite, uraninite or uraninite B) has been confirmed in the case of reducing leaching. An original interpretation of the Rutherford backscattering spectra has allowed to describe the decomposition of the samples in a succession of layers of different densities. A very good agreement between the analyses of the solids and those of the solutions has been obtained in the experiments occurring in reducing conditions. Complementary leaching involving solutions containing stable isotopes (deuterium, O 18 ) have revealed the formation of an hydrated layer and the contribution of grain boundaries to the corrosion phenomenon of uranium dioxide. The results of the current hydro-geochemistry study on the uranium Oklo deposit prove the realism of the experiments that have been carried out in the laboratory. (O.M.)

  13. Corrosion studies of a chromium steel in imitated seawater

    International Nuclear Information System (INIS)

    Lakatos-Varsanyi, M.; Meisel, W.

    2002-01-01

    A series of in-door experiments was performed to get some insight into the corrosion behavior of a commercial alloy Fe-12% Cr (3CR12) exposed to imitated seawater. Applying different analytical methods, the main corrosion process was found to be the formation of flakes on the surface which, peel off after they have reached a certain size. Some Cr is dissolved in the solution, its relative concentration with respect to Fe is higher than in the bulk material. The flakes consist mainly of mixed oxihydroxides of the type FeOOH containing some Cr and Mg. The oxidic layer on the interface is very thin, behaves essentially stationary with a slight growth of about 0.05 nm/day. It consists of Cr oxide with some inclusions of Fe and Mg and is not of a chromite type. Immediately below this oxidic layer, the metallic substrate exhibits a thin layer depleted in Cr and behaving like α-Fe (bcc). As compared with stainless steel, potentiostatic current vs. time records at anodic potentials below the pitting potential indicate a very different stability of the surface films for 3CR12. The kinetics of the passive layer formation on 3CR12 was found to follow a parabolic law initially and to change later (after 10...100 seconds in deaerated solution and even earlier in aerated solution) to a linear law. After some time, pitting corrosion and/or cracks due to internal stresses play the dominant role. Cr does not form a protective oxidic layer. The surface morphology of samples exposed at -200 mV for 20 and 80 minutes has been studied by scanning electron microscopy and scanning Auger microprobe. The results reflect the competing formation of oxidic layers and pitting, the participation of Cr in the dissolution process. It is also suggested that Mg, which is a component of the solution was incorporated into the rust and some Mg was also found on the metallic surface. (author)

  14. In-Vitro Corrosion Studies of Bioabsorbable Alloys

    Science.gov (United States)

    Gill, P.; Munroe, N.

    Magnesium alloys have inspired a significant amount of attention from researchers all over the world for cardiovascular and orthopedic applications due to their light weight, mechanical integrity and degradation behavior. In this investigation, cast manufactured binary, ternary and quaternary magnesium alloys were studied for their degradation behavior by potentiodynamic polarization tests in phosphate buffer saline solution (PBS) and PBS containing amino acids (cysteine, C and tryptophan, W) at 37 °C. Electrochemical impedance spectroscopy (EIS) tests were performed to determine the charge transfer resistance and immersion tests were performed to assess corrosion rate and hydrogen evolution from the alloys. Furthermore, the surface morphology and surface chemistry of the alloys were observed by scanning electron microscopy (SEM) and X-ray diffraction (XRD).

  15. WASTE PACKAGE CORROSION STUDIES USING SMALL MOCKUP EXPERIMENTS

    International Nuclear Information System (INIS)

    B.E. Anderson; K.B. Helean; C.R. Bryan; P.V. Brady; R.C. Ewing

    2005-01-01

    The corrosion of spent nuclear fuel and subsequent mobilization of radionuclides is of great concern in a geologic repository, particularly if conditions are oxidizing. Corroding A516 steel may offset these transport processes within the proposed waste packages at the Yucca Mountain Repository (YMR) by retaining radionuclides, creating locally reducing conditions, and reducing porosity. Ferrous iron, Fe 2+ , has been shown to reduce UO 2 2+ to UO 2(s) [1], and some ferrous iron-bearing ion-exchange materials adsorb radionuclides and heavy metals [2]. Of particular interest is magnetite, a potential corrosion product that has been shown to remove TcO 4 - from solution [3]. Furthermore, if Fe 2+ minerals, rather than fully oxidized minerals such as goethite, are produced during corrosion, then locally reducing conditions may be present. High electron availability leads to the reduction and subsequent immobilization of problematic dissolved species such as TcO 4 - , NpO 2 + , and UO 2 2+ and can also inhibit corrosion of spent nuclear fuel. Finally, because the molar volume of iron material increases during corrosion due to oxygen and water incorporation, pore space may be significantly reduced over long time periods. The more water is occluded, the bulkier the corrosion products, and the less porosity is available for water and radionuclide transport. The focus of this paper is on the nature of Yucca Mountain waste package steel corrosion products and their effects on local redox state, radionuclide transport, and porosity

  16. Corrosion studies on retrievable spent fuel containers: a progress report

    International Nuclear Information System (INIS)

    Ludemann, W.D.; Abrego, L.; McCright, R.D.

    1978-12-01

    Spent fuel canisters stored in halite (NaCl) deposits (salt beds) are subject to a severely corrosive environment when the hot brine inclusions, rich in calcium and magnesium chlorides, migrate to the canister. Since no data base exists on corrosion in halite brines, a survey was made of the corrosion resistance of potential canister materials in other concentrated brine environments. Corrosion-resistant metals include Ta, Ti Code 12, TiPd Alloy, Inconel 625, Hastelloy C-276, and Fe-base 29-4 Alloy. Although carbon steels have cost and availability advantages, they suffer from excessive corrosion rates in brines. Corrosion-resistant nonmetals include carbon, Teflon-type fluorocarbons, epoxide coatings, and polymer cements. While these materials are not suitable for constructing the canister, they could be used as a protective coating on a carbon steel canister. On the basis of this survey, we recommend a coated carbon steel canister, used with cathodic protection. It is important to start a test program to gather a data base on the corrosion of materials in halite brines and to verify the suitability of canister materials

  17. Corrosion studies on HGW-canister materials for marine disposal

    International Nuclear Information System (INIS)

    Taylor, K.J.; Bland, I.D.; Smith, S.; Marsh, G.P.

    1986-03-01

    Results are presented from theoretical and experimental work undertaken to investigate and assess the general corrosion behaviour of carbon steel canister/overpacks for heat generating nuclear waste under marine disposal conditions. The mean general corrosion rates of carbon steels, determined experimentally by polarisation resistance measurements on specimens in on-going immersion tests, are between 65-124 μm yr -1 at 90 0 C and 5-25 μm yr -1 at 25 0 C and are tending to increase with time. Anomalously high corrosion rates are being indicated by similar tests at 50 0 C. It is not clear what reliance should be placed on the polarisation resistance results, however, and therefore no conclusion will be drawn until the tests are dismantled and inspected in the 1985/86 programme. Tests with γ-radiation on forged carbon steel specimens immersed in deaerated seawater at 90 0 C show that this causes an acceleration of corrosion rate at the three dose rates down to at least 300 R h -1 . Deep ocean sediment from GME also accelerates the corrosion rate of carbon steel in deaerated seawater both with and without γ-radiation. The effect diminishes with continued exposure and is thought to be due to the presence of either an additional so far unidentified oxidising agent or some component which reduces the corrosion protection afforded by the build up of a corrosion product layer. Acquisition of improved electrochemical kinetic data for the mathematical model is now complete, and the model has been run for temperatures of 25 and 90 0 C, where it predicts steady corrosion rates of 19.3 and 180 μm/yr. The model has shown that the rate of attack is not influenced greatly by the depth of sediment, and that the component of corrosion caused by radiation is of the order of 7 mm over 1000 years. (author)

  18. Preliminary study on the corrosion behavior of carbon steel in Horonobe groundwater environment

    International Nuclear Information System (INIS)

    Taniguchi, Naoki; Kogawa, Noritaka; Maeda, Kazuto

    2006-08-01

    It is necessary to understand the corrosion behavior of candidate overpack materials to plan the in-situ engineered barrier test at underground laboratory constructing at Horonobe and to design the overpacks suitable to Horonobe environment. The preliminary corrosion tests of carbon steel which is a candidate material for overpacks were carried out using artificial groundwater and actual groundwater sampled at Horonobe. As the results of anodic polarization experiments, the anodic polarization curves of carbon steel in buffer material were active dissolution type, and the corrosion type of carbon steel in Horonobe groundwater environment was expected to be general corrosion. The results of immersion test under air equilibrium condition showed that the degrees of corrosion localization were not exceeded the data obtained in previous studies. The trend of corrosion rates in buffer material under anaerobic condition were similar to the data obtained in previous studies. Based on the experimental results, it was confirmed that the corrosion assessment model and assumed corrosion rate in second progress report (H12 report) can be applied to the assessment for Horonobe groundwater condition. (author)

  19. ELECTROCHEMICAL STUDIES OF URANIUM METAL CORROSION MECHANISM AND KINETICS IN WATER

    International Nuclear Information System (INIS)

    Boudanova, Natalya; Maslennikov, Alexander; Peretroukhine, Vladimir F.; Delegard, Calvin H.

    2006-01-01

    During long-term underwater storage of low burn-up uranium metal fuel, a corrosion product sludge forms containing uranium metal grains, uranium dioxide, uranates and, in some cases, uranium peroxide. Literature data on the corrosion of non-irradiated uranium metal and its alloys do not allow unequivocal prediction of the paragenesis of irradiated uranium in water. The goal of the present work conducted under the program 'CORROSION OF IRRADIATED URANIUM ALLOYS FUEL IN WATER' is to study the corrosion of uranium and uranium alloys and the paragenesis of the corrosion products during long-term underwater storage of uranium alloy fuel irradiated at the Hanford Site. The elucidation of the physico-chemical nature of the corrosion of irradiated uranium alloys in comparison with non-irradiated uranium metal and its alloys is one of the most important aspects of this work. Electrochemical methods are being used to study uranium metal corrosion mechanism and kinetics. The present part of work aims to examine and revise, where appropriate, the understanding of uranium metal corrosion mechanism and kinetics in water

  20. Corrosion Engineering.

    Science.gov (United States)

    White, Charles V.

    A description is provided for a Corrosion and Corrosion Control course offered in the Continuing Engineering Education Program at the General Motors Institute (GMI). GMI is a small cooperative engineering school of approximately 2,000 students who alternate between six-week periods of academic study and six weeks of related work experience in…

  1. Study of biofuels corrosiveness; Estudo da corrosividade de biocombustiveis

    Energy Technology Data Exchange (ETDEWEB)

    Nascimento, Rafaela da Conceicao; Branco, Lucas da Paz Nogueira; Guimaraes, Maria Jose de Oliveria Cavalcanti; Seidl, Peter Rudolf [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Escola de Quimica

    2012-07-01

    The replacement of crude oil derivatives with biofuels is part of an energy strategy, in which efficiency and conservation should play a leading role. The renewable nature of biodiesel is based in the fact that it is derived from raw materials from agricultural activities, instead of petroleum. Thinking about the increasingly production of biodiesel and its storage to make the proper mixtures, the corrosion of biodiesel tanks can occur over time. The copper corrosion test is used as the standard method for biodiesel corrosivity, however it is designed for diesel fuel from petroleum. Petrodiesel contains sulfur, which attacks the copper alloys. Since biodiesel is free of this element, it should be characterized in a different way. This work intends to analyze existing methodologies in order to evaluate the corrosivity of biodiesel. A literature search was performed in Web of Science database, selecting keywords for a comprehensive search. For the final analysis, a selection of papers classified according to publication year, country and main subject covered was used. Research on biofuels corrosivity is recent and major countries where published (USA, Malaysia and Brazil) which have advantages in terms of size and production of oil seeds. Biodiesel is more corrosive than petroleum diesel, but there is no sufficient evidences as to verify if the level of corrosion found in biodiesel is within acceptable limits for automotive components. Ferrous alloys are more resistant to biodiesel attack than non-ferrous alloys. Among non-ferrous alloys, copper and lead alloys are the most vulnerable, followed by aluminum. It is necessary to develop appropriate methodologies to determine and characterize the corrosivity of biodiesel on engine parts and alloys used in its manufacture and storage. (author)

  2. Study of corrosive-erosive wear behaviour of Al6061/albite composites

    International Nuclear Information System (INIS)

    Sharma, S.C.; Krishna, M.; Murthy, H.N. Narasimha; Tarachandra, R.; Satyamoorthy, M.; Bhattacharyya, D.

    2006-01-01

    This investigation analyses the influence of dispersed alumina particles on the wear behaviour of the Al/albite composites in a corrosive environment. The composites were prepared by modified pressure die-casting technique. The corrosive-erosive wear experiments were carried out on a proprietary corrosion-erosion wear tester to study the wear characteristics of the composites. The slurry was made up of water and alumina (size: 90-150 μm, proportion: 0-30 wt.%), while H 2 SO 4 (0.01, 0.1 and 1N) was added to create the corrosive conditions. Experiments were arranged to test the relationships among the corrosive-erosive wear rate, concentrations of H 2 SO 4 and alumina in the slurry, weight percent of albite in the composite, erosion speed and distance. Wear rate varies marginally at low speeds but sharply increases at higher speeds. The corrosive wear rate logarithmically increased with the increasing concentration of the corrosive medium. The effect of abrasive particles and corrosion medium on the wear behaviour of the composite is explained experimentally, theoretically and using scanning electron microscopy

  3. Study on tea leaves extract as green corrosion inhibitor of mild steel in hydrochloric acid solution

    Science.gov (United States)

    Hamdan, A. B.; Suryanto; Haider, F. I.

    2018-01-01

    Corrosion inhibitor from extraction of plant has been considered as the most preferable and most chosen technique to prevent corrosion of metal in acidic medium because of the environmental friendly factor. In this study, black tea leaves extraction was tested as corrosion inhibitor for mild steel in 0.1M of hydrochloric acid (HCl) with the absence and presence of corrosion inhibitor. The efficiency and effectiveness of black tea as corrosion inhibitor was tested by using corrosion weight loss measurement experiment was carried out with varies parameters which with different concentration of black tea extract solution. The extraction of black tea solution was done by using aqueous solvent method. The FT-IR result shows that black tea extract containing compounds such as catechin, caffeine and tannins that act as anti-corrosive reagents and responsible to enhance the effectiveness of black tea extract as corrosion inhibitor by forming the hydrophobic thin film through absorption process. As a result of weight loss measurement, it shows that loss in weight of mild steel reduces as the concentration of inhibitor increases. The surface analysis was done on the mild steel samples by using SEM.

  4. SRNL SHELF LIFE STUDIES - SCC STUDIES AT ROOM TEMPERTURE [stress corrosion cracking

    Energy Technology Data Exchange (ETDEWEB)

    Mickalonis, J.; Duffey, J.

    2014-11-12

    Phase II, Series 2 corrosion testing performed by the Savannah River National Laboratory (SRNL) for the Department of Energy 3013 container has been completed. The corrosion tests are part of an integrated plan conducted jointly by Los Alamos National Laboratory and the Savannah River Site. SRNL was responsible for conducting corrosion studies in small-scale vessels to address the influence of salt composition, water loading, and type of oxide/salt contact on the relative humidity inside a 3013 container and on the resulting corrosion of Type 304L and 316L stainless steel (304L and 316L). This testing was conducted in two phases: Phase I evaluated a broad spectrum of salt compositions and initial water loadings on the salt mixtures exposed to 304L and 316L and the resulting corrosion; Phase II evaluated the corrosion of 304L at specific water loadings and a single salt composition. During Phase I testing at high initial moisture levels (0.35 to 1.24 wt%)a, the roomtemperature corrosion of 304L exposed to a series of plutonium oxide/chloride salt mixtures ranged from superficial staining to pitting and stress corrosion cracking (SCC). 304L teardrop coupons that exhibited SCC were directly exposed to a mixture composed of 98 wt % PuO2, 0.9 wt % NaCl, 0.9 wt % KCl, and 0.2 wt % CaCl2. Cracking was not observed in a 316L teardrop coupon. Pitting was also observed in this environment for both 304L and 316L with depths ranging from 20 to 100 μm. Neither pitting nor SCC was observed in mixtures with a greater chloride salt concentration (5 and 28 wt%). These results demonstrated that for a corrosive solution to form a balance existed between the water loading and the salt chloride concentration. This chloride solution results from the interaction of loaded water with the hydrating CaCl2 salt. In Phase II, Series 1 tests, the SCC results were shown to be reproducible with cracking occurring in as little as 85 days. The approximate 0.5 wt% moisture level was found to

  5. 3D study of intermetallics and their effect on the corrosion morphology of rheocast aluminium alloy

    International Nuclear Information System (INIS)

    Mingo, B.; Arrabal, R.; Pardo, A.; Matykina, E.; Skeldon, P.

    2016-01-01

    In the present study, the effect of heat treatment T6.1 on the microstructure and corrosion behaviour of rheocast aluminium alloy A356 is investigated on the basis of 2D/3D characterization techniques and electrochemical and SKPFM measurements. Heat treatment strengthens the α-Al matrix, modifies the intermetallic particles and spheroidizes eutectic Si. These changes do not modify significantly the corrosion behaviour of the alloy. 3D SEM-Tomography clearly shows that the corrosion advances in the shape of narrow paths between closely spaced intermetallics without a major influence of eutectic Si. - Highlights: • T6.1 spheroidizes Si, strengthens the matrix and modifies the intermetallics. • Electrochemical behaviour of untreated and heat-treated alloys is similar. • 3D SEM-Tomography provides additional information on the corrosion morphology. • Corrosion advances as paths between intermetallics with little influence of Si.

  6. Study on the hot corrosion behavior of a cast Ni-base superalloy

    Energy Technology Data Exchange (ETDEWEB)

    Wang, W.; Guo, J.T.; Zhang, J.; Yuan, C.; Zhou, L.Z.; Hu, Z.Q. [Chinese Academy of Sciences, Shenyang (China). Inst. of Metal Research

    2010-07-01

    Hot corrosion behavior of Nickel-base cast superalloy K447 in 90% Na{sub 2}SO{sub 4} + 10% NaCl melting salt at 850 C and 900 C was studied. The hot corrosion kinetic of the alloy follows parabolic rate law under the experimental conditions. The external layer is mainly Cr{sub 2}O{sub 3} scale which is protective to the alloy, the intermediate layer is the Ti-rich phase, and the internal layer is mainly the international oxides and sulfides. With increased corrosion time and temperature, the oxide scales are gradually dissolved in the molten salt and then precipitate as a thick and non-protective scale. Chlorides cause the formation of volatile species, which makes the oxide scale disintegrate and break off. The corrosion kinetics and morphology examinations tend to support the basic dissolution model for hot corrosion mechanisms. (orig.)

  7. Studies of localized corrosion in welded aluminum alloys by the scanning reference electrode technique

    Science.gov (United States)

    Danford, M. D.; Nunes, A. C.

    1995-01-01

    Localized corrosion in welded samples of 2219-T87 Al alloy (2319 filler), 2090 Al-Li alloy (4043 and 2319 fillers), and 2195 Al-Li alloy (4043 and 2319 fillers) has been investigated using the relatively new scanning reference electrode technique. The weld beads are cathodic in all cases, leading to reduced anode/cathode ratios. A reduction in anode/cathode ratio leads to an increase in the corrosion rates of the welded metals, in agreement with results obtained in previous electrochemical and stress corrosion studies involving the overall corrosion rates of welded samples. The cathodic weld beads are bordered on both sides by strong anodic regions, with high propensity for corrosion.

  8. Fretting and Corrosion Damage in Taper Adapter Sleeves for Ceramic Heads: A Retrieval Study.

    Science.gov (United States)

    MacDonald, Daniel W; Chen, Antonia F; Lee, Gwo-Chin; Klein, Gregg R; Mont, Michael A; Kurtz, Steven M; Cates, Harold E; Kraay, Matthew J; Rimnac, Clare M

    2017-09-01

    During revision surgery with a well-fixed stem, a titanium sleeve can be used in conjunction with a ceramic head to achieve better stress distribution across the taper surface. In vitro testing suggests that corrosion is not a concern in sleeved ceramic heads; however, little is known about the in vivo fretting corrosion of the sleeves. The purpose of this study was to investigate fretting corrosion in sleeved ceramic heads in retrieved total hip arthroplasties. Thirty-seven sleeved ceramic heads were collected during revision. The femoral heads and sleeves were implanted 0.0-3.3 years. The implants were revised predominantly for instability, infection, and loosening. Fifty percent of the retrievals were implanted during a primary surgery. Fretting corrosion was assessed using the Goldberg-Higgs semiquantitative scoring system. Mild-to-moderate fretting corrosion scores (score = 2-3) were observed in 92% of internal tapers, 19% of external tapers, and 78% of the stems. Severe fretting corrosion was observed in 1 stem trunnion that was previously retained during revision surgery and none of the retrieved sleeves. There was no difference in corrosion damage of sleeves used in primary or revision surgery. The fretting corrosion scores in this study were predominantly mild and lower than reported fretting scores of cobalt-chrome heads in metal-on-polyethylene bearings. Although intended for use in revisions, we found that the short-term in vivo corrosion behavior of the sleeves was similar in both primary and revision surgery applications. From an in vivo corrosion perspective, sleeves are a reasonable solution for restoring the stem taper during revision surgery. Copyright © 2017. Published by Elsevier Inc.

  9. Flow-induced corrosion of absorbable magnesium alloy: In-situ and real-time electrochemical study

    International Nuclear Information System (INIS)

    Wang, Juan; Jang, Yongseok; Wan, Guojiang; Giridharan, Venkataraman; Song, Guang-Ling; Xu, Zhigang; Koo, Youngmi; Qi, Pengkai; Sankar, Jagannathan; Huang, Nan; Yun, Yeoheung

    2016-01-01

    Highlights: • An in-situ and real-time electrochemical monitoring of flow-induced corrosion of Mg alloy is designed in a vascular bioreactor. • Effect of hydrodynamics on corrosion kinetics, types, rates and products is analyzed. • Flow accelerates mass and electron transfer, leading to an increase in uniform and localized corrosions. • Flow increases not only the thickness of uniform corrosion product layer, but the removal rate of localized corrosion products. • Electrochemical impedance spectroscopy and linear polarization-measured polarization resistances provide a consistent correlation to corrosion rate calculated by computed tomography. - Abstract: An in-situ and real-time electrochemical study in a vascular bioreactor was designed to analyze corrosion mechanism of magnesium alloy (MgZnCa) under mimetic hydrodynamic conditions. Effect of hydrodynamics on corrosion kinetics, types, rates and products was analyzed. Flow-induced shear stress (FISS) accelerated mass and electron transfer, leading to an increase in uniform and localized corrosions. FISS increased the thickness of uniform corrosion layer, but filiform corrosion decreased this layer resistance at high FISS conditions. FISS also increased the removal rate of localized corrosion products. Impedance-estimated and linear polarization-measured polarization resistances provided a consistent correlation to corrosion rate calculated by computed tomography.

  10. Simulation study on insoluble granular corrosion products deposited in PWR core

    International Nuclear Information System (INIS)

    Yang Xu; Zhou Tao; Ru Xiaolong; Lin Daping; Fang Xiaolu

    2014-01-01

    In the operation of reactor, such as fuel rods, reactor vessel internals etc. will be affected by corrosion erosion of high pressure coolant. It will produce many insoluble corrosion products. The FLUENT software is adopted to simulate insoluble granular corrosion products deposit distribution in the reactor core. The fluid phase uses the standard model to predict the flow field in the channel and forecast turbulence variation in the near-wall region. The insoluble granular corrosion products use DPM (Discrete Phase Model) to track the trajectory of the particles. The discrete phase model in FLUENT follows the Euler-Lagrange approach. The fluid phase is treated as a continuum by solving the Navier-Stokes equations, while the dispersed phase is solved by tracking a large number of particles through the calculated flow field. Through the study found, Corrosion products particles form high concentration area near the symmetry, and the entrance section of the corrosion products particles concentration is higher than export section. Corrosion products particles deposition attached on large area for the entrance of the cladding, this will change the core neutron flux distribution and the thermal conductivity of cladding material, and cause core axial offset anomaly (AOA). Corrosion products particles dot deposit in the outlet of cladding, which can lead to pitting phenomenon in a sheath. Pitting area will cause deterioration of heat transfer, destroy the cladding integrity. In view of the law of corrosion products deposition and corrosion characteristics of components in the reactor core. this paper proposes regular targeted local cleanup and other mitigation measures. (authors)

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

    Directory of Open Access Journals (Sweden)

    Łyczkowska K.

    2017-06-01

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

  12. Experimental Study of Removing Surface Corrosion Products from Archaeological Iron Objects and Alternating Iron Corrosion Products by Nd:YAG Laser Cleaning System

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hye Youn; Cho, Nam Chul [Kongju National University, Daejeon (Korea, Republic of); Lee, Jong Myoung [IMT co. Ltd, Suwon (Korea, Republic of); Yu, Jae Eun [National Research Institute of Cultural Heritage, Daejeon (Korea, Republic of)

    2012-05-15

    The corrosion product of archaeological iron objects is supposed to be removed because it causes re-corrosion. So far it is removed by scapel and sand blaster but they depend on the skill and experience of a conservator and the glass-dust of the sand blaster is harmful to humans. Therefore this study applies a laser cleaning system which is used in various industrial cleaning processes, to remove corrosion product from archaeological iron objects. In addition, this work studies the alternation of corrosion product after laser irradiation, which evaluates the reliability of the laser cleaning system. Optical microscopy, SEM-EDS, XRD, Raman have been used to observe and analyse the surface of the objects. The results show the capacity of laser cleaning some corrosion product, but blackening appears with increasing pulses and laser energy, and some corrosion products, goethite and hematite, are partially altered to magnetite. These problems, blackening and alternation of corrosion product, should be solved by further studies which find the optimal laser irradiation condition and use a wetting agent.

  13. A theoretical study of carbohydrates as corrosion inhibitors of iron

    Energy Technology Data Exchange (ETDEWEB)

    Khalil, Salim M.; Ali, Nozha M. [Libyan Academy for Graduate Studies, Tripoli (Libyan Arab Jamahiriya). Chemistry Dept.; Ali-Shattle, Elbashir E. [Tripoli Univ. (Libyan Arab Jamahiriya). Chemistry Dept.

    2013-08-15

    The inhibitive effect of fructose, glucose, lactose, maltose, and sucrose against the iron corrosion is investigated using density functional theory at the B3LYP/6-31 G level (d) to search the relation between the molecular structure and corrosion inhibition. The electronic properties such as the energy of the highest occupied molecular orbital (HOMO), the energy of lowest unoccupied orbital (LUMO), the energy gap (LUMO-HOMO), quantum chemical parameters such as hardness, softness, the fraction of the electron transferred, and the electrophilicity index are reported. The inhibition efficiency of the investigated carbohydrates follows the trend: maltose < sucrose < lactose < fructose < glucose. (orig.)

  14. Experimental and theoretical studies of benzoxazines corrosion inhibitors

    Directory of Open Access Journals (Sweden)

    Abdulhadi Kadhim

    Full Text Available 2-Methyl-4H-benzo[d][1,3]oxazin-4-one (BZ1 and 3-amino-2-methylquinazolin-4(3H-one (BZ2 were evaluated for their corrosion inhibition properties on mild steel (MS in hydrochloric acid solution by weight loss technique and scanning electron microscopy. Results show the inhibition efficiency values depend on the amount of nitrogen in the inhibitor, the inhibitor concentration and the inhibitor molecular weight with maximum inhibition efficiency of 89% and 65% for BZ2 and BZ1 at highest concentration of the compounds. Keywords: Methylquinazoline, Benzoxazines, Corrosion, Inhibitors

  15. Test installation for studying erosion-corrosion of metals for coal washing plants

    Energy Technology Data Exchange (ETDEWEB)

    Hoey, G. R.; Dingley, W.; Wiles, C. T.

    1979-02-15

    A test installation was constructed for investigating erosion-corrosion of metals by coal-water slurries. Erosion-corrosion tests of mild steel panels were conducted using slurries of alundum, quartz, washed coal and coal refuse. Wear rates were found to depend on type of abrasive, particle size and water conductivity and were reduced by cathodic protection and inhibitors. Cathodic protection of mild steel in coal slurries containing sulphate ion reduced wear by 90% and 86% for stationary and rotating panels, respectively. This study has demonstrated that the successful application of corrosion control techniques would reduce metal wastage in coal washing plants. The test installation is considered suitable for developing the techniques.

  16. Stainless Steel Corrosion Studies Final Report: FY17 End of-Year

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, Daniel [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Milenski, Helen Marie [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Martinez, Destiny [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-09-08

    Two materials are being considered in applications requiring their contact against stainless steel surfaces. These materials include the solvent methyl ethyl ketone (MEK), and the polymer neoprene (polychloroprene). There is concern that contact of these materials with stainless steel substrates may lead to corrosion. To address these concerns we have undertaken corrosion studies under conditions expected to be more aggressive than in intended applications. These conditions include elevated temperature and humidity, and submersion and suspension in solvent vapors, in an attempt to accelerate any potential deleterious interactions. Corrosion rates below 0.1 mpy have historically been deemed INSIGNIFICANT from a WR Production standpoint; corresponding guidelines for non-production applications are lacking.

  17. Study on applying technology of utilizing long-term materials for corrosion facilities

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae Chul; Park, Young Kyu; Baek, Soo Gon; Lee, Jong Sub [Korea Electric Power Research Institute, Taejon (Korea, Republic of); Park, Yong Soo [Yonsei University, Seoul (Korea, Republic of); Hwang, Won Suk [Inha University (Korea, Republic of); Song, Rhyo Seong [Hankuk Aviation, University (Korea, Republic of)

    1996-12-31

    Nowadays, as the pollution in seawater is escalating rapidly because of fast industrialization, corrosion rate and repairing frequency of seawater facilities in power plant are increasing. In addition, new construction is restricted with narrow limits due to the deterioration of social condition, asking for extension of facility life and repairing frequency. The objectives of this study are to select the appropriate new high corrosion resistance materials and apply them in the field, to make the corrosion data base in accordance with their usage conditions and to predict the remaining life and optimum repairing period by predicting the life of facilities. (author). 77 refs., 54 figs.

  18. A Study on the Corrosion and Wear Behavior of Electrodeposited Ni-W-P Coating

    Science.gov (United States)

    Lee, Hung Bin; Wu, Meng Yen

    2017-10-01

    In this study, the tribocorrosion of electroplated Ni-W-P alloy coating (3.9 to 4.3 at. pct W and 13.1 to 14.7 at. pct P) on a cylindrical copper substrate was investigated using a block-on-ring tester. The wear and corrosion performance of the coating and their synergic effect were measured at different overpotentials. Under simple immersion corrosion conditions with an increasing overpotential from open-circuit potential to +400 mVSCE, the surface of the coating initially showed no obvious corrosion, eventually developing pitting holes that subsequently enlarged and showing the spreading of cracks. The corrosion products were a mixture of NiO, WO3, and phosphate, and the corroded surface was P-rich, porous, and less crystalline than the pristine coating. Corrosion and mechanical wear had little influence on tribocorrosion at low overpotential values. However, the synergic effect drastically became stronger at high overpotentials. The surface was full of large pitting holes and grooves. The weight loss due to the corrosion component increased linearly with the overpotential but was limited in comparison with the wear component, which was the main cause of weight loss. On the other hand, the friction coefficient first increased and then decreased with an increase in overpotential. Both the surface morphology of the corroded coating and the thickness of the corrosion oxide play important roles in this friction characteristic.

  19. Studies of corrosion resistance of Japanese steels in liquid lead-bismuth

    International Nuclear Information System (INIS)

    Kamata, Kin-ya; Ono, Hiroshi; Kitano, Teruaki; Ono, Mikinori

    2003-01-01

    Liquid lead-bismuth has attractive characteristics as a coolant in future fast reactors and Accelerator Driven Sub-critical Systems (ADS) applications. The corrosion behavior of structural materials in lead-bismuth eutectic is one of key problems in developing nuclear power plants and installations using lead-bismuth coolant. Our experiences with heat exchangers using liquid lead-bismuth and the results of corrosion tests of Japanese steels are reported in this paper. A series of corrosion tests was carried out in collaboration with the Institute of Physics and Power Engineering (IPPE). Test specimens of various Japanese steels were exposed in a non-isothermal forced circulation loop. The influence of maximum temperature and oxygen content in lead bismuth were chosen for study as the primary causes of corrosion in Japanese steels. After the corrosion tests, corrosion behavior was analyzed by visual inspection, measurement of weight loss and metallurgical examination of the microstructure of the corroded zone. The corrosion mechanism in liquid lead bismuth is discussed on the basis of the metallurgical examination of the corroded zone. (author)

  20. Study crevice corrosion alloys C-22 and 625 by electrochemical noise

    International Nuclear Information System (INIS)

    Ungaro, María L.; Carranza, Ricardo M.; Rodríguez, Martín A.

    2013-01-01

    C-22 and 625 alloys are two of the Ni –Cr-Mo alloys considered as candidate materials to form the corrosion resistance engineered barriers for nuclear waste repositories. The corrosion resistance of these alloys is remarkable in a wide variety of environments. Despite of their resistance these alloys are susceptible to crevice corrosion in a certain aggressive environments. This work presents the use of electrochemical noise technique to study crevice corrosion susceptibility of alloys C-22 and 625 in 1M NaCl acidic solutions at 60ºC and 90ºC. Asymmetrical electrodes and a complementary platinum electrode were used to assess the influence of cathodic reaction in crevice process. The obtained records were analyzed directly and through statistical parameters. The potential drop and the simultaneous increment of the current records indicated the occurrence of crevice corrosion. The alternative use of a platinum electrode resulted in higher currents and higher potentials and reduced the induction time to crevice formation. The reason for this behavior is that platinum surface allows faster cathodic reactions than C-22 and 625 alloys. The standard deviation of the current records was responsive to the crevice corrosion intensity. C-22 alloy had better crevice corrosion performance than 625 alloy. (author)

  1. Comparative corrosion study of Ag–Pd and Co–Cr alloys used in ...

    Indian Academy of Sciences (India)

    Administrator

    composition of the passive layers, their thickness and the degree of .... Aerated corrosion media were used in the present study ... are near from that of pure Ag. The alloys are more active ..... pean Social Fund and the Romanian Government.

  2. Initial study and verification of a distributed fiber optic corrosion monitoring system for transportation structures.

    Science.gov (United States)

    2012-07-01

    For this study, a novel optical fiber sensing system was developed and tested for the monitoring of corrosion in : transportation systems. The optical fiber sensing system consists of a reference long period fiber gratings (LPFG) sensor : for corrosi...

  3. Review: Results of studying atmospheric corrosion in Vietnam 1995–2005

    Directory of Open Access Journals (Sweden)

    Le Thi Hong Lien, Pham Thy San and Hoang Lam Hong

    2007-01-01

    Full Text Available Vietnam is situated in the wet tropical zone; thus, atmospheric conditions are characterized by high temperatures and a long time of wetness (TOW. In addition, the salt air coming in from the sea causes a high chloride concentration in coastal areas. Furthermore, Vietnam is a developing country, which means that air pollution is increasing with the development of industry. These factors result in significant damage to materials by atmospheric corrosion. In this report, the results of a recent study on the corrosion of carbon steel and zinc-galvanized steel at 6–8 testing sites in Vietnam over 10 recent years (1995–2005 are focused on as well as the effects of environmental factors on atmospheric corrosion. The results showed that the corrosion of carbon steel is dominated by TOW, whereas zinc-galvanized-steel corrosion strongly depends on the chloride ion concentration in the air. The corrosion losses of both carbon- and zinc-galvanized steel fit the power model well with high correlation coefficients. In addition, the characteristics of the Vietnamese climate are introduced in the form of distribution maps of temperature (T, relative humidity (RH, total rainfall and TOW. A relationship between TOW, T and RH was found that enabled the calculation of TOW from T and RH data, which are available at meteorological stations. Finally, atmospheric corrosivity is determined on the basis of data on TOW, Cl− and SO2 concentrations, and the carbon steel corrosion rate. It is shown that in Vietnam, TOW is so long that the corrosion rate of carbon steel is in the C3 category; nevertheless, Cl− and SO2 concentrations in the atmosphere are not high.

  4. Experimental Study of Laser - enhanced 5A03 Aluminum Alloy and Its Stress Corrosion Resistance

    Science.gov (United States)

    Wang, Guicheng; Chen, Jing; Pang, Tao

    2018-02-01

    Based on the study of improving the stress corrosion resistance of 5A03 aluminum alloy for ship, this paper mainly studied the tensile test, surface morphology and residual stress under laser shock, high temperature and stress corrosion. It is found that the residual compressive stress and the grain refinement on the surface of the material during the heat strengthening process increase the breaking strength of the sample in the stress corrosion environment. Appropriate high temperature maintenance helps to enhance the effect of deformation strengthening. In the 300°C environment insulation, due to recrystallization of the material, the performance decreased significantly. This study provides an experimental basis for effectively improving the stress corrosion resistance of 5A03 aluminum alloy.

  5. Corrosion Studies of Platinum Nano-Particles for Fuel Cells

    DEFF Research Database (Denmark)

    Shim, Signe Sarah

    The main focus of the present thesis is on corrosion and prevention of corrosion of platinum particles supported on carbon. This is important for instance in connection with start up and shutdown of fuel cells. The degradation mechanism of platinum particles supported on carbon has been character......The main focus of the present thesis is on corrosion and prevention of corrosion of platinum particles supported on carbon. This is important for instance in connection with start up and shutdown of fuel cells. The degradation mechanism of platinum particles supported on carbon has been...... characterized during oxygen reduction reaction (ORR) condition using identical location (IL) transmission electron microscopy (TEM). A TEM grid was used as the working electrode in an electrochemical setup allowing a direct correlation between the electrochemical response and the TEM analysis. The main results...... thirds and one monolayer of gold on platinum supported on carbon were synthesized by an inverse micelle method. The results obtained appear independent of the gold coverage. It has been shown that the electrochemical active surface areas of the platinum and platinum gold particles synthesized...

  6. Pitting corrosion of copper. An equilibrium - mass transport study

    Energy Technology Data Exchange (ETDEWEB)

    Taxen, C

    1996-11-01

    A mathematical model for the propagation of corrosion pits on copper is described. The model is used to predict the potentials below which copper is immune to pitting. The criteria used for immunity against pitting is that the volume of the cuprous oxide formed at the site of the metal oxidation at the bottom of a corrosion pit must be smaller than the volume of the oxidised metal. Equal volumes would give a complete coverage of the metal in a pit by adherent cuprous oxide and propagation would not be possible. For potentials where copper is not immune to pitting an estimate of the maximum growth rate is given. The model uses equilibrium data and diffusion coefficients and calculates the stationary concentration profiles from the bulk water outside a corrosion pit to the site of the metal dissolution at the bottom a corrosion pit. Precipitation of oxides as well as of basic salts of copper is considered. A total of 26 aqueous species are considered in waters with compositions ranging from those of tap waters to that of sea water. Calculations are made for the temperatures 25 deg C and 75 deg C. 38 refs, 60 figs, 17 tabs

  7. The study of henna leaves extract as green corrosion inhibitor

    African Journals Online (AJOL)

    Chaudhari H.G and Vashi R.T

    2016-05-01

    May 1, 2016 ... Mild steel is widely used as constitutional material in many ... in produced water and was reported as a several concern in corrosion of mild steel pipeline in oil and .... Where R is gas constant and T is absolute temperature.

  8. Mechanistic studies of carbon steel corrosion inhibition by cashew ...

    African Journals Online (AJOL)

    The phenoxide, R-Ar-O- ions from the CNSL inhibitor were found to be responsible for the reduction of the corrosion rate of the carbon steel. Also, it was observed that the surface charge of the carbon steel electrodes was positive with respect to the solutions containing CNSL inhibitor. It is likely that the mechanism of the ...

  9. COPPER PITTING CORROSION AND PINHOLE LEAKS: A CASE STUDY

    Science.gov (United States)

    Localized corrosion, or "pitting", of copper drinking water pipe continues is a problem for many water utilities and their customers. Extreme attack leads to pinhole leaks that can potentially lead to water damage, mold growth, and costly repairs for the homeowners, as well as th...

  10. Study of the uniform corrosion of non alloy and stainless steels: combined utilization of acoustic emission and electrochemical techniques

    International Nuclear Information System (INIS)

    Jaubert, Lionel

    2004-01-01

    In chemical and petrochemical industry, uniform corrosion induces important economic and security disappointments. The mechanisms of this damaging corrosion mode are well understood, but methods for on-line detection are badly missing. Acoustic emission technique presents, to palliate this lack, potentialities that have been studied in an instrumented laboratory loop allowing the simulation of industrial uniform corrosion conditions. In acidic media, acoustic activity is related to the hydrogen evolution resulting from proton reduction; it is therefore well correlated to the damage severity. In neutral aerated media, the deposit formation of corrosion products is not very emissive. Yet, a specific study of frequency parameters allows detection of corrosion evolution, but in that case, the quantification of corrosion rate remains difficult. A subsidiary study confirms the technique applicability in the case of 'acidic' corrosion, even in very noisy conditions. (author) [fr

  11. Case studies of corrosion of mixed waste and transuranic waste drums

    International Nuclear Information System (INIS)

    Kosiewicz, S.T.

    1993-01-01

    This paper presents three case studies of corrosion of waste drums at the Los Alamos National Laboratory (LANL). Corrosion was not anticipated by the waste generators, but occurred because of subtle chemical or physical mechanisms. In one case, drums of a cemented transuranic (TRU) sludge experienced general and pitting corrosion. In the second instance, a chemical from a commercial paint stripper migrated from its primary containment drums to chemically attack overpack drums made of mild carbon steel. In the third case, drums of mixed low level waste (MLLW) soil corroded drum packaging even though the waste appeared to be dry when it was placed in the drums. These case studies are jointly discussed as ''lessons learned'' to enhance awareness of subtle mechanisms that can contribute to the corrosion of radioactive waste drums during interim storage

  12. Pitting corrosion behaviour study of aluminium matrix composites (A3xx.x/SiCp)

    International Nuclear Information System (INIS)

    Pardo, A.; Merino, M. C.; Merino, S.; Lopez, M. D.; Viejo, F.; Carboneras, M.; Arrabal, R.

    2004-01-01

    The influence of the SiCp proportion on the pitting corrosion of A3xx.x/SiC/xxp composites was studies by means of potenciodinamic polarization and double cyclic polarization in saline environment at 25 degree centigrade A360/SiC/xxp matrix does not contain copper, whereas the A380/SiC/xxp matric contains 1,39-1,44 wt %Cu. The kinetic study was carried out by gravimetric measurements. The nature of corrosion products was analysed by low angle XRD and Scanning Electron Microscopy (SEM). The corrosion is due to nucleation and growth of Al 2 O 3 -3H 2 O on the material surface. The corrosion increases with the reinforcement proportion, chloride concentration and copper content. (Author) 10 refs

  13. Corrosion studies on selected metallic materials for application in nuclear waste disposal containers

    International Nuclear Information System (INIS)

    Smailos, E.; Fiehn, B.; Gago, J.A.; Azkarate, I.

    1994-03-01

    In previous corrosion studies, carbon steels and the alloy Ti 99.8-Pd were identified as promising materials for heat-generating nuclear waste containers acting as a radionuclide barrier in a rock-salt repository. To characterize the long-term corrosion behaviour of these materials in more detail, a research programme including laboratory-scale and in-situ corrosion studies has been undertaken jointly by KfK and ENRESA/INASMET. In the period under review, gamma irradiation corrosion studies of up to about 6 months at 10 Gy/h and stress corrosion cracking studies at slow strain rates (10 -4 -10 -7 s -1 ) were performed on three preselected carbon steels in disposal relevant brines (NaCl-rich, MgCl 2 -rich) at 90 C and 150 C (TStE 355, TStE 460, 15 MnNi 6.3). Moreover, results were obtained from long-term in-situ corrosion studies (maximum test duration 9 years) conducted on carbon steel, Ti 99.8-Pd, Hastelloy C4, Ni-resist D4, and Si-cast iron in boreholes in the Asse salt mine. (orig./MM) [de

  14. Magnesium and its alloys as degradable biomaterials : Corrosion studies using potentiodynamic and EIS electrochemical techniques

    OpenAIRE

    Müller, Wolf Dieter; Nascimento, Maria Lucia; Zeddies, Miriam; Córsico, Mariana; Gassa, Liliana Mabel; Fernández Lorenzo de Mele, Mónica Alicia

    2007-01-01

    Magnesium is potentially useful for orthopaedic and cardiovascular applications. However, the corrosion rate of this metal is so high that its degradation occurs before the end of the healing process. In industrial media the behaviour of several magnesium alloys have been probed to be better than magnesium performance. However, the information related to their corrosion behaviour in biological media is insufficient. The aim of this work is to study the influence of the components of organic f...

  15. ELECTROCHEMICAL STUDIES FOR CORROSION INHIBITION OF MILD STEEL BY CHRYSOPHYLLUM ALBIDUM EXTRACT

    OpenAIRE

    Akoma Chigozie S.; Osarolube Eziaku; Abumere O. E.

    2018-01-01

    The corrosion behavior of mild steel in carbonated drinks produced by Nigerian Breweries (Fanta, Sprite and Coke) was studied in the presence and absence of an eco-friendly inhibitor, Chrysophyllum albidum using Potentiodynamic polarization technique at 25 °C. Results showed that Chrysophyllum albidum reduced the current density (icorr), which in turn means that the corrosion rate was reduced significantly. The inhibition efficiency was found to be 93%, 78.6% and 87.5% for Fanta, Sprite and C...

  16. Review and Study of Physics Driven Pitting Corrosion Modeling in 2024-T3 Aluminum Alloys (Postprint)

    Science.gov (United States)

    2015-05-01

    aluminum subjected to pitting corrosion under fatigue conditions ”, Journal of Aircraft, Vol. 46, No. 4, pp. 1253-1259 Wei, R.P. (2001) “A model for...and material microstructure applied to corrosion and fatigue of aluminum and steel alloys”, Engineering Fracture Mechanics , Vol. 76, pp. 695-708 Wei...Fatigue Behavior of Aluminum Alloy 7075 -T6: Modeling and Experimental Studies", Materials Science and Engineering: A, vol. 297, Issue: 1-2, 15, pp. 223

  17. Microbially influenced corrosion: studies on enterobacteria isolated from seawater environment and influence of toxic metals on bacterial biofilm and bio-corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Bermond-Tilly, D.; Pineau, S.; Dupont-Morral, I. [Corrodys, 50 - Equeurdreville (France); Janvier, M.; Grimont, P.A.D. [Institut Pasteur, Unite BBPE, 75 - Paris (France)

    2004-07-01

    of microbial clusters and the increase production of the EPS by bacteria (Fang et al., 2002). This study was conducted to test the corrosive activity of Citrobacter freundii, Proteus mirabilis and Klebsiella planticola on carbon steel coupons and the influence of a toxic metal Cr(III) found in polluted marine environment) on these bacteria and the EPS production of the biofilm formed on carbon steel by appropriate in vitro experiments. (authors)

  18. A mini-catalogue of metal corrosion products studied by Raman microscopy

    International Nuclear Information System (INIS)

    Bouchard, M.; Smith, D.C.

    2000-01-01

    Full text.The extensive development of physical methods of analysis since the beginning of this century has revolutionised the classical observation techniques most frequently used by the archaeologist. Raman Microscopy (RM) appears to be one of the most promising tools due to the many advantages that it offers: e.g. non-destructive, in situ, micro-analysis. RM is being applied to many archaeological fields as well as to industrial or environmental sectors. In relation with parallel studies made on the identification of corrosion products on archaeological materials, and according to the principal condition for the RM characterisation of an unknown product being the comparison of its Raman spectrum with known standard spectra, the essential aim of this study is to build a mini-catalogue of standard corrosion products susceptible to be found on metallic objects; these could be from archaeological as well as from modern contexts. However, it is noted that the identification of a corrosion product may suggest either an urgent intervention from the restoration team (in the case of active corrosion products), or a stabilisation of the corrosion layer if this is considered to be a protective layer. All the standard samples are natural minerals coming from the Museum National d'Histoire Naturelle in Paris (France) and correspond to the corrosion products most frequently found on metals such copper, zinc, lead or tin. These samples have been analyzed by RM and also confirmed by powder x-ray diffraction analysis. This catalogue, including more than 30 standard species corresponding to the most common metal corrosion products, is very useful for the different studies in progress in collaboration with different archaeological metal restoration teams. The near future will probably see a mobile Raman Microprobe (MRM) equipped with many different mini-catalogues on the site of a corroded mettalic bridge, a corroded canalisation or under the sea to rapidly identify the different

  19. Studies on corrosion protection of laser hybrid welded AISI 316 by laser remelting

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove; Ambat, Rajan; Rasmussen, A.J.

    2005-01-01

    laser surface melting on microstructure and corrosion behaviour of AISI 316L welds. Welding and laser treatment parameters were varied. General corrosion behaviour of the weld and laser treated surface was characterised using a gel visualization test. The local electrochemistry of the weld and laser......Unlike in autogenous laser welding, hybrid laser welding of stainless steel could introduce grain boundary carbides due to low cooling rates. Formation of grain boundary carbides leads to reduced corrosion properties. Studies have initially been carried out on hybrid laser welding and subsequent...... treated surface was investigated using a novel micro electrochemical technique with a tip resolution of ~1 mm. Results show that hybrid laser welding of 316L has increased corrosion susceptibility probably as a result of grain boundary carbide formation. However a suitable post laser treatment could...

  20. Study of a Triazole Derivative as Corrosion Inhibitor for Mild Steel in Phosphoric Acid Solution

    Directory of Open Access Journals (Sweden)

    Lin Wang

    2012-01-01

    Full Text Available The corrosion inhibition by a triazole derivative (PAMT on mild steel in phosphoric acid (H3PO4 solution has been investigated by weight loss and polarization methods. The experimental results reveal that the compound has a significant inhibiting effect on the corrosion of steel in H3PO4 solution. It also shows good corrosion inhibition at higher concentration of H3PO4. Potentiodynamic polarization studies have shown that the compound acts as a mixed-type inhibitor retarding the anodic and cathodic corrosion reactions with predominant effect on the cathodic reaction. The values of inhibition efficiency obtained from weight loss and polarization measurements are in good agreement. The adsorption of this compound is found to obey the Langmuir adsorption isotherm. Some kinetic and thermodynamic parameters such as apparent activation energy, frequency factor, and adsorption free energy have been calculated and discussed.

  1. Magnesium and its alloys as degradable biomaterials: corrosion studies using potentiodynamic and EIS electrochemical techniques

    Directory of Open Access Journals (Sweden)

    Wolf Dieter Müller

    2007-03-01

    Full Text Available Magnesium is potentially useful for orthopaedic and cardiovascular applications. However, the corrosion rate of this metal is so high that its degradation occurs before the end of the healing process. In industrial media the behaviour of several magnesium alloys have been probed to be better than magnesium performance. However, the information related to their corrosion behaviour in biological media is insufficient. The aim of this work is to study the influence of the components of organic fluids on the corrosion behaviour of Mg and AZ31 and LAE442 alloys using potentiodynamic, potentiostatic and EIS techniques. Results showed localized attack in chloride containing media. The breakdown potential decreased when chloride concentration increased. The potential range of the passivation region was extended in the presence of albumin. EIS measurements showed that the corrosion behaviour of the AZ31 was very different from that of LAE442 alloy in chloride solutions.

  2. Corrosion studies on materials of construction for spent nuclear fuel reprocessing plant equipment

    International Nuclear Information System (INIS)

    Kamachi Mudali, U.; Dayal, R.K.; Gnanamoorthy, J.B.

    1993-01-01

    Corrosion studies on specimens of commercial Type 304L stainless steel (SS), nuclear grade type 304L SS, extra low-carbon nitric acid grade (NAG) Uranus-16 SS, NAG Uranus-65 SS, Ti, Ti-5% Ta, Ti-0.25% Pd, Zircaloy-2, weldments of Ti and of Ti-5% Ta, and surface-modified (thermally oxidised and anodised) Ti were carried out to assess their corrosion resistance in nitric acid medium. The results indicated that Zircaloy-2, Ti-5% Ta, Uranus-16 SS and Uranus-65 SS have excellent corrosion resistance in boiling nitric acid solution. Specimens of Zircaloy-2, Ti-5% Ta and thermally-oxidised Ti showed excellent corrosion resistance also in a simulated uranium-containing reprocessing medium in a concentrated nitric acid solution. SEM and XRD analyses were carried out on the tested specimens to examine the scale morphology and phases present on the surface. (orig.)

  3. In-Plant Corrosion Study of Steels in Distillery Effluent Treatment Plant

    Science.gov (United States)

    Ram, Chhotu; Sharma, Chhaya; Singh, A. K.

    2015-05-01

    The present study deals with corrosion and performance of steels observed in an effluent treatment plant (ETP) of a distillery. For this purpose, the metal coupons were exposed in primary (untreated effluent) and secondary tank (anaerobic treatment effluent) of the ETP. The extent of attack has been correlated with the composition of the effluent with the help of laboratory immersion and electrochemical tests. Untreated distillery effluent found to be more corrosive than the anaerobic-treated effluents and is assigned due to chloride, phosphate, calcium, nitrate, and nitrite ions, which enhances corrosivity at acidic pH. Mild steel showed highest uniform and localized corrosion followed by stainless steels 304L and 316L and lowest in case of duplex 2205.

  4. Atomistic studies of cation transport in tetragonal ZrO2 during zirconium corrosion

    International Nuclear Information System (INIS)

    Bai, Xian-Ming; Zhang, Yongfeng; Tonks, Michael R.

    2015-01-01

    Zirconium alloys are the major fuel cladding materials in current reactors. The water-side corrosion is a significant degradation mechanism of these alloys. During corrosion, the transport of oxidizing species in zirconium dioxide (ZrO 2 ) determines the corrosion kinetics. Previously, it has been argued that the outward diffusion of cations is important for forming protective oxides. In this work, the migration of Zr defects in tetragonal ZrO 2 is studied with temperature accelerated dynamics and molecular dynamics simulations. The results show that Zr interstitials have anisotropic diffusion and migrate preferentially along the [001] or c direction in tetragonal ZrO 2 . The compressive stresses can increase the Zr interstitial migration barrier significantly. The migration of Zr interstitials at a grain boundary is much slower than in a bulk oxide. The implications of these atomistic simulation results in the Zr corrosion are discussed. (authors)

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

    International Nuclear Information System (INIS)

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

    1999-01-01

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

  6. Studies of corrosion in metallic container for storage of high level radioactive wastes; Estudios de corrosion de materiales metalicos para capsulas de almacenamiento de residuos de alta actividad

    Energy Technology Data Exchange (ETDEWEB)

    Azkarate, I; Madina, V; Insausti, M

    1999-11-01

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

  7. Resistance of Cementitious Binders to Chloride Induced Corrosion of Embedded Steel by Electrochemical and Microstructural Studies

    International Nuclear Information System (INIS)

    Song, Ha Won; Ann, Ki Yong; Kim, Tae Sang

    2009-01-01

    The high alkaline property in the concrete pore solution protects the embedded steel in concrete from corrosion due to aggressive ions attack. However, a continuous supply of those ions, in particular, chlorides altogether with a pH fall in electrochemical reaction on the steel surface eventually depassivate the steel to corrode. To mitigate chloride-induced corrosion in concrete structures, finely grained mineral admixtures, for example, pulverized fuel ash (PFA), ground granulated blast furnace slag (GGBS) and silica fume (SF) have been often advised to replace ordinary Portland cement (OPC) partially as binder. A consistent assessment of those partial replacements has been rarely performed with respect to the resistance of each binder to corrosion, although the studies for each binder were extensively looked into in a way of measuring the corrosion rate, influence of microstructure or chemistry of chlorides ions with cement hydrations. The paper studies the behavior of steel corrosion, chloride transport, pore structure and buffering capacity of those cementitious binders. The corrosion rate of steel in mortars of OPC, 30% PFA, 60% GGBS and 10% SF respectively, with chloride in cast ranging from 0.0 to 3.0% by weight of binder was measured at 7, 28 and 150 days to determine the chloride threshold level and the rate of corrosion propagation, using the anodic polarization technique. Mercury intrusion porosimetry was also applied to cement pastes of each binder at 7 and 28 days to ensure the development of pore structure. Finally, the release rate of bound chlorides (I.e. buffering capacity) was measured at 150 days. The chloride threshold level was determined assuming that the corrosion rate is beyond 1-2 mA/m 3 at corrosion and the order of the level was OPC > 10% SF > 60% GGBS > 30% PFA. Mercury intrusion porosimetry showed that 10% SF paste produced the most dense pore structure, followed by 60% GGBS, 30% PFA and OPC pastes, respectively. It was found that OPC

  8. EIS study on corrosion and scale processes and their inhibition in cooling system media

    Energy Technology Data Exchange (ETDEWEB)

    Marin-Cruz, J. [Universidad Autonoma Metropolitana, Departamento de Quimica, Apdo. Postal 55-534, 09340 Mexico, DF (Mexico) and Instituto Mexicano del Petroleo, Coordinacion de Ingenieria Molecular, Competencia de Quimica Aplicada, Eje Central Lazaro Cardenas No. 152, CP 07730, DF (Mexico)]. E-mail: jmarin@imp.mx; Cabrera-Sierra, R. [Universidad Autonoma Metropolitana, Departamento de Quimica, Apdo. Postal 55-534, 09340 Mexico, DF (Mexico); Escuela Superior de Ingenieria Quimica e Industrias Extractivas (ESIQIE-IPN), Departamento de Metalurgia, UPALM Zacatenco AP 75-874, CP 07338, DF (Mexico); Pech-Canul, M.A. [Departamento de Fisica Aplicada, Centro de Investigacion y de Estudios, Avanzados del IPN, AP 73 Cordemex, CP 97310, Merida, Yucatan (Mexico); Gonzalez, I. [Universidad Autonoma Metropolitana, Departamento de Quimica, Apdo. Postal 55-534, 09340 Mexico, DF (Mexico)]. E-mail: igm@xanum.uam.mx

    2006-01-20

    A study of the carbon steel/cooling water interface was carried out using electrochemical impedance spectroscopy (EIS). EIS spectra reveal that a layer of corrosion and scale products forms naturally and evolves with the immersion time modifying the carbon steel/cooling water interface and giving rise to corrosion and scale processes. In addition, the nature of the layer formed on the metal was found to depend on the inhibitor used. It was established that the corrosion inhibitor (hydroxyphosphonoacetic acid (HPA)) chelates with Ca(II) ion generating a layer with resistive properties that provides good protection against corrosion. In contrast, the scale inhibitor (1-hydroxy-ethane-1,1-diphosphonic acid (HEDP)) is incorporated into the calcium carbonate crystals at the surface, modifying the structure and diminishing scale formation in the surface; this additive additionally inhibited corrosion. These observations were supported by scanning electronic microscopy (SEM) and corroborate previous studies performed by other techniques on HPA and HEDP. Finally, a synergistic effect was observed between these inhibitors that provides good protection to steel against corrosion and scaling in cooling media.

  9. EIS study on corrosion and scale processes and their inhibition in cooling system media

    International Nuclear Information System (INIS)

    Marin-Cruz, J.; Cabrera-Sierra, R.; Pech-Canul, M.A.; Gonzalez, I.

    2006-01-01

    A study of the carbon steel/cooling water interface was carried out using electrochemical impedance spectroscopy (EIS). EIS spectra reveal that a layer of corrosion and scale products forms naturally and evolves with the immersion time modifying the carbon steel/cooling water interface and giving rise to corrosion and scale processes. In addition, the nature of the layer formed on the metal was found to depend on the inhibitor used. It was established that the corrosion inhibitor (hydroxyphosphonoacetic acid (HPA)) chelates with Ca(II) ion generating a layer with resistive properties that provides good protection against corrosion. In contrast, the scale inhibitor (1-hydroxy-ethane-1,1-diphosphonic acid (HEDP)) is incorporated into the calcium carbonate crystals at the surface, modifying the structure and diminishing scale formation in the surface; this additive additionally inhibited corrosion. These observations were supported by scanning electronic microscopy (SEM) and corroborate previous studies performed by other techniques on HPA and HEDP. Finally, a synergistic effect was observed between these inhibitors that provides good protection to steel against corrosion and scaling in cooling media

  10. Inhibition study of additives towards the corrosion of ferrous metal in palm biodiesel

    International Nuclear Information System (INIS)

    Fazal, M.A.; Sazzad, B.S.; Haseeb, A.S.M.A.; Masjuki, H.H.

    2016-01-01

    Highlights: • TBA doped biodiesel exhibits fairly good corrosion inhibition efficiency. • TBA forms nitrogen-containing layer on metal surface and protects the corrosion. • Materials exposed to TBA doped biodiesel show less surface roughness. - Abstract: Some efforts have already been given by other researchers to characterize the corrosion behavior of different metals in biodiesel. However, there is very limited information on its remedial measure. Therefore, this study investigates the effects of tert-butylamine (TBA), benzotriazole (BTA), butylate-dhydroxytoluene (BHT), and pyrogallol (PY) on the corrosion of cast iron (CI) and low carbon steel (LCS) through an immersion test in palm biodiesel (B100) at 300 K. Result shows that TBA-doped biodiesel exhibits fairly good corrosion-inhibiting properties for materials exposed to B100. Inhibition efficiency of TBA is found to be 86.54% and 86.71% for CI and LCS, respectively which is far better than other tested additives in this study. The high inhibition efficiency could be attributed to the dominant physical adsorption of N-containing compound which creates a protective layer over the metal surface and prevents corrosion.

  11. Flow-induced corrosion of absorbable magnesium alloy: In-situ and real-time electrochemical study

    Science.gov (United States)

    Wang, Juan; Jang, Yongseok; Wan, Guojiang; Giridharan, Venkataraman; Song, Guang-Ling; Xu, Zhigang; Koo, Youngmi; Qi, Pengkai; Sankar, Jagannathan; Huang, Nan; Yun, Yeoheung

    2016-01-01

    An in-situ and real-time electrochemical study in a vascular bioreactor was designed to analyze corrosion mechanism of magnesium alloy (MgZnCa) under mimetic hydrodynamic conditions. Effect of hydrodynamics on corrosion kinetics, types, rates and products was analyzed. Flow-induced shear stress (FISS) accelerated mass and electron transfer, leading to an increase in uniform and localized corrosions. FISS increased the thickness of uniform corrosion layer, but filiform corrosion decreased this layer resistance at high FISS conditions. FISS also increased the removal rate of localized corrosion products. Impedance-estimated and linear polarization-measured polarization resistances provided a consistent correlation to corrosion rate calculated by computed tomography. PMID:28626241

  12. High temperature corrosion studies on friction-welded dissimilar metals

    International Nuclear Information System (INIS)

    Arivazhagan, N.; Singh, Surendra; Prakash, Satya; Reddy, G.M.

    2006-01-01

    Understanding the behaviour of weldment at elevated temperatures and especially their corrosion behaviour has become an object of scientific investigation recently. Investigation has been carried out on friction-welded AISI 4140 and AISI 304 under molten salt of Na 2 SO 4 + V 2 O 5 (60%) environment at 500 and 550 deg. C under cyclic condition. The influences of welding parameters on the hot corrosion have been discussed. The resulting oxide scales in the weldment have been characterized systematically using surface analytical techniques. Scale thickness on low alloy steel side was found to be more and was prone to spalling. Weld region has been found to be more prone to degradation than base metals due to inter diffusion of element across the interface and the formation of intermetallic compound

  13. High temperature corrosion studies on friction-welded dissimilar metals

    Energy Technology Data Exchange (ETDEWEB)

    Arivazhagan, N. [Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Roorkee (India)]. E-mail: arivadmt@iitr.ernet.in; Singh, Surendra [Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Roorkee (India); Prakash, Satya [Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Roorkee (India); Reddy, G.M. [Defense Metallurgical and Research Laboratory, Hyderabad (India)

    2006-07-25

    Understanding the behaviour of weldment at elevated temperatures and especially their corrosion behaviour has become an object of scientific investigation recently. Investigation has been carried out on friction-welded AISI 4140 and AISI 304 under molten salt of Na{sub 2}SO{sub 4} + V{sub 2}O{sub 5} (60%) environment at 500 and 550 deg. C under cyclic condition. The influences of welding parameters on the hot corrosion have been discussed. The resulting oxide scales in the weldment have been characterized systematically using surface analytical techniques. Scale thickness on low alloy steel side was found to be more and was prone to spalling. Weld region has been found to be more prone to degradation than base metals due to inter diffusion of element across the interface and the formation of intermetallic compound.

  14. Electrochemical Study about Microorganisms Induced Corrosion in Inconel

    OpenAIRE

    Domínguez-Sánchez, G.; Tiburcio, C. Gaona; Almeraya-Calderón, F.M.; Martínez-Villafañe, A.

    2005-01-01

    Inconel 600 has been designed to heat resistance. It is used in the chemistry industry, food industry and, of course, in the production of electric energy, among others. The goal of this project was to decrease the costs in the equipments and pipes deterioration by prolonging their lifetime, controlling and preventing their deterioration by means of appropriated and programmed maintenance, but above all knowing the mechanism and kinetic of corrosion that affects them. We used polarization cur...

  15. Corrosion studies of titanium in borated water for TPX

    International Nuclear Information System (INIS)

    Wilson, D.F.; Pawel, S.J.; DeVan, J.H.; Cole, M.J.; Nelson, B.E.

    1995-01-01

    Corrosion testing was performed to demonstrate the compatibility of the titanium vacuum vessel with borated water. Borated water is proposed to fill the annulus of the double wall vacuum vessel to provide effective radiation shielding. Borating the water with 110 grams of boric acid per liter is sufficient to reduce the nuclear heating in the Toroidal Field Coil set and limit the activation of components external to the vacuum vessel. Constant extension rate tensile (CERT) and electrochemical potentiodynamic tests were performed. Results of the CERT tests confirm that stress corrosion cracking is not significant for Ti-6Al4V or Ti-3AI-2.5V. Welded and unwelded specimens were tested in air and in borated water at 150 degree C. Strength, elongation, and time to failure were nearly identical for all test conditions, and all the samples exhibited ductile failure. Potentiodynamic tests on Ti-6A1-4V and Ti in borated water as a function of temperature showed low corrosion rates over a wide passive potential range. Further, this passivity appeared stable to anodic potentials substantially greater than those expected from MHD effects

  16. Alkali chloride induced corrosion of superheaters under biomass firing conditions: Improved insights from laboratory scale studies

    DEFF Research Database (Denmark)

    Okoro, Sunday Chukwudi; Montgomery, Melanie; Jappe Frandsen, Flemming

    2015-01-01

    One of the major operational challenges experienced by power plants firing biomass is the high corrosion rate of superheaters. This limits the outlet steam temperature of the superheaters and consequently, the efficiency of the power plants. The high corrosion rates have been attributed to the fo......One of the major operational challenges experienced by power plants firing biomass is the high corrosion rate of superheaters. This limits the outlet steam temperature of the superheaters and consequently, the efficiency of the power plants. The high corrosion rates have been attributed......, [1–3]). However, complete understanding of the corrosion mechanism under biomass-firing conditions has not yet been achieved. This is attributed partly to the complex nature of the corrosion process since there are many species produced from fuel combustion which can interact with one another...... and the steel surface. Many studies have focused on specific parameters such as, deposit composition (KCl, K2SO4, K2CO3, etc.) or gas species such as HCl, SO2, H2O [4–6], however, more research is necessary to understand the interaction of deposits and gas mixtures with each other and metallic superheater...

  17. Corrosion Mechanism and Bond-Strength Study on Galvanized Steel in Concrete Environment

    Energy Technology Data Exchange (ETDEWEB)

    Kouril, M.; Pokorny, P.; Stoulil, J. [University of Chemistry and Technology, Prague (Czech Republic)

    2017-04-15

    Zinc coating on carbon steels give the higher corrosion resistance in chloride containing environments and in carbonated concrete. However, hydrogen evolution accompanies the corrosion of zinc in the initial activity in fresh concrete, which can lead to the formation of a porous structure at the reinforcement -concrete interface, which can potentially reduce the bond-strength of the reinforcement with concrete. The present study examines the mechanism of the corrosion of hot-dip galvanized steel in detail, as in the model pore solutions and real concrete. Calcium ion plays an important role in the corrosion mechanism, as it prevents the formation of passive layers on zinc at an elevated alkalinity. The corrosion rate of galvanized steel decreases in accordance with the exposure time; however, the reason for this is not the zinc transition into passivity, but the consumption of the less corrosion-resistant phases of hot-dip galvanizing in the concrete environment. The results on the electrochemical tests have been confirmed by the bond-strength test for the reinforcement of concrete and by evaluating the porosity of the cement adjacent to the reinforcement.

  18. [Study on corrosion resistance of three non-noble porcelain alloys].

    Science.gov (United States)

    Wu, Zhikai; Xu, Sheng; Li, Wei; Teng, Jin; Li, Ning

    2011-10-01

    To study the electrochemical corrosion behavior of Co-Cr, Ni-Cr and Ni-Cr-Be based porcelain alloys in NaCl solution. Five samples of each alloy were made respectively, electric polarization curve of each alloy was obtained using potentiodynamic polarization technique. Self-corrosion potential (E(corr)), self-corrosion current density (I(corr), passive region and transpassivation potential were tested. Microstructure and constituent was examined using scanning electron microscopy and energy dispersive spectroscopy. Co-Cr alloy possessed the most desirable corrosion resistance because of its integrated, homogeneous and compact passive film. The poor compactness of Ni-Cr alloy's passive film decreased its corrosion resistance. Ni-Cr-Be alloy exhibited the worst corrosion resistance due to the Cr and Mo depleted Ni-Be eutectic phases in the alloy. Taking biological security into consideration, it is necessary to avoid the application of porcelain alloys with Be element. Co-Cr alloy with better biocompatibility possesses much broader prospect in the field of dental restoration.

  19. Corrosion-fatigue studies of the Zr-based Vitreloy 105 bulk metallic glass

    International Nuclear Information System (INIS)

    Horton Jr, Joe A.; Morrison, M.L.; Buchanan, R.A.; Liaw, Peter K.; Green, B.A.; Wang, G.Y.

    2007-01-01

    The purpose of this study was to characterize the stress-life behavior of the Vitreloy 105 BMG alloy in the four-point bending configuration in a 0.6 M. NaCl electrolyte. At high stress amplitudes, the corrosion-fatigue life was similar to the fatigue lives observed in air. The environment became increasingly detrimental with decreases in stress, and the corrosion-fatigue endurance limit decreased to about 50 MPa, an 88% decrease relative to testing in air. Similar to the tests conducted in air, oxide particles were found on the fracture surfaces but did not appear to significantly affect the corrosion-fatigue lives. However, wear and the resultant corrosion at the outer loading pins resulted in crack initiation in most of the samples. Thus, these results are considered conservative estimates of the corrosion-fatigue behavior of this BMG alloy. Monitoring of the samples and the open-circuit potentials revealed that the onset of significant crack growth occurred at an average of 92% of the total fatigue life. The mechanism of corrosion-fatigue degradation was found to be anodic dissolution

  20. Shadow corrosion phenomenon. An out-of-pile study on electrochemical effects

    Energy Technology Data Exchange (ETDEWEB)

    Weber, Nadine

    2017-04-28

    The focus of the present thesis was the study of the enhanced corrosion phenomenon named ''Shadow Corrosion''. Within the context of researching based on the corrosion mechanism as well as the influencing parameters and driving forces, which cause or even intensify the corrosion, a variety of electrochemical characterization and surface analysis techniques were used. The first part of this thesis gives a short introduction with the definition of the term Shadow Corrosion and of the specific type called ''Enhanced Spacer Shadow Corrosion'' (ESSC). This is followed by a description of the involved materials being Zircaloy and Inconel 718. Chapter 2 introduces the background knowledge including fundamentals about environ-mental conditions under which Shadow Corrosion occurs as well as the oxidation behavior of Zircaloy and Inconel 718. Furthermore, the state of the art about the Shadow Corrosion mechanism is presented and a description of the influencing effects on the enhanced corrosion phenomenon, like galvanic corrosion, water radiolysis, and photo-effect, is given. Further information and parameters on the part of AREVA GmbH concerning water impurities and a used coating layer on Inconel 718 are listed, which are of interest for the issue concerning the phenomenon Shadow Corrosion. The last part of this chapter contains the experimental conditions and parameters for the laboratory experiments with focus on water chemistry, specimen geometry, and UV-light exposure for photoexcitation and water radiolysis. Three different working hypotheses of this thesis are described in chapter 3. One hypothesis regarding the Shadow Corrosion Phenomenon is based on a galvanic corrosion mechanism between Zircaloy and Inconel 718. In addition, it is supposed that the galvanic corrosion could be influenced by the deposition of silver on Zircaloy and Inconel 718 in the form of an increased galvanic current. A further assumption is that the

  1. Shadow corrosion phenomenon. An out-of-pile study on electrochemical effects

    International Nuclear Information System (INIS)

    Weber, Nadine

    2017-01-01

    The focus of the present thesis was the study of the enhanced corrosion phenomenon named ''Shadow Corrosion''. Within the context of researching based on the corrosion mechanism as well as the influencing parameters and driving forces, which cause or even intensify the corrosion, a variety of electrochemical characterization and surface analysis techniques were used. The first part of this thesis gives a short introduction with the definition of the term Shadow Corrosion and of the specific type called ''Enhanced Spacer Shadow Corrosion'' (ESSC). This is followed by a description of the involved materials being Zircaloy and Inconel 718. Chapter 2 introduces the background knowledge including fundamentals about environ-mental conditions under which Shadow Corrosion occurs as well as the oxidation behavior of Zircaloy and Inconel 718. Furthermore, the state of the art about the Shadow Corrosion mechanism is presented and a description of the influencing effects on the enhanced corrosion phenomenon, like galvanic corrosion, water radiolysis, and photo-effect, is given. Further information and parameters on the part of AREVA GmbH concerning water impurities and a used coating layer on Inconel 718 are listed, which are of interest for the issue concerning the phenomenon Shadow Corrosion. The last part of this chapter contains the experimental conditions and parameters for the laboratory experiments with focus on water chemistry, specimen geometry, and UV-light exposure for photoexcitation and water radiolysis. Three different working hypotheses of this thesis are described in chapter 3. One hypothesis regarding the Shadow Corrosion Phenomenon is based on a galvanic corrosion mechanism between Zircaloy and Inconel 718. In addition, it is supposed that the galvanic corrosion could be influenced by the deposition of silver on Zircaloy and Inconel 718 in the form of an increased galvanic current. A further assumption is that the galvanic current could be decreased by a Cr

  2. Experimental study on dew point corrosion characteristics of the heating surface in a 65 t/h biomass-fired circulating fluidized bed boiler

    International Nuclear Information System (INIS)

    Wang, Yungang; Ma, Haidong; Liang, Zhiyuan; Chen, Heng; Zhao, Qinxin; Jin, Xin

    2016-01-01

    Highlights: • Dew point corrosion and ash deposit tests in a biomass-fired boiler were performed. • The XRD, XRF and SEM methods were used to analyze corrosion samples. • The deposits were made up of ash deposit layer, coupling layer and corrosion layer. • The metal matrix simultaneously confronted chlorine corrosion and oxygen corrosion. - Abstract: The dew point corrosion characteristics of the heating surface in a 65 t/h biomass-fired circulating fluidized bed (CFB) boiler were experimentally studied. The cross-sectional morphology and composition of the ash deposition were analyzed by scanning electron microscope (SEM), X-ray diffraction (XRD) and X-ray fluorescence spectrum (XRF), respectively. The results showed that the test tube surface was covered by ash deposit layer, coupling layer and corrosion layer. The ash deposit layer and the coupling layer were prone to spall off together. The coupling layer consists of partial ash and corrosion products. The corrosion layer was mainly composed of chlorides (FeCl_3, FeCl_2, and FeOCl) and oxides (FeOOH, Fe_2O_3). With the increase of the tube wall temperature, the corrosion depth decreased dramatically and the dew point corrosion was alleviated efficiently. The metal matrix simultaneously suffered from chlorine corrosion and oxygen corrosion. As the tube wall temperature was above water dew point, the main corrosion mode was oxygen corrosion. As the tube wall temperature was below water dew point, the main corrosion mode was chlorine corrosion.

  3. Corrosion/96 conference papers

    International Nuclear Information System (INIS)

    Anon.

    1996-01-01

    Topics covered by this conference include: cathodic protection in natural waters; cleaning and repassivation of building HVAC systems; worldwide opportunities in flue gas desulfurization; advancements in materials technology for use in oil and gas service; fossil fuel combustion and conversion; technology of corrosion inhibitors; computers in corrosion control--modeling and information processing; recent experiences and advances of austenitic alloys; managing corrosion with plastics; corrosion measurement technology; corrosion inhibitors for concrete; refining industry; advances in corrosion control for rail and tank trailer equipment; CO 2 corrosion--mechanisms and control; microbiologically influenced corrosion; corrosion in nuclear systems; role of corrosion in boiler failures; effects of water reuse on monitoring and control technology in cooling water applications; methods and mechanisms of scale and deposit control; corrosion detection in petroleum production lines; underground corrosion control; environmental cracking--relating laboratory results and field behavior; corrosion control in reinforced concrete structures; corrosion and its control in aerospace and military hardware; injection and process addition facilities; progress reports on the results of reinspection of deaerators inspected or repaired per RP0590 criteria; near 100% volume solids coating technology and application methods; materials performance in high temperature environments containing halides; impact of toxicity studies on use of corrosion/scale inhibitors; mineral scale deposit control in oilfield related operations; corrosion in gas treating; marine corrosion; cold climate corrosion; corrosion in the pulp and paper industry; gaseous chlorine alternatives in cooling water systems; practical applications of ozone in recirculating cooling water systems; and water reuse in industry. Over 400 papers from this conference have been processed separately for inclusion on the data base

  4. Boundary element inverse analysis for rebar corrosion detection: Study on the 2004 tsunami-affected structure in Aceh

    Directory of Open Access Journals (Sweden)

    S. Fonna

    2018-06-01

    Full Text Available Evaluation of rebar/reinforcing-steel corrosion for the 2004 tsunami-affected reinforced concrete (RC buildings in Aceh was conducted using half-cell potential mapping technique. However, the results only show qualitative meaning as corrosion risk rather than the corrosion itself, such as the size and location of corrosion. In this study, boundary element inverse analysis was proposed to be performed to detect rebar corrosion of the 2004 tsunami-affected structure in Aceh, using several electrical potential measurement data on the concrete surface. One RC structure in Peukan Bada, an area heavily damaged by the tsunami, was selected for the study. In 2004 the structure was submerged more than 5 m by the tsunami. Boundary element inverse analysis was developed by combining the boundary element method (BEM and particle swarm optimization (PSO. The corrosion was detected by evaluating measured and calculated electrical potential data. The measured and calculated electrical potential on the concrete surface was obtained by using a half-cell potential meter and by performing BEM, respectively. The solution candidates were evaluated by employing PSO. Simulation results show that boundary element inverse analysis successfully detected the size and location of corrosion for the case study. Compared with the actual corrosion, the error of simulation result was less than 5%. Hence, it shows that boundary element inverse analysis is very promising for further development to detect rebar corrosion. Keywords: Inverse analysis, Boundary element method, PSO, Corrosion, Reinforced concrete

  5. Corrosion of metals exposed to 25% magnesium chloride solution and tensile stress: Field and laboratory studies

    Directory of Open Access Journals (Sweden)

    Xianming Shi

    2017-12-01

    Full Text Available The use of chemicals for snow and ice control operations is a common practice for improving the safety and mobility of roadways in cold climate, but brings significant concerns over their risks including the corrosive effects on transportation infrastructure and motor vehicles. The vast majority of existing studies and methods to test the deicer corrosivity have been restricted to laboratory environments and unstressed metals, which may not reliably simulate actual service conditions. As such, we report a case study in which stainless steel SS 304 (unstressed and externally tensile stressed, aluminum (Al 1100 and low carbon steel (C1010 coupons were exposed to 25% MgCl2 under field conditions for six weeks. A new corrosion test-bed was developed in Montana to accelerate the field exposure to this deicer. To further investigate the observed effect of tensile stress on the corrosion of stainless steel, SS 304 (unstressed and externally stressed coupons were exposed to 25% MgCl2 solution under the laboratory conditions. The C 1010 exhibited the highest percentage of rust area and suffered the most weight loss as a result of field exposure and MgCl2 sprays. In terms of ultimate tensile strength, the Al 1100 coupons saw the greatest reduction and the unstressed and externally stressed SS 304 coupons saw the least. The ability of MgCl2 to penetrate deep into the matrix of aluminum alloy poses great risk to such structural material. Tensile stressed SS 304 suffered more corrosion than unstressed SS 304 in both the field and laboratory conditions. Results from this case study may shed new light on the deicer corrosion issue and help develop improved field testing methods to evaluate the deicer corrosivity to metals in service.

  6. Corrosion and corrosion control

    International Nuclear Information System (INIS)

    Khanna, A.S.; Totlani, M.K.

    1995-01-01

    Corrosion has always been associated with structures, plants, installations and equipment exposed to aggressive environments. It effects economy, safety and product reliability. Monitoring of component corrosion has thus become an essential requirement for the plant health and safety. Protection methods such as appropriate coatings, cathodic protection and use of inhibitors have become essential design parameters. High temperature corrosion, especially hot corrosion, is still a difficult concept to accommodate in corrosion allowance; there is a lack of harmonized system of performance testing of materials at high temperatures. In order to discuss and deliberate on these aspects, National Association for Corrosion Engineers International organised a National Conference on Corrosion and its Control in Bombay during November 28-30, 1995. This volume contains papers presented at the symposium. Paper relevant to INIS is indexed separately. refs., figs., tabs

  7. Dictionary corrosion and corrosion control

    International Nuclear Information System (INIS)

    1985-01-01

    This dictionary has 13000 entries in both languages. Keywords and extensive accompanying information simplify the choice of word for the user. The following topics are covered: Theoretical principles of corrosion; Corrosion of the metals and alloys most frequently used in engineering. Types of corrosion - (chemical-, electro-chemical, biological corrosion); forms of corrosion (superficial, pitting, selective, intercrystalline and stress corrosion; vibrational corrosion cracking); erosion and cavitation. Methods of corrosion control (material selection, temporary corrosion protection media, paint and plastics coatings, electro-chemical coatings, corrosion prevention by treatment of the corrosive media); Corrosion testing methods. (orig./HP) [de

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2004-07-01

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

  9. Review of lithium iron-base alloy corrosion studies

    International Nuclear Information System (INIS)

    DeVan, J.H.; Selle, J.E.; Morris, A.E.

    1976-01-01

    An extensive literature search was conducted on the compatibility of ferrous alloys with lithium, with the emphasis on austenitic stainless steels. The information is summarized and is divided into two sections. The first section gives a brief summary and the second is an annotated bibliography. Comparisons of results are complicated by differences in lithium purity, alloy composition, alloy treatment, flow rates, and lithium handling procedures. For long-term application, austenitic stainless steels appear to be limited to about 500 0 C. While corrosion can probably not be decreased to zero, a considerable reduction to tolerable and predictable amounts appears possible

  10. General and crevice corrosion study of the in-wall shielding materials for ITER vacuum vessel

    Science.gov (United States)

    Joshi, K. S.; Pathak, H. A.; Dayal, R. K.; Bafna, V. K.; Kimihiro, Ioki; Barabash, V.

    2012-11-01

    Vacuum vessel In-Wall Shield (IWS) will be inserted between the inner and outer shells of the ITER vacuum vessel. The behaviour of IWS in the vacuum vessel especially concerning the susceptibility to crevice of shielding block assemblies could cause rapid and extensive corrosion attacks. Even galvanic corrosion may be due to different metals in same electrolyte. IWS blocks are not accessible until life of the machine after closing of vacuum vessel. Hence, it is necessary to study the susceptibility of IWS materials to general corrosion and crevice corrosion under operations of ITER vacuum vessel. Corrosion properties of IWS materials were studied by using (i) Immersion technique and (ii) Electro-chemical Polarization techniques. All the sample materials were subjected to a series of examinations before and after immersion test, like Loss/Gain weight measurement, SEM analysis, and Optical stereo microscopy, measurement of surface profile and hardness of materials. After immersion test, SS 304B4 and SS 304B7 showed slight weight gain which indicate oxide layer formation on the surface of coupons. The SS 430 material showed negligible weight loss which indicates mild general corrosion effect. On visual observation with SEM and Metallography, all material showed pitting corrosion attack. All sample materials were subjected to series of measurements like Open Circuit potential, Cyclic polarization, Pitting potential, protection potential, Critical anodic current and SEM examination. All materials show pitting loop in OC2 operating condition. However, its absence in OC1 operating condition clearly indicates the activity of chloride ion to penetrate oxide layer on the sample surface, at higher temperature. The critical pitting temperature of all samples remains between 100° and 200°C.

  11. A Study on Accelerated Corrosion Test by Combined Deteriorating Action of Salt Damage and Freeze-Thaw

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sang-Soon; So, Byung-Tak [Sangmyung University, Cheonan (Korea, Republic of)

    2016-01-15

    In this study, the accelerated corrosion test by combined deteriorating action of salt damage and freeze-thaw was investigated. freeze-thaw cycle is one method for corrosion testing; corrosion initiation time was measured in four types of concrete samples, i.e., two samples mixed with fly ash (FA) and blast furnace slag (BS), and the other two samples having two water/cement ratio (W/C = 0.6, 0.35) without admixture (OPC60 and OPC35). The corrosion of rebar embedded in concrete occurred most quickly at the 30th freeze-thaw cycle. Moreover, a corrosion monitoring method with a half-cell potential measurement and relative dynamic elastic modulus derived from resonant frequency measures was conducted simultaneously. The results indicated that the corrosion of rebar occurred when the relative dynamic elastic modulus was less than 60%. Therefore, dynamic elastic modulus can be used to detect corrosion of steel bar. The results of the accelerated corrosion test exhibited significant difference according to corrosion periods combined with each test condition. Consequently, the OPC60 showed the lowest corrosion resistance among the samples.

  12. A Fundamental study of remedial technology development to prevent stress corrosion cracking of steam generator tubing

    Energy Technology Data Exchange (ETDEWEB)

    Park, In Gyu; Lee, Chang Soon [Sunmoon University, Asan (Korea)

    1998-04-01

    Most of the PWR Steam generators with tubes in Alloy 600 alloy are affected by Stress Corrosion Cracking, such as PWSCC(Primary Water Stress Corrosion Cracking) and ODSCC(Outside Diameter Stress Corrosion Cracking). This study was undertaken to establish the background for remedial technology development to prevent SCC. in the report are included the following topics: (1) General: (i) water chemistry related factors, (ii) Pourbaix(Potential-pH) Diagram, (iii) polarization plot, (iv) corrosion mode of Alloy 600, 690, and 800, (v) IGA/SCC growth rate, (vi) material suspetibility of IGA/SCC, (vii) carbon solubility of Alloy 600 (2) Microstructures of Alloy 600 MA, Alloy 600 TT, Alloy 600 SEN Alloy 690 TT(Optical, SEM, and TEM) (3) Influencing factors for PWSCC initiation rate of Alloy 600: (i) microstructure, (ii) water chemistry(B, Li), (iii) temperature, (iv) plastic deformation, (v) stress relief annealing (4) Influencing factors for PWSCC growth rate of Alloy 600: (i) water chemistry(B, Li), (ii) Scott Model, (iii) intergranular carbide, (iv) temperature, (v) hold time (5) Laboratory conditions for ODSCC initiation rate: 1% NaOH, 316 deg C; 1% NaOH, 343 deg C; 50% NaOH, 288 deg C; 10% NaOH, 302 deg C; 10% NaOH, 316 deg C; 50% NaOH, 343 deg C (6) Sludge effects for ODSCC initiation rate: CuO, Cr{sub 2}O{sub 3}, Fe{sub 3}O{sub 4} (7) Influencing factors for PWSCC growth rate of Alloy 600: (i) Caustic concentration effect, (ii) carbonate addition effect (8) Sulfate corrosion: (i) sulfate ratio and pH effect, (ii) wastage rate of Alloy 600 and Alloy 690 (9) Crevice corrosion: (i) experimental setup for crevice corrosion, (ii) organic effect, (iii) (Na{sub 2}SO{sub 4} + NaOH) effect (10) Remedial measures for SCC: (i) Inhibitors, (ii) ZnO effect. (author). 30 refs., 174 figs., 51 tabs.

  13. Study on the corrosion assessment of overpack welds-II (Joint research)

    International Nuclear Information System (INIS)

    Mitsui, Hiroyuki; Otsuki, Akiyoshi; Asano, Hidekazu; Taniguchi, Naoki; Kawakami, Susumu; Yui, Mikazu

    2006-06-01

    The corrosion resistance at the overpack welds is possible to be inferior to that at base metal, so that it has been concerned that a short-term failure of overpack may occur due to the corrosion penetration at the welds. In this study, corrosion mechanisms specific to the welds were extracted for carbon steel which is one of the candidate materials for overpacks. And then the corrosion experiments for welded carbon steel were planed to evaluate long-term integrity of overpack welds. Based on this plan, electrochemical tests for welded carbon steel using the samples welded by EBW and TIG were carried out, and the corrosion behavior of welded zone was compared with that of base metal. The results of anodic polarization tests in 0.01M and 0.1M carbonate aqueous solutions for base metal, heat affected zone and welded metal showed that; As for EBW, the anodic polarization curves were not affected by welding although the metallurgical structures vary with base metal, heat affected zone and welded metal. As for TIG, the current density of welded metal was larger than that of base metal and of heat affected zone, and local dissolution with immediate in current density was observed in 0.01M-pH10 carbonate aqueous solution. As shown in these results, it is expected that the corrosion resistance at the welds by EBW will be equal to that at base metal. As for TIG, however, it was indicated that the corrosion resistance is possible to be lower than base metal. (author)

  14. Study by electronic microscopy of corrosion features of graphite after hot oxidation (air, 620 C)

    International Nuclear Information System (INIS)

    Jodon de Villeroche, Suzanne

    1968-01-01

    The author reports the study of corrosion features of graphite after hot oxidation in the air at 620 C. It is based on observations made by electronic microscopy. This study comes after another one dedicated to oxidation features obtained by hot corrosion of natural graphite, and aims at comparing pyrolytic graphite before and after irradiation in an atomic pile, and at performing tests on a graphite processed with ozone. After a recall of generalities about natural graphite and of some issues related to hot corrosion of natural graphite, the author presents some characteristics and features of irradiated and non-irradiated pyrolytic graphite. He reports the study of the oxidation of samples of pyrolytic graphite: production of thin lamellae, production of glaze-carbon replicates, oxidation of irradiated and of non-irradiated graphite, healing of irradiation defects, and oxidation of ozone-processed natural graphite [fr

  15. Study of sulphate-reducing bacteria corrosion in the weld joint for API X-70 steel

    Energy Technology Data Exchange (ETDEWEB)

    Flores, J. E.; Patino-Carachure, C.; Alfonso, I.; Rodriguez, J. A.; Rosas, G.

    2012-11-01

    The corrosion behavior originated by sulfate-reducing bacteria (SRB) was studied in two regions of welded API X-70 steel pipeline. The studies were focused on base material (BM) and heat affected zone (HAZ), from the internal region of the pipe. SRB were extracted from oil and grown in a Postgate medium. Corrosion was evaluated at 60 degree centigrade for times between 5 and 64 days. Potentiodynamic polarization curves, obtained by electrochemical techniques, indicated surface activation at short times. Structural and morphological characterizations were carried out by scanning electron microscopy (SEM) and optical microscopy (OM). H{sub 2}S concentration and pH were also measured. Results showed an important increase in the corrosion damage up to 20 days, influenced by the SRB activity, which lead to a maximum of H{sub 2}S (pH minimum). It was found a localized corrosion attack in the HAZ in a higher quantity compared to BM; and the formation of a thin film on the steel surface, originated by corrosion products and bacterial activity. (Author) 15 refs.

  16. Integrated analytical methodologies for the study of corrosion processes in archaeological bronzes

    Energy Technology Data Exchange (ETDEWEB)

    Alberghina, Maria Francesca; Barraco, Rosita; Brai, Maria; Schillaci, Tiziano, E-mail: tschillaci@unipa.it; Tranchina, Luigi

    2011-02-15

    The investigations on structure and micro-chemical composition of archaeological metal alloys are needed in archaeometry. The aim of this study is devoted both to acquire information about their provenance and production technology, and to improve our understanding about the corrosion processes. In this paper we present the study of the corrosion phenomena of bronze samples, laboratory-made according to binary, ternary and quaternary alloys typical of Roman archaeometallurgical production through an integrated methodology based on the use of non or micro invasive physical techniques. Among the analysed samples, two were artificially aged through burial in the archaeological site of Tharros, along the west coast of Sardinia (Italy). The corrosion products, typical of the bronzes in archaeological sites near the sea, have been characterized by non invasive and micro-destructive measurements. In particular, the corrosion patinas were examined through optical microscopy, scanning electron microscopy and microanalysis, X-ray fluorescence and laser ablation spectroscopy. The use of integrated technologies allowed us to determine both the elemental composition and surface morphology of the patina, highlighting the correlation between patina nature and chemical composition of the burial context. Moreover, data obtained by the laser-induced breakdown spectroscopy along the depth profile on the samples, have yielded information about the stratigraphic layers of corrosion products and their growth. Finally, the depth profiles allowed us to verify both the chemical elements constituting the patina, the metal ions constituting the alloy and the occurrence of migration phenomena from bulk to the surface.

  17. Integrated analytical methodologies for the study of corrosion processes in archaeological bronzes

    International Nuclear Information System (INIS)

    Alberghina, Maria Francesca; Barraco, Rosita; Brai, Maria; Schillaci, Tiziano; Tranchina, Luigi

    2011-01-01

    The investigations on structure and micro-chemical composition of archaeological metal alloys are needed in archaeometry. The aim of this study is devoted both to acquire information about their provenance and production technology, and to improve our understanding about the corrosion processes. In this paper we present the study of the corrosion phenomena of bronze samples, laboratory-made according to binary, ternary and quaternary alloys typical of Roman archaeometallurgical production through an integrated methodology based on the use of non or micro invasive physical techniques. Among the analysed samples, two were artificially aged through burial in the archaeological site of Tharros, along the west coast of Sardinia (Italy). The corrosion products, typical of the bronzes in archaeological sites near the sea, have been characterized by non invasive and micro-destructive measurements. In particular, the corrosion patinas were examined through optical microscopy, scanning electron microscopy and microanalysis, X-ray fluorescence and laser ablation spectroscopy. The use of integrated technologies allowed us to determine both the elemental composition and surface morphology of the patina, highlighting the correlation between patina nature and chemical composition of the burial context. Moreover, data obtained by the laser-induced breakdown spectroscopy along the depth profile on the samples, have yielded information about the stratigraphic layers of corrosion products and their growth. Finally, the depth profiles allowed us to verify both the chemical elements constituting the patina, the metal ions constituting the alloy and the occurrence of migration phenomena from bulk to the surface.

  18. Studies of corrosion morphologies by use of experiments and computer models

    Energy Technology Data Exchange (ETDEWEB)

    Johnsen, Terje

    1997-12-31

    CO{sub 2} corrosion of carbon steel is frequently encountered in the oil industry. This thesis studies the morphology of corroded metals and the dynamical evolution of corrosion attacks, especially pits and general corroded fronts, experimentally and by computerized simulation. Two experimental systems of carbon steel in CO{sub 2} bearing waters and aluminium in chloride containing electrolytes were used. Fractal geometry was used in analysing the corrosion patterns and found to be a fruitful technique. The position of the corroding fronts was obtained by destructive methods as well as non-destructive ones. To study fragile corrosion product layers or the corrosion process in situ, a grazing angle lighting technique was developed and found superior to other techniques. A computer model was developed that uses Monte Carlo technique to simulate the generation of localized pits and more general corroded front morphologies. A three-dimensional model and two versions of a two-dimensional model were developed. The three-dimensional model was used to provide incremental data of corroded volume and depth as a function of the simulation time. 185 refs., 97 figs., 16 tabs.

  19. Potentiodynamic polarization study of the corrosion behavior of palladium-silver dental alloys.

    Science.gov (United States)

    Sun, Desheng; Brantley, William A; Frankel, Gerald S; Heshmati, Reza H; Johnston, William M

    2018-04-01

    Although palladium-silver alloys have been marketed for over 3 decades for metal-ceramic restorations, understanding of the corrosion behavior of current alloys is incomplete; this understanding is critical for evaluating biocompatibility and clinical performance. The purpose of this in vitro study was to characterize the corrosion behavior of 3 representative Pd-Ag alloys in simulated body fluid and oral environments and to compare them with a high-noble Au-Pd alloy. The study obtained values of important electrochemical corrosion parameters, with clinical relevance, for the rational selection of casting alloys. The room temperature in vitro corrosion characteristics of the 3 Pd-Ag alloys and the high-noble Au-Pd alloy were evaluated in 0.9% NaCl, 0.09% NaCl, and Fusayama solutions. After simulated porcelain firing heat treatment, 5 specimens of each alloy were immersed in the electrolytes for 24 hours. For each specimen, the open-circuit potential (OCP) was first recorded, and linear polarization was then performed from -20 mV to +20 mV (versus OCP) at a rate of 0.125 mV/s. Cyclic polarization was subsequently performed on 3 specimens of each alloy from -300 mV to +1000 mV and back to -300 mV (versus OCP) at a scanning rate of 1 mV/s. The differences in OCP and corrosion resistance parameters (zero-current potential and polarization resistance) among alloys and electrolyte combinations were compared with the 2-factor ANOVA (maximum-likelihood method) with post hoc Tukey adjustments (α=.05). The 24-hour OCPs and polarization resistance values of the 3 Pd-Ag alloys and the Au-Pd alloy were not significantly different (P=.233 and P=.211, respectively) for the same electrolyte, but significant differences were found for corrosion test results in different electrolytes (Palloy and electrolyte (P=.249 and P=.713, respectively). The 3 Pd-Ag silver alloys appeared to be resistant to chloride ion corrosion, and passivation and de-alloying were identified for these

  20. Electrochemical Study of Welded AISI 304 and 904L Stainless Steel in Seawater in View of Corrosion

    Directory of Open Access Journals (Sweden)

    Richárd Székely

    2010-10-01

    Full Text Available This is a comparative study of the corrosion behaviour of welds in AISI 304 and AISI 904L stainless steels carried out in seawater model solution in the temperature range 5-35°C and the standard of corrosion testing of welds was followed. The corrosion rate and corrosion attack characteristics were determined for welds of the examined steels with several type of treatment. The aim of this work was to compare the steels based on their resistance against the corrosion in terms of pitting potential (Epit and repassivation potential (Erepass. Seawater is an electrochemically aggressive medium, which can initiate localised corrosion in welded stainless steels. Different electrochemical and testing methods were used, including cyclic voltammetry, chronopotentiometry, electrochemical impedance spectroscopy (EIS, pH measuring and penetration tests.

  1. Fundamental Studies of the Role of Grain Boundaries on Uniform Corrosion of Advanced Nuclear Reactor Materials

    International Nuclear Information System (INIS)

    Taheri, Mitra; Motta, Arthur; Marquis, Emmanuelle

    2016-01-01

    The main objective of this proposal is to develop fundamental understanding of the role of grain boundaries in stable oxide growth. To understand the process of oxide layer destabilization, it is necessary to observe the early stages of corrosion. During conventional studies in which a sample is exposed and examined after removal from the autoclave, the destabilization process will normally have already taken place, and is only examined post facto. To capture the instants of oxide destabilization, it is necessary to observe it in situ; however, significant questions always arise as to the influence of the corrosion geometry and conditions on the corrosion process. Thus, a combination of post facto examinations and in situ studies is proposed, which also combines state-of-the-art characterization techniques to derive a complete understanding of the destabilization process and the role of grain boundaries.

  2. Fundamental Studies of the Role of Grain Boundaries on Uniform Corrosion of Advanced Nuclear Reactor Materials

    Energy Technology Data Exchange (ETDEWEB)

    Taheri, Mitra [Drexel Univ., Philadelphia, PA (United States); Motta, Arthur [Pennsylvania State Univ., University Park, PA (United States); Marquis, Emmanuelle [Univ. of Michigan, Ann Arbor, MI (United States)

    2016-05-20

    The main objective of this proposal is to develop fundamental understanding of the role of grain boundaries in stable oxide growth. To understand the process of oxide layer destabilization, it is necessary to observe the early stages of corrosion. During conventional studies in which a sample is exposed and examined after removal from the autoclave, the destabilization process will normally have already taken place, and is only examined post facto. To capture the instants of oxide destabilization, it is necessary to observe it in situ; however, significant questions always arise as to the influence of the corrosion geometry and conditions on the corrosion process. Thus, a combination of post facto examinations and in situ studies is proposed, which also combines state-of-the-art characterization techniques to derive a complete understanding of the destabilization process and the role of grain boundaries.

  3. Study of corrosion of aluminium alloys of nuclear purity in ordinary water, пart one

    Directory of Open Access Journals (Sweden)

    Pešić Milan P.

    2004-01-01

    Full Text Available Effects of corrosion of aluminum alloys of nuclear purity in ordinary water of the spent fuel storage pool of the RA research reactor at VINČA Institute of Nuclear Sciences has been examined in the frame work of the International Atomic Energy Agency Coordinated Research Project "Corrosion of Research Reactor Aluminum-Clad Spent Fuel in Water" since 2002. The study presented in this paper comprises activities on determination and monitoring of chemical parameters and radio activity of water and sludge in the RA spent fuel storage pool and results of the initial study of corrosion effects obtained by visual examinations of surfaces of various coupons made of aluminum alloys of nuclear purity of the test racks exposed to the pool water for a period from six months to six years.

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

    Science.gov (United States)

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

    2018-03-01

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

  5. The study on intergranular corrosion of sensitized Alloy 600 using DL-EPR and Huey method

    International Nuclear Information System (INIS)

    Lee, B. G.; Lee, H. R.; Kim, H. P.; Ryu, W. S.; Rhee, C. K.

    1998-01-01

    Intergranular corrosion(IGC) of sensitized Alloy 600 has been studied with double loop-electrochemical potentiokinetic reactivation(DL-EPR) and Huey tests. Corrosion of solution annealed Ni-XCr-10Fe(X=6∼15) alloys was also evaluated with DL-EPR and Huey methods to simulate corrosion of Cr-depleted grain boundary region of Alloy 600. Cr concentration of Cr-depleted grain boundary region of Alloy 600. Cr concentration profile across grain boundary was measured with TEM. In the range of the Cr concentration from 6 to 8%, corrosion rates of solution annealed Ni-XCr-10Fe(X=6∼15) alloys were much higher in Huey test than those in DL-EPR. But in the range of the Cr concentration from 12 to 15%, the trend was reversed. The width of IGC crack of Alloy 600 was higher in DL-EPR test than in Huey test in agreement with corrosion of solution annealed Ni-XCr-10Fe alloys. Width of IGC produced by DL-EPR test was almost uniform and wide while that produced by Huey test was sharp and marrow. These results suggest that IGC in DL-EPR test conforms to uniform dissolution model and IGC in Huey test conforms to Cr concentration dependent dissolution model

  6. A mechanistic study of the uniform corrosion of copper in compacted clay-sand soil

    International Nuclear Information System (INIS)

    Litke, C.D.; Ryan, S.R.; King, F.

    1992-08-01

    The results of a study of the mechanism of uniform corrosion of copper under simulated nuclear fuel waste disposal conditions are presented. Evidence is given that suggests that the rate-controlling process is the transport of copper corrosion products away from the corroding surface. In the experiments described here, the copper diffused through a column of compacted clay-sand buffer. The properties of the buffer material, especially its ability to sorb copper species, are significant in determining the rate of uniform corrosion of copper. The evidence that copper diffusion is rate-controlling stems from the effect of γ-radiation on the tests. In the presence of γ-radiation, copper diffused farther along the column of compacted buffer material than in the unirradiated tests, but the corrosion rate was lower. These two effects can be best explained in terms of a slow copper-diffusion process. Irradiation is thought to reduce the extent of sorption of copper by the clay component of the buffer. This results in a more mobile copper species and a smaller interfacial flux of copper (i.e., a lower corrosion rate)

  7. Electrochemical Impedance and Polarization Corrosion Studies of Tantalum Surface Modified by DC Plasma Electrolytic Oxidation

    Directory of Open Access Journals (Sweden)

    Maciej Sowa

    2018-04-01

    Full Text Available Tantalum has recently become an actively researched biomaterial for the bone reconstruction applications because of its excellent corrosion resistance and successful clinical records. However, a bare Ta surface is not capable of directly bonding to the bone upon implantation and requires some method of bioactivation. In this study, this was realized by direct current (DC plasma electrolytic oxidation (PEO. Susceptibility to corrosion is a major factor determining the service-life of an implant. Therefore, herein, the corrosion resistance of the PEO coatings on Ta was investigated in Ringer’s solution. The coatings were formed by galvanostatic anodization up to 200, 300 and 400 V, after which the treatment was conducted potentiostatically until the total process time amounted to 5 min. Three solutions containing Ca(H2PO22, Ca(HCOO2 and Mg(CH3COO2 were used in the treatment. For the corrosion characterization, electrochemical impedance spectroscopy and potentiodynamic polarization techniques were chosen. The coatings showed the best corrosion resistance at voltages low enough so that the intensive sparking was absent, which resulted in the formation of thin films. The impedance data were fitted to the equivalent electrical circuits with two time constants, namely R(Q[R(QR] and R(Q[R(Q[RW

  8. Study of the formation and transport of corrosion products in PWR primary circuit simulators

    International Nuclear Information System (INIS)

    Noe, M.; Frejaville, G.; Camp, J.J.

    1983-01-01

    The formation, migration and deposition of corrosion products in PWR primary circuits are studied in out-of-reactor loops. The aim of these studies is to limit the build-up of the radiation fields impinging on out-of-flux walls and to reduce the danger of rapid corrosion of fuel cans, taking into account the tougher conditions imposed on current trends in the operation of such industrial plants. Four simulator loops and their respective possibilities and research methods are described. (author)

  9. Studies on corrosion of mild steel by water using Moessbauer spectroscopy

    International Nuclear Information System (INIS)

    Nigam, A.N.; Tripathi, R.P.; Jangid, M.L.

    1987-01-01

    The corrosion of mild steel as a result of interaction with various types of local natural water samples and distilled water is studied with the help of Moessbauer spectroscopy. The data are supplemented with the studies on IR and magnetic properties as and when required. Distilled water and potable water behave in almost similar fashion wherein ferrihydrite and FeOOH are observed to be the precursors of magnetite, the end corrosion product. In case of brakish water, the additional species, viz., FeCl 2 , βFeOOH and an intermediate possibly FeOCl are accounted, and possible mechanisms are suggested. (author)

  10. Corrosion study of resorbable Ca60Mg15Zn25 bulk metallic glasses in physiological fluids

    Directory of Open Access Journals (Sweden)

    Rafał Babilas

    2017-10-01

    Full Text Available The corrosion activity of amorphous plates of Ca60Mg15Zn25 alloy was investigated. The biocompatible elements were selected for the alloy composition. The electrochemical corrosion and immersion tests were carried out in a multi-electrolyte fluid and Ringer's solution. Better corrosion behavior was observed for the samples tested in a multi-electrolyte fluid despite the active dissolution of Ca and Mg in Ringer's solution. The experimental results indicated that reducing concentration of NaCl from 8.6 g/dm3 for Ringer's solution to 5.75 g/dm3 caused the decrease of the corrosion rate. The volume of the hydrogen evolved after 480 min in Ringer's solution (40.1 ml/cm2 was higher in comparison with that obtained in a multi-electrolyte fluid (24.4 ml/cm2. The values of open-circuit potential (EOCP for the Ca60Mg15Zn25 glass after 1 h incubation in Ringer's solution and a multi-electrolyte fluid were determined to be −1553 and −1536 mV vs. a saturated calomel electrode (SCE. The electrochemical measurements indicated a shift of the corrosion current density (jcorr from 1062 μA/cm2 for the sample tested in Ringer's solution to 788 μA/cm2 for the specimen immersed in a multi-electrolyte fluid. The corrosion products analysis was conducted by using the X-ray photoelectron spectroscopy (XPS. The corrosion products were identified to be CaCO3, Mg(OH2, CaO, MgO and ZnO. The mechanism of corrosion process was proposed and described based on the microscopic observations. The X-ray diffraction and Fourier transform infrared spectroscopy (FTIR also indicated that Ca(OH2, CaCO3, Zn(OH2 and Ca(Zn(OH32·2H2O mainly formed on the surface of the studied alloy. Keywords: Ca-based metallic glasses, X-ray photoelectron spectroscopy, FTIR spectroscopy, X-ray diffraction, Corrosion resistance, Hydrogen evaluation

  11. Study on corrosion test techniques in lead bismuth eutectic flow. Joint research report in JFY2002

    International Nuclear Information System (INIS)

    Takahashi, Minoru; Sekimoto, Hiroshi

    2003-03-01

    The evaluation of corrosion behaviors of core and structural materials in lead bismuth eutectic is one of the key issues for the utilization of lead bismuth eutectic as a coolant of the primary loops of lead bismuth cooled fast breeder reactors (FBRs) and the intermediate heat transport media of new-type steam generators of the sodium cooled FBRs. The purpose of the present study is to establish corrosion test techniques in lead bismuth eutectic flow. The techniques of steel corrosion test and oxygen control in flowing lead bismuth eutectic, and the technologies of a lead bismuth flow test at high temperature and high velocity were developed through corrosion test using a lead bismuth flow test loop of the Tokyo Institute of Technology in JFY2002. The major results are summarized as follows: (1) Techniques of fabrication, mount and rinse of corrosion specimens, measurement method of weight loss, and SEM/EDX analysis method have been established through lead bismuth corrosion test. (2) Weight losses were measured, corrosion and lead bismuth-adhered layers and eroded parts were observed in two 1000 hr-corrosion tests, and the results were compared with each other for twelve existing steels including ODS, F82H and SUH-3. (3) An oxygen sensor made of zirconia electrolyte structurally resistant to thermal stress and thermal shock was developed and tested in the lead bismuth flow loop. Good performance has been obtained. (4) An oxygen control method by injecting argon and hydrogen mixture gas containing steam into lead bismuth was applied to the lead bismuth flow loop, and technical issues for the development of the oxygen control method were extracted. (5) Technical measures for freezing and leakage of lead bismuth in the flow loop were accumulated. (6) Technical measures for flow rate decrease/blockage due to precipitation of oxide and corrosion products in a low temperature section of the lead bismuth flow loop were accumulated. (7) Electromagnetic flow meters with MI

  12. Study on mitigation of stress corrosion cracking by peening

    International Nuclear Information System (INIS)

    Maeguchi, Takaharu; Tsutsumi, Kazuya; Toyoda, Masahiko; Ohta, Takahiro; Okabe, Taketoshi; Sato, Tomonobu

    2010-01-01

    In order to verify stability of residual stress improvement effect of peeing for mitigation of stress corrosion cracking in components of PWR plant, relaxation behavior of residual stress induced by water jet peening (WJP) and ultrasonic shot peening (USP) on surface of alloy 600 and its weld metal was investigated under various thermal aging and stress condition considered for actual plant operation. In the case of thermal aging at 320-380degC, surface residual stress relaxation was observed at the early stage of thermal aging, but no significant stress relaxation was observed after that. Applied stress below yield stress does not significantly affect stress relaxation behavior of surface residual stress. Furthermore, it was confirmed that cyclic stress does not accelerate stress relaxation. (author)

  13. Moessbauer study of corrosion induced by acid rain

    International Nuclear Information System (INIS)

    Arshed, M.; Hussain, N.; Siddiqui, M.; Anwar-ul-Islam, M.; Rehman, S.; Butt, N.M.

    1997-01-01

    Strictly speaking acid rain refers to wet precipitation of pollutants S0/sub 2/SO/sub 3/ and NO/sub x/HNO/sub 3/ which have dissolved in cloud and rain droplets to from sulphuric and nitric acids. Acid rain has seriously damaged pine and spruce forests in Canada, USA and Europe. In these areas it has caused damage to buildings, reduced fish population due to acidification of lakes and rivers, and affected health of human beings as a result of poor water quality. The corrosion products formed in a simulated acid rain environment have been identified with transmission Moessbauer spectroscopy using a /sup 57/Co source. They were found to be gamma-FeOOH, alpha-FeOOH, gamma-Fe/sub 2/O/sub 3/ and a phase with unfamiliar parameters which seems to be amorphous in nature and can be considered as an intermediate phase. (author)

  14. A novel high-strength and highly corrosive biodegradable Fe-Pd alloy: Structural, mechanical and in vitro corrosion and cytotoxicity study.

    Science.gov (United States)

    Čapek, Jaroslav; Msallamová, Šárka; Jablonská, Eva; Lipov, Jan; Vojtěch, Dalibor

    2017-10-01

    Recently, iron-based materials have been considered as candidates for the fabrication of biodegradable load-bearing implants. Alloying with palladium has been found to be a suitable approach to enhance the insufficient corrosion rate of iron-based alloys. In this work, we have extensively compared the microstructure, the mechanical and corrosion properties, and the cytotoxicity of an FePd2 (wt%) alloy prepared by three different routes - casting, mechanical alloying and spark plasma sintering (SPS), and mechanical alloying and the space holder technique (SHT). The properties of the FePd2 (wt%) were compared with pure Fe prepared in the same processes. The preparation route significantly influenced the material properties. Materials prepared by SPS possessed the highest values of mechanical properties (CYS~750-850MPa) and higher corrosion rates than the casted materials. Materials prepared by SHT contained approximately 60% porosity; therefore, their mechanical properties reached the lowest values, and they had the highest corrosion rates, approximately 0.7-1.2mm/a. Highly porous FePd2 was tested in vitro according to the ISO 10993-5 standard using L929 cells, and two-fold diluted extracts showed acceptable cytocompatibility. In general, alloying with Pd enhanced both mechanical properties and corrosion rates and did not decrease the cytocompatibility of the studied materials. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Corrosion Behavior of Surface-Treated Implant Ti-6Al-4V by Electrochemical Polarization and Impedance Studies

    Science.gov (United States)

    Paul, Subir; Yadav, Kasturi

    2011-04-01

    Implant materials for orthopedic and heart surgical services demand a better corrosion resistance material than the presently used titanium alloys, where protective oxide layer breaks down on a prolonged stay in aqueous physiological human body, giving rise to localized corrosion of pitting, crevice, and fretting corrosion. A few surface treatments on Ti alloy, in the form of anodization, passivation, and thermal oxidation, followed by soaking in Hank solution have been found to be very effective in bringing down the corrosion rate as well as producing high corrosion resistance surface film as reflected from electrochemical polarization, cyclic polarization, and Electrochemical Impedance Spectroscopy (EIS) studies. The XRD study revealed the presence of various types of oxides along with anatase and rutile on the surface, giving rise to high corrosion resistance film. While surface treatment of passivation and thermal oxidation could reduce the corrosion rate by 1/5th, anodization in 0.3 M phosphoric acid at 16 V versus stainless steel cathode drastically brought down the corrosion rate by less than ten times. The mechanism of corrosion behavior and formation of different surface films is better understood from the determination of EIS parameters derived from the best-fit equivalent circuit.

  16. Study on Mitigation Method of Solder Corrosion for Crystalline Silicon Photovoltaic Modules

    Directory of Open Access Journals (Sweden)

    Ju-Hee Kim

    2014-01-01

    Full Text Available The corrosion of 62Sn36Pb2Ag solder connections poses serious difficulties for outdoor-exposed photovoltaic (PV modules, as connection degradation contributes to the increase in series resistance (RS of PV modules. In this study, we investigated a corrosion mitigation method based on the corrosion mechanism. The effect of added sacrificial metal on the reliability of PV modules was evaluated using the oxidation-reduction (redox reaction under damp heat (DH conditions. Experimental results after exposure to DH show that the main reason for the decrease in power was a drop in the module’s fill factor. This drop was attributed to the increase of RS. The drop in output power of the PV module without added sacrificial metal is greater than that of the sample with sacrificial metal. Electroluminescence and current-voltage mapping analysis also show that the PV module with sacrificial metal experienced less degradation than the sample without sacrificial metal.

  17. Study on fracture and stress corrosion cracking behavior of casing sour service materials

    International Nuclear Information System (INIS)

    Sequera, C.; Gordon, H.

    2003-01-01

    Present work describes sulphide stress corrosion cracking and fracture toughness tests performed to high strength sour service materials of T-95, C-100 and C-110 oil well tubular grades. P-110 was considered as a reference case, since it is one of the high strength materials included in specification 5CT of American Petroleum Institute, API. Sulphide stress corrosion cracking, impact and fracture toughness values obtained in the tests show that there is a correspondence among them. A decreasing classification order was established, namely C-100, T-95, C-110 and P-110. Special grades steels studied demonstrated a better behavior in the evaluated properties than the reference case material grade: P-110. Results obtained indicate that a higher sulphide stress corrosion cracking resistance is related to a higher toughness. The fracture toughness results evidence the hydrogen influence on reducing the toughness values. (author)

  18. Electrolytic corrosion of water pipeline system in the remote distance from stray currents—Case study

    Directory of Open Access Journals (Sweden)

    Krzysztof Zakowski​

    2016-06-01

    Full Text Available Case study of corrosion failure of urban water supply system caused by the harmful effects of stray currents was presented. The failure occurred at a site distant from the sources of these currents namely the tramway and railway traction systems. Diagnosis revealed the stray currents flow to pipeline over a remote distance of 800/1000 m from the point of failure. At the point of failure stray currents flowed from the pipeline to the ground through external insulation defects, causing the process of electrolytic corrosion of the metal. Long distance between the affected section of the pipeline and the sources of stray currents excludes the typical protection against stray currents in the form of electrical polarized drainage. Corrosion protection at this point can be achieved by using the earthing electrodes made of magnesium, which will also provide cathodic current protection as galvanic anode.

  19. Use of electrochemical techniques to study the corrosion of metals in model fluoride melts

    Energy Technology Data Exchange (ETDEWEB)

    Fabre, S. [EDF R and D, Département MMC, Groupe Chimie et Corrosion, 77818 Moret-sur-Loing Cedex (France); Cabet, C., E-mail: celine.cabet@cea.fr [CEA, DEN, DPC, SCCME, Laboratoire d’Etude de la Corrosion Non Aqueuse, F-91191 Gif-sur-Yvette (France); Cassayre, L.; Chamelot, P. [Université Toulouse, INPT, UPS, Laboratoire de Génie Chimique, Département Procédés Electrochimiques, F-31062 Toulouse Cedex 09 (France); Delepech, S. [ENSCP, Laboratoire d’Électrochimie, de Chimie des Interface et Modélisation pour l’Energie, UMR 7575, 11 rue Pierre et Marie Curie, 75232 Paris Cedex 5 (France); Finne, J. [EDF R and D, Département MMC, Groupe Chimie et Corrosion, 77818 Moret-sur-Loing Cedex (France); Massot, L. [Université Toulouse, INPT, UPS, Laboratoire de Génie Chimique, Département Procédés Electrochimiques, F-31062 Toulouse Cedex 09 (France); Noel, D. [EDF R and D, Département MMC, Groupe Chimie et Corrosion, 77818 Moret-sur-Loing Cedex (France)

    2013-10-15

    Molten fluorides are appealing coolants for innovative nuclear systems but structural alloys may undergo corrosion at high temperature. Because corrosion primarily occurs via electrochemical reactions, electrochemical techniques are ideal for the study of corrosion thermochemistry and kinetics. Examples are given. An electrochemical series was established using voltammetry in LiF–NaF at 1173 K. Stability increases in the following order: Na, Cr, Fe, Ni, Mo/W, Ag, Au. Various alloys were also classified according to their oxidation resistance. A cathodic protection method was developed to curb the intergranular attack of some nickel alloys in molten LiF–CaF{sub 2}–MgF{sub 2}–ZrF{sub 4} containing tellurium vapor at 953 K. Voltammetry and polarization resistance measurement were used to estimate the rate of chromium selective dissolution for nickel base alloys immersed in LiF–NaF at 1073 K and 1173 K.

  20. Quantitative Study on Corrosion of Steel Strands Based on Self-Magnetic Flux Leakage

    Directory of Open Access Journals (Sweden)

    Runchuan Xia

    2018-05-01

    Full Text Available This paper proposed a new computing method to quantitatively and non-destructively determine the corrosion of steel strands by analyzing the self-magnetic flux leakage (SMFL signals from them. The magnetic dipole model and three growth models (Logistic model, Exponential model, and Linear model were proposed to theoretically analyze the characteristic value of SMFL. Then, the experimental study on the corrosion detection by the magnetic sensor was carried out. The setup of the magnetic scanning device and signal collection method were also introduced. The results show that the Logistic Growth model is verified as the optimal model for calculating the magnetic field with good fitting effects. Combined with the experimental data analysis, the amplitudes of the calculated values (BxL(x,z curves agree with the measured values in general. This method provides significant application prospects for the evaluation of the corrosion and the residual bearing capacity of steel strand.

  1. Laboratory Study of High Temperature Corrosion in Straw-fired Power Plants

    DEFF Research Database (Denmark)

    Montgomery, Melanie; Maahn, Ernst emanuel

    1997-01-01

    The components contributing to corrosion, HCl(g)SO2(g), KCl and K2SO4 were studied in the laboratory for Sandvik 8LR30 and Sanicro 28. The influence of HCl and SO2 was investigated at 600C material temperature and 600/800C flue gas temperature at time intervals up to 300 hours. The influence of ash...... deposits in air was examined at 525C-700C. Finally exposures were undertaken combining the aforementioned aggressive gas environment with the ash deposits. Thus the corrosion potential of individual components were evaluated and also whether they had a synergistic, antagonistic or additive effect on one...... another to influence the overall corrosion rate....

  2. Study of vanadium-based chemical conversion coating on the corrosion resistance of magnesium alloy

    International Nuclear Information System (INIS)

    Yang, K.H.; Ger, M.D.; Hwu, W.H.; Sung, Y.; Liu, Y.C.

    2007-01-01

    In this study, magnesium alloy (AZ61) was immersed in vanadium containing bath with various conditions, such as the vanadium concentration, immersion time and bath temperature. The results indicate that increase of both vanadium concentration and immersion time produces a thicker conversion layer. However, when immersion time is too long, it will worsen the corrosion resistance due to the increasing of the crack density. The experimental parameter of bath temperature has no significant effect on corrosion resistance. Our results demonstrated that the better corrosion resistance coating can be obtained when the samples are submitted to an immersion in the conversion bath containing NaVO 3 with concentration of 30 g l -1 for 10 min at 80 deg. C. The presented conversion treatment has its potential to replace the chrome-based conversion coating treatment

  3. Corrosion studies on Cu-Ni alloys and ferritic steel in salt water for desalination service

    International Nuclear Information System (INIS)

    Shibad, P.R.; Balachandra, J.

    1975-01-01

    Corrosion studies on In 838 and In 848 alloys in 3% NaCl solution, synthetic sea water and in 3% NaCl at pH3 and pH10 indicate that the latter alloy is more corrosion resistant than the former at room (28 0 C), and boiling temperature (101 0 C) and at 125 0 C. Ferritic steel is unaffected in boiling synthetic sea water. In boiling 3% NaCl solution at pH3 and pH10, (the pH values adjusted at room temperature) increase in the rate of corrosion of ferritic steel compared to that at room temperature has been observed. A fair correlation between polarization characteristics and dissolution rates in these solutions is seen for all these materials. (author)

  4. A comparative study of leaves extracts for corrosion inhibition effect on aluminium alloy in alkaline medium

    Directory of Open Access Journals (Sweden)

    Namrata Chaubey

    2017-12-01

    Full Text Available This paper deals with the comparative inhibition study of some plants leaves extract namely Cannabis sativa (CS, Rauwolfia serpentina (RS, Cymbopogon citratus (CC, Annona squamosa (AS and Adhatoda vasica (AV on the corrosion of aluminium alloy (AA in 1 M NaOH. The corrosion tests were performance by using gravimetric, electrochemical impedance spectroscopy (EIS, potentiodynamic polarization and linear polarization resistance (LPR techniques. RS showed maximum inhibition efficiency (η%, 97% at 0.2 g L−1. Potentiodynamic polarization curves justified that all the inhibitors are mixed-type. Surface morphology of AA is carried by scanning electron microscopy (SEM and atomic force microscopy (AFM.

  5. Electron microscopy studies in a high corrosion resistant Ti-Ta-Nb alloy

    International Nuclear Information System (INIS)

    Mythili, R.; Saroja, S.; Vijayalakshmi, M.

    2010-01-01

    Electron microscopy has played an important role in the indigenous development of Ti-5Ta-1.8Nb, an α+β alloy, for reprocessing applications. TEM was used to study the Widmanstatten, martensitic, and the omega phase transformations in the system. A wide spectrum of phase transformations could be introduced into the system, by modifying the composition of the β phase and the cooling rate. PEELS was used to understand the corrosion mechanism, by characterizing the passive film after the corrosion reactions

  6. Study of scratch-induced stress corrosion cracking for steam generator tubes and scratch control

    International Nuclear Information System (INIS)

    Meng, F.; Xu, X.; Liu, X.; Wang, J.

    2014-01-01

    This paper introduces field cases for scratch-induced stress corrosion cracking (SISCC) of steam generator tubes in PWR and current studies in laboratories. According to analysis result of broke tubes, scratches caused intergranular stress corrosion cracking (IGSCC) with outburst. The effect of microstructure for nickel-base alloys, residual stresses caused by scratching process and water chemistry on SISCC and possible mechanism of SISCC are discussed. The result shows that scratch-induced microstructure evolution contributes to SISCC significantly. The causes of scratches during steam generator tubing manufacturing and installation process are stated and improved reliability with scratch control is highlighted for steam generator tubes in newly built nuclear power plants. (author)

  7. Study of scratch-induced stress corrosion cracking for steam generator tubes and scratch control

    Energy Technology Data Exchange (ETDEWEB)

    Meng, F.; Xu, X.; Liu, X. [Shanghai Nuclear Engineering Research and Design Institute, Shanghai (China); Wang, J. [Chinese Academy of Sciences, Institute of Metal Research, Shenyang (China)

    2014-07-01

    This paper introduces field cases for scratch-induced stress corrosion cracking (SISCC) of steam generator tubes in PWR and current studies in laboratories. According to analysis result of broke tubes, scratches caused intergranular stress corrosion cracking (IGSCC) with outburst. The effect of microstructure for nickel-base alloys, residual stresses caused by scratching process and water chemistry on SISCC and possible mechanism of SISCC are discussed. The result shows that scratch-induced microstructure evolution contributes to SISCC significantly. The causes of scratches during steam generator tubing manufacturing and installation process are stated and improved reliability with scratch control is highlighted for steam generator tubes in newly built nuclear power plants. (author)

  8. Thermometric Study of Inhibition of Aluminium Corrosion in Hydrochloric Acid Solution

    OpenAIRE

    Al Gaber, A.S. [امينة سلطان الجابر; Seliman, S. A.; Mourad, M.

    1997-01-01

    The use of 6- amino - 4- (4-phenyl)-l,4- dihydro -3- methylpyrano [2,3- c] pyrazole -5- carbonitrile and some related compounds as corrosion inhibitors for aluminium in 2 M HCl solution was studied by the thermometric method. The results indicate that the additives reduce the corrosion rate via weak adsorption through the cationic oxygen of the pyran ring. They act as mixed inhibitors and their adsorption was found to obey Frumkin's isotherm. The inhibition efficiency of the additives is rela...

  9. Study of alloy 600'S stress corrosion cracking mechanisms in high temperature water

    International Nuclear Information System (INIS)

    Rios, R.

    1994-06-01

    In order to better understand the mechanisms involved in Alloy 600's stress corrosion cracking in PWR environment, laboratory tests were performed. The influence of parameters pertinent to the mechanisms was studies : hydrogen and oxygen overpressures, local chemical composition, microstructure. The results show that neither hydrogen nor dissolution/oxidation, despite their respective roles in the process, are sufficient to account for experimental facts. SEM observation of micro-cleavage facets on specimens' fracture surfaces leads to pay attention to a new mechanism of corrosion/plasticity interactions. (author). 113 refs., 73 figs., 15 tabs., 4 annexes

  10. Study of alloy 600 (NC15Fe) stress corrosion cracking mechanisms in high temperature water

    International Nuclear Information System (INIS)

    Rios, Richard

    1993-01-01

    In order to better understand the mechanisms involved in Alloy 600's stress corrosion cracking in PWR environment, laboratory tests were performed. The influence of parameters pertinent to the mechanisms was studies: hydrogen and oxygen overpressures, local chemical composition, microstructure. The results show that neither hydrogen nor dissolution/oxidation, despite their respective roles in the process, are sufficient to account for experimental facts. SEM observation of micro-cleavage facets on specimens' fracture surfaces leads to pay attention to a new mechanism of corrosion/plasticity interactions. (author) [fr

  11. Effect of elevated lithium on the waterside corrosion of zircaloy-4: Experimental and predictive studies

    International Nuclear Information System (INIS)

    Pecheur, D.; Giordano, A.; Picard, E.; Billot, P.; Thomazet, J.

    1997-01-01

    Lithium and boron content in the coolant are known to influence the oxidation behaviour of the fuel cladding. Since new PWR operating conditions could consist in an increase of the lithium and the boron concentration in the coolant early in the cycle, a specific study has been conducted to analyze and to predict the effect of such new water chemistry conditions on the oxidation kinetics of the Zircaloy-4 material. Experimental studies have been performed in out-of-pile loop tests, under one and two phase flow heat transfer in various water chemistry conditions (0≤Li≤350 ppm, 0≤B≤1000 ppm, 0≤K≤56 ppm). A simulation of the effect of elevated lithium on the corrosion has been made using the semi-empirical COCHISE corrosion code. Under one phase flow heat transfer conditions, the addition of lithium hydroxide in the coolant increases the oxidation rate, essentially in the post-transition regime for low lithium levels (≤ 75 ppm) and immediately in the pre-transition phase for very high lithium level (350 ppm). Under two phase flow heat transfer, an enhancement of the corrosion is observed in the area of the rod submitted to boiling. Based on the out-of-pile loop test performed in presence of KOH instead of LiOH, such an enhancement of the corrosion appears to be due to a lithium enrichment in the oxide layer induced by boiling and not to a pH effect. The simulation of the increase of lithium content in the coolant from 2.2 to 3.5 ppm leads to an enhancement in corrosion rates which becomes only significant at high burn up. This predictive result of elevated lithium effect on corrosion is then compared with oxidation data derived from reactors operating under an elevated lithium regime. (author). 14 refs, 9 figs, 3 tabs

  12. Positive aspects issued from bio corrosion studies: from hydrogen production to biofuel cells

    International Nuclear Information System (INIS)

    Silva Munoz, L. de

    2007-12-01

    Microbially influenced corrosion or bio corrosion is a problem that generates heavy global economic losses (several billion euros per year). In spite of the progress made on the understanding of the underlying mechanisms, the complexity of the phenomenon has prevented finding definitive solutions to the problem and continues to inspire many research works. The participation in bio corrosion of catalytic mechanisms induced by weak acids was studied in this work. Another objective of the thesis has been to take advantage from catalytic phenomena found in bio corrosion research to apply them in other areas: energy production with biofuel cells or electrochemical hydrogen production in mild conditions. This work has shown that the presence of weak acids and amino acids inside bio-films could play a major role in steel bio corrosion accelerating the phenomenon through the catalysis of the water reduction reaction. The reversibility of this mechanism, discerned and proved here, could explain the corrosion increase when hydrogen is removed (bacterial consumption, agitation...). In addition, phosphates allow the production of hydrogen by electrolysis in mild pH conditions (pH 4.0 - 8.0) with an equal or better performance than those found in alkaline electrolysis. Finally, industrial materials like stainless steel and titanium could be used in the fabrication of enzymatic electrodes for biosensors or microsystems. The use of the glucose oxidase/glucose system in an aqueous fuel cell with a stainless steel cathode, allows the improvement of the cell performance thanks to the production of hydrogen peroxide that is easily reduced. Moreover, the use of materials with micro-structured surfaces like sandblasted steels deserve to be studied in detail to exploit the remarkable reactivity they present compared to smooth electrodes. (author)

  13. Positive aspects issued from bio-corrosion studies: from hydrogen production to biofuel cells

    International Nuclear Information System (INIS)

    De Silva Munoz, Leonardo

    2007-01-01

    Microbially influenced corrosion or bio-corrosion is a problem that generates heavy global economic losses (several billion euros per year). In spite of the progress made on the understanding of the underlying mechanisms, the complexity of the phenomenon has prevented finding definitive solutions to the problem and continues to inspire many research works. The participation in bio-corrosion of catalytic mechanisms induced by weak acids was studied in this work. Another objective of the thesis has been to take advantage from catalytic phenomena found in bio corrosion research to apply them in other areas: energy production with biofuel cells or electrochemical hydrogen production in mild conditions. This work has shown that the presence of weak acids and amino acids inside bio films could play a major role in steel bio-corrosion accelerating the phenomenon through the catalysis of the water reduction reaction. The reversibility of this mechanism, discerned and proved here, could explain the corrosion increase when hydrogen is removed (bacterial consumption, agitation...). In addition, phosphates allow the production of hydrogen by electrolysis in mild ph conditions (pH 4.0 - 8.0) with an equal or better performance than those found in alkaline electrolysis. Finally, industrial materials like stainless steel and titanium could be used in the fabrication of enzymatic electrodes for biosensors or microsystems. The use of the glucose oxidase / glucose system in an aqueous fuel cell with a stainless steel cathode, allows the improvement of the cell performance thanks to the production of hydrogen peroxide that is easily reduced. Moreover, the use of materials with micro-structured surfaces like sandblasted steels deserve to be studied in detail to exploit the remarkable reactivity they present compared to smooth electrodes. (author) [fr

  14. Effect of elevated lithium on the waterside corrosion of zircaloy-4: Experimental and predictive studies

    Energy Technology Data Exchange (ETDEWEB)

    Pecheur, D; Giordano, A; Picard, E; Billot, P [CEA Centre d` Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France); Thomazet, J [FRAMATOME, Nuclear Fuel Div., Lyon (France)

    1997-02-01

    Lithium and boron content in the coolant are known to influence the oxidation behaviour of the fuel cladding. Since new PWR operating conditions could consist in an increase of the lithium and the boron concentration in the coolant early in the cycle, a specific study has been conducted to analyze and to predict the effect of such new water chemistry conditions on the oxidation kinetics of the Zircaloy-4 material. Experimental studies have been performed in out-of-pile loop tests, under one and two phase flow heat transfer in various water chemistry conditions (0{<=}Li{<=}350 ppm, 0{<=}B{<=}1000 ppm, 0{<=}K{<=}56 ppm). A simulation of the effect of elevated lithium on the corrosion has been made using the semi-empirical COCHISE corrosion code. Under one phase flow heat transfer conditions, the addition of lithium hydroxide in the coolant increases the oxidation rate, essentially in the post-transition regime for low lithium levels ({<=} 75 ppm) and immediately in the pre-transition phase for very high lithium level (350 ppm). Under two phase flow heat transfer, an enhancement of the corrosion is observed in the area of the rod submitted to boiling. Based on the out-of-pile loop test performed in presence of KOH instead of LiOH, such an enhancement of the corrosion appears to be due to a lithium enrichment in the oxide layer induced by boiling and not to a pH effect. The simulation of the increase of lithium content in the coolant from 2.2 to 3.5 ppm leads to an enhancement in corrosion rates which becomes only significant at high burn up. This predictive result of elevated lithium effect on corrosion is then compared with oxidation data derived from reactors operating under an elevated lithium regime. (author). 14 refs, 9 figs, 3 tabs.

  15. Digital mapping of corrosion risk in coastal urban areas using remote sensing and structural condition assessment: case study in cyprus

    Directory of Open Access Journals (Sweden)

    Neocleous Kyriacos

    2016-01-01

    Full Text Available Atmospheric corrosion is one of the main factors leading to performance deterioration of reinforced concrete buildings; and, hence, periodic structural condition monitoring is required to assess and repair the adverse effects of corrosion. However, this can become a cumbersome and expensive task to undertake for large populations of buildings, scattered in large urban areas. To optimize the use of available resources, appropriate tools are required for the assessment of corrosion risk of reinforced concrete construction. This paper proposes a framework for the production of digital corrosion risk maps for urban areas; Cyprus was used as a case study. This framework explored multi-temporal satellite remote sensing data from the Landsat sensors as well as corrosion risk factors derived from the results of a recently completed research project, entitled “STEELCOR”. This framework was used to develop two corrosion risk scenarios within Geographical Information Systems, and to produce corrosion risk maps for three coastal cities of Cyprus. The thematic maps indicated that, for slight corrosion damage, the distance of reinforced concrete buildings from the coast was more influential than the building age. While, for significant corrosion damage, the maps indicated that the age of RC buildings was more influential than the distance from the coast.

  16. Erosion-corrosion

    International Nuclear Information System (INIS)

    Aghili, B.

    1999-05-01

    A literature study on erosion-corrosion of pipings in the nuclear industry was performed. Occurred incidents are reviewed, and the mechanism driving the erosion-corrosion is described. Factors that influence the effect in negative or positive direction are treated, as well as programs for control and inspection. Finally, examples of failures from databases on erosion-corrosion are given in an attachment

  17. Metal alloys for the new generation of compressors at hydrogen stations: Parametric study of corrosion behavior

    DEFF Research Database (Denmark)

    Arjomand Kermani, Nasrin; Petrushina, Irina; Nikiforov, Aleksey Valerievich

    2017-01-01

    , consequently, significantly reduce the final cost of hydrogen production. The correct choice of ionic liquid and construction materials is critical for avoiding significant corrosion problems. Hence, the objective of this study is to evaluate the compatibility of various austenitic stainless steels and nickel...

  18. Studies on yttrium oxide coatings for corrosion protection against molten uranium

    International Nuclear Information System (INIS)

    Chakravarthy, Y.; Bhandari, Subhankar; Pragatheeswaran; Thiyagarajan, T.K.; Ananthapadmanabhan, P.V.; Das, A.K.; Kumar, Jay; Kutty, T.R.G.

    2012-01-01

    Yttrium oxide is resistant to corrosion by molten uranium and its alloys. Yttrium oxide is recommended as a protective oxide layer on graphite and metal components used for melting and processing uranium and its alloys. This paper presents studies on the efficacy of plasma sprayed yttrium oxide coatings for barrier applications against molten uranium

  19. Exploratory shaft liner corrosion estimate

    International Nuclear Information System (INIS)

    Duncan, D.R.

    1985-10-01

    An estimate of expected corrosion degradation during the 100-year design life of the Exploratory Shaft (ES) is presented. The basis for the estimate is a brief literature survey of corrosion data, in addition to data taken by the Basalt Waste Isolation Project. The scope of the study is expected corrosion environment of the ES, the corrosion modes of general corrosion, pitting and crevice corrosion, dissimilar metal corrosion, and environmentally assisted cracking. The expected internal and external environment of the shaft liner is described in detail and estimated effects of each corrosion mode are given. The maximum amount of general corrosion degradation was estimated to be 70 mils at the exterior and 48 mils at the interior, at the shaft bottom. Corrosion at welds or mechanical joints could be significant, dependent on design. After a final determination of corrosion allowance has been established by the project it will be added to the design criteria. 10 refs., 6 figs., 5 tabs

  20. Electrochemical and surface analysis studies on corrosion inhibition of Q235 steel by imidazoline derivative against CO2 corrosion

    International Nuclear Information System (INIS)

    Wang, B.; Du, M.; Zhang, J.; Gao, C.J.

    2011-01-01

    Research highlights: → The TAI inhibitor showed peak-value-phenomenon due to the change of adsorption mode. → The adsorption of TAI inhibitor made the PZC shift toward positive direction. → The adsorption film occurred by forming coordination bonds between heteroatom and Fe. → Bigger adhesive force owing to hydrophobic interaction was detected in TAI solution. → The long range-repulsive force reduced by screening effect of surface charges of TAI. - Abstract: The inhibition performance of a newly synthesized thioureido imidazoline inhibitor (TAI) in CO 2 corrosion was studied by using electrochemical impedance spectroscopy (EIS), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). Results show that the values of inhibition efficiency show peak-value-phenomenon at concentration of 0.15 mmol dm -3 owing to the change of adsorption mode. The adsorption of protonated TAI molecules on the negatively charged steel surface makes the potential of zero charge (PZC) shift to positive direction, and the long-range electrostatic exclusive forces between AFM tip and sample surface are reduced by screening effect of surface charges.

  1. Quantum chemical studies on the some inorganic corrosion inhibitors

    International Nuclear Information System (INIS)

    Sayin, Koray; Karakaş, Duran

    2013-01-01

    Highlights: •Some quantum chemical parameters are important to determine inhibition efficiency. •Quantum chemical calculations were performed on six inorganic inhibitors. •Five experimental reports were used to explain the theoretical results. •Atomic charges and %contributions were used to determine the atom at protonation process. •For inorganic inhibitors, the best method and basis set were investigated. -- Abstract: Some quantum chemical parameters were calculated by using Hartree–Fock (HF) approximation, Density Functional Theory (DFT/B3LYP) and Møller Plesset perturbation theory (MP3) methods at LANL2DZ, LANL2MB and SDD levels in gas phase and water for dichromate (Cr 2 O 7 2- ), chromate (CrO 4 2- ), tungstate (WO 4 2- ), molybdate (MoO 4 2- ), nitrite (NO 2 - ) and nitrate (NO 3 - ) which are used as inorganic corrosion inhibitors. All theoretical results and experimental inhibition efficiencies of inhibitors were subjected to correlation analyses. In a summary, MP3/SDD level in water was found as the best level. In this level, the inhibition efficiency ranking was found as CrO 4 2- >WO 4 2- >MoO 4 2- >Cr 2 O 7 2- >NO 2 - ≈NO 3 -

  2. Study of ion plating parameters, coating structure, and corrosion protection for aluminum coatings on uranium

    International Nuclear Information System (INIS)

    Egert, C.M.; Scott, D.G.

    1987-01-01

    A study of ion-plating parameters (primarily deposition rate and substrate bias voltage), coating structure, and the corrosion protection provided by aluminum coatings on uranium is presented. Ion plating at low temperatures yields a variety of aluminum coating structures on uranium. For example, aluminum coatings produced at high deposition rates and low substrate bias voltages are columnar with voids between columns, as expected for high-rate vapor deposition at low temperatures. On the other hand, low deposition rate and high bias voltage produce a modified coating with a dense, noncolumnar structure. These results are not in agreement with other studies that have found no relationship between deposition rate and coating structure in ion plating. This discrepancy is probably due to the high deposition rates used in these studies. An accelerated, water vapor corrosion test indicates that the columnar aluminum coatings provide some corrosion protection despite their porous nature; however, the dense noncolumnar coatings provide significantly greater protection. These results indicate that ion-plated aluminum coatings produced at low deposition rates and high substrate bias voltages creates dense coating structures that are most effective in protecting uranium from corrosion

  3. Pullulan as a potent green inhibitor for corrosion mitigation of aluminum composite: Electrochemical and surface studies.

    Science.gov (United States)

    B P, Charitha; Rao, Padmalatha

    2018-06-01

    This work emphasizes the corrosion inhibition ability of pullulan, an environmentally benign fungal polysaccharide on acid corrosion of 6061Aluminum-15% (v) SiC (P) composite material (Al-CM). The electrochemical measurements such as potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) studies were carried out for the corrosion inhibition studies. Conditions were optimized to obtain maximum inhibition efficiency, by performing the experiment at varying concentrations of inhibitor, in the temperature range of 308K- 323K. Surface morphology studies were done to reaffirm the adsorption of inhibitor on the surface of composite material. Pullulan acted as mixed type of inhibitor with a maximum efficiency of 89% at 303K for the addition of 1.0 gL -1 of inhibitor. Evaluation of kinetic and thermodynamic parameters revealed that inhibitor underwent physical adsorption onto the surface of Al-CM and obeyed Freundlich adsorption isotherm. The surface characterization like SEM-EDX, AFM confirmed the adsorption of pullulan molecule. Pullulan can be considered as effective, eco friendly green inhibitor for the corrosion control of Al-CM. Copyright © 2018 Elsevier B.V. All rights reserved.

  4. Feasibility Study of Non-Destructive Techniques to Measure Corrosion in SAVY Containers

    Energy Technology Data Exchange (ETDEWEB)

    Davenport, Matthew Nicholas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-07-15

    Stainless Steel SAVY containers are used to transport and store nuclear material. They are prone to interior corrosion in the presence of certain chemicals and a low-oxygen environment. SAVY containers also have relatively thin walls to reduce their weight, making their structural integrity more vulnerable to the effects of corrosion. A nondestructive evaluation system that finds and monitors corrosion within containers in use would improve safety conditions and preclude hazards. Non-destructive testing can determine whether oxidation or corrosion is occurring inside the SAVY containers, and there are a variety of non-destructive testing methods that may be viable. The feasibility study described will objectively decide which method best fits the requirements of the facility and the problem. To improve efficiency, the containers cannot be opened during the non-destructive examination. The chosen technique should also be user-friendly and relatively quick to apply. It must also meet facility requirements regarding wireless technology and maintenance. A feasibility study is an objective search for a new technology or product to solve a particular problem. First, the design, technical, and facility feasibility requirements are chosen and ranked in order of importance. Then each technology considered is given a score based upon a standard ranking system. The technology with the highest total score is deemed the best fit for a certain application.

  5. A study of the inhibition of iron corrosion in HCl solutions by some amino acids

    International Nuclear Information System (INIS)

    Amin, Mohammed A.; Khaled, K.F.; Mohsen, Q.; Arida, H.A.

    2010-01-01

    The performance of three selected amino acids, namely alanine (Ala), cysteine (Cys) and S-methyl cysteine (S-MCys) as safe corrosion inhibitors for iron in aerated stagnant 1.0 M HCl solutions was evaluated by Tafel polarization and impedance measurements. Results indicate that Ala acts mainly as a cathodic inhibitor, while Cys and S-MCys function as mixed-type inhibitors. Cys, which contains a mercapto group in its molecular structure, was the most effective among the inhibitors tested, while Ala was less effective than S-MCys. The low inhibition efficiency recorded for S-MCys compared with that of Cys was attributed to steric effects caused by the substituent methyl on the mercapto group. Electrochemical frequency modulation (EFM) technique and inductively coupled plasma atomic emission spectrometry (ICP-AES), were also applied to make accurate determination of corrosion rates. Validation of the Tafel extrapolation method for measuring corrosion rates was tested. Rates of corrosion rates (in μm y -1 ) obtained from Tafel extrapolation method are in good agreement with those measured using EFM and ICP methods. Some theoretical studies, including molecular dynamics (MD) and density functional theory (DFT), were also employed to establish the correlation between the structure (molecular and electronic) of the three tested inhibitors and the inhibition efficiency. Adsorption via hydrogen bonding was discussed here based on some theoretical studies. Experimental and theoretical results were in good agreement.

  6. Detection of the corrosion in reinforced concrete with GPR: the case study of the Park Guell

    Science.gov (United States)

    Sossa, Viviana; Perez-Gracia, Vega; Gonzalez-Drigo, Ramon; Caselles, Oriol; Clapes, Jaume

    2017-04-01

    Detection of corrosion is important in cultural heritage assessment. Many structures contain metallic targets embedded in masonry or mortar, and corrosion cab cause important damage. However, detection using non-destructive methods is difficult and highly localized, providing in most cases incomplete results. In order to obtain a more extended analysis, GPR was applied and evaluated to detect damage as consequence of corrosion. This technique is a non-destructive method that covers a large area of study while other methods are constrained to a small areas or specific points. Therefore, some controlled laboratory tests were designed to determine possible differences in radargrams obtained in the case of corroded and non-corroded targets. These analysis allowed to observe that the corrosion seems to increase the attenuation of the radar signal, being difficult to detect targets near the damaged bars. The results were applied to study the mosaic roofs in the Park Guell, in Barcelona. This park is one of the most important Modernista (Art Noveau) complex in Barcelona. It is characterized by structures with roofs and banks with tessellation. Some of these structures are most likely supported by metal elements, and seepage cause important damage observed over the tessellation. The objective of the study was to define the possible existence of those metallic targets, determining their location. And, in the case of existence of metallic elements, defining which are the zones more affected by corrosion. The results demonstrates the existence of metallic supports in many parts, as well as some defined areas that could be damaged. Acknowledgement: This work has been partially funded by the Spanish Government and by the European Commission with FEDER funds, through the research projects CGL2011-23621 and CGL2015-65913-P. The study is also a contribution to the EU funded COST Action TU1208, "Civil Engineering Applications of Ground Penetrating Radar", to the working group 2.2.

  7. Potentiostatic pulse-deposition of calcium phosphate on magnesium alloy for temporary implant applications--an in vitro corrosion study.

    Science.gov (United States)

    Kannan, M Bobby; Wallipa, O

    2013-03-01

    In this study, a magnesium alloy (AZ91) was coated with calcium phosphate using potentiostatic pulse-potential and constant-potential methods and the in vitro corrosion behaviour of the coated samples was compared with the bare metal. In vitro corrosion studies were carried out using electrochemical impedance spectroscopy and potentiodynamic polarization in simulated body fluid (SBF) at 37 °C. Calcium phosphate coatings enhanced the corrosion resistance of the alloy, however, the pulse-potential coating performed better than the constant-potential coating. The pulse-potential coating exhibited ~3 times higher polarization resistance than that of the constant-potential coating. The corrosion current density obtained from the potentiodynamic polarization curves was significantly less (~60%) for the pulse-deposition coating as compared to the constant-potential coating. Post-corrosion analysis revealed only slight corrosion on the pulse-potential coating, whereas the constant-potential coating exhibited a large number of corrosion particles attached to the coating. The better in vitro corrosion performance of the pulse-potential coating can be attributed to the closely packed calcium phosphate particles. Copyright © 2012 Elsevier B.V. All rights reserved.

  8. Acoustic emission analysis coupled with thermogravimetric experiments dedicated to high temperature corrosion studies on metallic alloys

    International Nuclear Information System (INIS)

    Serris, Eric; Al Haj, Omar; Peres, Veronique; Cournil, Michel; Kittel, Jean; Grosjean, Francois; Ropital, Francois

    2014-01-01

    High temperature corrosion of metallic alloys (like iron, nickel, zirconium alloys) can damage equipment of many industrial fields (refinery, petrochemical, nuclear..). Acoustic emission (AE) is an interesting method owing to its sensitivity and its non-destructive aspect to quantify the level of damage in use of these alloys under various environmental conditions. High temperature corrosive phenomena create stresses in the materials; the relaxation by cracks of these stresses can be recorded and analyzed using the AE system. The goal of our study is to establish an acoustic signals database which assigns the acoustic signals to the specific corrosion phenomena. For this purpose, thermogravimetric analysis (TGA) is coupled with acoustic emission (AE) devices. The oxidation of a zirconium alloy, zircaloy-4, is first studied using thermogravimetric experiment coupled to acoustic emission analysis at 900 C. An inward zirconium oxide scale, preliminary dense, then porous, grow during the isothermal isobaric step. The kinetic rate increases significantly after a kinetic transition (breakaway). This acceleration occurs with an increase of acoustic emission activity. Most of the acoustic emission bursts are recorded after the kinetic transition. Acoustic emission signals are also observed during the cooling of the sample. AE numerical treatments (using wavelet transform) completed by SEM microscopy characterizations allows us to distinguish the different populations of cracks. Metal dusting represents also a severe form of corrosive degradation of metal alloy. Iron metal dusting corrosion is studied by AE coupled with TGA at 650 C under C 4 H 10 + H 2 + He atmosphere. Acoustic emission signals are detected after a significant increase of the sample mass.

  9. Morphological characterisation and spectroscopic studies of the corrosion behaviour of tungsten heavy alloys

    International Nuclear Information System (INIS)

    Ogundipe, A.; Greenberg, B.; Braida, W.; Christodoulatos, C.; Dermatas, D.

    2006-01-01

    Tungsten-based alloys have been used in a wide variety of industrial and military applications. These alloys are composed mainly of tungsten (88-95%) with various combinations of nickel, cobalt, iron and copper usually making up the remaining fraction. The corrosion behaviours of five munitions grade tungsten alloys of interest have been examined using immersion tests and wet-dry cycle tests to determine the mechanisms involved in the release of the metallic components. Analyses carried out using SEM, EDS and grazing incidence XRD techniques, show the release of tungsten as well as alloying elements due to galvanic corrosion resulting from the difference in electrode potential between the tungsten phase and the binder phase in all cases studied. The extent of corrosion was directly related with the dissolution of tungsten in the binder phase during the sintering stage of manufacture. In W-Ni-Co-Fe alloys binder phase corrosion was observed while the relatively noble tungsten phase was less affected. The reverse was observed for a W-Cu alloy

  10. Comparative Studies on microstructure, mechanical and corrosion behaviour of DMR 249A Steel and its welds

    Science.gov (United States)

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

    2018-03-01

    DMR249A Medium strength (low carbon) Low-alloy steels are used as structural components in naval applications due to its low cost and high availability. An attempt has been made to weld the DMR 249A steel plates of 8mm thickness using shielded metal arc welding (SMAW) and gas tungsten arc welding (GTAW). Welds were characterized for metallography to carry out the microstructural changes, mechanical properties were evaluated using vickers hardness tester and universal testing machine. Potentio-dynamic polarization tests were carried out to determine the pitting corrosion behaviour. Constant load type Stress corrosion cracking (SCC) testing was done to observe the cracking tendency of the joints in a 3.5%NaCl solution. Results of the present study established that SMA welds resulted in formation of relatively higher amount of martensite in ferrite matrix when compared to gas tungsten arc welding (GTAW). It is attributed to faster cooling rates achieved due to high thermal efficiency. Improved mechanical properties were observed for the SMA welds and are due to higher amount of martensite. Pitting corrosion and stress corrosion cracking resistance of SMA welds were poor when compared to GTA welds.

  11. A study on corrosion resistance of electrodeposited Zn-base alloy steel sheet

    International Nuclear Information System (INIS)

    Park, Hyun Soon

    1986-01-01

    Effects of electrodeposits of Zn-Ni or Zn-Co alloy with small amounts of Mo or W in sulphate bath on the corrosion resistance of plated steel sheet were studied. 1) The electrodeposition of Zn-Ni and Zn-Co alloy shows both anomalous codeposition behavior. The grade of anomalous codeposition of Zn-Co alloy rises with adding Mo or W in bath. 2) The Ni content in Zn-Ni deposits increases with decreasing cathode current density and with increasing bath temperature. 3) In case of electroplating of Zn-Co, the increase of cathodic current density of bath bring on increasing of the Co content, but on decreasing of the Mo content in deposits. And rising bath temperature increases both Co and Mo deposits. 4) The corrosion resistance of the Zn-Ni electrodeposited steel sheet is shown a maximum at the Ni content of 10-17%. The structure of Zn-Ni of these composition range was finegrained γ-phase. 5) The corrosion resistance of the Zn-Co electrodeposited steel sheet is improved with increasing Co content. The corrosion resistance of the Zn-Co-Mo or Zn-Co-W deposits electroplated by proper plating conditions was improved much more than that of Zn-Co deposits. (Author)

  12. Corrosion Study of Stainless Steels in Peracetic Acid Bleach Media With and Without Chloride and Chelant

    Directory of Open Access Journals (Sweden)

    Rohtash

    2014-12-01

    Full Text Available The paper industries are adopting non-chlorine containing chemicals e.g. peroxide, ozone, peracids etc. as alternate of chlorine based bleach chemicals e.g. chlorine and chlorine dioxide etc. with the aim of eco-friend atmospheres. Changeover to the new chemicals in the bleaching process is likely to affect the metallurgy of the existing bleach plants due to change in the corrosivity of the media. Accordingly, corrosion investigations were performed in a peracid namely peracetic acid to test the suitability of austenitic stainless steels 654SMO, 265SMO, 2205, 317L and 316L. The performance of above stainless steels was evaluated through long term immersion tests and Electrochemical polarization measurements in peracetic acid (PAA bleach media at pH value 4 maintaining concentration 0.2 % as active oxygen along with three chloride levels 0, 500 and 1000 ppm in pulp-free laboratory. To study the effect of corrosion inhibitors with extending limit of chloride in liquors, measurements were also made with two types of chelants- EDTA & MgSO4. The results showed that corrosivity of PAA reduced by addition of chelant while increased with concentration of Cl¯. The results also exhibited that EDTA is better inhibitor than MgSO4.

  13. Contribution to the study of metallic materials bio-corrosion phenomena

    International Nuclear Information System (INIS)

    Feron, D.

    2004-05-01

    After having recalled the main electrochemical methods used for the study of metallic materials bio-deterioration phenomena, the corrosion of non or low alloy steels in anaerobic conditions is dealt with: the obtained results reveal a strong interaction between the metallic ions and the growth of sulfato reducing bacteria with inhibiting or accelerating ions of this growth. Concerning the corrosion, the chromium and molybdenum additions have a favourable effect on the resistance of low alloy steels. The sulfides impose the electrochemical behaviour of these materials, whereas the role of hydrogenases on the cathodic reaction is still to be specified to explain the observed localized corrosion, including the pure cultures of sulfato-reducing bacteria. The behaviour of stainless steels in seawater can be explained by an enzymatic catalysis of the cathodic reaction. Such a model takes into account the general behaviour of passivable alloys in natural waters in a general way and has allowed to perfect a synthetic seawater which leads to corrosion phenomena by crevice effect on stainless steels similar to those observed in natural seawater. The coupling of the aerobic conditions with the leading part of the enzymes on the cathodic reaction and of the anaerobic conditions with the presence of sulfides (which decrease the resistance of the passive layer) is the most unfavourable situation for the resistance of passivable alloys. These results lead to the concept of electrochemically activated bio-films which could be used in particular in energy production (fuel cells). (O.M.)

  14. Copper corrosion in bentonite: Studying of parameters (pH, Eh/O2) of importance for Cu corrosion

    International Nuclear Information System (INIS)

    Carlsson, T.; Muurinen, A.

    2007-06-01

    The report describes the development of methods and equipment for studying the parameters (pH, Eh/O 2 ) of importance for copper corrosion. The work involved the fabrication of electrodes for determining Eh and pH in compacted water-saturated bentonite. MX-80 and the Indian Asha 505 bentonites were used in the study. The redox-measurements were carried out by using electrodes prepared of Au and Pt wires. The pH measurements were carried out by using solid IrO x electrodes. The report describes testing of electrodes in different solutions and in bentonite. A destructive method for determining oxygen content in compacted bentonite was tested, too. The electrodes were used in measurements inside compacted bentonite with about the same density as is intended to be used in the Finnish repository for spent nuclear fuel. The results indicate that Au and Pt redox-electrodes and IrO x pH electrodes function in compacted bentonite. The oxygen measurement in bentonite seems to work, too, and can complement the Eh measurements. Eh-values in originally aerobic bentonite samples having a dry densitiy of ≤1.5 g/cm 3 , exhibit mostly a decrease during the first days, which may mainly be ascribed to the depletion of oxygen. The Eh-decrease thereafter is probably associated with redox-reactions involving other species than oxygen. In samples with a dry density of 1.8 g/cm 3 , the observed Eh-decrease is mostly slower. No significant difference between the Eh and pH measurements in MX-80 and Asha 505 could be observed. (orig.)

  15. Corrosion Study of the Injection Equipments in Water in Al-Ahdeb Wells ‐Iraq

    Directory of Open Access Journals (Sweden)

    Hassan Abdulkadhim Alwan Alsaadi

    2015-01-01

    Full Text Available Water injection equipments such as pipelines, which are used in the second recovery of oil in the Al-Ahdeb wells, suffer from the corrosion in water during maintaining vacuum deoxygenated tower that used to decrease concentration of the dissolved oxygen gas in the water from 6.2-9.1 ppm to o.5 ppm. This study involved calculation the corrosion rates of the internal surfaces of the pipelines either during operation of the vacuum unit or when the tower out of operation. Finally, find the solution by one of the following suggestions. In the first suggestion removal of the dissolved O2 from water is achieved by increasing the dosage of the oxygen scavenger (sodium sulphite. The second suggestion involves removing the dissolved O2 from water by bubbling the oxygenated water with nitrogen gas. The study showed that the corrosion rates of various inside diameter pipelines are between 0.13 mm/yr and 1.5 mm/yr during operation of the vacuum tower and between 3.2 mm/yr and 18.5 mm/yr when the tower out of the operation. While the results showed that the corrosion rate of the pipelines when the tower out of operation reached to the acceptable value of 0.1 mm/y when the dissolved oxygen in the injected water removed by increasing the dosage of the sodium sulphite (Na2SO3 to 48-72 ppm. The results also explained that corrosion rates of the pipelines reached to 0.5 mm/y when the dissolved oxygen removed by bubbling the water with nitrogen gas.

  16. Study of caffeine as corrosion inhibitors of carbon steel in chloride solution containing hydrogen sulfide using electrochemical impedance spectroscopy (EIS)

    Science.gov (United States)

    Solehudin, Agus; Berman, Ega Taqwali; Nurdin, Isdiriayani

    2015-09-01

    The corrosion behaviour of steel surface in the absence and presence of caffeine in 3.5% NaCl solution containing dissolved H2S gas is studied using electrochemical impedance spectroscopy (EIS). The experimental results of carbon steel corrosion in 3.5% NaCl solution containing 500 mg/l H2S at different caffeine concentrations showed that corrosion rate of carbon steel decreases with increasing of caffeine concentrations from 0 to 0,1 mmol/l. Whereas, the corrosion rate increase with increasing of caffeine concentrations from 1 to 10 mmol/l. It is clear that no inhibition efficiency increases with increasing inhibitor concentration. The optimum value of inhibition efficiency was 90% at a caffeine concentration of 0.1 mmol/l. This suggests that caffeine's performance as a corrosion inhibitor is more effective at a concentration of 0.1 mmol/l.

  17. Studies on dissolution characteristics of simulated corrosion products on pressurized water reactor primary coolant loops. Pt.2: Cobalt simulated corrosion product

    International Nuclear Information System (INIS)

    Li Shan; Zhou Xianyu

    1997-01-01

    The studies on the dissolution characteristics of simulated corrosion product of cobalt on pressurized water reactor primary coolant loops in aqueous solution of citric acid, hydrogen peroxide and citric acid-hydrogen peroxide have been performed. The results show that the portion of the dissolved simulated corrosion product of cobalt in citric acid aqueous solution clearly increases with a rise in citric acid concentration and is ten times above the corresponding value of iron. The portion of the products that dissolve is the largest at pH 3.00 in the pH range of 2.33∼4.50 and at 70 degree C in the range of 60∼80 degree C. It is shown that the portion of the dissolved simulated corrosion product of cobalt in hydrogen peroxide aqueous solution is smaller than the corresponding value in citric acid, and that the portion of the dissolved simulated corrosion product of cobalt in aqueous solution of hydrogen peroxide-citric acid is larger than the corresponding value in single citric acid aqueous solution

  18. Effects of combined organic and inorganic corrosion inhibitors on the nanostructure cerium based conversion coating performance on AZ31 magnesium alloy: Morphological and corrosion studies

    International Nuclear Information System (INIS)

    Saei, E.; Ramezanzadeh, B.; Amini, R.; Kalajahi, M. Salami

    2017-01-01

    Highlights: •Cn-Mn-polyvinyl alcohol conversion coating led to more uniform and crack free film deposition. •The corrosion resistance of Ce film was noticeably improved by using combination of polyvinyl alchol and Mn2+ cations. •A synergistic effect between polyvinyl alchol-Mn2+ resulted in Ce film with enhanced morphology and corrosion resistance. -- Abstract: Magnesium (Mg) AZ31 samples were chemically treated by a series of room temperature nanostructure cerium based conversion coatings containing Mn(NO 3 ) 2 ·4H 2 O, Co(NO 3 ) 2 ·6H 2 O, and polyvinyl alcohol (PVA). The microstructure and corrosion protection properties of different samples were studied by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS) and polarization test in 3.5 wt.% NaCl solution. Results demonstrated that the AZ31 Mg alloy sample treated by Ce-Mn-PVA showed the highest corrosion resistance. A denser Ce film with lower crack was precipitated on the sample treated by Ce-Mn-PVA conversion coating.

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

    International Nuclear Information System (INIS)

    Helie, Max

    2015-01-01

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

  20. Part I. Corrosion studies of continuous alumina fiber reinforced aluminum-matrix composites. Part II. Galvanic corrosion between continuous alumina fiber reinforced aluminum-matrix composites and 4340 steel

    Science.gov (United States)

    Zhu, Jun

    Part I. The corrosion performance of continuous alumina fiber reinforced aluminum-matrix composites (CF-AMCs) was investigated in both the laboratory and field environments by comparing them with their respective monolithic matrix alloys, i.e., pure Al, A1-2wt%Cu T6, and Al 6061 T6. The corrosion initiation sites were identified by monitoring the changes in the surface morphology. Corrosion current densities and pH profiles at localized corrosion sites were measured using the scanning-vibrating electrode technique and the scanning ion-selective electrode technique, respectively. The corrosion damage of the materials immersed in various electrolytes, as well as those exposed in a humidity chamber and outdoor environments, was evaluated. Potentiodynamic polarization behavior was also studied. The corrosion initiation for the composites in 3.15 wt% NaCl occurred primarily around the Fe-rich intermetallic particles, which preferentially existed around the fiber/matrix interface on the composites. The corrosion initiation sites were also caused by physical damage (e.g., localized deformation) to the composite surface. At localized corrosion sites, the buildup of acidity was enhanced by the formation of micro-crevices resulting from fibers left in relief as the matrix corroded. The composites that were tested in exposure experiments exhibited higher corrosion rates than their monolithic alloys. The composites and their monolithic alloys were subjected to pitting corrosion when anodically polarized in the 3.15 wt% NaCl, while they passivated when anodically polarized in 0.5 M Na2SO4. The experimental results indicated that the composites exhibited inferior corrosion resistance compared to their monolithic matrix alloys. Part II. Galvanic corrosion studies were conducted on CF-AMCs coupled to 4340 steel since CF-AMCs have low density and excellent mechanical properties and are being considered as potential jacketing materials for reinforcing steel gun barrels. Coupled and

  1. Study of MHD Corrosion and Transport of Corrosion Products of Ferritic/Martensitic Steels in the Flowing PbLi and its Application to Fusion Blanket

    Science.gov (United States)

    Saeidi, Sheida

    Two important components of a liquid breeder blanket of a fusion power reactor are the liquid breeder/coolant and the steel structure that the liquid is enclosed in. One candidate combination for such components is Lead-Lithium (PbLi) eutectic alloy and advanced Reduced Activation Ferritic/Martensitic (RAFM) steel. The research performed here is aimed at: (1) better understanding of corrosion processes in the system including RAFM steel and flowing PbLi in the presence of a strong magnetic field and (2) prediction of corrosion losses in conditions of a Dual Coolant Lead Lithium (DCLL) blanket, which is at present the key liquid metal blanket concept in the US. To do this, numerical and analytical tools have been developed and then applied to the analysis of corrosion processes. First, efforts were taken to develop a computational suite called TRANSMAG (Transport phenomena in Magnetohydrodynamic Flows) as an analysis tool for corrosion processes in the PbLi/RAFM system, including transport of corrosion products in MHD laminar and turbulent flows. The computational approach in TRANSMAG is based on simultaneous solution of flow, energy and mass transfer equations with or without a magnetic field, assuming mass transfer controlled corrosion and uniform dissolution of iron in the flowing PbLi. Then, the new computational tool was used to solve an inverse mass transfer problem where the saturation concentration of iron in PbLi was reconstructed from the experimental data resulting in the following correlation: CS = e 13.604--12975/T, where T is the temperature of PbLi in K and CS is in wppm. The new correlation for saturation concentration was then used in the analysis of corrosion processes in laminar flows in a rectangular duct in the presence of a strong transverse magnetic field. As shown in this study, the mass loss increases with the magnetic field such that the corrosion rate in the presence of a magnetic field can be a few times higher compared to purely

  2. Corrosion inhibitors

    International Nuclear Information System (INIS)

    El Ashry, El Sayed H.; El Nemr, Ahmed; Esawy, Sami A.; Ragab, Safaa

    2006-01-01

    The corrosion inhibition efficiencies of some triazole, oxadiazole and thiadiazole derivatives for steel in presence of acidic medium have been studied by using AM1, PM3, MINDO/3 and MNDO semi-empirical SCF molecular orbital methods. Geometric structures, total negative charge on the molecule (TNC), highest occupied molecular energy level (E HOMO ), lowest unoccupied molecular energy level (E LUMO ), core-core repulsion (CCR), dipole moment (μ) and linear solvation energy terms, molecular volume (V i ) and dipolar-polarization (π *), were correlated to corrosion inhibition efficiency. Four equations were proposed to calculate corrosion inhibition efficiency. The agreement with the experimental data was found to be satisfactory; the standard deviations between the calculated and experimental results ranged between ±0.03 and ±4.18. The inhibition efficiency was closely related to orbital energies (E HOMO and E LUMO ) and μ. The correlation between quantum parameters and experimental inhibition efficiency has been validated by single point calculations for the semi-empirical AM1 structures using B3LYP/6-31G** as a higher level of theory. The proposed equations were applied to predict the corrosion inhibition efficiency of some related structures to select molecules of possible activity from a presumable library of compounds

  3. Studies on the Inhibition of Mild Steel Corrosion by Rauvolfia serpentina in Acid Media

    Science.gov (United States)

    Bothi Raja, P.; Sethuraman, M. G.

    2010-07-01

    Alkaloid extract of Rauvolfia serpentina was tested as corrosion inhibitor for mild steel in 1 M HCl and H2SO4 using weight loss method at three different temperatures, viz., 303, 313, and 323 K, potentiodynamic polarization, electrochemical impedance spectroscopy and scanning electron microscope (SEM) studies. It is evident from the results of this study that R. serpentina effectively inhibits the corrosion in both the acids through adsorption process following Tempkin adsorption isotherm. The protection efficiency increased with increase in inhibitor concentration and temperature. Free energy of adsorption calculated from the temperature studies also revealed the chemisorption. The mixed mode of action exhibited by the inhibitor was confirmed by the polarization studies while SEM analysis substantiated the formation of protective layer over the mild steel surface.

  4. Plant applications of online corrosion monitoring: CO2 capture amine plant case study

    NARCIS (Netherlands)

    Kane, R.D.; Srinivasan, S.; Khakharia, P.M.; Goetheer, E.L.V.; Mertens, J.; Vroey, S. de

    2015-01-01

    Over the past several years, there has been a significant effort to bring corrosion monitoring into the realm of online, real-time management with plant process control technology. As part of this new direction in corrosion monitoring, corrosion data (e.g. information on corrosion rate, measured

  5. Study of the morphology of corrosion features of natural graphite oxidised by dry and humid air

    International Nuclear Information System (INIS)

    Senevat, Jean

    1965-12-01

    The author reports a study which aimed at highlighting the morphology differences between corrosion features which affect flakes of natural graphite oxidised by dry air and by humid air. The study is based on observations made by optical and transmission electronic microscopy, this last one being performed on replicates. As the so-called 'Hennig' replicates did not result in a sufficient resolution of corrosion feature details, another method has been developed. Three classes of samples (in relationship with the rate of impurities present in samples) have been studied. Flakes have thus been sorted and each flake has then been oxidised at different wear rates. This highlights the influence of damages created by impurities in the lattice [fr

  6. Preliminary study of corrosion mechanisms of actinides alloys: calibration of FT-IR spectroscopy

    International Nuclear Information System (INIS)

    Magnien, Veronique; Cadignan, Marx; Faivret, Olivier; Rosa, Gaelle

    2008-01-01

    In situ analyzes of gaseous atmospheres could be performed by FT-IR spectroscopy in order to study the corrosion reactions of actinides. Nevertheless experimental conditions and the nature of studied species have a strong effect on IR absorption laws. Thus a prior calibration of our set-up is required to obtain an accurate estimation of gas concentration. For this purpose, the behavior of several air pure gases has been investigated according to their concentration from IR spectra. Reproducible results revealed subsequent increases of the most significant peak areas with gas pressure and small deviations from Beer Lambert's law. This preliminary work allowed to determine precise absorption laws for each studied pure gas in our in situ experimental conditions. Besides our FT-IR set-up was well suitable to quantitative analysis of gaseous atmosphere during corrosion reactions. Finally the effect of foreign gas will be investigated through more complex air mixtures to obtain a complete calibration network. (authors)

  7. Mechanism study of c.f.c Fe-Ni-Cr alloy corrosion in supercritical water

    International Nuclear Information System (INIS)

    Payet, M.

    2011-01-01

    Supercritical water can be use as a high pressure coolant in order to improve the thermodynamic efficiency of power plants. For nuclear concept, lifetime is an important safety parameter for materials. Thus materials selection criteria concern high temperature yield stress, creep resistance, resistance to irradiation embrittlement and also to both uniform corrosion and stress corrosion cracking.This study aims for supplying a new insight on uniform corrosion mechanism of Fe-Ni-Cr f.c.c. alloys in deaerated supercritical water at 600 C and 25 MPa. Corrosion tests were performed on 316L and 690 alloys as sample autoclaves taking into account the effect of surface finishes. Morphologies, compositions and crystallographic structure of the oxides were determined using FEG scanning electron microscopy, glow discharge spectroscopy and X-ray diffraction. If supercritical water is expected to have a gas-like behaviour in the test conditions, the results show a significant dissolution of the alloy species. Thus the corrosion in supercritical water can be considered similar to corrosion in under-critical water assuming the higher temperature and its effect on the solid state diffusion. For alloy 690, the protective oxide layer formed on polished surface consists of a chromia film topped with an iron and nickel mixed chromite or spinel. The double oxide layer formed on 316L steel seems less protective with an outer porous layer of magnetite and an inhomogeneous Cr-rich inner layer. For each alloy, the study of the inner protective scale growth mechanisms by marker or tracer experiments reveals that diffusion in the oxide scale is governed by an anionic process. However, surface finishes impact deeply the growth mechanisms. Comparisons between the results for the steel suggest that there is a competition between the oxidation of iron and chromium in supercritical water. Sufficient available chromium is required in order to form a thin oxide layer. Highly deformed or ultra fine

  8. Corrosion studies on type AISI 316L stainless steel and other materials in lithium-salt solutions

    International Nuclear Information System (INIS)

    Zheng, J.H.; Bogaerts, W.F.; Agema, K.; Phlippo, K.; Bruggeman, A.; Lorenzetto, P.; Embrechts, M.J.

    1991-01-01

    A possible concept for the blanket for next generation fusion devices is the lithium salt blanket, where lithium salt is dissolved in an aqueous coolant in order to provide for tritium. Type AISI 316L stainless steel has been considered as a structural material for such a blanket for NET (Next European Torus), and a systematic study of the corrosion behaviour of 316L stainless steel has been carried out in a number of lithium salt solutions. The experiments include cyclic potentiodynamic polarization measurement, crevice corrosion fatigue and stress corrosion cracking (SCC) tests. This paper presents a part of novel corrosion results concerning the compatibility of 316L steel and a series of other materials relevant to a fusion blanket environment. No major uniform corrosion problem has been observed, but localized corrosion, particularly corrosion fatigue and SCC, of 316L stainless steel have been found so far in a lithium hydroxide solution under some specific potential conditions. The critical electrochemical potential zones for SCC have been identified in the present study. (orig.)

  9. Study on the correlation between long-term exposure tests and accelerated corrosion tests by the combined damage of salts

    International Nuclear Information System (INIS)

    Park, Sang Soon; Lee, Min Woo

    2014-01-01

    Interest in the durability assessment and structural performance has increased according to an increase of concrete structures in salt damage environment recent years. Reliable way ensuring the most accelerated corrosion test is a method of performing the rebar corrosion monitoring as exposed directly to the marine test site exposure. However, long-term exposure test has a disadvantage because of a long period of time. Therefore, many studies on reinforced concrete in salt damage environments have been developed as alternatives to replace this. However, accelerated corrosion test is appropriate to evaluate the critical chlorine concentration in the short term, but only accelerated test method, is not easy to get correct answer. Accuracy of correlation acceleration test depends on the period of the degree of exposure environments. Therefore, in this study, depending on the concrete mix material, by the test was performed on the basis of the composite degradation of the salt damage, and investigate the difference of corrosion initiation time of the rebar, and indoor corrosion time of the structure, of the marine environment of the actual environments were investigated. The correlation coefficient was derived in the experiment. Long-term exposure test was actually conducted in consideration of the exposure conditions submerged zone, splash zone and tidal zone. The accelerated corrosion tests were carried out by immersion conditions, and by the combined deterioration due to the carbonation and accelerated corrosion due to wet and dry condition

  10. Probability distribution of pitting corrosion depth and rate in underground pipelines: A Monte Carlo study

    International Nuclear Information System (INIS)

    Caleyo, F.; Velazquez, J.C.; Valor, A.; Hallen, J.M.

    2009-01-01

    The probability distributions of external-corrosion pit depth and pit growth rate were investigated in underground pipelines using Monte Carlo simulations. The study combines a predictive pit growth model developed by the authors with the observed distributions of the model variables in a range of soils. Depending on the pipeline age, any of the three maximal extreme value distributions, i.e. Weibull, Frechet or Gumbel, can arise as the best fit to the pitting depth and rate data. The Frechet distribution best fits the corrosion data for long exposure periods. This can be explained by considering the long-term stabilization of the diffusion-controlled pit growth. The findings of the study provide reliability analysts with accurate information regarding the stochastic characteristics of the pitting damage in underground pipelines.

  11. Probability distribution of pitting corrosion depth and rate in underground pipelines: A Monte Carlo study

    Energy Technology Data Exchange (ETDEWEB)

    Caleyo, F. [Departamento de Ingenieria Metalurgica, ESIQIE, IPN, UPALM Edif. 7, Zacatenco, 07738 Mexico, D.F. (Mexico)], E-mail: fcaleyo@gmail.com; Velazquez, J.C. [Departamento de Ingenieria Metalurgica, ESIQIE, IPN, UPALM Edif. 7, Zacatenco, 07738 Mexico, D.F. (Mexico); Valor, A. [Facultad de Fisica, Universidad de La Habana, San Lazaro y L, Vedado, 10400, La Habana (Cuba); Hallen, J.M. [Departamento de Ingenieria Metalurgica, ESIQIE, IPN, UPALM Edif. 7, Zacatenco, 07738 Mexico, D.F. (Mexico)

    2009-09-15

    The probability distributions of external-corrosion pit depth and pit growth rate were investigated in underground pipelines using Monte Carlo simulations. The study combines a predictive pit growth model developed by the authors with the observed distributions of the model variables in a range of soils. Depending on the pipeline age, any of the three maximal extreme value distributions, i.e. Weibull, Frechet or Gumbel, can arise as the best fit to the pitting depth and rate data. The Frechet distribution best fits the corrosion data for long exposure periods. This can be explained by considering the long-term stabilization of the diffusion-controlled pit growth. The findings of the study provide reliability analysts with accurate information regarding the stochastic characteristics of the pitting damage in underground pipelines.

  12. Lithium-system corrosion/erosion studies for the FMIT project

    International Nuclear Information System (INIS)

    Bazinet, G.D.

    1983-04-01

    The corrosion behavior of selected materials in a liquid lithium environment has been studied in support of system and component designs for the Fusion Materials Irradiation Test (FMIT) Facility. The liquid lithium test resources and the capabilities of several laboratories were used to study specific concerns associated with the overall objective. Testing conditions ranged from approx. 3700 hours to approx. 6500 hours of exposure to flowing lithium at temperatures from 230 0 C to 270 0 C and static lithium at temperatures from 200 0 C to 500 0 C. Principal areas of investigation included lithium corrosion/erosion effects of FMIT lithium system materials (largely Type 304 and Type 304L austenitic stainless steels) and candidate materials for major system components

  13. Lithium-system corrosion/erosion studies for the FMIT project

    Energy Technology Data Exchange (ETDEWEB)

    Bazinet, G D [comp.

    1983-04-01

    The corrosion behavior of selected materials in a liquid lithium environment has been studied in support of system and component designs for the Fusion Materials Irradiation Test (FMIT) Facility. The liquid lithium test resources and the capabilities of several laboratories were used to study specific concerns associated with the overall objective. Testing conditions ranged from approx. 3700 hours to approx. 6500 hours of exposure to flowing lithium at temperatures from 230/sup 0/C to 270/sup 0/C and static lithium at temperatures from 200/sup 0/C to 500/sup 0/C. Principal areas of investigation included lithium corrosion/erosion effects of FMIT lithium system materials (largely Type 304 and Type 304L austenitic stainless steels) and candidate materials for major system components.

  14. Electrochemical Study on Newly Synthesized Chlorocurcumin as an Inhibitor for Mild Steel Corrosion in Hydrochloric Acid

    Directory of Open Access Journals (Sweden)

    Ahmed A. Al-Amiery

    2013-11-01

    Full Text Available A new curcumin derivative, i.e., (1E,4Z,6E-5-chloro-1,7-bis(4-hydroxy-3-methoxyphenylhepta-1,4,6-trien-3-one (chlorocurcumin, was prepared starting with the natural compound curcumin. The newly synthesized compound was characterized by elemental analysis and spectral studies (IR, 1H-NMR and 13C-NMR. The corrosion inhibition of mild steel in 1 M HCl by chlorocurcumin has been studied using potentiodynamic polarization (PDP measurements and electrochemical impedance spectroscopy (EIS. The inhibition efficiency increases with the concentration of the inhibitor but decreases with increases in temperature. The potentiodynamic polarization reveals that chlorocurcumin is a mixed-type inhibitor. The kinetic parameters for mild steel corrosion were determined and discussed.

  15. Electrochemical Study on Newly Synthesized Chlorocurcumin as an Inhibitor for Mild Steel Corrosion in Hydrochloric Acid

    Science.gov (United States)

    Al-Amiery, Ahmed A.; Kadhum, Abdul Amir H.; Mohamad, Abu Bakar; Musa, Ahmed Y.; Li, Cheong Jiun

    2013-01-01

    A new curcumin derivative, i.e., (1E,4Z,6E)-5-chloro-1,7-bis(4-hydroxy-3-methoxyphenyl)hepta-1,4,6-trien-3-one (chlorocurcumin), was prepared starting with the natural compound curcumin. The newly synthesized compound was characterized by elemental analysis and spectral studies (IR, 1H-NMR and 13C-NMR). The corrosion inhibition of mild steel in 1 M HCl by chlorocurcumin has been studied using potentiodynamic polarization (PDP) measurements and electrochemical impedance spectroscopy (EIS). The inhibition efficiency increases with the concentration of the inhibitor but decreases with increases in temperature. The potentiodynamic polarization reveals that chlorocurcumin is a mixed-type inhibitor. The kinetic parameters for mild steel corrosion were determined and discussed. PMID:28788402

  16. Study of the Effect of Swelling on Irradiation Assisted Stress Corrosion Cracking

    Energy Technology Data Exchange (ETDEWEB)

    Teysseyre, Sebastien Paul [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-09-01

    This report describes the methodology used to study the effect of swelling on the crack growth rate of an irradiation-assisted stress corrosion crack that is propagating in highly irradiated stainless steel 304 material irradiated to 33 dpa in the Experimental Breeder Reactor-II. The material selection, specimens design, experimental apparatus and processes are described. The results of the current test are presented.

  17. Corrosion Inhibition Study of Al-Cu-Ni Alloy in Simulated Sea-Water ...

    African Journals Online (AJOL)

    A study on the inhibition of Al-Cu-Ni alloy in simulated sea-water environment was investigated using Sodium Chromate as inhibitor. The inhibitor concentration was varied as control, 0.25, 0.5, 1.0, 1.5 and 2.0 Molar. Al-Cu-Ni alloy was sand cast into cylindrical bars of 20 mm x 300 mm dimension. The corrosion of the ...

  18. The role of nuclear analytical techniques in the study of aqueous corrosion of glasses

    International Nuclear Information System (INIS)

    Trocellier, P.

    1984-01-01

    Direct observation of resonant nuclear reactions, backscattering spectrometry and X ray microanalysis with a nuclear microprobe were used to determine elementary depth profiles in the near surface region of leached glasses. Some computing programs required to interpretate the analytical information detected were built. Experimental conditions to characterize glass samples without secondary effects were defined; and the influence of some leaching parameters was studied to describe the first stages of aqueous corrosion of borosilicate glasses [fr

  19. Electrochemical corrosion studies on a selected carbon steel for application in nuclear waste disposal containers: Influence of chemical species in brines on corrosion

    International Nuclear Information System (INIS)

    Farvaque-Bera, A.M.; Smailos, E.

    1994-04-01

    In previous corrosion studies, carbon steels were identified as promising materials for the manufacture of long-lived high-level waste containers that could act as an engineered barrier in a rock-salt repository. In this paper, the influence of chemical species, potentially present in salt brines, on the electrochemical corrosion behavior of the preselected fine-grained steel TStE 355 was studied. The steel was examined at 90 C in a disposal relevant NaCl-rich brine containing various species (Br - , I - , Cu 2+ , Mn 2+ , S 2- , B(OH )4 - and Fe 3+ ) at concentrations between 10 -5 M/I and 10 -1 M/I. (orig.) [de

  20. Study on transition behavior of corrosion related environment near disposal site

    International Nuclear Information System (INIS)

    Masuda, K.; Nakanishi, T.; Kato, O.; Wada, R.

    2005-01-01

    Full text of publication follows: Disposal vessels are desired to stand for a certain period of time to stabilize radioactive wastes containing heat-generating substances. Besides, in case of wastes containing irradiated metal, which is a source of long-lived 14 C, long-term capability to enclose such long-life species is desired to the vessels. Since endurance of vessels is very affected by surrounding environment, evaluation of long-term environmental transition is important. In this study, we focused on the behavior of red-ox conditions and pH by reactive transport modeling in order to obtain fundamental knowledge about long-term transition of corrosion-related environment around metal vessels or metal-containing radioactive wastes. A two-dimensional reactive transport simulation was applied to a modeled repository site with engineering barrier system including cement and bentonite, etc., in consideration of following chemical models: - The metal corrosion rate was modeled to consider its effect on red-ox conditions. - The corrosion rate of carbon steel was modeled as kinetic reaction rate of production of ferrous ion and electrons as a function of pH and oxygen concentration, based on the experimental results observed under highly-controlled reducing conditions (1). - Formation of corrosion products was modeled by solubility products of iron oxides, such as magnetite, according to analytical results by in-situ XPS (2). - Cement composition and its reaction with groundwater were modeled by chemical equilibrium of primary and secondary minerals, for example, calcium silicates with several C/S ratios to consider the long-term transition of pH with cement degradations. According to the simulation results, the variation of red-ox conditions and pH around the disposal vessels has been estimated. Main component of cement composition slowly changes to calcium silicate having lower C/S ratios, resulting in decrease of pH. Although it depends on the bentonite efficiency

  1. Determination of sulfur isotopic composition for the study of iron sulfides origin, biotic or abiotic, in anoxic corrosion

    International Nuclear Information System (INIS)

    Grousset, Sophie

    2016-01-01

    The first goal of this project was to develop a methodology based on the study of the sulfur isotopic composition enabling the determination of iron sulfides origin, biotic or abiotic, within the corrosion products layers (CPL). Then, the aim was to apply this methodology to real corrosion systems in order to determine the mechanisms of iron sulfides formation. Sulfur isotopic analyses methodologies, adapted to micrometric iron sulfides layers observed in real corrosion systems, were developed in nanoSIMS and ToF-SIMS. The study of iron sulfides formed in anoxic carbonated medium with or without sulphate-reducing bacteria validated the use of these methods for the determination of iron sulfides origin. The application of these methods coupled with the precise characterization of irons sulfides formed in the real corrosion systems show two kind of corrosion pattern. In pattern 1, the iron sulfides are localized in the external part of the CPL. They result from the Fe 2+ migration from the metal surface to areas rich in biotic S 2- . In this pattern, corrosion rates are lower than 20 μm/year for laboratory systems, and lower than 5 μm/year for archaeological objects. In pattern 2, the large presence of conductive phases in the CPL results in the delocalization of electrons, and so a disequilibrium of the charges at the metal's surface. That leads to the migration of biotic S 2- in the CPL till the metal where they precipitate in iron sulphides. This pattern shows high corrosion rates (∼100 μm/an) that might be resulting from the accumulation of bio-corrosion and chloride corrosion mechanisms. (author) [fr

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

    Science.gov (United States)

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

    2018-03-01

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

  3. Study of the corrosion of nickel base alloys in molten fluorides medium

    International Nuclear Information System (INIS)

    Fabre, St.; Finne, J.; Noel, D.; Catalette, H.; Cabet, C.; Chamelot, P.; Taxil, P.; Cassayre, L.

    2007-01-01

    The aim of this work is to study the corrosion mechanisms of nickel and its alloys in molten fluoride media. In a first part, the behaviour of the pure alloy metals has been studied (Ni, Mo, W, Fe and Cr) in three different salts mixtures: LiF-NaF, LiF-CaF 2 and LiF-AlF 3 in a temperature range of 700-1000 C. An experimental assembly allowing the implementation of electrochemical methods has been fabricated and validated. Linear scanning volt-amperometry has been used for studying the corrosion reactions of metals. It has then been possible to obtain intensity-potential curves and to determine the currents and corrosion potentials by the plotting of Tafel straight lines. These experimental results have finely been interpreted in considering the thermodynamic data accessible in literature (potential-oxo-acidity diagrams of metals in salts built from HSC Chemistry 5.1) and the influence of temperature and the nature of the bath have been estimated. (O.M.)

  4. Electrochemical corrosion studies of the TStE 355 fine-grained structural steel in sulfide containing brine

    International Nuclear Information System (INIS)

    Farvaque-Bera, A.M.; Berg, H. von.

    1994-04-01

    Previous corrosion studies have shown that the unalloyed fine-grained steel TStE 355 (Material No. 1.0566) is a promising material for the manufacturing of long-lived high-level waste (HLW) containers that could act as a barrier in a rock-salt repository. Considering this fact, further electrochemical corrosion tests were performed in order to determine the influence of sulfide ions (1 -200 ppm), present as salt impurities in disposal relevant NaCl-brine (T = 55 -90 C), on the corrosion behaviour of this steel grade. For comparison, tests were carried out in the sulfide-free brine, too. (orig.) [de

  5. Study on the fabrication of the Stress Corrosion Crack by vapor pressure in the Alloy 600 Pipe

    International Nuclear Information System (INIS)

    Kim, Jae Seong; An, Ju Seon; Hwang, Woong Ki; Lee, Bo Young

    2010-01-01

    The stress corrosion crack is one of the life-limiting mechanisms in nuclear power plant conditions. During the operation of a power plant stress corrosion cracks can initiate and grow in dissimilar metal weld pipe joints of primary loop components. In particular, stress corrosion cracking usually occurs when the following three factors exist at the same time; susceptible material, corrosive environment, and tensile stress (including residual stress). Thus, residual stress becomes very critical for stress-corrosion cracking when it is difficult to improve the material corrosivity of the components and their environment under operating conditions. Since the research conducted by Coriou et al., it is well known that Ni-based alloy is susceptible to stress corrosion cracking(SCC) in deaerated pure water at high temperature and the SCC is difficult to be reproduced in laboratory. The aim of this study was to fulfill the need by developing an artificial SCC manufacturing method, which would produce realistic SCC in the Alloy 600 pipe

  6. Brief description of out-of-pile test facilities for study in corrosion and fission product behaviour in flowing sodium

    International Nuclear Information System (INIS)

    Iizawa, K.; Sekiguchi, N.; Atsumo, H.

    1976-01-01

    The experimental methods to perform tests for study in corrosion and fission products behaviour in flowing sodium are outlined. Flow diagrams for the activated materials and fission products behaviour test loop are given

  7. Study of electrochemical corrosion parameters in the detection of fission fragments in solid state trace detectors (SSTD)

    International Nuclear Information System (INIS)

    Silva Oliveira, S. da; Rogers, J.D.

    1980-01-01

    The basic properties of the electrochemical corrosion method, for the Makrofol E plastic, irradiated with fission fragments from a 252 Cf source were studied and discussed in this paper. (A.C.A.S.) [pt

  8. Study of corrosion resistance of AISI 444 ferritic stainless steel for application as a biomaterial

    International Nuclear Information System (INIS)

    Marques, Rogerio Albuquerque

    2014-01-01

    Ferritic stainless steels are ferromagnetic materials. This property does not allow their use in orthopedic prosthesis. Nevertheless, in some specific applications, this characteristic is very useful, such as, for fixing dental and facial prostheses by using magnetic attachments. In this study, the corrosion resistance and cytotoxicity of the AISI 444 ferritic stainless steel, with low nickel content, extra-low interstitial levels (C and N) and Ti and Nb stabilizers, were investigated for magnetic dental attachments application. The ISO 5832-1 (ASTM F-139) austenitic stainless steel and a commercial universal keeper for dental attachment (Neo-magnet System) were evaluated for comparison reasons. The first stainless steel is the most used metallic material for prostheses, and the second one, is a ferromagnetic keeper for dental prostheses (NeoM). In vitro cytotoxicity analysis was performed by the red neutral incorporation method. The results showed that the AISI 444 stainless steel is non cytotoxic. The corrosion resistance was studied by anodic polarization methods and electrochemical impedance spectroscopy (EIS), in a saline phosphate buffered solution (PBS) at 37 °C. The electronic properties of the passive film formed on AISI 444 SS were evaluated by the Mott-Schottky approach. All tested materials showed passivity in the PBS medium and the passive oxide film presented a duplex nature. The highest susceptibility to pitting corrosion was associated to the NeoM SS. This steel was also associated to the highest dopant concentration. The comparatively low levels of chromium (nearly 12.5%) and molybdenum (0.3%) of NeoM relatively to the other studied stainless steels are the probable cause of its lower corrosion resistance. The NeoM chemical composition does not match that of the SUS444 standards. The AISI 444 SS pitting resistance was equivalent to the ISO 5832-1 pointing out that it is a potential candidate for replacement of commercial ferromagnetic alloys used

  9. A comparative study of the corrosion resistance of incoloy MA 956 and PM 2000 superalloys

    Directory of Open Access Journals (Sweden)

    Maysa Terada

    2010-12-01

    Full Text Available Austenitic stainless steels, titanium and cobalt alloys are widely used as biomaterials. However, new medical devices require innovative materials with specific properties, depending on their application. The magnetic properties are among the properties of interest for some biomedical applications. However, due to the interaction of magnetic materials with Magnetic Resonance Image equipments they might used only as not fixed implants or for medical devices. The ferromagnetic superalloys, Incoloy MA 956 and PM 2000, produced by mechanical alloying, have similar chemical composition, high corrosion resistance and are used in high temperature applications. In this study, the corrosion resistance of these two ferritic superalloys was compared in a phosphate buffer solution. The electrochemical results showed that both superalloys are passive in this solution and the PM 2000 present a more protective passive film on it associated to higher impedances than the MA 956.

  10. Corrosion Inhibition of Copper-nickel Alloy: Experimental and Theoretical Studies

    Energy Technology Data Exchange (ETDEWEB)

    Khadom, Anees A. [Univ. of Daiyla, Baquba (Iran, Islamic Republic of); Yaro, Aprael S. [Univ. of Baghdad, Aljadreaa (Iran, Islamic Republic of); Musa, Ahmed Y.; Mohamad, Abu Bakar; Kadhum, Abdul Amir H. [UniversitiKebangsaan Malaysia, Bangi (Malaysia)

    2012-08-15

    The corrosion inhibition of copper-nickel alloy by Ethylenediamine (EDA) and Diethylenetriamine (DETA) in 1.5M HCl has been investigated by weight loss technique at different temperatures. Maximum value of inhibitor efficiency was 75% at 35 .deg. C and 0.2 M inhibitor concentration EDA, while the lower value was 4% at 35 .deg. C and 0.01 M inhibitor concentration DETA. Two mathematical models were used to represent the corrosion rate data, second order polynomial model and exponential model respectively. Nonlinear regression analysis showed that the first model was better than the second model with high correlation coefficient. The reactivity of studied inhibitors was analyzed through theoretical calculations based on density functional theory (DFT). The results showed that the reactive sites were located on the nitrogen (N1, N2 and N4) atoms.

  11. The study of the corrosion protection of the low-carbon steel using film-products

    International Nuclear Information System (INIS)

    Aiancului, L.; Millet, Jean-Pierre

    2001-01-01

    The paper reports studies on the efficiency of the film-inhibitors that covered low-carbon steel placed in a humid medium, and also, the optimization of the working conditions to improve the resistance to corrosion. The analyzes were done in the Industrial Physical - Chemical Laboratories of INSA - Lyon by electrochemical stationary techniques. The experimental device was a potentiometer of type EGG PAR (Princeton Applied Research). It was connected with a computer and three potential electrodes introduced in a cell with NaCl 30 g/l solution to acquire the data and to process the information. The film-products used were organic hydrosoluble polymers with diphosphonic 'heads' that permit a very good absorption at the metallic surface. This research is used to protect the installations of low-carbon steel against the atmospheric and high temperature corrosion. (authors)

  12. Electrochemical impedance spectroscopy and Surface Studies of Steel Corrosion by Sulphate-Reducing Bacteria

    International Nuclear Information System (INIS)

    Fathul Karim Sahrani; Zaharah Ibrahim; Madzlan Aziz; Adibah Yahya

    2009-01-01

    Sulphate-reducing bacteria (SRB), implicated in microbiologically influenced corrosion were isolated from the deep subsurface at the vicinity of Pasir Gudang, Johor, Malaysia. Electrochemical impedance spectroscopic (EIS) study was carried out to determine the polarization resistance in various types of culturing solutions, with SRB1, SRB2, combination of SRB1 and SRB2 and without SRBs inoculated (control). EIS results showed that in the presence of SRB1, SRB2 and mixed culture SRB1 and SRB2, polarisation resistance values were 7170, 6370 and 7190 ohms respectively compared to that of control, 92400 ohm. X-ray analysis (EDS) of the specimens indicated high sulphur content in the medium containing SRBs. Localized corrosion was observed on the metal surface which was associated with the SRB activity. (author)

  13. Novel electrochemical approach to study corrosion mechanism of Al-Au wire-bond pad interconnections

    DEFF Research Database (Denmark)

    Elisseeva, O. V.; Bruhn, A.; Cerezo, J.

    2013-01-01

    A gold-aluminium material combination is typically employed as an interconnection for microelectronic devices. One of the reliability risks of such devices is that of corrosion of aluminium bond pads resulting from the galvanic coupling between an aluminium bond pad and a gold wire. The research...... presented in this manuscript focuses on studying bond pad corrosion by selecting an appropriate model system and a dedicated set of electrochemical and analytical experimental tools. Taking into account the complex three-dimensional structure and the small dimensions of Au-Al interconnections (around 50......-100 μm), a dedicated and novel experimental approach was developed. Au-Al covered silicon chips were developed under clean room conditions. Three-dimensional electrodes were mimicked as flat, two-dimensional bond pad model systems, allowing the use of microelectrochemical local probe techniques. Thin...

  14. Experimental Study on Corrosion Detection of Aluminum Alloy Using Lamb Wave Mixing Technique

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Heeung; Lee, Jaesun; Cho, Younho [Pusan Nat’l Univ., Busan (Korea, Republic of)

    2016-11-15

    In this study, the Lamb wave mixing technique, which is basised on advanced research on the nonlinear bulk wave mixing technique, is applied for corrosion detection. To demonstrate the validity of the Lamb wave mixing technique, an experiment was performed with normal and corroded specimens. Comparison group in an experimentation are selected to mode and frequency with dominant in-plane displacement and out-of-plane displacement of Lamb waves. The results showed that the Lamb wave mixing technique can monitor corrosion defects, and it has a trend similar to that of the conventional Lamb wave technique. It was confirmed that the dominant displacement and mode matching the theory were generated. Flaw detectability is determined depending on displacement ratio instead of using the measurement method and mode selection.

  15. A fundamental study on stress corrosion cracking of SUS 304 steel in high temperature water

    International Nuclear Information System (INIS)

    Mukai, Yoshihiko; Murata, Masato

    1985-01-01

    SCC susceptibility of sensitized SUS 304 stainless steel in high temperature water was studied. The results obtained are as follows. SCC susceptibility was increased by adding crevices to the tensile specimen surface, for the corrodent became acidified by hydrolysis in crevices. SCC susceptibility was best fit to TTS curve obtained by EPR test, not by other corrosion tests such as Strauss test or the grain boundary corrosion test in high temperature water. In addition, by giving a simulated weld thermal cycle before the sensitizing heat treatment, the sensitization was clearly promoted. This seemed to be caused by the reason that nucleation of carbide occured in the simulated weld thermal cycle process and it promoted the carbide growth and the formation of Cr poor layer around carbide in the subsequent sensitization process. (author)

  16. Experimental and Theoretical Studies on Corrosion Inhibition of Niobium and Tantalum Surfaces by Carboxylated Graphene Oxide

    Directory of Open Access Journals (Sweden)

    Valbonë Mehmeti

    2018-05-01

    Full Text Available The corrosion of two different metals, niobium and tantalum, in aqueous sulfuric acid solution has been studied in the presence and absence of carboxylated graphene oxide. Potentiodynamic measurements indicate that this nanomaterial inhibits corrosion due to its adsorption on the metal surfaces. The adsorbed layer of carboxylated graphene hinders two electrochemical reactions: the oxidation of the metal and the transport of metal ions from the metal to the solution but also hydrogen evolution reaction by acting as a protective barrier. The adsorption behavior at the molecular level of the carboxylated graphene oxide with respect to Nb, NbO, Ta, and TaO (111 surfaces is also investigated using Molecular Dynamic and Monte Carlo calculations.

  17. Semiempirical Theoretical Studies of 1,3-Benzodioxole Derivatives as Corrosion Inhibitors

    Directory of Open Access Journals (Sweden)

    Omnia A. A. El-Shamy

    2017-01-01

    Full Text Available The efficiency of 1,3-benzodioxole derivatives as corrosion inhibitors is theoretically studied using quantum chemical calculation and Quantitative Structure Activity Relationship (QSAR. Different semiempirical methods (AM1, PM3, MNDO, MINDO/3, and INDO are applied in order to determine the relationship between molecular structure and their corrosion protection efficiencies. Different quantum parameters are obtained as the energy of highest occupied molecular orbital EHOMO, the energy of the lowest unoccupied molecular orbital ELUMO, energy gap ΔEg, dipole moment μ, and Mulliken charge on the atom. QSAR approach is applied to elucidate some important parameters as the hydrophobicity (Log P, surface area (S.A, polarization (P, and hydration energy (EHyd.

  18. Study of the corrosion of nickel base alloys in molten fluorides medium; Etude de la corrosion des alliages base nickel en milieu de fluorures fondus

    Energy Technology Data Exchange (ETDEWEB)

    Fabre, St.; Finne, J.; Noel, D.; Catalette, H. [Electricite de France (EDF/RD), Dept. Materiaux et Mecanique des Composants, Groupe Chimie et Corrosion, 77 - Ecuelles (France); Cabet, C. [CEA Saclay, Dept. de Physico-Chimie (DEN/DANS/DPC/SCCME), 91 - Gif sur Yvette (France); Chamelot, P.; Taxil, P.; Cassayre, L. [Universite Paul Sabatier, Lab. de Genie Chimique UMR 5503, Dept. Procedes Electrochimiques, 31 - Toulouse (France)

    2007-07-01

    The aim of this work is to study the corrosion mechanisms of nickel and its alloys in molten fluoride media. In a first part, the behaviour of the pure alloy metals has been studied (Ni, Mo, W, Fe and Cr) in three different salts mixtures: LiF-NaF, LiF-CaF{sub 2} and LiF-AlF{sub 3} in a temperature range of 700-1000 C. An experimental assembly allowing the implementation of electrochemical methods has been fabricated and validated. Linear scanning volt-amperometry has been used for studying the corrosion reactions of metals. It has then been possible to obtain intensity-potential curves and to determine the currents and corrosion potentials by the plotting of Tafel straight lines. These experimental results have finely been interpreted in considering the thermodynamic data accessible in literature (potential-oxo-acidity diagrams of metals in salts built from HSC Chemistry 5.1) and the influence of temperature and the nature of the bath have been estimated. (O.M.)

  19. Study of pitting corrosion in line-pipe steel under the influence of remanent magnetization

    Energy Technology Data Exchange (ETDEWEB)

    Espina-Hernandez, J H; Caleyo, F; Hallen, J M [Instituto Politecnico Nacional (IPN), Zacatenco (Mexico)

    2009-07-01

    The influence of remanent magnetization on pitting corrosion in line-pipe steels is studied. Pitting corrosion experiments have been carried out on samples of an API 5L grade 52 steel under a magnetization level of the same order of magnitude of the remanent magnetization in the pipeline wall after in-line inspection based on magnetic flux leakage. The samples were magnetized using rings of the same grade as the investigated steel. Immediately after magnetization, the investigated samples were subjected to pitting by immersing them in a solution containing dissolved Cl{sup -} and SO{sup 2-}{sub 4} and ions. The pitting experiments were conducted during a seven days period. The pit depth distribution and the maximum pit depth in each sample were recorded and used to conduct extreme value analyses of the pitting process in magnetized and non-magnetized control samples. The statistical assessment of the pitting corrosion data collected during this study shows that the magnetic field reduces the average depth of the pit population and also the extreme pit depth values that can be predicted from the maximum values observed in the magnetized samples in comparison with to the non-magnetized control samples. Scanning electron microscopy observations show that the magnetic field alters the pit morphology by increasing the pit mouth opening. (author)

  20. Corrosion Study and Intermetallics Formation in Gold and Copper Wire Bonding in Microelectronics Packaging

    Directory of Open Access Journals (Sweden)

    Christopher Breach

    2013-07-01

    Full Text Available A comparison study on the reliability of gold (Au and copper (Cu wire bonding is conducted to determine their corrosion and oxidation behavior in different environmental conditions. The corrosion and oxidation behaviors of Au and Cu wire bonding are determined through soaking in sodium chloride (NaCl solution and high temperature storage (HTS at 175 °C, 200 °C and 225 °C. Galvanic corrosion is more intense in Cu wire bonding as compared to Au wire bonding in NaCl solution due to the minimal formation of intermetallics in the former. At all three HTS annealing temperatures, the rate of Cu-Al intermetallic formation is found to be three to five times slower than Au-Al intermetallics. The faster intermetallic growth rate and lower activation energy found in this work for both Au/Al and Cu/Al as compared to literature could be due to the thicker Al pad metallization which removed the rate-determining step in previous studies due to deficit in Al material.

  1. A study on corrosion resistance of the Ti-10Mo experimental alloy after different processing methods

    International Nuclear Information System (INIS)

    Alves, A.P.R.; Santana, F.A.; Rosa, L.A.A.; Cursino, S.A.; Codaro, E.N.

    2004-01-01

    The purpose of this work was to evaluate the microstructure and corrosion resistance of the experimental Ti-10Mo (wt.%) alloy as-cast and treated. These alloys were divided into three groups for analysis: as-cast, after solution heat treatment at 1000 deg. C in argon atmosphere and remelting in centrifugal machine (investment casting). The microstructure formed from each condition was studied using optical microscopy. Corrosion behavior of titanium-molybdenum alloys in fluoridated physiological serum (0.15 M NaCl+0.03 M NaF [pH=6]) was studied and compared with Ti-6Al-4V alloy. In all electrodes systems, similar electrochemical response was obtained. In naturally aerated physiological serum, the corrosion rate is mainly controlled by dissolution process of a complex passive film. This film appears to be formed by titanium species with different oxidation states. Experimental Ti-10Mo alloy exhibit the lowest passive current densities, in particular, samples after heat treatment

  2. Fundamental studies of aluminum corrosion in acidic and basic environments: Theoretical predictions and experimental observations

    International Nuclear Information System (INIS)

    Lashgari, Mohsen; Malek, Ali M.

    2010-01-01

    Using quantum electrochemical approaches based on density functional theory and cluster/polarized continuum model, we investigated the corrosion behavior of aluminum in HCl and NaOH media containing phenol inhibitor. In this regard, we determined the geometry and electronic structure of the species at metal/solution interface. The investigations revealed that the interaction energies of hydroxide corrosive agents with aluminum surface should be more negative than those of chloride ones. The inhibitor adsorption in acid is more likely to have a physical nature while it appears as though to be chemical in basic media. To verify these predictions, using Tafel plots, we studied the phenomena from experimental viewpoint. The studies confirmed that the rate of corrosion in alkaline solution is substantially greater than in HCl media. Moreover, phenol is a potential-molecule having mixed-type inhibition mechanism. The relationship between inhibitory action and molecular parameters was discussed and the activity in alkaline media was also theoretically anticipated. This prediction was in accord with experiment.

  3. Corrosion Inhibition of Q235A Steel in Acid Medium Using Isatin Derivatives: A Qsar Study

    International Nuclear Information System (INIS)

    Abdo M Al-Fakih; Madzlan Aziz; Abdo M Al-Fakih; Abdallah, H.H.; Hasmerya Maarof; Rosmahaida Jamaludin; Bishir Usman

    2016-01-01

    Quantitative Structure-Activity Relationship (QSAR) study was performed on 10 isatin derivatives which were reportedly used as corrosion inhibitors. Dragon software was used to calculate the molecular descriptors. Partial least square (PLS) method was used to run the regression analysis between the descriptors and the corrosion inhibition efficiencies (IE) of the inhibitors. A predictive QSAR model was developed with a correlation coefficient (r 2 cal ) of 0.9676. The model validity was assessed through internal and external validation. The results show that cross-validation regression coefficient (r 2 cv ) and prediction regression coefficient (r 2 pred ) are 0.8163 and 0.9189, respectively. The model was used to predict the IE for ten isatin derivatives. The results confirm a good stability and predictive ability of the model. Dragon-based descriptors provide a very good description of the corrosion inhibition properties of the inhibitors. The results of the QSAR study were found to be consistent with the experimental data. (author)

  4. Theoretical studies of three triazole derivatives as corrosion inhibitors for mild steel in acidic medium

    International Nuclear Information System (INIS)

    Guo, Lei; Zhu, Shanhong; Zhang, Shengtao; He, Qiao; Li, Weihua

    2014-01-01

    Highlights: • Three triazole derivatives as corrosion inhibitors were theoretically investigated. • Quantum chemical calculations and Monte Carlo simulations were performed. • Quantitative structure activity relationship (QSAR) approach has been used. • Theoretical conclusions are validated by the consistency with experimental findings. - Abstract: Corrosion inhibitive performance of 4-chloro-acetophenone-O-1′-(1′.3′.4′-triazolyl)-metheneoxime (CATM), 4-fluoro-acetophenone-O-1′-(1′.3′.4′-triazolyl)-metheneoxime (FATM), and 3,4-dichloro-acetophenone-O-1′-(1′.3′.4′-triazolyl)-metheneoxime (DATM) during the acidic corrosion of mild steel surface was investigated using density functional theory (DFT). Quantum chemical parameters such as the highest occupied molecular orbital energy (E HOMO ), the lowest unoccupied molecular orbital energy (E LUMO ), energy gap (ΔE), Mulliken charges, hardness (ξ), dipole moment (μ), and the fraction of electrons transferred (ΔN), were calculated. Quantitative structure activity relationship (QSAR) approach has been used, and a composite index of above-mentioned descriptors was performed to characterize the inhibition performance of the studied molecules. Furthermore, Monte Carlo simulation studies were applied to search for the best configurational space of iron/triazole derivative system

  5. A study on the Stress Corrosion Cracking reduction method of Steam Generator secondary side of KSNP

    International Nuclear Information System (INIS)

    Kim, June Hoon; Lee, Goune Jin

    2014-01-01

    In order to avoid sludge accumulation affecting the life of the steam generator, the best way is to prevent the sludge inflow in advance by optimization of water quality management through chemical concentration and pH control etc. However it is very difficult to prevent sludge accumulation under the weak condition of corrosion, such as condensation, boiling and high temperature of feed-water in NPPs. Particularly stress corrosion cracking occurs in a top-of-tube sheet area of steam generator with an increase in number of operation years of Korea Standard Nuclear Plant(KSNP)... The purpose of this study is to improve suppression of stress corrosion cracking and life extension for steam generator and improve plant efficiency by performing full length bulk high chemical cleaning in order to remove iron oxide of steam generator secondary side in KSNP Hanbit Unit 6. This study analyzed the Free EDTA and Fe concentrations and sludge removal after performed full length bulk high temperature chemical cleaning for removing the iron oxide of steam generator secondary side, which of Hanbit unit 6 of KSNP. 1) It showed a typical pattern that Fe concentration increased in accordance with to decrease Free EDTA(Ethylene Diamine Tetea acetic Acid) concentration. 2) Sludge removal based on iron oxide after performing the full length bulk high temperature chemical cleaning was 3001kg and sludge removal by lancing additionally was 200.1kg

  6. Electrochemical and surface studies of some Porphines as corrosion inhibitor for J55 steel in sweet corrosion environment

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Ambrish, E-mail: ambrish.16752@ipu.co.in [State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation (Southwest Petroleum University), Chengdu, Sichuan 610500 (China); Department of Chemistry, LFTS, Lovely Professional University, Phagwara, Punjab 144402 (India); Lin, Yuanhua, E-mail: yhlin28@163.com [State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation (Southwest Petroleum University), Chengdu, Sichuan 610500 (China); Ansari, K.R.; Quraishi, M.A. [Department of Applied Chemistry, Indian Institute of Technology, Banaras Hindu University, Varanasi, U.P. (India); Ebenso, Eno. E. [Department of Chemistry, School of Mathematical & Physical Sciences, North-West University(Mafikeng Campus), Private Bag X2046, Mmabatho 2735 (South Africa); Chen, Songsong; Liu, Wanying [CNPC Key Lab for Tubular Goods Engineering (Southwest Petroleum University), Chengdu, Sichuan 610500 (China)

    2015-12-30

    Graphical abstract: Corrosion inhibition of J55 steel in 3.5 wt.% NaCl solution saturated with CO2 by the three Porphines 5,10,15,20-Tetra(4-pyridyl)-21H,23H-porphine (P1), 5,10,15,20-Tetraphenyl-21H,23H-porphine (P2), 5,10,15,20-Tetrakis(4-hydroxyphenyl)-21H,23H-porphine (P3), electrochemical impedance spectroscopy (EIS), contact angle measurement, scanning electrochemical microscopy (SECM), and atomic force microscopy (AFM). - Highlights: • J55 steel protection in 3.5% NaCl solution saturated with CO2 by Porphines. • Weight loss and impedance results are in good agreement. • The adsorption of Porphines obeys the Langmuir adsorption isotherm. • Scanning electrochemical microscopy is used to discuss the insulated and conductive surface. • Examination of surface morphology by AFM. - Abstract: Corrosion inhibition of J55 steel in 3.5 wt.% NaCl solution saturated with CO{sub 2} by the three Porphines 5,10,15,20-Tetra(4-pyridyl)-21H,23H-porphine (P1), 5,10,15,20-Tetraphenyl-21H,23H-porphine (P2), 5,10,15,20-Tetrakis(4-hydroxyphenyl)-21H,23H-porphine (P3), electrochemical impedance spectroscopy (EIS), Contact angle measurement, scanning electrochemical microscopy (SECM), and atomic force microscopy (AFM). Adsorption of such Porphines on the J55 steel surface obeyed to the Langmuir adsorption isotherm. Atomic force microscopy (AFM), SECM, and Contact angle results confirm the formation of inhibitor film on J55 steel surface thereby mitigating corrosion.

  7. Electrochemical and surface studies of some Porphines as corrosion inhibitor for J55 steel in sweet corrosion environment

    International Nuclear Information System (INIS)

    Singh, Ambrish; Lin, Yuanhua; Ansari, K.R.; Quraishi, M.A.; Ebenso, Eno. E.; Chen, Songsong; Liu, Wanying

    2015-01-01

    Graphical abstract: Corrosion inhibition of J55 steel in 3.5 wt.% NaCl solution saturated with CO2 by the three Porphines 5,10,15,20-Tetra(4-pyridyl)-21H,23H-porphine (P1), 5,10,15,20-Tetraphenyl-21H,23H-porphine (P2), 5,10,15,20-Tetrakis(4-hydroxyphenyl)-21H,23H-porphine (P3), electrochemical impedance spectroscopy (EIS), contact angle measurement, scanning electrochemical microscopy (SECM), and atomic force microscopy (AFM). - Highlights: • J55 steel protection in 3.5% NaCl solution saturated with CO2 by Porphines. • Weight loss and impedance results are in good agreement. • The adsorption of Porphines obeys the Langmuir adsorption isotherm. • Scanning electrochemical microscopy is used to discuss the insulated and conductive surface. • Examination of surface morphology by AFM. - Abstract: Corrosion inhibition of J55 steel in 3.5 wt.% NaCl solution saturated with CO_2 by the three Porphines 5,10,15,20-Tetra(4-pyridyl)-21H,23H-porphine (P1), 5,10,15,20-Tetraphenyl-21H,23H-porphine (P2), 5,10,15,20-Tetrakis(4-hydroxyphenyl)-21H,23H-porphine (P3), electrochemical impedance spectroscopy (EIS), Contact angle measurement, scanning electrochemical microscopy (SECM), and atomic force microscopy (AFM). Adsorption of such Porphines on the J55 steel surface obeyed to the Langmuir adsorption isotherm. Atomic force microscopy (AFM), SECM, and Contact angle results confirm the formation of inhibitor film on J55 steel surface thereby mitigating corrosion.

  8. Measurement of electrochemical noise for the study of corrosion processes of metallic alloys; Medida de ruido electroquimico para el estudio de rocesoso de corrosion de aleaciones metalicas

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Amaya, J. M.; Bethencourt, M.; Gonzalez-Rovira, L.; Botana, F. J.

    2009-07-01

    Electrochemical noise (EN) is a technique that allows the estimation of both the rate and the corrosion mechanism of different metallic alloys by means of the measurement and the analysis of the fluctuations of current and voltage. Its main advantage against other electrochemical techniques is that during the measurement process, the corrosive systems under study are not instrumentally disturbed, and therefore, the systems are kept at their natural corrosion potential. Two steps are necessary to use this technique: measurement and analysis of the EN signals. In this paper, the most important concepts related only to the measurement of EN are revised. The parameters most employed in the literature to analyse the EN signals will be described in another paper. In the present article, the experimental devices normally used to measure EN signals are firstly analysed. Subsequently, the most important properties of the EN signals are studied. Finally, the external sources of instrumental noise that can affect to the EN signals are described. (Author) 65 refs.

  9. Electrochemical corrosion studies on a selected carbon steel for application in nuclear waste disposal containers: Influence of radiolytic products on corrosion in brines

    International Nuclear Information System (INIS)

    Farvaque-Bera, A.M.; Smailos, E.

    1994-07-01

    In previous corrosion studies, carbon steels were identified as promising materials for the manufacturing of long-lived high-level waste containers that could act as a radionuclide barrier in a rock-salt repository. In the present work, the influence of some important oxidizing radiolytic products generated in gamma irradiated brines on the electrochemical corrosion behaviour of the preselected fine-grained steel TStE 355 was studied. The steel was examined by potentiodynamic and potentiostatic polarization methods at 90 C in a disposal relevant NaCl-rich brine containing radiolytic products such as H 2 O 2 , ClO - , ClO 3 - and ClO 4 - at concentrations between 10 -4 and 10 -2 M/l. The significance of the radiolytic products to steel corrosion depends on their concentration at the metal-brine interface, which in turn, depends on many factors such as the dose rate, the amount of water present in the disposal area, the escape of gases (e.g. H 2 )

  10. Study on stainless steel electrode based on dynamic aluminum liquid corrosion mechanism.

    Science.gov (United States)

    Hou, Hua; Yang, Ruifeng

    2009-01-01

    Scanning electrion microscope (SEM) was performed for investigations on the corrosion mechanism of stainless steel electrode in dynamic melting aluminum liquid. Microstructures and composition analysis was made by electron probe analysis (EPA) combined with metallic phase analysis. It can be concluded that the corrosion process is mainly composed of physical corrosion (flowing and scouring corrosion) and chemical corrosion (forming FeAl and Fe2Al5) and the two mechanisms usually exist simultaneously. The corrosion interface thickness is about 10 μm, which is different to usual interface width of hundreds μm in the static melting Al with iron matrix.

  11. Corrosion in Haas expanders with and without use of an antimicrobial agent: an in situ study

    Science.gov (United States)

    BAGATIN, Cristhiane Ristum; ITO, Izabel Yoko; ANDRUCIOLI, Marcela Cristina Damião; NELSON-FILHO, Paulo; FERREIRA, José Tarcísio Lima

    2011-01-01

    Objectives The purpose of this study was to evaluate in situ the occurrence of corrosion in the soldering point areas between the wire, silver brazing and band in Haas expanders. Material and Methods Thirty-four 7-12-year-old patients who needed maxillary expansion with a Haas expander were randomly assigned to two groups of 17 individuals each, according to the oral hygiene protocol adopted during the orthodontic treatment: Group I (control), toothbrushing with a fluoride dentifrice and Group II (experimental), toothbrushing with the same dentifrice plus 0.12% chlorhexidine gluconate (Periogard®) mouthrinses twice a week. The appliances were removed after approximately 4 months. Fragments of the appliances containing a metallic band with a soldered wire were sectioned at random for examination by stereomicroscopy, scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS). Data were analyzed statistically by Fisher's test at 5% significance level. Results The analysis by optical microscopy revealed areas with color change suggestive of corrosion in the soldering point areas joining the band and the wire in all specimens of both groups, with no statistically significant difference between the groups (p=1). The peaks of chemical elements (Ni, Fe, Cr, O, C and P) revealed by EDS were also similar in both groups. Conclusion: Color changes and peaks of chemical elements suggestive of corrosion were observed in the soldering point areas between the wire, silver brazing and band in both control and experimental groups, which indicate that the 0.12% chlorhexidine gluconate mouthrinses did not influence the occurrence of corrosion in situ. PMID:22231004

  12. Studies of the corrosion and cracking behavior of steels in high temperature water by electrochemical techniques

    International Nuclear Information System (INIS)

    Cheng, Y.F.; Bullerwell, J.; Steward, F.R.

    2003-01-01

    Electrochemical methods were used to study the corrosion and cracking behavior of five Fe-Cr alloy steels and 304L stainless steel in high temperature water. A layer of magnetite film forms on the metal surface, which decreases the corrosion rate in high temperature water. Passivity can be achieved on A-106 B carbon steel with a small content of chromium, which cannot be passivated at room temperature. The formation rate and the stability of the passive film (magnetite film) increased with increasing Cr-content in the steels. A mechanistic model was developed to simulate the corrosion and cracking processes of steels in high temperature water. The crack growth rate on steels was calculated from the maximum current of the repassivation current curves according to the slip-oxidation model. The highest crack growth rate was found for 304L stainless steel in high temperature water. Of the four Fe-Cr alloys, the crack growth rate was lower on 0.236% Cr- and 0.33% Cr-steels than on 0.406% Cr-steel and 2.5% Cr-1% Mo steel. The crack growth rate on 0.33% Cr-steel was the smallest over the tested potential range. A higher temperature of the electrolyte led to a higher rate of electrochemical dissolution of steel and a higher susceptibility of steel to cracking, as shown by the positive increase of the electrochemical potential. An increase in Cr-content in the steel is predicted to reduce the corrosion rate of steel at high temperatures. However, this increase in Cr-content is predicted not to reduce the susceptibility of steel to cracking at high temperatures. (author)

  13. Study on corrosion resistance of high - entropy alloy in medium acid liquid and chemical properties

    International Nuclear Information System (INIS)

    Florea, I; Buluc, G; Florea, R M; Carcea, I; Soare, V

    2015-01-01

    High-entropy alloy is a new alloy which is different from traditional alloys. The high entropy alloys were started in Tsing Hua University of Taiwan since 1995 by Yeh et al. Consisting of a variety of elements, each element occupying a similar compared with other alloy elements to form a high entropy. We could define high entropy alloys as having approximately equal concentrations, made up of a group of 5 to 11 major elements. In general, the content of each element is not more than 35% by weight of the alloy. During the investigation it turned out that this alloy has a high hardness and is also corrosion proof and also strength and good thermal stability. In the experimental area, scientists used different tools, including traditional casting, mechanical alloying, sputtering, splat-quenching to obtain the high entropy alloys with different alloying elements and then to investigate the corresponding microstructures and mechanical, chemical, thermal, and electronic performances. The present study is aimed to investigate the corrosion resistance in a different medium acid and try to put in evidence the mechanical properties. Forasmuch of the wide composition range and the enormous number of alloy systems in high entropy alloys, the mechanical properties of high entropy alloys can vary significantly. In terms of hardness, the most critical factors are: hardness/strength of each composing phase in the alloy, distribution of the composing phases. The corrosion resistance of an high entropy alloy was made in acid liquid such as 10%HNO 3 -3%HF, 10%H 2 SO 4 , 5%HCl and then was investigated, respectively with weight loss experiment. Weight loss test was carried out by put the samples into the acid solution for corrosion. The solution was maintained at a constant room temperature. The liquid formulations used for tests were 3% hydrofluoric acid with 10% nitric acid, 10% sulphuric acid, 5% hydrochloric acid. Weight loss of the samples was measured by electronic scale. (paper)

  14. In-situ electrochemical study of interaction of tribology and corrosion in artificial hip prosthesis simulators.

    Science.gov (United States)

    Yan, Yu; Dowson, Duncan; Neville, Anne

    2013-02-01

    The second generation Metal-on-Metal (MoM) hip replacements have been considered as an alternative to commonly used Polyethylene-on-Metal (PoM) joint prostheses due to polyethylene wear debris induced osteolysis. However, the role of corrosion and the biofilm formed under tribological contact are still not fully understood. Enhanced metal ion concentrations have been reported widely from hair, blood and urine samples of patients who received metal hip replacements and in isolated cases when abnormally high levels have caused adverse local tissue reactions. An understanding of the origin of metal ions is really important in order to design alloys for reduced ion release. Reciprocating pin-on-plate wear tester is a standard instrument to assess the interaction of corrosion and wear. However, more realistic hip simulator can provide a better understanding of tribocorrosion process for hip implants. It is very important to instrument the conventional hip simulator to enable electrochemical measurements. In this study, simple reciprocating pin-on-plate wear tests and hip simulator tests were compared. It was found that metal ions originated from two sources: (a) a depassivation of the contacting surfaces due to tribology (rubbing) and (b) corrosion of nano-sized wear particles generated from the contacting surfaces. Copyright © 2012 Elsevier Ltd. All rights reserved.

  15. A study on structural analysis of highly corrosive melts at high temperature

    CERN Document Server

    Ohtori, N

    2002-01-01

    When sodium is burned at high temperature in the atmosphere, it reacts simultaneously with H sub 2 O in the atmosphere so that it can produce high temperature melt of sodium hydroxide as a solvent. If this melt includes peroxide ion (O sub 2 sup 2 sup -), it will be a considerably active and corrosive for iron so that several sodium iron double oxides will be produced as corrosion products after the reaction with steel structures. The present study was carried out in order to investigate the ability of presence of peroxide ion in sodium hydroxide solvent at high temperature and that of identification of the several corrosion products using laser Raman spectroscopy. The measurement system with ultraviolet laser was developed simultaneously in the present work to improve the ability of the measurement at high temperature. As results from the measurements, the possibility of the presence of peroxide ion was shown up to 823K in sodium peroxide and 823K in the melt of sodium hydroxide mixed with sodium peroxide. A...

  16. Study of Rust Effect on the Corrosion Behavior of Reinforcement Steel Using Impedance Spectroscopy

    Science.gov (United States)

    Bensabra, Hakim; Azzouz, Noureddine

    2013-12-01

    Most studies on corrosion of steel reinforcement in concrete are conducted on steel samples with polished surface (free of all oxides) in order to reproduce the same experimental conditions. However, before embedding in concrete, the steel bars are often covered with natural oxides (rust), which are formed during exposure to the atmosphere. The presence of this rust may affect the electrochemical behavior of steel rebar in concrete. In order to understand the effect of rust on the corrosion behavior of reinforcement steel, potentiodynamic and electrochemical impedance spectroscopy (EIS) tests were carried out in a simulated concrete pore solution using steel samples with two different surface conditions: polished and rusted samples. The obtained results have shown that the presence of rust on the steel bar has a negative effect on its corrosion behavior, with or without the presence of chlorides. This detrimental effect can be explained by the fact that the rust provokes a decrease of the electrolyte resistance at the metal-concrete interface and reduces the repassivating ability. In addition, the rust layer acts as a barrier against the hydroxyl ion diffusion, which prevents the realkalinization phenomenon.

  17. Corrosion study of steels exposed over five years to the humid tropical atmosphere of Panama

    Energy Technology Data Exchange (ETDEWEB)

    Jaén, Juan A., E-mail: juan.jaen@up.ac.pa [Departamento de Química Física, Edificio de Laboratorios Científicos-VIP (Panama); Iglesias, Josefina [Laboratorio de Análisis Industriales y Ciencias Ambientales (Panama)

    2017-11-15

    The results of assessing five-year corrosion of low-carbon and conventional weathering steels exposed to the Panamanian tropical atmosphere is presented. Two different test sites, one in Panama City: 5 km from the shoreline of the Pacific Ocean, and another in the marine environment of Fort Sherman, Caribbean coast of Panama; namely, Fort Sherman Coastal site: 100 m from coastline. The corrosion products, formed in the skyward and earthward faces in the studied tropical environment, were mainly identified using room temperature and low temperature (15 K) Mössbauer spectroscopy, and ATR-FTIR. In all samples, lepidocrocite (γ-FeOOH) and goethite (α-FeOOH) were the main constituents. Some maghemite (γ-Fe{sub 2}O{sub 3}), was also identified in Tocumen by Mössbauer spectroscopy and traces of feroxyhyte (δ-FeOOH) using ATR-FTIR. The corrosion rate values obtained are discussed in light of the atmospheric exposure conditions and atmospheric pollutants.

  18. Impedance study on the corrosion of PVD and CVD titanium nitride coatings

    International Nuclear Information System (INIS)

    Elsener, B.; Rota, A.; Boehni, H.

    1989-01-01

    Titanium nitride (TiN) coatings, produced by physical (PVD) or chemical (CVD) vapor deposition techniques are used routinely to improve the wear and corrosion resistance of a surface. The main problem in using TiN as a protective coating in aggressive environements are pores and pinholes in the coating where the substrate is exposed to the electrolyte. In this work, the electrochemical and corrosion behaviour of TiN films on quartz glass, carbon steel, 304 and 316 stainless steel is studied by polarization curves and electrochemical impedance spectroscopy (EIS) in hydrochloric acid. It is shown that the TiN coating can be used successfully only on substrates that passivate easily. On mild steel rapid corrosion takes place at pores in the coating due to the very noble steady state potential of the TiN coating. The interaction of the metallic substrate with the TiN coating is discussed for the two limiting cases mild steel (active) and 316SS (passive). It is shown that the determination of the coating porosity is possible for the active substrate only. On the passive substrate the occurence of an additional time constant in the high frequency region of the spectrum qualitatively indicates the presence of pores. A quality control of the coatings based on this fact might be possible. (author) 15 refs., 6 figs., 2 tabs

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

    International Nuclear Information System (INIS)

    Fellmann, Daniel

    1982-01-01

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

  20. Contribution to the study of the influence of zinc bath composition on corrosion resistance of coatings obtained by galvanization

    International Nuclear Information System (INIS)

    Cabrillac, Claude

    1969-01-01

    This research thesis deals with the influence of zinc purity on the corrosion resistance of a coating obtained by galvanization, and on its effect on cathodic protection. This study therefore addresses methods and tests processes (notably salt spray test) aiming at assessing the efficiency of steel protection by hot galvanization, and aims at highlighting the influence of galvanization bath purity or composition on corrosion resistance of galvanized layers

  1. Galvanic corrosion study of aluminium alloy plates mounted to stainless and mild steel bolts by accelerated exposure test

    OpenAIRE

    MREMA, Emmanuel; ITOH, Yoshito; KANEKO, Akira; HIROHATA, Mikihito

    2016-01-01

    Despite the fact that aluminium alloy members have a proven durability over stainless steel members, their joint fasteners like bolts, nuts and washers are drawn from steel material due to aluminium alloy inferior mechanical properties. Bare contact between aluminium alloy members and stainless steel fasteners results to galvanic corrosion of aluminium alloy members. A corrosion behaviour study was carried out on different aluminium alloy types with different surface treatments mounted to sta...

  2. In-situ TEM Studies : Heat-treatment and Corrosion

    NARCIS (Netherlands)

    Malladi, S.R.K.

    2014-01-01

    Transmission electron microscopy (TEM) has been well known as a powerful characterisation tool to understand the structure and composition of various materials down to the atomic level. Over the years, several TEM studies have been carried out to understand the compositional, structural and

  3. Synthesis and corrosion inhibition application of NATN on mild steel surface in acidic media complemented with DFT studies

    Science.gov (United States)

    Al-Baghdadi, Shaimaa B.; Hashim, Fanar G.; Salam, Ahmed Q.; Abed, Talib K.; Gaaz, Tayser Sumer; Al-Amiery, Ahmed A.; Kadhum, Abdul Amir H.; Reda, Khalid S.; Ahmed, Wahab K.

    2018-03-01

    The corrosion inhibition effectiveness of thiosemicarbazide compound, namely 3-nitro-5-(2-amino-1,3,4-thiadiazolyl)nitrobenzene (NATN), on mild steel in 1 M hydrochloric acid media has been investigated by weight loss technique. The results exhibit that the corrosion ratio of mild steel was reduced regarding to adding NATN. The corrosion inhibition rate for the NATN was 92.3% at the highest investigated NATN concentration. From the weight loss results it could be concluded that NATN with sulfur, nitrogen and oxygen atoms has clarified best corrosion inhibition achievement comparing to 3,5-dinitrobenzoic acid. Regarding to theoretical studies, DFT was employee to figured geometrical structure and electronic characteristics on NATN. The investigation have been extensive to the HOMO and LUMO analysis to evaluate the energy gap, Ionization potential, Electron Affinity, Global Hardness, Chemical Potential, Electrophilicity, Electronegativity and Polarizability.

  4. Xanthium strumarium leaves extracts as a friendly corrosion inhibitor of low carbon steel in hydrochloric acid: Kinetics and mathematical studies

    Directory of Open Access Journals (Sweden)

    Anees A. Khadom

    2018-06-01

    Full Text Available Corrosion inhibition of low carbon steel in 1 M HCl was investigated in absence and presence of Xanthium strumarium leaves (XSL extracts as a friendly corrosion inhibitor. The effect of temperature and inhibitor concentration was studied using weight loss method. The result obtained shown that Xanthium strumarium leaves extracts act as an inhibitor for low carbon steel in HCl and reduces the corrosion rate. The inhibition efficiency was found to increases with increase in inhibitor concentration and temperature. Higher inhibition efficiency was 94.82% at higher level of inhibitor concentration and temperature. The adsorption of Xanthium strumarium leaves extracts was found to obey Langmuir adsorption isotherm model. The values of the free energy of adsorption was more than −20 kJ/mol, which is indicative of mixed mode of physical and chemical adsorption. Keywords: Corrosion, Green inhibitor, Natural extracts, Low carbon steel, Acid, Adsorption

  5. Synthesis and corrosion inhibition application of NATN on mild steel surface in acidic media complemented with DFT studies

    Directory of Open Access Journals (Sweden)

    Shaimaa B. Al-Baghdadi

    2018-03-01

    Full Text Available The corrosion inhibition effectiveness of thiosemicarbazide compound, namely 3-nitro-5-(2-amino-1,3,4-thiadiazolylnitrobenzene (NATN, on mild steel in 1 M hydrochloric acid media has been investigated by weight loss technique. The results exhibit that the corrosion ratio of mild steel was reduced regarding to adding NATN. The corrosion inhibition rate for the NATN was 92.3% at the highest investigated NATN concentration. From the weight loss results it could be concluded that NATN with sulfur, nitrogen and oxygen atoms has clarified best corrosion inhibition achievement comparing to 3,5-dinitrobenzoic acid. Regarding to theoretical studies, DFT was employee to figured geometrical structure and electronic characteristics on NATN. The investigation have been extensive to the HOMO and LUMO analysis to evaluate the energy gap, Ionization potential, Electron Affinity, Global Hardness, Chemical Potential, Electrophilicity, Electronegativity and Polarizability. Keywords: NATN, Mild steel, Weight loss, Dinitrobenzoic acid

  6. A study of the effect of clinical washing decontamination process on corrosion resistance of Martensitic Stainless Steel 420.

    Science.gov (United States)

    Xu, Yunwei; Huang, Zhihong; Corner, George

    2016-09-28

    Corrosion of surgical instruments provides a seat for contamination and prevents proper sterilisation, placing both patients and medical staff at risk of infection. Corrosion can also compromise the structural integrity of instruments and lead to mechanical failure in use. It is essential to understand the various factors affecting corrosion resistance of surgical instruments and how it can be minimised.This paper investigates the effect on corrosion resistance from the clinical washing decontamination (WD) process, specifically by studying the changes in surface roughness and Cr/Fe ratio. Results indicate that the WD process provides a positive effect on smooth polished samples, while a lesser positive effect was observed on rough reflection reduced samples.

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

    Science.gov (United States)

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

    2018-04-01

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

  8. A study on the effect of solution heat treatment on the corrosion resistance of super duplex stainless steels

    International Nuclear Information System (INIS)

    Park, Jee Yong; Park, Yong Soo; Kim, Soon Tae

    2001-01-01

    High temperature solution heat treatment(typically higher than 1100 .deg. C) is known generally to reduces the resistance to localized corrosion on super duplex stainless. This is attributed to the formation of zone depleted of alloying elements. In this study, the corrosion properties were investigated on super duplex stainless steels with various solution heat treatments. The corrosion resistance of these steels was evaluated in terms of critical pitting temperature and cyclic potentiodynamic polarization test. Chemical composition of the austenite and ferrite phases were analyzed by SEM-EDS. The following results were obtained. (1) By conducting furnace cooling, critical pitting temperature and repassivation potential increased. (2) By omitting furnace cooling, solution heat treatment produced Cr and Mo depleted zone in the phase boundary. (3) During furnace cooling, Cr and Mo rediffused through the phase boundary. This increased the corrosion resistance of super duplex stainless steels

  9. Studies in pitting corrosion on archaeological bronzes. Copper

    International Nuclear Information System (INIS)

    Bresle, Aa.; Saers, J.; Arrhenius, B.

    1983-01-01

    Copper has been proposed as a canister material for use in the long-term storage of radioactive waste from nuclear power reactors. The storage period has been set to at least 100 000 years, during which time the copper cylinders must remain intact so that the contained waste has no possibility of leaking out. In this work, the pitting factor in archaelogical copper objects have been determined. The absolute values of the pitting factor obtained are generally very low. In the case of the most thoroughly studied material the pitting factor is only slightly more than three units. Nor does the native copper, with a presumed burial period of about 8000 years, exhibit particularly high values. In summary, it can therefore be concluded that the present study does not provide support for the assumption of extremely high pitting factors in copper-base material that has been buried for periods of several millenia. (G.B.)

  10. Study on the Synthesis and Corrosion Inhibition Performance of Mannich-Modified Imidazoline

    Directory of Open Access Journals (Sweden)

    Xiangjun Kong

    2016-07-01

    Full Text Available A novel Mannich-modified imidazoline (MMI as cationic emulsifier was synthesised for corrosion harm reduction, through three steps — acylation, cyclization, and Mannich reaction. The surface activity was characterized by determination of surface tensions and critical micelle concentration (CMC. The corrosion inhibition performance of five types of steels in the simulated corrosion solution in the presence of the MMI was investigated by static weight loss tests. The results showed that the MMI had good surface activities, with CMC of 19.8 μg g−1 and surface tension of 36.4 mN m−1. The corrosion test results indicated that the corrosion rates of different materials were decreased significantly, and degrees of corrosion inhibition were always higher than 80.0 %. The main inhibition mechanism was most likely due to the adsorption of the corrosion inhibitor on the steel surface, leading to the prevention of corrosion medium from the metal surface.

  11. Corrosion engineering

    Energy Technology Data Exchange (ETDEWEB)

    Fontana, M.G.

    1986-01-01

    This book emphasizes the engineering approach to handling corrosion. It presents corrosion data by corrosives or environments rather than by materials. It discusses the corrosion engineering of noble metals, ''exotic'' metals, non-metallics, coatings, mechanical properties, and corrosion testing, as well as modern concepts. New sections have been added on fracture mechanics, laser alloying, nuclear waste isolation, solar energy, geothermal energy, and the Statue of Liberty. Special isocorrosion charts, developed by the author, are introduced as a quick way to look at candidates for a particular corrosive.

  12. Corrosion studies on containment materials for vitrified high level nuclear waste

    International Nuclear Information System (INIS)

    Taylor, K.J.; Bland, I.D.; Marsh, G.P.

    1984-01-01

    The general corrosion of carbon steels buried in granite or bentonite beds and saturated with synthetic granitic ground water is investigated. Corrosion rates were measured after 170 and 470 days, and pitting corrosion after 200hrs and 300hrs. Experiments to measure corrosion rates due to radiolysis of γ-radiated argon-purged ground water were also carried out. Results support the feasibility of using carbon steel packs for isolating high-level wastes for 500-1000 yrs. (U.K.)

  13. Electrokinetic and electrochemical corrosion studies related to crud formation

    International Nuclear Information System (INIS)

    Scenini, Fabio; Palumbo, Gaetano; Stevens, Nicholas; Cook, Tony; Banks, Andrew

    2012-09-01

    A potentially important mechanism for the flow-induced deposition of CRUD from pressurised high temperature primary water is the effect of 'streaming potentials' that develop across the electrochemical double layer of a metallic surface as a result of fluid flow across a pressure gradient or orifice. Thus, under such conditions, streaming currents develop normal to a surface and may result in preferential oxidation, for example of dissolved ferrous to ferric ions with their subsequent deposition as an oxide. The approach presented in this paper was to consider the electrokinetic problem is to firstly consider the magnitude of currents that can be developed under a given set of flow/mass transport conditions and, secondly, to consider the way in which these relatively small currents might give rise to oxide deposition. Electrochemical measurements on 304L samples were carried out over a range of temperatures in hydrogenated, alkaline water. The test conditions were chosen in order to simulate PWR primary water conditions. Furthermore, in order to facilitate the electrochemical studies, the ferrous ion concentration in the solution was also enhanced by the presence of a mild steel plate left in the autoclave to corrode. By employing the cyclic voltammetry technique interpreted using the Randles-Sevcik equation it was possible to calculate the concentration of ferrous ions and their diffusion coefficient. A miniature flow cell was designed for the purpose of creating regions of accelerated flow with consequent formation of anodic and cathodic regions so as to be able to measure the streaming currents. A study was carried out in order to better understand the potential which is associated with the streaming potential as function of the velocity and temperature at fixed pH. (authors)

  14. Study of the corrosion and microstructure with annealing conditions of a β-quenched HANA-4 alloy

    International Nuclear Information System (INIS)

    Kim, Hyun-Gil; Kim, Il-Hyun; Choi, Byung-Kwan; Park, Jeong-Yong; Jeong, Yong-Hwan; Kim, Kyu-Tae

    2010-01-01

    Research highlights: → The optimum annealing temperature to obtain good corrosion resistance of HANA-4 alloy (Zr-1.5Nb-0.4Sn-0.2Fe-0.1Cr) is find out. → The correlation between second phase characteristics and corrosion resistance is explained by oxide study. - Abstract: The variation of microstructure and corrosion characteristics with the applied annealing conditions of a HANA-4 (Zr-1.5Nb-0.4Sn-0.2Fe-0.1Cr) alloy were studied by utilizing transmission electron microscopy and a corrosion test at 360 o C in a water environment. The samples were annealed at temperature ranges from 540 to 660 o C up to 16 h after β quenching at 1050 o C. The corrosion behaviour with the annealing conditions was divided into two groups following the second phase characteristics. The suitable annealing temperature to obtain good corrosion resistance in the HANA-4 alloy ranged from 570 to 600 o C.

  15. Evaluation of thiosulfate as a substitute for hydrogen sulfide in sour corrosion fatigue studies

    Science.gov (United States)

    Kappes, Mariano Alberto

    This work evaluates the possibility of replacing hydrogen sulfide (H 2S) with thiosulfate anion (S2O32- ) in sour corrosion fatigue studies. H2S increases the corrosion fatigue crack growth rate (FCGR) and can be present in carbon steel risers and flowlines used in off-shore oil production. Corrosion tests with gaseous H2S require special facilities with safety features, because H2S is a toxic and flammable gas. The possibility of replacing H2S with S2O32-, a non-toxic anion, for studying stress corrosion cracking of stainless and carbon steels in H2S solutions was first proposed by Tsujikawa et al. ( Tsujikawa et al., Corrosion, 1993. 49(5): p. 409-419). In this dissertation, Tsujikawa work will be extended to sour corrosion fatigue of carbon steels. H2S testing is often conducted in deareated condition to avoid oxygen reaction with sulfide that yields sulfur and to mimic oil production conditions. Nitrogen deareation was also adopted in S2O3 2- testing, and gas exiting the cell was forced through a sodium hydroxide trap. Measurements of the sulfide content of this trap were used to estimate the partial pressure of H2S in nitrogen, and Henry's law was used to estimate the content of H2S in the solution in the cell. H2S was produced by a redox reaction of S2O 32-, which required electrons from carbon steel corrosion. This reaction is spontaneous at the open circuit potential of steel. Therefore, H2S concentration was expected to be maximum at the steel surface, and this concentration was estimated by a mass balance analysis. Carbon steel specimens exposed to S2O32- containing solutions developed a film on their surface, composed by iron sulfide and cementite. The film was not passivating and a good conductor of electrons. Hydrogen permeation experiments proved that this film controls the rate of hydrogen absorption of steels exposed to thiosulfate containing solutions. The absorption of hydrogen in S2O3 2- solutions was compared with the absorption of hydrogen in

  16. Contribution to Yttria corrosion study by liquid uranium

    International Nuclear Information System (INIS)

    Tournier, C.

    1995-02-01

    We are studying liquid uranium and polycrystalline Yttria interactions under secondary vacuum. The type, morphology and thickness of interfacial reaction products between U and Y 2 O 3 are examined by optical and confocal microscopy, SEM, X ray diffraction, X analysis and XPS. The most important parameters are the stoechiometry and microstructure of the Yttria, the oxygen partial pressure of the furnace atmosphere, pO 2 , and the duration and temperature of experiments. In the thermodynamic modelization, we take into account exchanges at the ceramic/metal interface and exchanges between the molten metal and the furnace atmosphere. Liquid uranium reacts with Yttria to form UO 2 at the interface which gradually changes into a solid solution UO 2 -Y 2 O 3 . The total thickness of reaction products results from two opposing reactions: (i) oxidation of uranium by Yttria (low pO 2 ) or by the atmosphere (high pO 2 ), controlled by migration of oxygen vacancies at Yttria grain boundaries. (ii) deoxidation caused by the formation of volatile uranium monoxide. On the other hand, we observed a transition of the type ''non-wettability → wettability '' which occurs subsequent to an increase of the stoichiometric variation x in Y 2 O 3-x . (author). 69 refs., 76 figs., 30 tabs

  17. A study on the corrosion characteristics of gear steel by shot peening

    International Nuclear Information System (INIS)

    Kang, Jin Shik; Kim, Tae Hyung; Cheong, Seong Kyun; Yoon, Jong Ku; Lee, Seung Ho

    2001-01-01

    The surface treatment technique to increase corrosion resistance is very important in mechanical components of structures. Therefore, this paper investigates the effects of shot peening on the corrosion resistance of SCM 420steel. The results show that the surface compressive residual stress largely increases, which cause the increase of corrosion resistance

  18. Evaluation of steel corrosion by numerical analysis

    OpenAIRE

    Kawahigashi, Tatsuo

    2017-01-01

    Recently, various non-destructive and numerical methods have been used and many cases of steel corrosion are examined. For example, methods of evaluating corrosion through various numerical methods and evaluating macrocell corrosion and micro-cell corrosion using measurements have been proposed. However, there are few reports on estimating of corrosion loss with distinguishing the macro-cell and micro-cell corrosion and with resembling an actuality phenomenon. In this study, for distinguishin...

  19. Comparative study of the corrosion resistance of steels covered by the processes galvalume and galvannealing

    International Nuclear Information System (INIS)

    Pritzel, Alvaro; Rodrigues, Joel da Silva; Dick, Luis Frederico Pinheiro

    2010-01-01

    Zinc has been used since a long time as a protective coating on automotive bodies. However, the industry is looking increasingly for protective coatings more resistant to corrosion, which have good weldability, paintability and especially low cost. This work aims to study the influence of parameters on the protection efficiency of zinc coatings on steel. The electrochemical behavior of zinc coatings (GA, GI and Galvalume) was studied by scanning vibrating electrode techniques (SVET). The samples were characterized by Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectrometry (EDS). It was also observed the presence of Anodic currents were observed at distances much higher than the thickness of Zn coatings. (author)

  20. Pitting corrosion studies on nitrogen implanted 316L SS for biomedical applications

    International Nuclear Information System (INIS)

    Subbaiyan, M.; Veerabadran, K.M.; Thampi, N.S.; Kanwar Krishnan; Kamachi Mudali, U.; Dayal, R.K.

    1997-01-01

    Traditionally, human bone fracture and defects have been corrected using metal and alloy fixing devices. Austenitic stainless steels (such as 316L alloy studied here) are favoured because of low cost, compared to titanium alloys, ease of fabrication and fair corrosion resistance. Localized attack on 316l stainless steel, however, results in iron, chromium and nickel ions leaching into surrounding body fluids. This study reports on the successful use of nitrogen ion implantation into 316lSS to evaluate the optimum dose needed to minimise this localised attack, in a physiological saline solution. (UK)

  1. Comparative study on the corrosion behavior of Ti-Nb and TMA alloys for dental application in various artificial solutions

    International Nuclear Information System (INIS)

    Bai, Y.J.; Wang, Y.B.; Cheng, Y.; Deng, F.; Zheng, Y.F.; Wei, S.C.

    2011-01-01

    The corrosion behavior of Ti-Nb dental alloy in artificial saliva with and without the addition of lactic acid and sodium fluoride was investigated by electrochemical techniques, with the commercial Titanium-molybdenum alloy (TMA) as a comparison. The chemical composition, microstructure and constitutional phase were characterized via energy dispersive spectrometry, optical microscope and X-ray diffraction, meanwhile the open circuit potential, electrochemical impedance spectroscopy and potentiodynamic polarization measurements were carried out to study the corrosion resistance of experimental alloys, with the corroded surface being further characterized by scanning electron microscopy and X-ray photoelectron spectroscopy. It was found that the corrosion behavior of Ti-Nb alloy was similar to those TMA alloy samples in both artificial and acidified saliva solutions, whereas statistical analysis of the electrochemical impedance spectroscopy and polarization parameters showed Ti-Nb alloy exhibited better corrosion resistance in fluoridated saliva and fluoridated acidified saliva. SEM observation indicated that TMA alloy corroded heavily than Ti-Nb alloy in fluoride containing saliva. XPS surface analysis suggested that Nb 2 O 5 played an important role in anti-corrosion from the attack of fluoride ion. Based on the above finding, Ti-Nb alloy is believed to be suitable for the usage in certain fluoride treated dental works with excellent corrosion resistance in fluoride-containing oral media.

  2. A Study on the Characteristics of Corrosion in Cold Worked Flexible STS 304 Stainless Steel Pipes

    International Nuclear Information System (INIS)

    Kim, In Soo; Kim, Sung Jin

    1993-01-01

    Effects of cold working on the corrosion resistance of austenitic STS 304 stainless steel pipes were investigated using anodic polarization method, EDX analysis and SEM technique. Corrosion products had a lots of S and Cl - ion. Generally, corrosion patterns as a result of STS 304 stainless steel to concrete environment were proceeded in the order of the pitting to intergranular corrosion. In the case of the flexible pipes were covered tightly with other polymer materials, crevice corrosion occurred to a much greater extent on austenitic than on martensitic region

  3. Study on electrochemical corrosion mechanism of steel foot of insulators for HVDC lines

    Science.gov (United States)

    Zheng, Weihua; Sun, Xiaoyu; Fan, Youping

    2017-09-01

    The main content of this paper is the mechanism of electrochemical corrosion of insulator steel foot in HVDC transmission line, and summarizes five commonly used artificial electrochemical corrosion accelerated test methods in the world. Various methods are analyzed and compared, and the simulation test of electrochemical corrosion of insulator steel feet is carried out by water jet method. The experimental results show that the experimental environment simulated by water jet method is close to the real environment. And the three suspension modes of insulators in the actual operation, the most serious corrosion of the V type suspension hardware, followed by the tension string suspension, and the linear string corrosion rate is the slowest.

  4. In vitro eye corrosion study of agrochemicals on isolated chicken eye.

    Science.gov (United States)

    Buda, I; Budai, P; Szabó, R; Lehel, J

    2013-01-01

    Agrochemicals must undergo numberless toxicological tests before marketing. The eye irritation test is part of this test packet. Nowadays, OECD 405 can be used to classify the irritation potential of substances, the base of the OECD 405 guideline is the Draize test, which is one of the most criticized in vivo methods because of the injuries of the test animals and subjective nature of the test in recording the results. Therefore, several in vitro tests have been developed to replace totally or partly the in vivo eye irritation testing. The isolated chicken eye test method (OECD 438), which was used, is one of these alternative methods. Five different agrochemicals were examined in the following way: All test compounds were applied in a single dose onto the cornea of isolated chicken eyes in order to potentially classify the test compounds as ocular corrosive and/or severe irritant. The damages caused by the test substances were assessed by the determination of corneal swelling, opacity, fluorescein retention and morphological effects. These parameters were evaluated pre-treatment and starting at approximately 30, 75, 120, 180, and 240 minutes after the post-treatment rinse. The endpoints evaluated were corneal opacity, swelling, fluorescein retention and morphological effects. All of the endpoints, with the exception of fluorescein retention (which was determined only at pre-treatment and 30 minutes after test substance exposure) were determined at each of the above time points. Positive and negative controls were used and they showed the expected results in each study. In these in vitro eye corrosives and severe irritants studies, using the Isolated Chicken Eye model with five different products, no ocular corrosion or severe irritation potential were observed. These results correspond to the available information about the tested agrochemicals, so these studies with isolated chicken eye are considered to be successful.

  5. Superheater fireside corrosion mechanisms in MSWI plants: Lab-scale study and on-site results

    Energy Technology Data Exchange (ETDEWEB)

    Brossard, J.M.; Chaucherie, X.; Nicol, F. [Veolia Environnement R and D, Zone Portuaire de Limay, 291 Avenue Dreyfous Ducas, Limay 78520 (France); Diop, I. [Veolia Environnement R and D, Zone Portuaire de Limay, 291 Avenue Dreyfous Ducas, Limay 78520 (France); Institut Jean Lamour, departement Chimie et physique des solides et des surfaces, UMR 7198 CNRS - Universite Henri Poincare Nancy 1, Vandoeuvre-Les-Nancy (France); Rapin, C.; Vilasi, M. [Institut Jean Lamour, departement Chimie et physique des solides et des surfaces, UMR 7198 CNRS - Universite Henri Poincare Nancy 1, Vandoeuvre-Les-Nancy (France)

    2011-06-15

    Combustion of municipal waste generates highly corrosive gases (HCl, SO{sub 2}, NaCl, KCl, and heavy metals chlorides) and ashes containing alkaline chlorides and sulfates. Currently, corrosion phenomena are particularly observed on superheater's tubes. Corrosion rates depend mainly on installation design, operating conditions i.e., gas and steam temperature and velocity of the flue gas containing ashes. This paper presents the results obtained using an innovative laboratory-scale corrosion unit, which simulates MSWI (Municipal Solid Waste Incineration) boilers conditions characterized by a temperature gradient at the metal tube in the presence of corrosive gases and ashes. The presented corrosion tests were realized on carbon steel at fixed metal temperature (400 C). The influence of the flue gas temperature, synthetic ashes composition, and flue gas flow pattern were investigated. After corrosion test, cross sections of tube samples were characterized to evaluate thickness loss and estimate corrosion rate while the elements present in corrosion layers were analyzed. Corrosion tests were carried out twice in order to validate the accuracy and reproducibility of results. First results highlight the key role of molten phase related to the ash composition and flue gas temperature as well as the deposit morphology, related to the flue gas flow pattern, on the mechanisms and corrosion rates. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Study of localized corrosion in AA2024 aluminium alloy using electron tomography

    International Nuclear Information System (INIS)

    Zhou, X.; Luo, C.; Hashimoto, T.; Hughes, A.E.; Thompson, G.E.

    2012-01-01

    Highlights: ► SEM tomography of localized corrosion has been achieved. ► Nanotomography provides evidence that links microstructure and corrosion propagation path. ► IGC stemmed from localized corrosion associated with buried clusters of intermetallics. ► IGC started beneath the alloy surface and may emerge on the alloy surface. - Abstract: SEM based tomography of localized corrosion has been achieved using selective detection of backscattered electrons. The high resolution tomography provides direct evidence that links the surface appearance of corroded alloy, the alloy microstructure and the corrosion propagation path. Stable localized corrosion of AA2024-T351 aluminium alloy was initiated at locations where large clusters of S phase particles were buried beneath the surface. Propagating away from the initiation sites, corrosion developed preferentially along the grain boundary network. The grain boundary attack started beneath the alloy surface, proceeded along preferred grain boundaries and may emerge at the alloy surface.

  7. Study of corrosion resistance of different thin paint films by I S

    International Nuclear Information System (INIS)

    Gonzalez, J.E.G.; Mirza-Rosca, J.C.

    1998-01-01

    One of the most modern methods to characterize the protective properties of coatings is the Electrochemical Impedance Spectroscopy (EIS). The EIS can provide useful information about transport of water and corrosive species through a coating. In this study, the impedance measurements were performed in different frequency ranges at open circuit potential for different coatings in 3 % NaCl. Two methods of data interpretation were considered: the break-point frequency method and the most probable equivalent circuit method (MPI). The interpretation of impedance spectra permitted the determination of water permeation, formation of blisters, swelling of the coating and the loss of adhesion including the delaminated area. (Author)

  8. X-ray diffraction study of slags forming during corrosion resistant steel production

    International Nuclear Information System (INIS)

    Slavov, V.I.; Zadorozhnaya, V.N.; Shurygina, A.V.

    1990-01-01

    Using X-ray diffraction analysis slags, forming during corrosion-resistant 12Kh18N10T grade steel production by two flowsheets, are studied. Standard two-slag technology of steel production does not provide efficient disintegration of chromospinelides in slags, gives high steel contamination with respect to nonmetallic impurities, coarse structure and, as a consequence, presence of macrodefects on rolled products surface. One-slag steel melting technology with titanium alloying of the steel at vacuum causes fast removal of chromospinelides at the beginning of reduction period, promotes titanium absorption by the steel, refines nonmetallic inclusions, provides more fine structure and steel plasticity, removes surface defects

  9. Preliminary study of radionuclide corrosion products in primary cooling water at RSG-GAS

    International Nuclear Information System (INIS)

    Lestari, D.E.; Pudjojanto, M.S.; Subiharto; Budi, S.

    1998-01-01

    Analysis of radionuclides emitting gamma rays at the primary cooling water at RSG-GAS has been carried out. The water coolant samples was performed using a low level background gamma spectrometer unit, including of high resolution of gamma detector HP-Ge Tennelec and Multichannel Analyzer (MCA) ADCAM 100 ORTEC. The result indicated Na-24 and Mn-56 radionuclides that may be as corrosion product and should studied deeply in the future. The expected activity concentration radionuclide for Mn-56 is lower than those written in the Safety Analysis Report (SAR), while for Na-24 is in agreement

  10. Study of corrosion using long period fiber gratings coated with iron exposed to salty water

    Science.gov (United States)

    Coelho, L.; Santos, J. L.; Jorge, P. A. S.; de Almeida, J. M. M.

    2017-04-01

    A study of long period fiber gratings (LPFG) over coated with iron (Fe) and subjected to oxidation in water with different sodium chloride (NaCl) concentrations is presented. The formation of iron oxides and hydroxides was monitored in real time by following the features of the LPFG attenuation band. Preliminary results show that Fe coated LPFGs can be used as sensors for early warning of corrosion in offshore and in coastal projects where metal structures made of iron alloys are in contact with sea or brackish water.

  11. Evaluation of corrosive behavior of SAE 5155 by corrosion environment

    International Nuclear Information System (INIS)

    An, Jae Pil; Park, Keyung Dong

    2005-01-01

    In this study, the influence of shot peening and corrosive condition for corrosion property was investigated on immersed in 3.5% NaCl, 10% HNO 3 + 3% HF, 6% FeCl 3 . The immersion test was performed on two kinds of specimen. The immersion periods was performed 30days. Corrosion potential, weight loss were investigated from experimental results. From test results, the effect of shot peening on the corrosion was evaluated

  12. A STUDY OF LEAKAGE OF TRACE METALS FROM CORROSION OF THE MUNICIPAL DRINKING WATER DISTRIBUTION SYSTEM

    Directory of Open Access Journals (Sweden)

    M.R SHA MANSOURI

    2003-09-01

    Full Text Available Introduction: A high portion of lead and copper concentration in municipal drinking water is related to the metallic structure of the distribution system and facets. The corrosive water in pipes and facets cause dissolution of the metals such as Pb, Cu, Cd, Zn, Fe and Mn into the water. Due to the lack of research work in this area, a study of the trace metals were performed in the drinking water distribution system in Zarin Shahr and Mobareke of Isfahan province. Methods: Based on the united states Environmental protection Agency (USEPA for the cities over than 50,000 population such as Zarin Shahr and Mobareke, 30 water samples from home facets with the minimum 6 hours retention time of water in pipes, were collected. Lead and cadmium concentration were determined using flameless Atomic Absorption. Cupper, Zinc, Iron and Manganese were determined using Atomic Absorption. Results: The average concentration of Pb, Cd, Zn, Fe and Mn in water distribution system fo Zarin Shahr were 5.7, 0.1, 80, 3042, 23065 and in Mobareke were 7.83, 0.8,210,3100, 253, 17µg respectively. The cocentration of Pb, Cd and Zn were zero at the beginning of the water samples from the municipal drinking water distribution system for both cities. Conclusion: The study showed that the corrosion by products (such as Pb, Cd and Zn was the results of dissolution of the galvanized pipes and brass facets. Lead concentration in over that 10 percent of the water samples in zarin shahr exceeded the drinking water standard level, which emphasize the evaluation and control of corrosion in drinking water distribution systems.

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

    Directory of Open Access Journals (Sweden)

    López, M. F.

    1996-12-01

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

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

  14. Mitigation of caustic stress corrosion cracking of steam generator tube materials by blowdown -a case study

    International Nuclear Information System (INIS)

    Dutta, Anu; Patwegar, I.A.; Chaki, S.K.; Venkat Raj, V.

    2000-01-01

    The vertical U-tube steam generators are among the most important equipment in nuclear power plants as they form the vital link between the reactor and the turbogenerator. Over ∼ 35 years of operating experience of water cooled reactor has demonstrated that steam generator tubes are susceptible to various forms of degradation. This degradation leads to failure and outages of the power plant. A majority of these failures have been attributed to concentrated alkali attacks in the low flow areas such as crevices in the tube to tube sheet joints, baffle plate location and the areas of sludge deposits. Free hydroxides can be produced by improper maintenance of phosphate chemical control in the secondary side of the steam generators and also by the thermal decomposition of impurities present in the condenser cooling water which may leak into the feed water through the condenser tubes. The free hydroxides concentrate in the low flow areas. This buildup of free hydroxide in combination with residual stress leads to caustic stress corrosion cracking. In order to mitigate caustic stress corrosion cracking of Inconel 600 tubes, the trend is to avoid phosphate dosing. Instead All Volatile Treatment (AVT) for secondary water is used backed by full flow condensate polishing. Sodium hydroxide concentration is now being considered as the basis for steam generator blowdown. A methodology has been established for determining the blowdown requirement in order to mitigate caustic stress corrosion cracking in the secondary side of the vertical U-tube natural circulation steam generator. A case study has been carried out for zero solid treatment (AVT coupled with full flow condensate polishing plant) water chemistry. Only continuous blowdown schemes have been studied based on maximum caustic concentration permissible in the secondary side of the steam generator. The methodology established can also be used for deciding concentration of any other impurities

  15. Aluminum Corrosion and Turbidity

    International Nuclear Information System (INIS)

    Longtin, F.B.

    2003-01-01

    Aluminum corrosion and turbidity formation in reactors correlate with fuel sheath temperature. To further substantiate this correlation, discharged fuel elements from R-3, P-2 and K-2 cycles were examined for extent of corrosion and evidence of breaking off of the oxide film. This report discusses this study

  16. Study of the corrosion of AA 6061 in spent fuel materials

    International Nuclear Information System (INIS)

    Rodriguez, Sebastian; Haddad, Roberto; Lanzani, Liliana A.

    2003-01-01

    Localized attack induced by dust or other particles deposited on alloy AA 6061 surface under water has been addressed as a matter of concern after completion of an IAEA Coordinated Research Program (CRP) on the corrosion of aluminum clad spent fuel during storage in water basins. This attack has been observed in all kinds of waters, although it is more pronounced in those of higher conductivity. In these cases a strong attack (similar to pitting corrosion) up to several hundred microns in depth and about a millimeter in length has been found beneath the aluminum hydroxide blister formed in those places where specks had seated on. As this problem could seriously affect the fission product containing capacity of stored spent fuel even in well maintained high quality water, it is important to learn about the involved mechanism of attack and find out about the influence of particle composition, in order to establish the convenience or disapproval of the use of materials and procedures in storage basins. With this objective, an experimental approach has been developed to study the mechanism of corrosion attack linked with the deposition of particles of different composition on aluminum surfaces; this include two kinds of iron flakes, concrete powder, and sand particles. Immersion tests of up to 40 days have been conducted in nuclear grade demineralized water and sodium citrate solutions of several conductivities. The position of sediments was marked and followed through the process and the final state of the aluminum surfaces was assessed by optical and electron microscopy and other microanalysis techniques. Other complementary activities carried on in relation with this work are: through characterization of intermetallic particles in AA 6061, and the study of the electrochemical behavior of precipitates in high purity water. Mg 2 Si particles perform very actively, dissolving even in high pure water at open circuit potential, leaving a small hole on the surface. Iron

  17. Selected durability studies of geopolymer concrete with respect to carbonation, elevated temperature, and microbial induced corrosion

    Science.gov (United States)

    Badar, Mohammad Sufian

    This thesis reports a comprehensive study related to the experimental evaluation of carbonation in reinforced geopolymer concrete, the evaluation of geopolymer concretes at elevated temperature, and the resistance of geopolymer concrete to microbial induced corrosion (MIC). Carbonation: Reinforced concretes, made of geopolymer, prepared from two class F fly ashes and one class C fly ash, were subjected to accelerated carbonation treatment for a period of 450 days. Electrochemical, microstructure and pore structure examinations were performed to evaluate the effect of corrosion caused due to carbonation. GPC specimens prepared from class F fly ash exhibited lower corrosion rates by a factor of 21, and higher pH values (pH>12) when compared with concrete specimens prepared from class C Fly ash (GPCMN). Microstructure and pore characterization of GPC prepared using class F fly ash revealed lower porosity by a factor of 2.5 as compared with thier counterparts made using GPC-MN. The superior performace of GPC prepared with the class F fly ash could be attributed to the dense pore structure and formation of the protective layer of calcium and sodium alumino silicate hydrates (C/N-A-S-H) geopolymeric gels around the steel reinforcement. Elevated Temperature: Geopolymers are an emerging class of cementitious binders which possess a potential for high temperature resistance that could possibly be utilized in applications such as nozzles, aspirators and refractory linings. This study reports on the results of an investigation into the performance of a fly ash based geopolymer binder in high temperature environments. Geopolymer concrete (GPC) was prepared using eleven types of fly ashes obtained from four countries. High content alumina and silica sand was used in the mix for preparing GPC. GPC was subjected to thermal shock tests following ASTM C 1100-88. The GPC samples prepared with tabular alumina were kept at 1093° C and immediately quenched in water. GPC specimens

  18. Study on Characteristics of Corrosion Fatigue Crack Propagation for Austenitic Stainless Steel

    International Nuclear Information System (INIS)

    Lim, Uh Joh; Kim, Bu Ahn

    1988-01-01

    The characteristics of the corrosion fatigue cracking of both TIG weld heat affected zone and base metal for austenitic stainless steel were investigated under the environments of various specific resistance and the air. The corrosion fatigue crack initiation sensitivity was quantitatively investigated for SUS 304 weldments in the various specific resistances. Also, the characteristics of corrosion fatigue cracking for the weldments were investigated from mechanical, electrochemical, and microstructural point of view. Main results obtained are as follows: (1) The corrosion fatigue crack initiation sensitivity on the base metal and weld hea affected zone increases as the specific resistance of corrosion environment decreases, and the sensitivity of the weld heat affected zone appears increasing more than that of the base metal. (2) The corrosion potentials of various specific resistances are almost constant in initial corrosion fatigue cracking, but the corrosion potential becomes less noble promptly with the corrosion fatigue crack growth as the specific resistances decrease. (3) The corrosion fatigue crack growth of the weld heat affected zone rapid than that of the base metal, because of the softening and the less noble potential caused by welding heat cycle

  19. A study on the corrosion test of equipment material handling hot molten salt

    International Nuclear Information System (INIS)

    Ro, Seung Gy; Jeong, M.S.; Hong, S.S.; Cho, S.H.; Shin, Y.J.; Park, H.S.; Zhang, J.S.

    1999-02-01

    On this technical report, corrosion behavior of austenitic stainless steels of SUS 316L and SUS 304L in molten salt of LiCl-Li 2 O has been investigated in the temperature range of 650 - 850 dg C. Corrosion products of SUS 316L in molten salt consisted of two layers, an outer layer of LiCrO 2 and inner layer of Cr 2 O 3 .The corrosion layer was uniform in molten salt of LiCl, but the intergranular corrosion occurred in addition to the uniform corrosion in mixed molten salt of LiCl-Li 2 O. The corrosion rate increased slowly with the increase of temperature up to 750 dg C, but above 750 dg C rapid increase in corrosion rate observed. SUS 316L stainless steel showed slower corrosion rate and higher activation energy for corrosion than SUS 304L, exhibiting higher corrosion resistance in the molten salt. In heat-resistant alloy, dense protective oxide scale of LiCrO 2 was formed in molten salt of LiCl. Whereas in mixed molten salt of LiCl-Li 2 O, porous non-protective scale of Li(Cr, Ni, Fe)O 2 was formed. (Author). 44 refs., 4 tabs., 16 figs

  20. Studies on the Corrosion Behavior of TiCode-12 with the Variation of Environmental Factors and Heat Treatment Conditions

    International Nuclear Information System (INIS)

    Yoon, S. R.; Kim, T. Y.; Lee, K. H.

    1989-01-01

    Corrosion behavior of TiCode-12 (Ti-0.8Ni-0.3Mo) has been studied by means of electrochemical polarization measurements and corrosion morphology examinations in various corrosive environments and different heat treatment conditions of the alloy. 1N H 2 SO 4 at 45 .deg. C was taken as a standard corrosive solution in which Cl - , Fe 3+ and Br - ion were added to investigate their effects. Acid concentration and temperature were also varied. Polarization behaviors of pure Ti, Ni, Mo and Ti 2 Ni were compared with those of heat-treated TiCode-12 specimens to find out how the constituent elements and the intermetallic compound formed during heat treatment of TiCode-12 affect the corrosion of the alloy. Mill-annealed TiCode-12 showed primary and secondary active-passive transition behavior in all the tested H 2 SO 4 solutions. The former behavior was confirmed to be due to Ti and the latter due to Ni and Mo. The passive current densities increased with increased Cl - ion concentration but decreased reversely beyond certain concentration. Fe 3+ ion raised the corrosion potential of TiCode-12 to the passive region, thus reducing the corrosion rate. Br - ion was turned out to be a critical species to induce the pitting of TiCode-12 by some unknown reason. Cathodic polarization behavior of pure Ni and Ti 2 Ni revealed that hydrogen evolution reaction was promoted on these electrodes in acid media. This was ascribed to the cause for sensitization phenomena of TiCode-12 heat-treated in the temperature range in which the eutectoid reaction β→α + Ti 2 Ni occurs. Near pits, observed on a sensitized TiCode-12 specimen immersed in H 2 SO 4 , always found were β crystals in which Ni peak was detected by EDS

  1. Stress corrosion of austenitic steels mono and polycrystals in Mg Cl2 medium: micro fractography and study of behaviour improvements

    International Nuclear Information System (INIS)

    Chambreuil-Paret, A.

    1997-01-01

    The austenitic steels in a hot chlorinated medium present a rupture which is macroscopically fragile, discontinuous and formed with crystallographic facets. The interpretation of these facies crystallographic character is a key for the understanding of the stress corrosion damages. The first aim of this work is then to study into details the micro fractography of 316 L steels mono and polycrystals. Two types of rupture are observed: a very fragile rupture which stresses on the possibility of the interatomic bonds weakening by the corrosive medium Mg Cl 2 and a discontinuous rupture (at the micron scale) on the sliding planes which is in good agreement with the corrosion enhanced plasticity model. The second aim of this work is to search for controlling the stress corrosion by the mean of a pre-strain hardening. Two types of pre-strain hardening have been tested. A pre-strain hardening with a monotonic strain is negative. Indeed, the first cracks starts very early and the cracks propagation velocity is increased. This is explained by the corrosion enhanced plasticity model through the intensifying of the local corrosion-deformation interactions. On the other hand, a cyclic pre-strain hardening is particularly favourable. The first micro strains starts later and the strain on breaking point levels are increased. The delay of the starting of the first strains is explained by a surface distortion structure which is very homogeneous. At last, the dislocations structure created in fatigue at saturation is a planar structure of low energy which reduces the corrosion-deformation interactions, source of micro strains. (O.M.)

  2. Molten salt corrosion behavior of structural materials in LiCl-KCl-UCl3 by thermogravimetric study

    Science.gov (United States)

    Rao, Ch Jagadeeswara; Ningshen, S.; Mallika, C.; Mudali, U. Kamachi

    2018-04-01

    The corrosion resistance of structural materials has been recognized as a key issue in the various unit operations such as salt purification, electrorefining, cathode processing and injection casting in the pyrochemical reprocessing of spent metallic nuclear fuels. In the present work, the corrosion behavior of the candidate materials of stainless steel (SS) 410, 2.25Cr-1Mo and 9Cr-1Mo steels was investigated in molten LiCl-KCl-UCl3 salt by thermogravimetric analysis under inert and reactive atmospheres at 500 and 600 °C, for 6 h duration. Insignificant weight gain (less than 1 mg/cm2) in the inert atmosphere and marginal weight gain (maximum 5 mg/cm2) in the reactive atmosphere were observed at both the temperatures. Chromium depletion rates and formation of Cr-rich corrosion products increased with increasing temperature of exposure in both inert and reactive atmospheres as evidenced by SEM and EDS analysis. The corrosion attack by LiCl-KCl-UCl3 molten salt, under reactive atmosphere for 6 h duration was more in the case of SS410 than 9Cr-1Mo steel followed by 2.25Cr-1Mo steel at 500 °C and the corrosion attack at 600 °C followed the order: 9Cr-1Mo steel >2.25Cr-1Mo steel > SS410. Outward diffusion of the minor alloying element, Mo was observed in 9Cr-1Mo and 2.25Cr-1Mo steels at both temperatures under reactive atmosphere. Laser Raman spectral analysis of the molten salt corrosion tested alloys under a reactive atmosphere at 500 and 600 °C for 6 h revealed the formation of unprotected Fe3O4 and α-as well as γ-Fe2O3. The results of the present study facilitate the selection of structural materials for applications in the corrosive molten salt environment at high temperatures.

  3. The efficiency of sucralfate in corrosive esophagitis: a randomized, prospective study.

    Science.gov (United States)

    Gümürdülü, Yüksel; Karakoç, Emre; Kara, Banu; Taşdoğan, Burçak Evren; Parsak, Cem Kaan; Sakman, Gürhan

    2010-03-01

    Ingestion of a chemical agent is a serious problem, and several treatment protocols to prevent stricture formation have been proposed. We conducted a randomized prospective study to evaluate the effectiveness of oral intensive sucralfate plus conventional therapy compared to conventional therapy alone. Fifteen patients with stage 2b and 3 corrosive esophagitis admitted to our gastroenterology, general surgery and intensive care units between 2004 and 2007 were included. Patients were divided into two groups. The patients in the first group (n=8) received intensive sucralfate therapy plus conventional therapy, while the other group (n=7) received only conventional therapy. We performed upper endoscopic procedures on days: 0, 21, 45, 90 and 180 to identify the emergent complications. In the first group, only one patient had stricture formation, allowing passage of a 9.2 mm endoscope and causing no dysphagia, on day 45. There was no progression in the stricture on follow-ups at the 3rd and 6th months. In the second group, 6 patients had stricture formation causing narrowing and dysphagia. Intensive sucralfate therapy may decrease the frequency of stricture formation in patients with advanced corrosive esophagitis. Further studies with large groups of patients are required to confirm our findings.

  4. Study of the iron corrosion at the interface of different media (water, air) submitted to protons irradiation

    International Nuclear Information System (INIS)

    Lapuerta, S.

    2005-10-01

    During the deep geological disposal, stainless steel containers of the vitrified waste will be put in carbon steel overpacks. After the closing of the storage site, overpacks will be in contact with a humid air and a radioactive medium. After hundred years, overpacks could be in contact with water radiolysis in an anoxic medium. In this context, my PhD work is a fundamental study which is the understanding of the corrosion mechanisms of pure iron under proton irradiation. This corrosion is affected by the contact of iron with different atmospheres (air, nitrogen) and water. In the case of the atmospheric iron corrosion under irradiation, we have studied the influence of the proton beam flux. During this work, we have characterized the structure of the oxides formed at the iron surface. The structure formed does not correspond to iron oxides and hydroxides indexed. However, we have shown that the oxide structure is close to that of lepidocrocite and bernalite. Moreover, we have determined the oxygen diffusion coefficient in iron under irradiation and we have shown that the irradiation accelerates of 6 orders of magnitude the iron corrosion. In addition, the irradiations which were realized in different gas have put in evidence the negligible role of nitrates, and the importance of the O 2 /H 2 O coupling on the iron corrosion. Finally, we have shown the influence of the relative humidity, the maximum of the corrosion being observed for a relative humidity close to 45%. In the case of the iron corrosion in aqueous media under irradiation, the influence of the oxygen dissolved in water has been studied using a surface marker. We have put in evidence that the corrosion is twice more significant in aerated medium than in deaerated medium. Moreover, the influence of radicals has been shown. An irradiated sample is more corroded than a sample put in contact with a H 2 O 2 solution. Finally, the follow-up of the iron potential under irradiation have shown the majority role

  5. Hanford Double Shell Waste Tank Corrosion Studies - Final Report FY2015

    Energy Technology Data Exchange (ETDEWEB)

    Fuentes, R. E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Wyrwas, R. B. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-05-01

    During FY15, SRNL performed corrosion testing that supported Washington River Protection Solutions (WRPS) with their double shell tank (DST) integrity program. The testing investigated six concerns including, 1) the possibility of corrosion of the exterior of the secondary tank wall; 2) the effect of ammonia on vapor space corrosion (VSC) above waste simulants; 3) the determination of the minimum required nitrite and hydroxide concentrations that prevent pitting in concentrated nitrate solutions (i.e., waste buffering); 4) the susceptibility to liquid air interface (LAI) corrosion at proposed stress corrosion cracking (SCC) inhibitor concentrations; 5) the susceptibility of carbon steel to pitting in dilute solutions that contain significant quantities of chloride and sulfate; and 6) the effect of different heats of A537 carbon steel on the corrosion response. For task 1, 2, and 4, the effect of heat treating and/ or welding of the materials was also investigated.

  6. Pitting corrosion behaviour study of aluminium matrix composites (A3xx.x/SiCp); Estudio del comportamiento a la corrosion por picadura de materiales compuestos de matriz de aluminio (A3xx.x/SiCp)

    Energy Technology Data Exchange (ETDEWEB)

    Pardo, A.; Merino, M. C.; Merino, S.; Lopez, M. D.; Viejo, F.; Carboneras, M.; Arrabal, R.

    2004-07-01

    The influence of the SiCp proportion on the pitting corrosion of A3xx.x/SiC/xxp composites was studies by means of potenciodinamic polarization and double cyclic polarization in saline environment at 25 degree centigree A360/SiC/xxp matrix does not contain copper, whereas the A380/SiC/xxp matric contains 1,39-1,44 wt %Cu. The kinetic study was carried out by gravimetric measurements. The nature of corrosion products was analysed by low angle XRD and Scanning Electron Microscopy (SEM). The corrosion is due to nucleation and growth of Al{sub 2}O{sub 3}-3H{sub 2}O on the material surface. The corrosion increases with the reinforcement proportion, chloride concentration and copper content. (Author) 10 refs.

  7. Statistical Study of Corrosion Types in Constructions in South Region of Rio De Janeiro -Brazil

    OpenAIRE

    Lacerda Da Cruz , Carolina; Gonçalves De Lima , Thalita; S Sampaio , Nilo Antônio; Jesus Silva , José Wilson de

    2017-01-01

    International audience; Some of the most difficult and troubling problems encountered in construction are those caused by corrosive processes. The corrosion processes are constituted by some material degradation, generally metallic material, by means of chemical or electrochemical actions of environment in which the material are and can or cannot be combined with mechanical stress. Corrosion is present in the materials in general. Their deterioration is caused by such physical-chemical intera...

  8. Structural, theoretical and corrosion inhibition studies on some transition metal complexes derived from heterocyclic system

    Science.gov (United States)

    Gupta, Shraddha Rani; Mourya, Punita; Singh, M. M.; Singh, Vinod P.

    2017-06-01

    A Schiff base, (E)-N‧-((1H-indol-3-yl)methylene)-2-aminobenzohydrazide (Iabh) and its Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes have been synthesized. These compounds have been characterized by different physico-chemical and spectroscopic tools (UV-Vis, IR, NMR and ESI-Mass). The molecular structure of Iabh is determined by single crystal X-ray diffraction technique. The ligand Iabh displays E-configuration about the >Cdbnd N- bond. The structure of ligand is stabilized by intra-molecular H-bonding. In all the metal complexes the ligand coordinates through azomethine-N and carbonyl-O resulting a distorted octahedral geometry for Mn(II), Co(II) and Cu(II) complexes in which chloride ions occupy axial positions. Ni(II) and Zn(II) complexes, however, form 4-coordinate distorted square planer and tetrahedral geometry around metal ion, respectively. The structures of the complexes have been satisfactorily modeled by calculations based on density functional theory (DFT) and time dependent-DFT (TD-DFT). The corrosion inhibition study of the compounds have been performed against mild steel in 0.5 M H2SO4 solution at 298 K by using weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). They show appreciable corrosion inhibition property.

  9. Parametric studies for stress corrosion in Type 304 stainless steel pipe

    International Nuclear Information System (INIS)

    Horn, R.M.

    1984-01-01

    Stress corrosion tests were conducted in the General Electric Pipe Test Laboratory using 4-inch diameter welded pipe to evaluate the role of stress, oxygen level, cyclic loading rate, temperature, and material composition on the intergranular stress corrosion cracking (IGSCC) behavior of welded Type-304 stainless steel in high temperature, high purity water. The role of applied stress was evaluated in environments containing either 0.2 ppm or 8 ppm oxygen. The tests established that applied stress is the dominant variable among those studied. An increase in applied axial stress from 116 MPa (16.9 ksi) to 254 MPa (36.9 ksi) produced up to a 30 old decrease in lifetime. The change in oxygen level from 0.2 to 8 ppm produced up to a factor of four decrease in lifetime. The role of cyclic loading rate, investigated with only limited tests, was found to accelerate failure at high applied stresses. Finally one test was conducted at 232 0 C with no effect on pipe lifetime. The effects of the above parameters were defined using one heat of material. To compare the results with that of other susceptible heats, additional tests were conducted using material taken from an archive heat that had cracked in the field and from a second heat with lower carbon content that had not cracked in the field. The archive heat exhibited lifetimes that were consistent with the other test results. The low carbon material did not fail demonstrating its much reduced cracking tendency

  10. Pilot study on the corrosion monitoring and control of the crude oil refining system by thin layer activation (TLA) technique

    International Nuclear Information System (INIS)

    Choochartchaikulkarn, Bodin; Chueinta, Siripone; Santawamaitre, Todsadol

    2001-01-01

    This report represents a pilot study on application of Ta technique for measurement monitoring the corrosion rates occurring in the refinery crude oil overhead crude oil system at the Bangchak Petroleum Co., Ltd. in Thailand during mid 1999 to mid 2000. TLA coupons containing very low activity of 5 6 Co produced by the accelerator was attached to the used electrical resistance probe inserted into production system at the test position. Gamma intensity of 56 Co was routinely monitored at external cladding and corrosion rates calculated in comparison with the non corroded standard after decay correction. From the study, TLA technique provides accurate corrosion rates less than 75 mm/year as compared to the standard Electrical Resistance Probes (ERP) technique. (author)

  11. Study through potentiodynamic techniques of the corrosion resistance of different aluminium base MMC's with boron additions

    International Nuclear Information System (INIS)

    Abenojar, J.; Bautista, A.; Guzman, S.; Velasco, F.; Martinez, M.A.

    2009-01-01

    This paper compares a wrought aluminium with a PM aluminium and PM aluminium alloys with boron-base additions, containing boron carbide and Fe/B (obtained by mechanical alloying during 36 hours from a Fe-B 50% mixture by weight). The effect of sintering temperature for the Fe/B containing material and the effect of mechanical alloying for the boron carbide containing aluminium alloy on the corrosion resistance of those materials have been studied. Their behaviour is followed through cyclic anodic polarization curves in chloride media. In the Al+20%Fe/B composite, low sintering temperatures (650- 950 deg C) exert a negative effect. However, when the material was sintered at high temperature (1000-1100 deg C) its behaviour was very similar to the PM pure aluminium. The effect of mechanical alloying studied in aluminium with boron carbide was also important in corrosion resistance, finding a lower corrosion rate in the mechanically alloyed material. (author)

  12. Study of hot corrosion of flakes of non purified graphite and of purified graphite

    International Nuclear Information System (INIS)

    Boule, Michel

    1967-01-01

    The author reports the study of hot corrosion of the Ticonderoga graphite. He reports the study of the defects of graphite flakes (structure defects due to impurities), the dosing of these impurities, and then their removal by purification. Flakes have then been oxidised by means of a specially designed apparatus. Based on photographs taken by optical and electronic microscopy, the author compares the oxidation features obtained in dry air and in humid air, between purified and non purified flakes. He also reports the study of the evolution of oxidation with respect to the initial rate of impurities, and the study of the evolution of oxidation features in humid air during oxidation. All these comparisons are made while taking the oxidation rate into account [fr

  13. Instant release fraction corrosion studies of commercial UO2 BWR spent nuclear fuel

    Science.gov (United States)

    Martínez-Torrents, Albert; Serrano-Purroy, Daniel; Sureda, Rosa; Casas, Ignasi; de Pablo, Joan

    2017-05-01

    The instant release fraction of a spent nuclear fuel is a matter of concern in the performance assessment of a deep geological repository since it increases the radiological risk. Corrosion studies of two different spent nuclear fuels were performed using bicarbonate water under oxidizing conditions to study their instant release fraction. From each fuel, cladded segments and powder samples obtained at different radial positions were used. The results were normalised using the specific surface area to permit a comparison between fuels and samples. Different radionuclide dissolution patterns were studied in terms of water contact availability and radial distribution in the spent nuclear fuel. The relationship between the results of this work and morphological parameters like the grain size or irradiation parameters such as the burn-up or the linear power density was studied in order to increase the understanding of the instant release fraction formation.

  14. Instant release fraction corrosion studies of commercial UO{sub 2} BWR spent nuclear fuel

    Energy Technology Data Exchange (ETDEWEB)

    Martínez-Torrents, Albert, E-mail: albert.martinez@ctm.com.es [Fundació CTM Centre Tecnològic, Plaça de la Ciència 2, 08243 Manresa (Spain); Serrano-Purroy, Daniel [European Commission, DG Joint Research Centre - JRC, Directorate G - Nuclear Safety & Security, Department G.III, P.O. Box 2340, D-76125 Karlsruhe (Germany); Sureda, Rosa [Fundació CTM Centre Tecnològic, Plaça de la Ciència 2, 08243 Manresa (Spain); Casas, Ignasi [Department of Chemical Engineering, Universitat Politècnica de Catalunya – Barcelona Tech, Eduard Maristany 14, 08019 Barcelona (Spain); Pablo, Joan de [Fundació CTM Centre Tecnològic, Plaça de la Ciència 2, 08243 Manresa (Spain); Department of Chemical Engineering, Universitat Politècnica de Catalunya – Barcelona Tech, Eduard Maristany 14, 08019 Barcelona (Spain)

    2017-05-15

    The instant release fraction of a spent nuclear fuel is a matter of concern in the performance assessment of a deep geological repository since it increases the radiological risk. Corrosion studies of two different spent nuclear fuels were performed using bicarbonate water under oxidizing conditions to study their instant release fraction. From each fuel, cladded segments and powder samples obtained at different radial positions were used. The results were normalised using the specific surface area to permit a comparison between fuels and samples. Different radionuclide dissolution patterns were studied in terms of water contact availability and radial distribution in the spent nuclear fuel. The relationship between the results of this work and morphological parameters like the grain size or irradiation parameters such as the burn-up or the linear power density was studied in order to increase the understanding of the instant release fraction formation.

  15. Moessbauer spectroscopy study on the corrosion resistance of plasma nitrided ASTM F138 stainless steel in chloride solution

    International Nuclear Information System (INIS)

    Souza, S.D. de; Olzon-Dionysio, M.; Basso, R.L.O.; Souza, S. de

    2010-01-01

    Plasma nitriding of ASTM F138 stainless steel samples has been carried out using dc glow discharge under 80% H 2 -20% N 2 gas mixture, at 673 K, and 2, 4, and 7 h time intervals, in order to investigate the influence of treatment time on the microstructure and the corrosion resistance properties. The samples were characterized by scanning electron microscopy, glancing angle X-ray diffraction and conversion electron Moessbauer spectroscopy, besides electrochemical tests in NaCl aerated solution. A modified layer of about 6 μm was observed for all the nitrided samples, independent of nitriding time. The X-ray diffraction analysis shows broad γ N phase peaks, signifying a great degree of nitrogen supersaturation. Besides γ N, the Moessbauer spectroscopy results indicated the occurrence of γ' and ε phases, as well as some other less important phases. Corrosion measurements demonstrate that the plasma nitriding time affects the corrosion resistance and the best performance is reached at 4 h treatment. It seems that the ε/γ' fraction ratio plays an important role on the resistance corrosion. Additionally, the Moessbauer spectroscopy was decisive in this study, since it was able to identify and quantify the iron phases that influence the corrosion resistance of plasma nitrided ASTM F138 samples.

  16. Electrochemical study of galvanic corrosion inhibitors in water-based and ethylene glycol-based heat transfer circuits

    International Nuclear Information System (INIS)

    Netter, Pierre

    1981-01-01

    This research thesis reports the search for and the efficiency assessment of mixes of inhibitors for coolant circuits of motor cars. After a discussion of the general properties of water-alcohol solvents (chemical properties, acid-base equilibriums) and of parameters affecting corrosion in coolant circuits, the author proposes an overview of the main inhibitors which are used to protect these circuits against corrosion, and discusses their action mechanism and efficiency. The different methods used to study the corrosion of these circuits are described, and the advantages and drawbacks of test methods are commented. The second part proposes a synthesis of the different corrosion electromechanical mechanisms which may occur with respect to the used metallic materials and to possible galvanic couplings. The next part describes the experimental installations. The last part focuses on the different protections obtained with the different used inhibitor class in terms of results obtained by gravimetric tests and visual examination of samples, current-voltage curves in hydrodynamic regime, and galvanic corrosion tests performed in laboratory or in situ in motor cars [fr

  17. Study for determination of industrial water corrosivity in Kashan Fajre Sepahan Galvanizing Mills during 2005-2006 Iran.

    Science.gov (United States)

    Rabbani, D; Miranzadeh, M B; Motlagh, A Ahmadi

    2008-01-01

    This research was carried out in Kashan Fajre Sepahan Galvanizing mills (KFSGM) for evaluation of water corrosivity during 2005-2006. A total of 18 samples were taken from various points of the water supply system for testing the specific parameters and calculation Langelier Index (LI), Ryznar Index (RI) and Pukorious Index (PI). This research showed that in raw water (sand filter effluent) LI were positive as well as RI and PI were lower than 7 which means that mentioned water is not corrosive. Also LI in treated water by reverse osmosis process was negative and RI and PI were higher than 7, so, this water has corrosive properties. Finally, calculated indexes indicate that according to LI, conditioned water is not corrosive but based on RI and P. this water tend to corrosivity which this findings is compatible with literature review statement. So it is recommended that, for water conditioning addition of preservative chemicals to be continued but at the same time another alternatives such as pH adjustment, air stripping and deoxygenating, control of carbonate concentration and split flow treatment should be studied.

  18. Study on the Effects of Corrosion Inhibitor According to the Functional Groups for Cu Chemical Mechanical Polishing in Neutral Environment

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Won; Kim, Jae Jeong [Institute of Chemical Process, Seoul National University, Seoul (Korea, Republic of)

    2015-08-15

    As the aluminum (Al) metallization process was replaced with copper (Cu), the damascene process was introduced, which required the planarization step to eliminate over-deposited Cu with Chemical Mechanical Polishing (CMP) process. In this study, the verification of the corrosion inhibitors, one of the Cu CMP slurry components, was conducted to find out the tendency regarding the carboxyl and amino functional group in neutral environment. Through the results of etch rate, removal rate, and chemical ability of corrosion inhibitors based on 1H-1,2,4-triazole as the base corrosion inhibitor, while the amine functional group presents high Cu etching ability, carboxyl functional group shows lower Cu etching ability than base-corrosion inhibitor which means that it increases passivation effect by making strong passivation layer. It implies that the corrosion inhibitor with amine functional group was proper to apply for 1st Cu CMP slurry owing to the high etch rate and with carboxyl functional group was favorable for the 2nd Cu CMP slurry due to the high Cu removal rate/dissolution rate ratio.

  19. Study of sulphate-reducing bacteria corrosion in the weld joint for API X-70 steel

    Directory of Open Access Journals (Sweden)

    Flores, J. E.

    2012-10-01

    Full Text Available The corrosion behavior originated by sulfate-reducing bacteria (SRB was studied in two regions of welded API X-70 steel pipeline. The studies were focused on base material (BM and heat affected zone (HAZ, from the internal region of the pipe. SRB were extracted from oil and grown in a Postgate medium. Corrosion was evaluated at 60 °C for times between 5 and 64 days. Potentiodynamic polarization curves, obtained by electrochemical techniques, indicated surface activation at short times. Structural and morphological characterizations were carried out by scanning electron microscopy (SEM and optical microscopy (OM. H2S concentration and pH were also measured. Results showed an important increase in the corrosion damage up to 20 days, influenced by the SRB activity, which lead to a maximum of H2S (pH minimum. It was found a localized corrosion attack in the HAZ in a higher quantity compared to BM; and the formation of a thin film on the steel surface, originated by corrosion products and bacterial activity.

    El comportamiento ante la corrosión, originada por bacterias sulfato-reductoras (SRB, fue estudiado en dos regiones de un tubo de acero soldado API X-70. Los estudios se enfocaron en el material base (BM y la zona afectada térmicamente (HAZ, en la parte interna del tubo. Las SRB fueron extraídas del petróleo y cultivadas en un medio Postgate. El comportamiento a la corrosión fue evaluado a una temperatura de 60 °C, por periodos comprendidos entre 5 y 64 días. El análisis de las curvas de polarización potenciodinámicas, obtenidas por técnicas electroquímicas, indicó la activación de la superficie para tiempos cortos. La superficie fue caracterizada estructural y morfológicamente mediante microscopia electrónica de barrido (SEM, así como mediante microscopía óptica (OM. La concentración de H2S y el pH también fueron medidos. Los resultados mostraron un aumento importante de la corrosi

  20. The coordinated use of synchrotron spectroelectrochemistry for corrosion studies on heritage metals.

    Science.gov (United States)

    Adriaens, Annemie; Dowsett, Mark

    2010-06-15

    Corrosion is a major source of degradation in heritage metal objects, and any remedial measures are subject to a strong (Western) ethic that favors conservation as opposed to restoration. Accordingly, major scientific challenges exist for developing appropriate treatment methods to stabilize and protect artifacts after they are recovered from an archaeological site, both before and during their display or storage in a museum. Because inappropriate treatments can cause irreversible damage to irreplaceable objects, it is crucial that the chemical processes involved are fully understood and characterized before any preservation work is undertaken. In this regard, large infrastructural facilities such as synchrotrons, neutron sources, and particle accelerators provide a wealth of analytical possibilities, unavailable in smaller scale laboratories. In general, the intensity of the radiation available allows measurements on a short time scale or with high spatial resolution (or both), so heterogeneous changes induced by a chemical process can be recorded while they occur. The penetrative nature of the radiation (e.g., X-rays, protons, or neutrons) also allows a sample to be studied in air. If necessary, complete artifacts (such as paintings or statuettes) can be examined. In situ analysis in a controlled environment, such as a liquid or corrosive atmosphere, also becomes an exciting possibility. Finally, there are many complementary techniques (local atomic structure or crystal structure determination, macroscopic 3-D imaging (tomographies), imaging chemical analysis, and so on) so the many distinct details of a problem can be thoroughly explored. In this Account, we discuss the application of this general philosophy to studies of corrosion and its prevention in cultural heritage metals, focusing on our recent work on copper alloys. More specifically, we use synchrotron-based techniques to evaluate the use of corrosion potential measurements as a possible monitoring

  1. AFM study of the early corrosion of a high strength steel in a diluted sodium chloride solution

    International Nuclear Information System (INIS)

    Sanchez, Javier; Fullea, Jose; Andrade, Carmen; Gaitero, Juan J.; Porro, Antonio

    2008-01-01

    The high strength steels employed as reinforcement in pre-stressed concrete structures are drawn wire steels of eutectoid composition with a pearlitic microstructure. This work is focused on the study, by atomic force microscopy, of the early stages of the corrosion of such steels as a consequence of their exposition to a sodium chloride solution. The obtained images show the pearlitic microstructure of the steel, with a preferential attack of the ferrite phase and the cementite acting as a cathode. The corrosion rate was determined by calculating the amount of material lost from a roughness analysis. The obtained results are in good agreement with the predictions of Galvelel's theory, according to which the corrosion rate slows down as the pit depth increases

  2. The use of odd random phase electrochemical impedance spectroscopy to study lithium-based corrosion inhibition by active protective coatings

    NARCIS (Netherlands)

    Meeusen, M.; Visser, P.; Fernández Macía, L.; Hubin, A.; Terryn, H.A.; Mol, J.M.C.

    2018-01-01

    In this work, the study of the time-dependent behaviour of lithium carbonate based inhibitor technology for the active corrosion protection of aluminium alloy 2024-T3 is presented. Odd random phase electrochemical impedance spectroscopy (ORP-EIS) is selected as the electrochemical tool to study

  3. Study of Henna (Lawsonia inermis) as Natural Corrosion Inhibitor for Aluminum Alloy in Seawater

    International Nuclear Information System (INIS)

    Nik, W B Wan; Zulkifli, F; Sulaiman, O; Samo, K B; Rosliza, R

    2012-01-01

    Commercial henna (Lawsonia inermis) was investigated to inhibit the corrosion of aluminum alloy through immersion in seawater. The aluminum alloy (5083) was prepared in size of 25mm × 25mm × 3mm. The immersion test was conducted in seawater with different concentration of henna, 100ppm, 300ppm, 500ppm for duration of 60 days. Four characterizations were performed in this study which was weight loss study, Fourier Transform Infrared (FTIR), Electrochemical Impedance Spectroscopy (EIS) and adsorption isotherm. The results indicated that henna has major constituents of lawsone which contributed to the chemisorptions or adsorption process by forming an isolation layers on the aluminum alloy surface which follows the Langmuir adsorption isotherm. It was found that the protection layer attached on metal was not permanent and precipitation occurred as the time increases. The highest inhibition efficiency was found at 88% (500ppm). This research found that henna is an excellent natural inhibitor for aluminum alloy in seawater.

  4. Inhibition of mild steel corrosion in acid solution by Pheniramine drug: Experimental and theoretical study

    Energy Technology Data Exchange (ETDEWEB)

    Ahamad, Ishtiaque [Department of Applied Chemistry, Institute of Technology, Banaras Hindu University, Varanasi 221 005 (India); Prasad, Rajendra [Department of Chemistry, SGB Amravati University, Amravati 444 602 (India); Quraishi, M.A., E-mail: maquraishi@rediffmail.co [Department of Applied Chemistry, Institute of Technology, Banaras Hindu University, Varanasi 221 005 (India)

    2010-09-15

    Inhibition of mild steel corrosion in 1 M HCl solution by Pheniramine drug was studied using weight loss, electrochemical impedance spectroscopy, linear polarization resistance, and potentiodynamic polarization measurements. The values of activation energy (E{sub a}) and different thermodynamic parameters such as adsorption equilibrium constant (K{sub ads}), free energy of adsorption ({Delta}G{sub ads}{sup o}), adsorption enthalpy ({Delta}H{sub ads}{sup o}) and adsorption entropy ({Delta}S{sub ads}{sup o}) were calculated and discussed. The adsorption process of studied drug on mild steel surface obeys the Langmuir adsorption isotherm. Potentiodynamic polarization measurements showed that Pheniramine is mixed-type inhibitor. Further, theoretical calculations were carried out and relations between computed parameters and experimental inhibition efficiency were discussed.

  5. Inhibition of mild steel corrosion in acid solution by Pheniramine drug: Experimental and theoretical study

    International Nuclear Information System (INIS)

    Ahamad, Ishtiaque; Prasad, Rajendra; Quraishi, M.A.

    2010-01-01

    Inhibition of mild steel corrosion in 1 M HCl solution by Pheniramine drug was studied using weight loss, electrochemical impedance spectroscopy, linear polarization resistance, and potentiodynamic polarization measurements. The values of activation energy (E a ) and different thermodynamic parameters such as adsorption equilibrium constant (K ads ), free energy of adsorption (ΔG ads o ), adsorption enthalpy (ΔH ads o ) and adsorption entropy (ΔS ads o ) were calculated and discussed. The adsorption process of studied drug on mild steel surface obeys the Langmuir adsorption isotherm. Potentiodynamic polarization measurements showed that Pheniramine is mixed-type inhibitor. Further, theoretical calculations were carried out and relations between computed parameters and experimental inhibition efficiency were discussed.

  6. Electrochemical Studies of Corrosion in Liquid Electrolytes for Energy Conversion Applications at Elevated Temperatures

    DEFF Research Database (Denmark)

    Nikiforov, Aleksey Valerievich; Petrushina, Irina; Bjerrum, Niels J.

    2016-01-01

    -temperature (200–400°C) water electrolysis. Pt, Ta, Nb, Ti, Inconel®625, and Ni demonstrated high corrosion resistance. Au and the rest of the tested materials were not corrosion resistant. It means that Ni, Ti and Inconel®625 may be used as relatively cheap construction materials for the intermediate......-temperature water electrolyzer....

  7. Fire-Side Corrosion: A Case Study of Failed Tubes of a Fossil Fuel Boiler

    Directory of Open Access Journals (Sweden)

    Majid Asnavandi

    2017-01-01

    Full Text Available The failures of superheater and reheater boiler tubes operating in a power plant utilizing natural gas or mazut as a fuel have been analysed and the fire-side corrosion has been suggested as the main reason for the failure in boiler tubes. The tubes have been provided by a fossil fuel power plant in Iran and optical and electron microscopy investigations have been performed on the tubes as well as the corrosion products on their surfaces. The results showed that the thickness of the failed tubes is not uniform which suggests that fire-side corrosion has happened on the tubes. Fire-side corrosion is caused by the reaction of combustion products with oxide layers on the tube surface resulting in metal loss and consequently tubes fracture. However, the tubes corrosion behaviour did not follow the conventional models of the fire-side corrosion. Given that, using the corrosion monitoring techniques for these boiler tubes seems essential. As a result, the thickness of the boiler tubes in different parts of the boiler has been recorded and critical points are selected accordingly. Such critical points are selected for installation of corrosion monitoring probes.

  8. Study on Increasing High Temperature pH(t) to Reduce Iron Corrosion Products

    International Nuclear Information System (INIS)

    Shin, Dong Man; Hur, Nam Yong; Kim, Waang Bae

    2011-01-01

    The transportation and deposition of iron corrosion products are important elements that affect both the steam generator (SG) integrity and secondary system in pressurized water reactor (PWR) nuclear power plants. Most of iron corrosion products are generated on carbon steel materials due to flow accelerated corrosion (FAC). The several parameters like water chemistry, temperature, hydrodynamic, and steel composition affect FAC. It is well established that the at-temperature pH of the deaerated water system has a first order effect on the FAC rate of carbon steels through nuclear industry researches. In order to reduce transportation and deposition of iron corrosion products, increasing pH(t) tests were applied on secondary system of A, B units. Increasing pH(t) successfully reduced flow accelerated corrosion. The effect of increasing pH(t) to inhibit FAC was identified through the experiment and pH(t) evaluation in this paper

  9. Electrochemical, Polarization, and Crevice Corrosion Testing of Nitinol 60, A Supplement to the ECLSS Sustaining Materials Compatibility Study

    Science.gov (United States)

    Lee, R. E.

    2016-01-01

    In earlier trials, electrochemical test results were presented for six noble metals evaluated in test solutions representative of waste liquids processed in the Environmental Control and Life Support System (ECLSS) aboard the International Space Station (ISS). Subsequently, a seventh metal, Nitinol 60, was added for evaluation and subjected to the same test routines, data analysis, and theoretical methodologies. The previous six test metals included three titanium grades, (commercially pure, 6Al-4V alloy and 6Al-4V low interstitial alloy), two nickel-chromium alloys (Inconel(RegisteredTrademark) 625 and Hastelloy(RegisteredTrademark) C276), and one high-tier stainless steel (Cronidur(RegisteredTrademark) 30). The three titanium alloys gave the best results of all the metals, indicating superior corrosive nobility and galvanic protection properties. For this current effort, the results have clearly shown that Nitinol 60 is almost as noble as titanium, being very corrosion-resistant and galvanically compatible with the other six metals electrochemically and during long-term exposure. is also quite noble as it is very corrosion resistant and galvanically compatible with the other six metals from both an electrochemical perspective and long-term crevice corrosion scenario. This was clearly demonstrated utilizing the same techniques for linear, Tafel and cyclic polarization, and galvanic coupling of the metal candidate as was done for the previous study. The high nobility and low corrosion susceptibility for Nitinol 60 appear to be intermediate to the nickel/chromium alloys and the titanium metals with indications that are more reflective of the titanium metals in terms of general corrosion and pitting behavior.

  10. Study of API 5L X70 steel corrosion processes when in contact with some Brazilian soils

    International Nuclear Information System (INIS)

    Jesus, Sergio Luis de

    2007-01-01

    Pipelines, fuel storage tanks and other metallic structures are in permanent contact and exposed to different types of soils, of horizons or layers, or of soil aggressiveness. This interaction may cause expressive damages to the environment and to the planned work. Contamination may occur due to leakage of stored products, splitting during transportation, accidents caused by pipelines without extensive maintenance. The result of these accidents could be, among others, some financial losses. In order to recognize the dynamic interactions between metallic surfaces and the environment it is crucial to have preventive actions and to develop better-applied materials. API steel 5L X70 has been used in structures of low and high pressure with high mechanical strength and corrosion and, even so, it is susceptible to etching corrosion since it is in contact with different environments from mangrove regions to industrial environments. The present case evaluated the role of 5L X70 API steel in contact with different soil horizons representative of the Brazilian soil. This investigation correlated chemical species with solute ions in soil solution, secondary and primary phase minerals besides physical and chemical characteristics as pH, electric conductivity, total dissolved solids, among others, to the results of corrosion resistance and ways of corrosion. The evaluation was carried out using x-ray diffractometry, scanning electron microscopy, total reflection x-ray fluorescence, fuel injection flow besides texture and gravimetric analyses to soil characterization and mineralogy, identification of corrosion products, soil solution analyses, evaluation of tested materials and classification of ways and types of corrosion. This was an attempt to integrate the data to a better understanding of the process involving reagents and products. The results showed that different soil horizons such as different types of analyzed soils produce specific etching in metallic structures

  11. The chloride induced localised corrosion of aluminium and beryllium: A study by electron and X-ray spectroscopies

    Science.gov (United States)

    Mallinson, Christopher F.

    Beryllium is an important metal in the nuclear industry for which there are no suitable replacements. It undergoes localised corrosion at the site of heterogeneities in the metal surface. Corrosion pits are associated with a range of second phase particles. To investigate the role of these particles in corrosion, a safe experimental protocol was established using an aluminium alloy as a corrosion material analogue. The 7075-T6 alloy had not previously been investigated using the experimental methodology used in this thesis. This work led to the development of the experimental methodology and safe working practices for handling beryllium. The range and composition of the second phase particles present in S-65 beryllium billet were identified using a combination of SEM, AES, EDX and WDX. Following the identification of a range of particles with various compositions, including the AlFeBe4 precipitate which has been previously associated with corrosion, the location of the particles were marked to enable their repeated study. Attention was focused on the microchemistry in the vicinity of second phase particles, as a function of immersion time in pH 7, 0.1 M NaCl solution. The corrosion process associated with different particles was followed by repeatedly relocating the particles to perform analysis by means of SEM, AES and EDX. The use of traditional chlorinated vapour degreasing solvents on beryllium was investigated and compared to two modern commercially available cleaning solutions designed as drop-in replacements. This work expanded the range of solvents suitable for cleaning beryllium and validated the conclusions from previous thermodynamic modelling. Additionally, a new experimental methodology has been developed which enables the acquisition of chemical state information from the surface of micron scale features. This was applied to sub-micron copper and iron particles, as well as a copper intermetallic.

  12. The study of intergranular corrosion in aircraft aluminium alloys using X-ray tomography

    International Nuclear Information System (INIS)

    Knight, S.P.; Salagaras, M.; Trueman, A.R.

    2011-01-01

    Research highlights: → IGC is stochastic, where initiation is statistical and growth kinetics was somewhat predictable. → Dissolved oxygen concentration was more important than the concentration of salt in the droplet. → A limiting depth occurred for AA2024, whereas no limiting depth occurs for AA7050 after 168 h exposure. → A limiting depth may be controlled by the transport of dissolved oxygen down the corrosion fissure. → A limiting IGC depth is dependent on the overpotential of the SDZ (adjacent to the grain boundary). - Abstract: Atmospheric corrosion is one of the leading causes of structural damage to aircraft. Of particular importance is pitting and intergranular corrosion, which can develop into fatigue cracks, stress corrosion cracks, or exfoliation. Therefore it is of interest to the Australian Defence Force (ADF) to understand how corrosion ensues in susceptible aircraft aluminium alloys, such as AA2024-T351 and 7050-T7451. However, there are many difficulties in measuring the extent of intergranular corrosion, since it is predominantly hidden below the surface. Traditionally, cross-sectioning has been used to view and measure the depth of attack. In the present work, 2 mm diameter pin specimens were contaminated with a droplet of 3.5% NaCl and exposed to constant humidity that resulted in intergranular corrosion. X-ray computed tomography was then used to non-destructively assess the depth and volume of corrosion both as a function of time in 97% relative humidity, and as a function of relative humidity after 168 h exposure. Both corrosion depth and volume increased with time, but there was evidence for a limiting depth in AA2024. Depth and volume also increased with relative humidity of the environment, for which the time-of-wetness and oxygen concentration of the droplets were considered the important factors in driving the corrosion process.

  13. Statistical study by digitalized image analysis of pitting corrosion of an AISI 304 type stainless steel in chloride environment

    International Nuclear Information System (INIS)

    Lacome, Isabelle

    1994-01-01

    This research thesis addresses the pitting corrosion of an AISI 304-type stainless steel in chloride environment, a phenomenon which is generally considered as comprising two main steps: pit initiation with local degradation of the passive film, and pit growth. By using a technique of analysis of digitalized images, the process is observed in situ and both steps are monitored. A statistical study of the initiation of all the noticed pits is performed. After a bibliographical survey on the pitting corrosion process, its mechanisms and the influence of different parameters, the author presents the studied material and the experimental methods, reports the investigation of the pitting corrosion process in potentiostatic mode over a wide range of potentials in order to study all the types of pits, discusses the influence of potential on pit initiation and growth, reports the study of the influence of hydrodynamic conditions and of ageing in solution on the different parameters, reports the analysis of passive films by photoelectron spectroscopy, and the study of the influence of an inhibitor (molybdate ions) on both steps of pitting corrosion [fr

  14. Stress Corrosion Cracking and Fatigue Crack Growth Studies Pertinent to Spacecraft and Booster Pressure Vessels

    Science.gov (United States)

    Hall, L. R.; Finger, R. W.

    1972-01-01

    This experimental program was divided into two parts. The first part evaluated stress corrosion cracking in 2219-T87 aluminum and 5Al-2.5Sn (ELI) titanium alloy plate and weld metal. Both uniform height double cantilever beam and surface flawed specimens were tested in environments normally encountered during the fabrication and operation of pressure vessels in spacecraft and booster systems. The second part studied compatibility of material-environment combinations suitable for high energy upper stage propulsion systems. Surface flawed specimens having thicknesses representative of minimum gage fuel and oxidizer tanks were tested. Titanium alloys 5Al-2.5Sn (ELI), 6Al-4V annealed, and 6Al-4V STA were tested in both liquid and gaseous methane. Aluminum alloy 2219 in the T87 and T6E46 condition was tested in fluorine, a fluorine-oxygen mixture, and methane. Results were evaluated using modified linear elastic fracture mechanics parameters.

  15. High-Temperature Corrosion Study for the RPP Low Activity Waste Melter

    International Nuclear Information System (INIS)

    Marshall, K.M.

    2003-01-01

    The River Protection Program (RPP) low activity waste (LAW) melter design incorporates a series of bubblers used to increase convection in the molten glass. Through runs of a pilot melter at Duratek, Inc. in Columbia, Maryland, the bubblers have been identified as the major component limiting LAW melter availability, requiring frequent replacement due to corrosive degradation, primarily at the melt line. Laboratory experiments were performed to evaluate the performance of several alloys and coatings in simulated RPP low activity waste melter vapor space and molten glass environments. The performance of the alloys and coatings was studied in order to advance our understanding of how these materials react at the melt/air interface inside the melter. The ultimate goal was to identify a material with superior performance compared to that of Inconel 693, and to deliver a bubbler sub-assembly made of that material to the RPP LAW melter pilot facility for further testing

  16. Stress corrosion of Zircaloy-4. Fracture mechanics study of the intergranular - transgranular transition

    International Nuclear Information System (INIS)

    Farina, Silvia B.; Duffo, Gustavo S.

    2003-01-01

    Stress corrosion cracking susceptibility of Zircaloy-4 wires was studied in 1M NaCl, 1M KBr and 1M KI aqueous solutions, and in iodine alcoholic solutions. In all cases, intergranular attack preceded transgranular propagation. It is generally accepted that the intergranular-transgranular transition occurs when a critical value of the stress intensity factor is reached. In the present work it was confirmed that the transition from intergranular to transgranular propagation cracking in Zircaloy-4 wires also occurs when a critical value of the stress intensity factor is reached. This critical stress intensity factor in wire samples is independent of the solution tested and close to 10 MPa.m-1/2. This value is in good agreement with those reported in the literature measured by different techniques. (author)

  17. Vascular anatomy of the pig kidney glomerulus: a qualitative study of corrosion casts.

    Science.gov (United States)

    Moore, B J; Holmes, K R; Xu, L X

    1992-09-01

    Pig kidney glomerular vascular anatomy was studied by scanning electron microscopy of vascular corrosion casts. A generalized vascular architecture is presented to describe the pig kidney glomerulus based upon the observation of 3,800 vascular cast glomeruli. The relative simplicity of the pig glomerular vascular architecture has allowed the characterization of different vascular segments more completely than has been possible in other mammals. Based upon relationships to the afferent arteriole, a nomenclature and definition of primary, secondary, tertiary and anastomotic vessels is proposed for the distributing vessels comprising the glomerular tuft. The existence and formation of a large central hemispheric vessel deep within the confines of a glomerular hemisphere is micrographically documented. Micrographic evidence is presented supporting the formation of the single efferent arteriole by the merging of two central hemispheric vessels within the confines of the glomerular tuft. Failure of the merging of these two vessels may result in multiple efferent arterioles.

  18. Corrosion behaviour of Alloy 800 in high temperature aqueous solutions: Electrochemical studies

    International Nuclear Information System (INIS)

    Olmedo, A.M.; Villegas, M.; Alvarez, M.G.

    1996-01-01

    The anodic behaviour and passivity breakdown of Alloy 800 in aqueous solutions of sodium chloride, sodium sulphate and sodium bicarbonate were studied by electrochemical techniques in the temperature range from 60 C to 280 C. The pitting resistance and pitting morphology of the alloy in chloride plus sulphate and chloride plus bicarbonate mixtures, at 60 C and 280 C, were also examined. Increasing bicarbonate or sulphate additions to chloride solutions shift the characteristic pitting potential of Alloy 800 to higher values, both at low and high temperatures. Changes in pitting morphology were observed in sulphate containing solutions while the morphology of the attack found in bicarbonate containing solutions was similar to that in pure chloride solutions. Finally, no localized or substantial generalized corrosion was detected in pure sulphate or bicarbonate solutions at any temperature. (orig.)

  19. Study of the corrosion behavior and the corrosion films formed on the surfaces of Mg–xSn alloys in 3.5 wt.% NaCl solution

    International Nuclear Information System (INIS)

    Wang, Jingfeng; Li, Yang; Huang, Song; Zhou, Xiaoen

    2014-01-01

    Highlights: • Corrosion of four cast Mg–xSn alloys in 3.5 wt.% NaCl solution was investigated. • Both Mg(OH) 2 /SnO 2 corrosion product film and Mg(OH) 2 /MgSnO 3 clusters formed on Mg–1.5Sn. • Compact Mg(OH) 2 /MgSnO 3 film suppressed the cathodic effect of the impurity inclusions. • Mg–xSn (x = 0.5, 1.0, 2.0 wt.%) alloys only formed loose Mg(OH) 2 /SnO 2 corrosion product film. - Abstract: The corrosion behavior and the corrosion films formed on the surfaces of Mg–xSn (x = 0.5, 1.0, 1.5, and 2.0 wt.%) alloys in 3.5 wt.% NaCl solution were investigated by immersion tests, electrochemical measurements, corrosion morphology observations, and X-ray diffraction analysis. Immersion tests and electrochemical measurements illustrated that the best corrosion resistance was reported for the Mg–1.5Sn alloy. Both Mg(OH) 2 /SnO 2 corrosion product film and Mg(OH) 2 /MgSnO 3 clusters formed on Mg–1.5Sn alloy surface. Mg(OH) 2 /MgSnO 3 clusters were compact and suppressed the cathodic effect of the impurity inclusions greatly. The Mg–xSn (x = 0.5, 1.0, and 2.0 wt.%) alloys only formed loose Mg(OH) 2 /SnO 2 corrosion product film during the corrosion process

  20. Studies on microstructure, mechanical and pitting corrosion behaviour of similar and dissimilar stainless steel gas tungsten arc welds

    Science.gov (United States)

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

    2018-03-01

    In the present study, an attempt has been made to weld dissimilar alloys of 5mm thick plates i.e., austenitic stainless steel (316L) and duplex stainless steel (2205) and compared with that of similar welds. Welds are made with conventional gas tungsten arc welding (GTAW) process with two different filler wires namely i.e., 309L and 2209. Welds were characterized using optical microscopy to observe the microstructural changes and correlate with mechanical properties using hardness, tensile and impact testing. Potentio-dynamic polarization studies were carried out to observe the pitting corrosion behaviour in different regions of the welds. Results of the present study established that change in filler wire composition resulted in microstructural variation in all the welds with different morphology of ferrite and austenite. Welds made with 2209 filler showed plate like widmanstatten austenite (WA) nucleated at grain boundaries. Compared to similar stainless steel welds inferior mechanical properties was observed in dissimilar stainless steel welds. Pitting corrosion resistance is observed to be low for dissimilar stainless steel welds when compared to similar stainless steel welds. Overall study showed that similar duplex stainless steel welds having favorable microstructure and resulted in better mechanical properties and corrosion resistance. Relatively dissimilar stainless steel welds made with 309L filler obtained optimum combination of mechanical properties and pitting corrosion resistance when compared to 2209 filler and is recommended for industrial practice.

  1. 1. The application of PIE techniques to the study of the corrosion of spent oxide fuel in deep-rock groundwaters. 2. Spent fuel degradation

    International Nuclear Information System (INIS)

    Forsyth, R.S.

    1991-01-01

    During the autumn of 1990, papers summarizing work performed at Studsvik as part of the SKB research programme designed to study the corrosion behaviour of spent nuclear fuel in deep-rock groundwater were presented at two scientific meetings: The first paper presents results and observations of the study of the corrosion of spent oxide fuel in deep-rock ground-waters. The PIE techniques were applied to the detailed study of spent fuel both before and after water contact. The second paper represents an up-dated reporting of results obtained in the Swedish programme relevant to preferential dissolution effects, including interim results from recently stored experiments specifically designed to study possible correlations between corrosion behaviour and fuel properties conditioned by burnup and/or local power variations. Recent observations during the search for corrosion sites in fuel exposed to corrosion for about 4 years are also presented. (KAE)

  2. A review on pipeline corrosion, in-line inspection (ILI), and corrosion growth rate models

    International Nuclear Information System (INIS)

    Vanaei, H.R.; Eslami, A.; Egbewande, A.

    2017-01-01

    Pipelines are the very important energy transmission systems. Over time, pipelines can corrode. While corrosion could be detected by in-line inspection (ILI) tools, corrosion growth rate prediction in pipelines is usually done through corrosion rate models. For pipeline integrity management and planning selecting the proper corrosion ILI tool and also corrosion growth rate model is important and can lead to significant savings and safer pipe operation. In this paper common forms of pipeline corrosion, state of the art ILI tools, and also corrosion growth rate models are reviewed. The common forms of pipeline corrosion introduced in this paper are Uniform/General Corrosion, Pitting Corrosion, Cavitation and Erosion Corrosion, Stray Current Corrosion, Micro-Bacterial Influenced Corrosion (MIC). The ILI corrosion detection tools assessed in this study are Magnetic Flux Leakage (MFL), Circumferential MFL, Tri-axial MFL, and Ultrasonic Wall Measurement (UT). The corrosion growth rate models considered in this study are single-value corrosion rate model, linear corrosion growth rate model, non-linear corrosion growth rate model, Monte-Carlo method, Markov model, TD-GEVD, TI-GEVD model, Gamma Process, and BMWD model. Strengths and limitations of ILI detection tools, and also corrosion predictive models with some practical examples are discussed. This paper could be useful for those whom are supporting pipeline integrity management and planning. - Highlights: • Different forms of pipeline corrosion are explained. • Common In-Line Inspection (ILI) tools and corrosion growth rate models are introduced. • Strength and limitations of corrosion growth rate models/ILI tools are discussed. • For pipeline integrity management programs using more than one corrosion growth rate model/ILI tool is suggested.

  3. Atmospheric corrosion in subtropical areas: XRD and electrochemical study of zinc atmospheric corrosion products in the province of Santa Cruz de Tenerife (Canary Islands, Spain)

    Energy Technology Data Exchange (ETDEWEB)

    Morales, J. [Departamento de Quimica Fisica, Universidad de La Laguna, 38071 La Laguna, Tenerife (Spain)]. E-mail: jmorales@ull.es; Diaz, F. [Departamento de Quimica Fisica, Universidad de La Laguna, 38071 La Laguna, Tenerife (Spain); Hernandez-Borges, J. [Departamento de Quimica Analitica, Nutricion y Bromatologia, Universidad de La Laguna, 38071 La Laguna, Tenerife (Spain); Gonzalez, S. [Departamento de Quimica Fisica, Universidad de La Laguna, 38071 La Laguna, Tenerife (Spain)

    2006-02-15

    In the present paper, zinc sheets have been exposed for 4 years to the action of different atmospheres in 35 test sites located in the province of Santa Cruz de Tenerife, Canary Islands, Spain. Corrosion products formed on the surface of the samples have been identified by means of X-ray diffraction (XRD) for the first and second year of exposure. Zincite, hydrozincite, simonkolleite, zinc chlorohydroxysulphate, zinc oxysulphate and zinc hydroxysulphate have been identified in the test sheets. Preliminary results of an electrochemical study of the breakdown potential of zinc samples are also presented in order to test the protective effect of the film formed on the surface of the samples. It was found that the protective effect of this film increases linearly with exposure time.

  4. Surface Studies of Ultra Strength Drilling Steel after Corrosion Fatigue in Simulated Sour Environment

    Energy Technology Data Exchange (ETDEWEB)

    M. Ziomek-Moroz; J.A. Hawk; R. Thodla; F. Gui

    2012-05-06

    The Unites States predicted 60% growth in energy demand by 2030 makes oil and natural gas primary target fuels for energy generation. The fact that the peak of oil production from shallow wells (< 5000 m) is about to be reached, thereby pushing the oil and natural gas industry into deeper wells. However, drilling to depths greater than 5000 m requires increasing the strength-to weight ratio of the drill pipe materials. Grade UD-165 is one of the ultra- high yield strength carbon steels developed for ultra deep drilling (UDD) activities. Drilling UDD wells exposes the drill pipes to Cl{sup -}, HCO{sub 3}{sup -}/CO{sub 3}{sup 2-}, and H{sub 2}S-containig corrosive environments (i.e., sour environments) at higher pressures and temperatures compared to those found in conventional wells. Because of the lack of synergism within the service environment, operational stresses can result in catastrophic brittle failures characteristic for environmentally assisted cracking (EAC). Approximately 75% of all drill string failures are caused by fatigue or corrosion fatigue. Since there is no literature data on the corrosion fatigue performance of UD-165 in sour environments, research was initiated to better clarify the fatigue crack growth (FCGR) behavior of this alloy in UDD environments. The FCGR behavior of ultra-strength carbon steel, grade UD-165, was investigated by monitoring crack growth rate in deaerated 5%NaCl solution buffered with NaHCO{sub 3}/Na{sub 2}CO{sub 3} and in contact with H{sub 2}S. The partial pressure of H{sub 2}S (p{sub H2S}) was 0.83 kPa and pH of the solution was adjusted by NaOH to 12. The fatigue experiments were performed at 20 and 85 C in an autoclave with surface investigations augmented by scanning electron microscopy (SEM) and energy dispersive x-ray (EDX) spectroscopy. In this study, research focused on surface analyses supported by the fatigue crack growth rate measurements. Fig. 1 shows an SEM micrograph of the crack that propagated from the

  5. Corrosion protection and control using nanomaterials

    CERN Document Server

    Cook, R

    2012-01-01

    This book covers the use of nanomaterials to prevent corrosion. The first section deals with the fundamentals of corrosion prevention using nanomaterials. Part two includes a series of case studies and applications of nanomaterials for corrosion control.$bCorrosion is an expensive and potentially dangerous problem in many industries. The potential application of different nanostructured materials in corrosion protection, prevention and control is a subject of increasing interest. Corrosion protection and control using nanomaterials explores the potential use of nanotechnology in corrosion control. The book is divided into two parts. Part one looks at the fundamentals of corrosion behaviour and the manufacture of nanocrystalline materials. Chapters discuss the impact of nanotechnology in reducing corrosion cost, and investigate the influence of various factors including thermodynamics, kinetics and grain size on the corrosion behaviour of nanocrystalline materials. There are also chapters on electrodeposition ...

  6. Monitoring corrosion and corrosion control of iron in HCl by non-ionic surfactants of the TRITON-X series - Part III. Immersion time effects and theoretical studies

    International Nuclear Information System (INIS)

    Amin, Mohammed A.; Ahmed, M.A.; Arida, H.A.; Kandemirli, Fatma; Saracoglu, Murat; Arslan, Taner; Basaran, Murat A.

    2011-01-01

    Graphical abstract: . Display Omitted Research highlights: → The inhibition effect of TX-100, TX-165 and TX-305 on iron corrosion in 1.0 M HCl was studied. → TX-305 inhibited iron corrosion more effectively than TX-100 and TX-165. → In most cases, inhibition efficiency increased with time during the first 60 min of immersion, then decreased. → Calculated quantum chemical parameters confirmed the experimental inhibition efficiencies of the tested surfactants. - Abstract: The inhibition performance of three selected non-ionic surfactants of the TRITON-X series, namely TRITONX-100 (TX-100), TRITON-X-165 (TX-165) and TRITON-X-305 (TX-305), on the corrosion of iron was studied in 1.0 M HCl solutions as a function of inhibitor concentration (0.01-0.20 g L -1 ) and immersion time (0.0-8 h) at 298 K. Measurements were conducted based on Tafel polarization, LPR and impedance studies. At high frequencies, the impedance spectrum showed a depressed capacitive loop in the complex impedance plane, whose diameter is a function of the immersion time and the type and concentration of the introduced surfactant. In all cases, an inductive loop was observed in the low frequency and this could be attributed to the adsorption behavior. The inhibition efficiency increased with immersion time, reached a maximum and then decreased. This was attributed to the orientation change of adsorbed surfactant molecules. TX-305 inhibited iron corrosion more effectively than TX-100 and TX-165. The frontier orbital energies, the energy gap between frontier orbitals, dipole moments (μ), charges on the C and O atoms, the polarizabilities, and the quantum chemical descriptors were calculated. The quantum chemical calculation results inferred that for the HOMO representing the condensed Fukui function for an electrophilic attack (f k + ), the contributions belong to the phenyl group and the oxygen atom attached to the phenyl group for each tested surfactant. Quantitative structure

  7. Comparative Studies on Microstructure, Mechanical and Pitting Corrosion of Post Weld Heat Treated IN718 Superalloy GTA and EB Welds

    Science.gov (United States)

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

    2018-03-01

    In the present study, an attempt has been made to weld Inconel 718 nickel-base superalloy (IN718 alloy) using gas tungsten arc welding (GTAW) and electron beam welding (EBW) processes. Both the weldments were subjected to post-weld heat treatment condition as follows -980°C / 20 min followed by direct aging condition (DA) as 720°C/8 h/FC followed by 620°C/8 h/AC. The GTA and EB welds of IN718 alloy were compared in two conditions as-received and 980STA conditions. Welds were characterized to observe mechanical properties, pitting corrosion resistance by correlating with observed microstructures. The rate of higher cooling ranges, the fusion zone of EBW exhibited discrete and relative finer lave phases whereas the higher niobium existed laves with coarser structure were observed in GTAW. The significant dissolution of laves were observed at 980STA of EBW. Due to these effects, the EBW of IN718 alloy showed the higher mechanical properties than GTAW. The electrochemical potentiostatic etch test was carried out in 3.5wt% sodium chloride (NaCl) solution to study the pitting corrosion behaviour of the welds. Results of the present investigation established that mechanical properties and pitting corrosion behaviour are significantly better in post weld heat treated condition. The comparative studies showed that the better combination of mechanical properties and pitting corrosion resistance were obtained in 980STA condition of EBW than GTAW.

  8. Electrochemical corrosion study of Mg–Al–Zn–Mn alloy in aqueous ethylene glycol containing chloride ions

    Directory of Open Access Journals (Sweden)

    Harish Medhashree

    2017-01-01

    Full Text Available Nowadays most of the automobiles use magnesium alloys in the components of the engine coolant systems. These engine coolants used are mainly composed of aqueous ethylene glycol along with some inhibitors. Generally the engine coolants are contaminated by environmental anions like chlorides, which would enhance the rate of corrosion of the alloys used in the coolant system. In the present study, the corrosion behavior of Mg–Al–Zn–Mn alloy in 30% (v/v aqueous ethylene glycol containing chloride anions at neutral pH was investigated. Electrochemical techniques, such as potentiodynamic polarization method, cyclic polarization and electrochemical impedance spectroscopy (EIS were used to study the corrosion behavior of Mg–Al–Zn–Mn alloy. The surface morphology, microstructure and surface composition of the alloy were studied by using the scanning electron microscopy (SEM, optical microscopy and energy dispersion X-ray (EDX analysis, respectively. Electrochemical investigations show that the rate of corrosion increases with the increase in chloride ion concentration and also with the increase in medium temperature.

  9. Study of the Corrosion Resistance of Austenitic Stainless Steels during Conversion of Waste to Biofuel

    Science.gov (United States)

    Cabrini, Marina; Lorenzi, Sergio; Pastore, Tommaso; Pellegrini, Simone; Burattini, Mauro; Miglio, Roberta

    2017-01-01

    The paper deals with the corrosion behavior of stainless steels as candidate materials for biofuel production plants by liquefaction process of the sorted organic fraction of municipal solid waste. Corrosion tests were carried out on AISI 316L and AISI 304L stainless steels at 250 °C in a batch reactor during conversion of raw material to bio-oil (biofuel precursor), by exposing specimens either to water/oil phase or humid gas phase. General corrosion rate was measured by weight loss tests. The susceptibility to stress corrosion cracking was evaluated by means of U-bend specimens and slow stress rate tests at 10−6 or 10−5 s−1 strain rate. After tests, scanning electron microscope analysis was carried out to detect cracks and localized attacks. The results are discussed in relation with exposure conditions. They show very low corrosion rates strictly dependent upon time and temperature. No stress corrosion cracking was observed on U-bend specimens, under constant loading. Small cracks confined in the necking cone of specimens prove that stress corrosion cracking only occurred during slow strain rate tests at stresses exceeding the yield strength. PMID:28772682

  10. Simple experiments studying the catastrophic corrosion of stainless steel caused by sodium leaks

    International Nuclear Information System (INIS)

    Mathison, J.; Trevalion, P.A.; Hamer, A.N.

    1971-01-01

    Under certain conditions, small quantities of soditum escaping through a small hole may cause extensive corrosion and cratering on the outside of the containment in the vicinity of the leak and there is a possibility that this might lead to a major rupture of the containment. It is difficult to estimate such a corrosion rate by conducting post mortems after an incident because of the lack of precise information about times and temperatures. Simple sodium burning experiments have therefore been carried out in an attempt to provide rough quantitative data on the size of these corrosion rates. These showed that the average rate of corrosion of specimens of 18.8.1 stainless steel beneath a burning pool of sodium was of the order of 0.05 cm/hr at 600 ° C and 0.005 cm/hr at 400 ° C. Enhanced corrosion occurs at the periphery of the burning sodium. The rate of penetration will depend on the shape of the corrosion profile which exists in the affected surface. The times needed to penetrate different wall thicknesses of stainless steel pipework have been calculated for various corrosion profiles similar to those which have been observed after incidents in REML. (author)

  11. An Experimental Study for Quantitative Estimation of Rebar Corrosion in Concrete Using Ground Penetrating Radar

    Directory of Open Access Journals (Sweden)

    Md Istiaque Hasan

    2016-01-01

    Full Text Available Corrosion of steel rebar in reinforced concrete is one the most important durability issues in the service life of a structure. In this paper, an investigation is conducted to find out the relationship between the amount of reinforced concrete corrosion and GPR maximum positive amplitude. Accelerated corrosion was simulated in the lab by impressing direct current into steel rebar that was submerged in a 5% salt water solution. The amount of corrosion was varied in the rebars with different levels of mass loss ranging from 0% to 45%. The corroded rebars were then placed into three different oil emulsion tanks having different dielectric properties similar to concrete. The maximum amplitudes from the corroded bars were recorded. A linear relationship between the maximum positive amplitudes and the amount of corrosion in terms of percentage loss of area was observed. It was proposed that the relationship between the GPR maximum amplitude and the amount of corrosion can be used as a basis of a NDE technique of quantitative estimation of corrosion.

  12. A study on the corrosion characteristics of lead-bismuth liquid metal

    International Nuclear Information System (INIS)

    Tak, Nam Il; Park, Won S.; Han, Seok Jung; Jeong, Won Seok

    1999-03-01

    Pb-Bi eutectic has been adopted as a coolant and spallation target material of HYPER (Hybrid Power Extraction Reactor), an accelerator driven subcritical transmutation system. The contents and scope of the present study are to implement systematic survey and analyses of available results on the corrosion characteristics of Pb-Bi liquid metal which are considered to be the most important among Pb-Bi coolant technologies and to provide fundamental bases for future research efforts. Major parameters affecting the corrosion of structural materials in liquid metals are temperature, flow velocity, contents of impurities in coolant, compositions of structural materials, and so forth. It was already known that for traditional commercial austenitic steels of 18Cr-10Ni-Ti type and 12%Cr ferritic steels, the operating temperatures of Pb-Bi coolant cannot be raised above 400 dg C and 450 dg C, respectively. However, extensive researches have been performed to protect structural materials under higher operating temperature such as the development of various kinds of coating methods for steels and the investigations of coolant inhibition by different chemical elements. The available experimental results show that the effective methods to improve the performance of structural materials in Pb-Bi coolant are the development of suitable steel alloys, the creation of oxide type coatings, and the control of oxygen inhibition. According to the recently presented research results of URRS, utilization of these methods makes it possible to raise the operating temperature limit to 620-650 dg C. It provides the possibility of usage of Pb-Bi coolant for the transmutation system, HYPER some day. (Author). 27 refs., 6 tabs., 15 figs

  13. A study on the corrosion characteristics of lead-bismuth liquid metal

    Energy Technology Data Exchange (ETDEWEB)

    Tak, Nam Il; Park, Won S.; Han, Seok Jung; Jeong, Won Seok

    1999-03-01

    Pb-Bi eutectic has been adopted as a coolant and spallation target material of HYPER (Hybrid Power Extraction Reactor), an accelerator driven subcritical transmutation system. The contents and scope of the present study are to implement systematic survey and analyses of available results on the corrosion characteristics of Pb-Bi liquid metal which are considered to be the most important among Pb-Bi coolant technologies and to provide fundamental bases for future research efforts. Major parameters affecting the corrosion of structural materials in liquid metals are temperature, flow velocity, contents of impurities in coolant, compositions of structural materials, and so forth. It was already known that for traditional commercial austenitic steels of 18Cr-10Ni-Ti type and 12%Cr ferritic steels, the operating temperatures of Pb-Bi coolant cannot be raised above 400 dg C and 450 dg C, respectively. However, extensive researches have been performed to protect structural materials under higher operating temperature such as the development of various kinds of coating methods for steels and the investigations of coolant inhibition by different chemical elements. The available experimental results show that the effective methods to improve the performance of structural materials in Pb-Bi coolant are the development of suitable steel alloys, the creation of oxide type coatings, and the control of oxygen inhibition. According to the recently presented research results of URRS, utilization of these methods makes it possible to raise the operating temperature limit to 620-650 dg C. It provides the possibility of usage of Pb-Bi coolant for the transmutation system, HYPER some day. (Author). 27 refs., 6 tabs., 15 figs.

  14. Stray current vs anodic polarization in reinforced mortar: a comparative study on steel corrosion behaviour in both regimes

    NARCIS (Netherlands)

    Chen, Zhipei; Koleva, D.A.; van Breugel, K.

    2015-01-01

    Stray current arising from direct current electrified traction systems and then circulat-ing in reinforced concrete structures may initiate corrosion or even accelerate existing corrosion processes on embedded reinforcement. Therefore, stray-current induced corrosion of nearby reinforced concrete

  15. An experimental study of crevice corrosion behaviour of 316L stainless steel in artificial seawater

    Energy Technology Data Exchange (ETDEWEB)

    Cai Baoping [School of Electromechanical Engineering, China University of Petroleum, Dongying, Shandong 257061 (China); Liu Yonghong, E-mail: liuyhupc@126.co [School of Electromechanical Engineering, China University of Petroleum, Dongying, Shandong 257061 (China); Tian Xiaojie; Wang Fei; Li Hang; Ji Renjie [School of Electromechanical Engineering, China University of Petroleum, Dongying, Shandong 257061 (China)

    2010-10-15

    The effects of applied torque on corrosion behaviour of 316L stainless steel with crevices were investigated using the cyclic potentiodynamic polarization method. Three kinds of crevices (316L-to-polytetrafluoroethylene, 316L-to-fluoroelastomeric and 316L-to-316L) were tested in artificial seawater at 50 {sup o}C. Corroded surface morphology was also investigated using scanning electron microscopy. Results indicate similar trends in crevice corrosion susceptibility with increasing applied torque. Among the three crevices, the 316L stainless steel specimen, coupled to the 316L stainless steel crevice former, is the most susceptible to crevice corrosion.

  16. An experimental study of crevice corrosion behaviour of 316L stainless steel in artificial seawater

    International Nuclear Information System (INIS)

    Cai Baoping; Liu Yonghong; Tian Xiaojie; Wang Fei; Li Hang; Ji Renjie

    2010-01-01

    The effects of applied torque on corrosion behaviour of 316L stainless steel with crevices were investigated using the cyclic potentiodynamic polarization method. Three kinds of crevices (316L-to-polytetrafluoroethylene, 316L-to-fluoroelastomeric and 316L-to-316L) were tested in artificial seawater at 50 o C. Corroded surface morphology was also investigated using scanning electron microscopy. Results indicate similar trends in crevice corrosion susceptibility with increasing applied torque. Among the three crevices, the 316L stainless steel specimen, coupled to the 316L stainless steel crevice former, is the most susceptible to crevice corrosion.

  17. Adhesion and corrosion studies of a lithium based conversion coating film on the 2024 aluminum alloy

    International Nuclear Information System (INIS)

    Castro, M.R.S.; Nogueira, J.C.; Thim, G.P.; Oliveira, M.A.S.

    2004-01-01

    AA2024-T3-aluminum alloy surfaces were coated using non-chromate and chromate conversion coatings. All coatings were painted with the 10P4-2-primer epoxy resin. Independent on the film formation process, films passed on the substrate/conversion coating wet tape adhesion test. However, only the chromate conversion coating passed on the conversion coating/primer epoxy resin adhesion test. Electrochemical corrosion measurements showed that non-chromate conversion coated surfaces present lower corrosion current density, bigger polarization resistance and less negative corrosion potential than chromate conversion coated surfaces

  18. The application of neutron reflectometry and atomic force microscopy in the study of corrosion inhibitor films

    International Nuclear Information System (INIS)

    John, Douglas; Blom, Annabelle; Bailey, Stuart; Nelson, Andrew; Schulz, Jamie; De Marco, Roland; Kinsella, Brian

    2006-01-01

    Corrosion inhibitor molecules function by adsorbing to a steel surface and thus prevent oxidation of the metal. The interfacial structures formed by a range of corrosion inhibitor molecules have been investigated by in situ measurements based on atomic force microscopy and neutron reflectometry. Inhibitors investigated include molecules cetyl pyridinium chloride (CPC), dodecyl pyridinium chloride (DPC), 1-hydroxyethyl-2-oleic imidazoline (OHEI) and cetyl dimethyl benzyl ammonium chloride (CDMBAC). This has shown that the inhibitor molecules adsorb onto a surface in micellar structures. Corrosion measurements confirmed that maximum inhibition efficiency coincides with the solution critical micelle concentration

  19. Study of benzotriazole as corrosion inhibitors of carbon steel in chloride solution containing hydrogen sulfide using electrochemical impedance spectroscopy (EIS)

    Energy Technology Data Exchange (ETDEWEB)

    Solehudin, Agus, E-mail: asolehudin@upi.edu [Department of Mechanical Engineering Education, Indonesia University of Education (UPI), Bandung, West Java (Indonesia); Nurdin, Isdiriayani [Department of Chemical Engineering, Bandung Institute of Technology, Bandung, West Java (Indonesia)

    2014-03-24

    Corrosion and inhibition studies on API 5LX65 carbon steel in chloride solution containing various concentrations of benzotriazole has been conducted at temperature of 70°C using Electrochemical Impedance Spectroscopy (EIS). Corroded carbon steel surface with and without inhibitor have been observed using X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), and Energy Dispersive Spectroscopy (EDS). The objectives of this research are to study the performance of benzotriazole as corrosion inhibitors. The experimental results of carbon steel corrosion in 3.5% NaCl solution containing 500 mg/l H{sub 2}S at different BTAH concentrations showed that corrosion rate of carbon steel decreases with increasing of BTAH concentrations from 0 to 10 mmol/l. The inhibition efficiency of BTAH was found to be affected by its concentration. The optimum efficiency obtained of BTAH is 93% at concentration of 5 mmol/l. The result of XRD and EDS analysis reveal the iron sulfide (FeS) formation on corroded carbon steel surface without inhibitor. The EDS spectrum show the Nitrogen (N) bond on carbon steel surface inhibited by BTAH.

  20. The Development of an In-Situ TEM Technique for Studying Corrosion Behavior as Applied to Zirconium-Based Alloys

    Science.gov (United States)

    Harlow, Wayne

    Zirconium-based alloys are a commonly used material for nuclear fuel rod cladding, due to its low neutron cross section and good corrosion properties. However, corrosion is still a limiting factor in fuel rod lifespan, which restricts burn up levels, and thus efficiency, that can be achieved. While long-term corrosion behavior has been studied through both reactor and autoclave samples, the oxide nucleation and growth behavior has not been extensively studied. This work develops a new technique to study the initial stages of corrosion in zirconium-based alloys and the microstructural effects on this process by developing an environmental cell system for the TEM. Nanoscale oxidation parameters are developed, as is a new FIB technique to support this method. Precession diffraction is used in conjunction with in-situ TEM to observe the initial stages of corrosion in these alloys, and oxide thickness is estimated using low-loss EELS. In addition, the stress stabilization of tetragonal ZrO 2 is explored in the context of sample preparation for TEM. It was found that in-situ environmental TEM using an environmental cell replicates the oxidation behavior observed in autoclaved samples in both oxide structure and phases. Utilizing this technique, it was shown that cracking of the oxide layer in zirconium-based alloys is related to oxide relaxation, and not thermal changes. The effect of secondary phase particles on oxidation behavior did not present significant results, however a new method for studying initial oxidation rates using low-loss EELS was developed.

  1. BWR steel containment corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Tan, C.P.; Bagchi, G.

    1996-04-01

    The report describes regulatory actions taken after corrosion was discovered in the drywell at the Oyster Creek Plant and in the torus at the Nine Mile Point 1 Plant. The report describes the causes of corrosion, requirements for monitoring corrosion, and measures to mitigate the corrosive environment for the two plants. The report describes the issuances of generic letters and information notices either to collect information to determine whether the problem is generic or to alert the licensees of similar plants about the existence of such a problem. Implementation of measures to enhance the containment performance under severe accident conditions is discussed. A study by Brookhaven National Laboratory (BNL) of the performance of a degraded containment under severe accident conditions is summarized. The details of the BNL study are in the appendix to the report.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-01-15

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

  3. Corrosion Characterization in Nickel Plated 110 ksi Low Alloy Steel and Incoloy 925: An Experimental Case Study

    Science.gov (United States)

    Thomas, Kiran; Vincent, S.; Barbadikar, Dipika; Kumar, Shresh; Anwar, Rebin; Fernandes, Nevil

    2018-04-01

    Incoloy 925 is an age hardenable Nickel-Iron-Chromium alloy with the addition of Molybdenum, Copper, Titanium and Aluminium used in many applications in oil and gas industry. Nickel alloys are preferred mostly in corrosive environments where there is high concentration of H2S, CO2, chlorides and free Sulphur as sufficient nickel content provides protection against chloride-ion stress-corrosion cracking. But unfortunately, Nickel alloys are very expensive. Plating an alloy steel part with nickel would cost much lesser than a part make of nickel alloy for large quantities. A brief study will be carried out to compare the performance of nickel plated alloy steel with that of an Incoloy 925 part by conducting corrosion tests. Tests will be carried out using different coating thicknesses of Nickel on low alloy steel in 0.1 M NaCl solution and results will be verified. From the test results we can confirm that Nickel plated low alloy steel is found to exhibit fairly good corrosion in comparison with Incoloy 925 and thus can be an excellent candidate to replace Incoloy materials.

  4. Study on the Microstructure, Mechanical Properties and Corrosion Behavior of Mg-Zn-Ca Alloy Wire for Biomaterial Application

    Science.gov (United States)

    Zheng, Maobo; Xu, Guangquan; Liu, Debao; Zhao, Yue; Ning, Baoqun; Chen, Minfang

    2018-03-01

    Due to their excellent biocompatibility and biodegradability, magnesium alloy wires have attracted much attention for biomaterial applications including orthopedic K-wires and sutures in wound closure. In this study, Mg-3Zn-0.2Ca alloy wires were prepared by cold drawing combined with proper intermediate annealing process. Microstructures, texture, mechanical properties and corrosion behavior of Mg-3Zn-0.2Ca alloy wire in a simulated body fluid were investigated. The results showed that the secondary phase and average grain size of the Mg-3Zn-0.2Ca alloy were refined in comparison with the as-extruded alloy and a strong (0002)//DD basal fiber texture system was formed after multi-pass cold drawing. After the annealing, most of the basal planes were tilted to the drawing direction (DD) by about 35°, presenting the characteristics of random texture, and the texture intensity decreased. The as-annealed wire shows good mechanical properties with the ultimate tensile strength (UTS), yield strength (YS) and elongation of 253 ± 8.5 MPa, 212 ± 11.3 MPa and 9.2 ± 0.9%, respectively. Electrochemical and hydrogen evolution measurements showed that the corrosion resistance of the Mg-3Zn-0.2Ca alloy wire was improved after the annealing. The immersion test indicated that the Mg-3Zn-0.2Ca wire exhibited uniform corrosion behavior during the initial period of immersion, but then exhibited local corrosion behavior.

  5. A comparative study of the corrosion of wire used in urological treatment under sterilization

    Directory of Open Access Journals (Sweden)

    W. Walke

    2012-04-01

    Full Text Available The purpose of the tests was to determine whether and how sterilization process of samples made of AISI 316L stainless steel with different strain impacts their corrosion resistance. Tests were made on steel samples that had been electrochemically polished in order to assure proper surface roughness. In order to evaluate the influence of sterilization on physical and chemical properties of steel surface, tests of corrosion resistance were made by means of potentiodynamical method. The tests were made in alternative solution simulating human urine. Recorded anodic polarization curves created the ground for determination of typical parameters describing pitting corrosion resistance, that enabled to evaluate steel wire corrosion behavior under sterilization conditions.

  6. Corrosion studies of modified organosilane coated magnesium-yttrium alloy in different environments

    Energy Technology Data Exchange (ETDEWEB)

    Xue Dingchuan [College of Engineering, University of Cincinnati, OH 45221 (United States); Tan Zongqing [Internal Medicine, College of Medicine, University of Cincinnati, OH 45221 (United States); Schulz, Mark J. [College of Engineering, University of Cincinnati, OH 45221 (United States); Vanooij, William J. [College of Engineering, University of Cincinnati, OH 45221 (United States); ECOSIL Technologies LLC, Fairfield, OH 45014 (United States); Sankar, Jagannathan [Biomedical Engineering Program, College of Engineering, North Carolina A and T State University, NC 27411 (United States); Yun Yeoheung, E-mail: yyun@ncat.edu [College of Engineering, University of Cincinnati, OH 45221 (United States); Biomedical Engineering Program, College of Engineering, North Carolina A and T State University, NC 27411 (United States); Dong Zhongyun [Internal Medicine, College of Medicine, University of Cincinnati, OH 45221 (United States)

    2012-07-01

    Magnesium (Mg) and its alloys have numerous potential applications as biodegradable implants, but the fast degradation rate of Mg alloys at the initial implanted stage could be a problem. This paper describes the modification of the water-based bis-[triethoxysilyl] ethane (BTSE) silane applied to the surface of magnesium-yttrium (Mg-4Y) to increase its corrosion resistance. Surface characterization by SEM, FTIR, and EDX showed that the hydrolysis and condensation of the silane resulted in a covalent bonding to the Mg-4Y surface. Corrosion behavior of the uncoated and coated Mg-4Y alloy was evaluated in different environments by using a novel self-developed corrosion probe. Based on the electrochemical results of DC polarization and electrochemical impedance spectroscopy (EIS), we conclude that the epoxy-modified BTSE silane coating successfully increases the corrosion resistance at the initial stage of implantation. The corrosion rates in the flesh of dead mice environments such as body cavity and subcutaneous tissue of the mice were lower than the corrosion rates in in vitro environments. - Highlights: Black-Right-Pointing-Pointer Modified silane was used on Mg-4Y for biological applications. Black-Right-Pointing-Pointer Modified silane-treated Mg-4Y increased its corrosion resistance in both In Vitro and In Vivo environments. Black-Right-Pointing-Pointer In Vitro testing environment is not consistent with In Vivo animal environment. Black-Right-Pointing-Pointer The modified silane mixture protecting mechanisms and its biocompatibility were discussed. Black-Right-Pointing-Pointer A novel three-electrode corrosion-monitoring probe was developed for realizing this work's In Vivo testing goals.

  7. Corrosion studies of modified organosilane coated magnesium–yttrium alloy in different environments

    International Nuclear Information System (INIS)

    Xue Dingchuan; Tan Zongqing; Schulz, Mark J.; Vanooij, William J.; Sankar, Jagannathan; Yun Yeoheung; Dong Zhongyun

    2012-01-01

    Magnesium (Mg) and its alloys have numerous potential applications as biodegradable implants, but the fast degradation rate of Mg alloys at the initial implanted stage could be a problem. This paper describes the modification of the water-based bis-[triethoxysilyl] ethane (BTSE) silane applied to the surface of magnesium–yttrium (Mg–4Y) to increase its corrosion resistance. Surface characterization by SEM, FTIR, and EDX showed that the hydrolysis and condensation of the silane resulted in a covalent bonding to the Mg–4Y surface. Corrosion behavior of the uncoated and coated Mg–4Y alloy was evaluated in different environments by using a novel self-developed corrosion probe. Based on the electrochemical results of DC polarization and electrochemical impedance spectroscopy (EIS), we conclude that the epoxy-modified BTSE silane coating successfully increases the corrosion resistance at the initial stage of implantation. The corrosion rates in the flesh of dead mice environments such as body cavity and subcutaneous tissue of the mice were lower than the corrosion rates in in vitro environments. - Highlights: ► Modified silane was used on Mg–4Y for biological applications. ► Modified silane-treated Mg–4Y increased its corrosion resistance in both In Vitro and In Vivo environments. ► In Vitro testing environment is not consistent with In Vivo animal environment. ► The modified silane mixture protecting mechanisms and its biocompatibility were discussed. ► A novel three-electrode corrosion-monitoring probe was developed for realizing this work's In Vivo testing goals.

  8. Mössbauer effect study of corrosion products from a Brazilian oil refinery

    Science.gov (United States)

    da Costa, M. I.; Kunrath, J. I.; Moro, J. T.; da Cunha, J. B. M.; Englert, G.; Comparsi, L. U.; Muller, I. L.

    1993-04-01

    Corrosion of an oil refining plant in southern Brazil is controlled by placing metallic coupons in strategic places of the unit. The amount of the corrosion products formed after two months of exposure of the coupons is then obtained by weight loss measurements. To have a better insight of these products an analysis by Conversion Electron and transmission Mössbauer spectroscopies was done on some of the coupons. This paper reports some of the findings.

  9. A Meta-Analysis Of Corrosion Studies for Maritime Patrol and Reconnaissance Aircraft (MPRA)

    Science.gov (United States)

    2016-09-01

    performed onsite. Aircraft rating was based upon the presence and/or extent of paint adhesion, paint cracking , clean ability, fluid damage, oxidation...because of corrosion control maintenance. No significant issues were observed related to paint cracking , fluid damage, corrosion, and clean ability of...HEXAMETHYLENEDIISOCYANATE 822-06-0 83194 X-310A; POLYURETHANE CATALYST XYLENE 1330-20-7 82649 X-530; HS EPOXY ENAMEL CURING SOLUTION BUTANOL 71-36-3

  10. Study of Plant Cordia Dichotoma as Green Corrosion Inhibitor for Mild Steel in Different Acid Media

    OpenAIRE

    R. Khandelwal; S. K. Arora; S. P. Mathur

    2011-01-01

    The corrosion inhibition of mild steel using extracts of Cordia dichotoma in different acid media was investigated by mass loss and thermometric methods. The experiments were carried out at 299±0.2 K in presence of different concentrations of dry fruit, leaves and stem extracts of Cordia dichotoma. The results reveal that the alcoholic extracts of Cordia dichotoma is a better corrosion inhibitor than that of toxic chemicals. The fruit extract is more potent than leaves and stem extracts to in...

  11. Study of anti corrosive behaviour on A I 6061 samples covered with Ni-P alloys obtained by autocatalytic method

    International Nuclear Information System (INIS)

    Castro, M. E; Barbero, J. A; Bubach, E

    2006-01-01

    There are many ways to keep safe an industrial material from corrosion attack.One is covering the piece with a layer of another material which corrosion resistance is higher to the one of the element to protect.The anticorrosion protection mechanism is achieved by the formation of a physical pore less barrier without any defects.This avoid the arrival of those agents from environment responsible of electrochemical attack.In this paper, corrosion resistance of metallic coatings over nuclear usage aluminum samples is analyzed.Our interest is aimed on nickel I phosphorous alloy coatings (Ni I P) obtained by electroless method (autocatalytic) over Al 6061 alloy samples.A comparative study is carried on with different phosphorous contents but always under 12 %.This job is completed with other nickel coating, Vitro vac 0080 (with no phosphorous content) in order to compare structures and anti corrosive properties.Besides, the comparison between mentioned materials and aluminum samples is made.The study is carried on using superficial characterization of each sample with or without coating through a series of complementary techniques such as chemical, electrochemical (linear sweep voltammetry, cyclic voltammetry, polarization resistance determination) and physical (scanning electronic microscopy, hardness determination) techniques.Finally, variable correlation is made as a function of the phosphorous content in the samples used in the experiences.The coating structure obtained is amorphous.It presents no pore or failure and its hardness shows important values.The electrochemical analysis allows to check that anti corrosive protection capacity of Ni-P alloy increases with the phosphorous content in the coat. Al 6061 by itself demonstrate an electrochemically bad behaviour.Substrate I coating adherence is very good [es

  12. Contribution to the study of the role of sulfate-reducing bacteria in bio-corrosion phenomenon

    International Nuclear Information System (INIS)

    Chatelus, C.

    1987-11-01

    By their metabolic activities of hydrogen consumption and of sulfides production, the sulfate-reducing bacteria are the main bacteria responsible of the metallic corrosion phenomena in the absence of oxygen. A physiological and enzymatic study of some Desulfovibrio has contributed to the understanding of the role of these bacteria in the anaerobic bio-corrosion phenomena. Desulfovibrio (D.) vulgaris in organic medium, after having oxidized the lactate, consumes the hydrogen formed by the electrochemical reaction of iron dissolution. The Desulfovibrio can be responsible either of a corrosion by a direct contact with the metal in using the H 2 layer formed at its surface, (bacteria are then adsorbed at the surface because of an iron sulfide crystalline lattice), or of a distant corrosion in consuming the dissolved or gaseous hydrogen. As their hydrogenases can be stable in time independently of the cellular structure (D. vulparis) and active at high temperatures (to 70 C - 75 C) (D. baculatus), these bacteria can act in conditions incompatible with the viability of cells but compatible with the enzymatic expression. A study in terms of temperature has shown that inside the mesophilic group of the Desulfovibrio, the behaviour towards this parameter is specific to each bacteria, that accounts for the permanent presence of the representatives of this population in sites where the temperature variations are important. A change of some degrees Celsius can induce modifications in the yields of bacteria growth and by a consequence in variations in the corrosion intensity. Moreover, sulfate D. multispirans can reduce with specific velocities of different growth, the nitrate, the nitrite and the fumarate. Some sulfato-reducing could then adapt themselves to the variations of concentrations in electron acceptors and metabolize the oxidized substances used as biocides too. The choice of an electron acceptor rather than another do not depend uniquely of the specificity of the

  13. A numerical study of under-deposit pitting corrosion in sour petroleum pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Z.; Sand, K.W.; Teevens, P.J. [Broadsword Corrosion Engineering Ltd., Calgary, AB (Canada)

    2010-07-01

    Insufficient fluid velocity in petroleum pipelines can lead to the deposit of sand, corrosion products, and non-corrosion products on the pipe's metal surface, which in turn can lead to pitting corrosion. There is currently no reliable means of detecting and preventing the pitting process. This paper presented a computerized simulation tool that used the finite element method to model mass transfer-governed internal pitting corrosion under solids deposition in sour petroleum pipelines. The computational domain consisted of a hemispherical pit and a thin stagnant solution film under a surface deposit. The moving mesh method was used to track pitting growth. A Poisson equation was used to determine aqueous path migration of ions. Pitting corrosion rates were estimated using the Nernst-Planck equation. The model was used to predict the effects of different operating parameters on pitting corrosion rates. The model can be used to develop pigging and in-line-inspection (ILI) procedures. 35 refs., 2 tabs., 16 figs.

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

    International Nuclear Information System (INIS)

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

    1991-01-01

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

  15. Long-term corrosion/oxidation studies under controlled humidity conditions

    International Nuclear Information System (INIS)

    Gdowski, G.

    1997-01-01

    Independent of thermal loading scenarios, the waste packages at the potential repository at Yucca Mountain, Nevada will be exposed to environmental conditions where there is the possibility of significant water film formation occurring on the waste packages. Water films can cause aggressive aqueous film electrochemical corrosion on susceptible metals or alloys. Water film formation will be facilitated when relative humidities are high, when hygroscopic salts are present on the surfaces, when corrosion products are hygroscopic, and when particles form crevices with the surfaces (capillary effect). Also certain gaseous contaminants, such as, NO x and SO 2 , can facilitate water film formation. It should be noted that water film formation can occur at isolated spots (e.g. surface defects and salt particles) and need not cover the entire surface for electrochemical corrosion to occur. This activity will characterize the long term corrosion of metal specimens at two nominal relative humidities (50 and 85%) and at 80 C. Under the low relative humidity (50%) condition, water film formation is expected to be limited and therefore aqueous film electrochemical corrosion is expected also to be limited. Under the high relative humidity (85%) condition, significant water film formation is expected to occur under some test conditions, and subsequently aqueous film electrochemical corrosion will occur on susceptible materials

  16. Quantitative measures of corrosion and prevention: application to corrosion in agriculture

    NARCIS (Netherlands)

    Schouten, J.C.; Gellings, P.J.

    1987-01-01

    The corrosion protection factor (c.p.f.) and the corrosion condition (c.c.) are simple instruments for the study and evaluation of the contribution and efficiency of several methods of corrosion prevention and control. The application of c.p.f. and c.c. to corrosion and prevention in agriculture in

  17. Carbon Dioxide Corrosion:

    DEFF Research Database (Denmark)

    Fosbøl, Philip Loldrup

    2008-01-01

    CO2 corrosion is a general problem in the industry and it is expensive. The focus of this study is an oil gas production related problem. CO2 corrosion is observed in offshore natural gas transportation pipelines. A general overview of the problem is presented in chapter 1. The chemical system...... with the basic thermodynamics of electrolytes in chapter 2, the extension and general description of electrolyte mass transport in chapter 3, and the electrochemical kinetics of corrosion in chapter 4. A literature overview of CO2 corrosion is shown in chapter 5 and possible extensions of the models...... and validated against heat capacity data. The model is also fitted to experimental data produced and shown in chapter 8 for SLE in the Na2CO3-NaHCO3-MEG-H2O system. The application of the above model is shown in chapter 9. Here the thermodynamic correction factors are calculated. These show how the diffusion...

  18. Influence of sulfate-reducing bacteria on the corrosion of steel in seawater: laboratory and in situ study

    International Nuclear Information System (INIS)

    Benbouzid-Rollet, N.

    1993-01-01

    A fouling reactor was designed to study, the influence of a mixed bio-film on AISI 316 L stainless steel. The bio-film was formed on the steel surface by the fermentative bacterium Vibrio natriegens. The sulfate-reducing bacterium Desulfovibrio vulgaris was then introduced in the reactor and colonized the surface, constituting approximately 5 % of the total population. The settlement of an anaerobic bacterium in the bio-film shows in it the existence of anaerobic micro-niches. Stainless steel electrochemical behavior was analyzed using open circuit potential and potentiodynamic polarization curves. Growth of the bio-film does not induce corrosion, but seems to change the cathodic oxygen reduction kinetics, diminishing the corrosion hazard. This effect increases when D. vulgaris grows in the bio-film. An ennobling of the open circuit potential was observed, similar to field cases already described. A case of drilling corrosion of carbon steel in a harbour area showed the characteristics of anaerobic corrosion related to sulfate-reducing bacteria. The total cultivatable SRB population was quantified and metabolic types were enumerated using specific electron donors. A maximum cell density of 1,1 x 10 8 cells/ cm 2 was estimated, revealing a very important growth of SRB on surfaces. Population structure was different in corroded and non-corroded areas. In corroded area, SRB utilizing benzoate and propionate were more abundant. A strain belonging to the sporulating genus Desulfotomaculum was isolated using these substrates, suggesting a partial aeration in the area of hole appearance. However, in vitro corrosion assays showed that the bacterial population sampled in this area induced a consequent weight loss of steel coupons, in the absence of oxygen. This was observed only with a diversified population, similar to that present in situ. It could not be reproduced with a mixed culture of two purified strains. (author)

  19. Application of neutron activation analysis to the corrosion study of gold coated studs used for piercing ears

    International Nuclear Information System (INIS)

    Saiki, M.; Rogero, S.O.; Costa, I.; Correa, O.V.; Higa, O.Z.

    1998-01-01

    Complete text of publication follows. Gold is known as a metal having little or no toxicity and it has been widely used for coating studs for ear piercing. However, for some people gold coated studs have caused serious allergy and inflammation problems. After piercing, the studs are usually kept in the ear lobes for at least one week, and during this period the stud surfaces in contact with the body fluids have caused swelling, pain and redness of the skin. Consequently, it is of great interest to evaluate if elements from the metallic substrate underneath the gold coatings migrate to the body fluids due to the corrosion and the presence of defects in gold coatings. The solutions for corrosion test were obtained by placing the gold coated studs in contact with the solutions of NaCl and of culture medium. Elemental analyses of these solutions by radioanalytical method of neutron activation analysis indicated the occurrence of substrate corrosion since the elements Cr, Fe, Ni and Zn were found in these solutions. These elements are substrate material components of alloys used to make the studs and they were quantified by X-ray fluorescence analysis. The defects of the coatings were also detected by scanning electron microscopy and energy dispersive spectroscopy analysis of the gold coated studs before and after the corrosion tests. Cytotoxicity studies indicated that after corrosion test the solution used was toxic in the culture cell assay. Among the elements quantified in the test solutions, Ni is considered responsible for most of allergic reactions. Results obtained in this work indicated the necessity to improve quality control of the coating process of studs and in the appropriate choice of material used as substrate

  20. Corrosion study of heat exchanger tubes in pressurized water cooled nuclear reactors by conversion electron Moessbauer spectroscopy

    International Nuclear Information System (INIS)

    Homonnay, Z.; Kuzmann, E.; Varga, K.; Nemeth, Z.; Szabo, A.; Rado, K.; Schunk, J.; Tilky, P.; Patek, G.

    2005-01-01

    Nuclear energy production tends to return into the focus of interest because of the constantly increasing energy need of the world and the green house effect problems of the strongest competitor oil or gas based power plants. In addition to the construction of new nuclear power plants, lifetime extension of the existing ones is the most cost effective investment in the energy business. However, feasibility and safety issues become very important at this point, and corrosion of the construction materials should be carefully investigated before decision on a potential lifetime extension of a reactor. 57 Fe-Conversion Electron Moessbauer Spectroscopy (CEMS) is a sensitive tool to analyze the phase composition of corrosion products on the surface of stainless steel. The upper ∼300 nm can be investigated due to the penetration range of conversion electrons. The corrosion state of heat exchanger tubes from the four reactor units of the Paks Nuclear Power Plant, Hungary, were analyzed by several methods including CEMS. The primary circuit side of the tubes was studied on selected samples cut out from the heat exchangers during regular maintenance. Cr- and Ni-substituted magnetite, sometimes hematite, amorphous Fe-oxides/oxyhydroxides as well as the signal of bulk austenitic steel of the tubes were detected. The level of Cr- and Ni-substitution in the magnetite phase could be estimated from the Moessbauer spectra. Correlation between earlier decontamination cycles and the corrosion state of the heat exchangers was sought. In combination with other methods, a hybrid structure of the surface oxide layer of several microns was established. It is suggested that previous AP-CITROX decontamination cycles can be responsible for this structure which makes the oxide layer mobile. This mobility may be responsible for unwanted corrosion product transport into the reactor vessel by the primary coolant.

  1. Application of surface science to the study of the corrosion of PWR primary circuit materials

    International Nuclear Information System (INIS)

    Harris, S.J.

    1989-04-01

    This thesis describes a study of the corrosion and oxidation of PWR primary circuit materials using surface sensitive spectroscopic techniques. An X-ray photoemission spectroscopy (XPS) study of a number of mixed oxides of known composition is described and the information obtained is related to XPS measurements made on the surface of iron and nickel based alloys oxidised under controlled conditions. A secondary ion mass spectroscopy (SIMA) study on these mixed transition metal oxides is also described. The gaseous oxidation of stainless steel 3041 and Inconel-690 is examined. Both alloys were oxidised at 600K in air with the composition of the oxide films formed studied by a range of surface spectroscopic methods. Further experimental work was performed on Inconel-690 to examine the effects of surface pretreatment and the effects of low oxygen partial pressures on the formation of oxide films at 600 K. The incorporation of the radionuclide, cobalt-60, into the oxide films formed on structural components of a PWR, result in the build up of radiation fields. A method of pretreating the surface of the alloy stainless steel 3041, in order to reduce the level of cobalt adsorbed into the oxide film formed under simulated primary coolant conditions is examined and contrasts with treatments which have been developed to release cobalt adsorbed in existing oxide layers under reactor conditions are discussed. (author)

  2. Corrosion of beryllium

    International Nuclear Information System (INIS)

    Mueller, J.J.; Adolphson, D.R.

    1987-01-01

    The corrosion behavior of beryllium in aqueous and elevated-temperature oxidizing environments has been extensively studied for early-intended use of beryllium in nuclear reactors and in jet and rocket propulsion systems. Since that time, beryllium has been used as a structural material in les corrosive environments. Its primary applications include gyro systems, mirror and reentry vehicle structures, and aircraft brakes. Only a small amount of information has been published that is directly related to the evaluation of beryllium for service in the less severe or normal atmospheric environments associated with these applications. Despite the lack of published data on the corrosion of beryllium in atmospheric environments, much can be deduced about its corrosion behavior from studies of aqueous corrosion and the experiences of fabricators and users in applying, handling, processing, storing, and shipping beryllium components. The methods of corrosion protection implemented to resist water and high-temperature gaseous environments provide useful information on methods that can be applied to protect beryllium for service in future long-term structural applications

  3. Studies on Stress Corrosion Cracking of Super 304H Austenitic Stainless Steel

    Science.gov (United States)

    Prabha, B.; Sundaramoorthy, P.; Suresh, S.; Manimozhi, S.; Ravishankar, B.

    2009-12-01

    Stress corrosion cracking (SCC) is a common mode of failure encountered in boiler components especially in austenitic stainless steel tubes at high temperature and in chloride-rich water environment. Recently, a new type of austenitic stainless steels called Super304H stainless steel, containing 3% copper is being adopted for super critical boiler applications. The SCC behavior of this Super 304H stainless steel has not been widely reported in the literature. Many researchers have studied the SCC behavior of steels as per various standards. Among them, the ASTM standard G36 has been widely used for evaluation of SCC behavior of stainless steels. In this present work, the SCC behavior of austenitic Fe-Cr-Mn-Cu-N stainless steel, subjected to chloride environments at varying strain conditions as per ASTM standard G36 has been studied. The environments employed boiling solution of 45 wt.% of MgCl2 at 155 °C, for various strain conditions. The study reveals that the crack width increases with increase in strain level in Super 304H stainless steels.

  4. Development of new corrosion inhibitor tested on mild steel supported by electrochemical study

    Directory of Open Access Journals (Sweden)

    Hussein Jwad Habeeb

    2018-03-01

    Full Text Available Mild steel is a metal which is commonly used in industrials and manufacturing of equipment for most industries round the world. It is cheaper cost compared with the other metals and its durable, hard and easy-to-wear physical properties make it a major choice in the manufacture of equipment parts. The main problem through the uses of mild steel in industry is its resistance against corrosion, especially in acidic solutions. This case led to raise the cost of maintenance of equipment that used mild steel and as a result increased costs for the company. Organic corrosive inhibitors that also act as green chemicals, 4-hydroxybenzylideneaminomethyl-5-ethyl-1,3,4-thiadiazol have been synthesized. This inhibitor is tested as corrosion inhibitor on a mild steel sample MS in 1 M hydrochloric acid solution (HCl using electrochemical measurements test includes PD (Potentiodynamic, EIS (Electrochemical impedance spectroscopy, OCP (Open circuit potential and EFM (electrochemical frequency modulation. The obtained results indicate that 4-hydroxybenzylideneaminomethyl-5-ethyl-1,3,4-thiadiazol acts as a good corrosion inhibitor for mild steel sample in HCl solution with efficiency above 90%. Changes in the impedance parameters postulated adsorption on the mild steel specimens' surfaces of, which it going to the formation of protective coating layer. It also shows that 4-hydroxybenzylideneaminomethyl-5-ethyl-1,3,4-thiadiazol corrosion inhibitors are effective in helping to reduce and slow down the corrosion process that occurs on mild steel surface in hydrochloric acid solution. Increase of corrosion inhibitor concentration provides a protective layer of mild steel. However, this protective layer becomes weak when the temperature of the solution increases. Keywords: Hydroxybenzylideneaminomethy, Potentiodynamic, Electrochemical frequency modulation, Impedance

  5. Development of new corrosion inhibitor tested on mild steel supported by electrochemical study

    Science.gov (United States)

    Habeeb, Hussein Jwad; Luaibi, Hasan Mohammed; Dakhil, Rifaat Mohammed; Kadhum, Abdul Amir H.; Al-Amiery, Ahmed A.; Gaaz, Tayser Sumer

    2018-03-01

    Mild steel is a metal which is commonly used in industrials and manufacturing of equipment for most industries round the world. It is cheaper cost compared with the other metals and its durable, hard and easy-to-wear physical properties make it a major choice in the manufacture of equipment parts. The main problem through the uses of mild steel in industry is its resistance against corrosion, especially in acidic solutions. This case led to raise the cost of maintenance of equipment that used mild steel and as a result increased costs for the company. Organic corrosive inhibitors that also act as green chemicals, 4-hydroxybenzylideneaminomethyl-5-ethyl-1,3,4-thiadiazol have been synthesized. This inhibitor is tested as corrosion inhibitor on a mild steel sample MS in 1 M hydrochloric acid solution (HCl) using electrochemical measurements test includes PD (Potentiodynamic), EIS (Electrochemical impedance spectroscopy), OCP (Open circuit potential) and EFM (electrochemical frequency modulation). The obtained results indicate that 4-hydroxybenzylideneaminomethyl-5-ethyl-1,3,4-thiadiazol acts as a good corrosion inhibitor for mild steel sample in HCl solution with efficiency above 90%. Changes in the impedance parameters postulated adsorption on the mild steel specimens' surfaces of, which it going to the formation of protective coating layer. It also shows that 4-hydroxybenzylideneaminomethyl-5-ethyl-1,3,4-thiadiazol corrosion inhibitors are effective in helping to reduce and slow down the corrosion process that occurs on mild steel surface in hydrochloric acid solution. Increase of corrosion inhibitor concentration provides a protective layer of mild steel. However, this protective layer becomes weak when the temperature of the solution increases.

  6. Zircaloy-4 corrosion in PWR's

    International Nuclear Information System (INIS)

    Fyfitch, S.; Smalley, W.R.; Roberts, E.

    1985-01-01

    Zircaloy-4 waterside corrosion has been studied extensively in the nuclear industry for a number of years. Following the early crud-related corrosion failures in the Saxton test reactor, Westinghouse undertook numerous programs to minimize crud deposition on fuel rods in power reactors through primary coolant chemistry control. Modern plants today are operating with improved coolant chemistry guidelines, and crud deposition levels are very low in proportion to earlier experience. Zircaloy-4 corrosion under a variety of coolant chemistry, heat flux and exposure conditions has been studied extensively. Experience to date, even in relatively high coolant temperature plants, has indicated that -for both fuel cladding and structural components- Zircaloy-4 waterside corrosion performance has been excellent. Recognizing future industry trends, however, which will result in Zircaloy-4 being subjected to ever increasing corrosion duties, Westinghouse will continue accumulating Zircaloy-4 corrosion experience in large power plants. 13 refs.

  7. The Application of Electrochemical and Surface Analysis Approaches to Studying Copper Corrosion in Water: Fundamentals, Limitations, and Examples

    Science.gov (United States)

    Corrosion control is a concern for many drinking water utilities. The Lead and Copper Rule established a regulatory need to maintain a corrosion control program. Other corrosion-related issues such as “red” water resulting from excessive iron corrosion and copper pinhole leaks ...

  8. Corrosion Evaluation and Corrosion Control of Steam Generators

    International Nuclear Information System (INIS)

    Maeng, W. Y.; Kim, U. C.; Sung, K. W.; Na, J. W.; Lee, Y. H.; Lee, D. H.; Kim, K. M.

    2008-06-01

    Corrosion damage significantly influences the integrity and efficiency of steam generator. Corrosion problems of steam generator are unsolved issues until now even though much effort is made around world. Especially the stress corrosion cracking of heat exchange materials is the first issue to be solved. The corrosion protection method of steam generator is important and urgent for the guarantee of nuclear plant's integrity. The objectives of this study are 1) to evaluate the corrosion properties of steam generator materials, 2) to optimize the water chemistry of steam generator and 3) to develop the corrosion protection method of primary and secondary sides of steam generator. The results will be reflected to the water chemistry guideline for improving the integrity and efficiency of steam generator in domestic power plants

  9. Corrosion Evaluation and Corrosion Control of Steam Generators

    Energy Technology Data Exchange (ETDEWEB)

    Maeng, W. Y.; Kim, U. C.; Sung, K. W.; Na, J. W.; Lee, Y. H.; Lee, D. H.; Kim, K. M

    2008-06-15

    Corrosion damage significantly influences the integrity and efficiency of steam generator. Corrosion problems of steam generator are unsolved issues until now even though much effort is made around world. Especially the stress corrosion cracking of heat exchange materials is the first issue to be solved. The corrosion protection method of steam generator is important and urgent for the guarantee of nuclear plant's integrity. The objectives of this study are 1) to evaluate the corrosion properties of steam generator materials, 2) to optimize the water chemistry of steam generator and 3) to develop the corrosion protection method of primary and secondary sides of steam generator. The results will be reflected to the water chemistry guideline for improving the integrity and efficiency of steam generator in domestic power plants.

  10. Lean duplex stainless steels-The role of molybdenum in pitting corrosion of concrete reinforcement studied with industrial and laboratory castings

    Energy Technology Data Exchange (ETDEWEB)

    Mesquita, T.J. [LEPMI, UMR5279CNRS, Grenoble INP, Universite de Savoie, Universite Joseph Fourier, BP 75, 38402 St Martin d' Heres (France); CRU Ugitech, Av Paul Girod 73400 Ugine (France); Chauveau, E.; Mantel, M. [CRU Ugitech, Av Paul Girod 73400 Ugine (France); Kinsman, N. [International Molybdenum Association, IMOA W4 4JE London (United Kingdom); Roche, V. [LEPMI, UMR5279CNRS, Grenoble INP, Universite de Savoie, Universite Joseph Fourier, BP 75, 38402 St Martin d' Heres (France); Nogueira, R.P., E-mail: ricardo.nogueira@grenoble-inp.fr [LEPMI, UMR5279CNRS, Grenoble INP, Universite de Savoie, Universite Joseph Fourier, BP 75, 38402 St Martin d' Heres (France)

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer Mo influence on corrosion of DSS was studied with industrial and laboratory heats. Black-Right-Pointing-Pointer Beneficial effect of Mo was associated with ferrite corrosion resistance. Black-Right-Pointing-Pointer Mo-species in the alkaline solution did not improve pit resistance. Black-Right-Pointing-Pointer Mo role in DSS under alkaline conditions was ascribed to its presence in oxide film. - Abstract: The influence of Mo addition on pitting corrosion resistance of lean duplex stainless steels is not clearly understood in alkaline chloride conditions even if this element is widely recognized to increase corrosion resistance in acidic and neutral environments. This work aims to study the effect of Mo on pitting corrosion of lean duplex stainless steels in synthetic concrete pore solutions simulating degraded concrete. Results are discussed with respect to the influence of Mo on pitting potential for two industrial alloys in chloride rich and carbonated solution simulating concrete pore environments. To establish the real effect of Mo addition on lean duplex corrosion and passivation properties, two specific laboratory lean duplex alloys, for which the only difference is strictly the Mo content, are also studied. Mo presented a strong positive influence on the pitting corrosion resistance of industrial and laboratory lean duplex stainless steels in all studied chloride-rich solutions, but its effect is as less pronounced as the pH increases. In presence of Mo, pitting initiates and propagates preferentially in the austenitic phase at high temperature.

  11. Adsorption and Corrosion Inhibition Studies of Some Selected Dyes as Corrosion Inhibitors for Mild Steel in Acidic Medium: Gravimetric, Electrochemical, Quantum Chemical Studies and Synergistic Effect with Iodide Ions

    Directory of Open Access Journals (Sweden)

    Thabo Peme

    2015-09-01

    Full Text Available The corrosion inhibition properties of some organic dyes, namely Sunset Yellow (SS, Amaranth (AM, Allura Red (AR, Tartrazine (TZ and Fast Green (FG, for mild steel corrosion in 0.5 M HCl solution, were investigated using gravimetric, potentiodynamic polarization techniques and quantum chemical calculations. The results showed that the studied dyes are good corrosion inhibitors with enhanced inhibition efficiencies. The inhibition efficiency of all the studied dyes increases with increase in concentration, and decreases with increase in temperature. The results showed that the inhibition efficiency of the dyes increases in the presence of KI due to synergistic interactions of the dye molecules with iodide (I− ions. Potentiodynamic polarization results revealed that the studied dyes are mixed-type inhibitors both in the absence and presence of KI. The adsorption of the studied dyes on mild steel surface, with and without KI, obeys the Langmuir adsorption isotherm and involves physical adsorption mechanism. Quantum chemical calculations revealed that the most likely sites in the dye molecules for interactions with mild steel are the S, O, and N heteroatoms.

  12. Adsorption and Corrosion Inhibition Studies of Some Selected Dyes as Corrosion Inhibitors for Mild Steel in Acidic Medium: Gravimetric, Electrochemical, Quantum Chemical Studies and Synergistic Effect with Iodide Ions.

    Science.gov (United States)

    Peme, Thabo; Olasunkanmi, Lukman O; Bahadur, Indra; Adekunle, Abolanle S; Kabanda, Mwadham M; Ebenso, Eno E

    2015-09-02

    The corrosion inhibition properties of some organic dyes, namely Sunset Yellow (SS), Amaranth (AM), Allura Red (AR), Tartrazine (TZ) and Fast Green (FG), for mild steel corrosion in 0.5 M HCl solution, were investigated using gravimetric, potentiodynamic polarization techniques and quantum chemical calculations. The results showed that the studied dyes are good corrosion inhibitors with enhanced inhibition efficiencies. The inhibition efficiency of all the studied dyes increases with increase in concentration, and decreases with increase in temperature. The results showed that the inhibition efficiency of the dyes increases in the presence of KI due to synergistic interactions of the dye molecules with iodide (I(-)) ions. Potentiodynamic polarization results revealed that the studied dyes are mixed-type inhibitors both in the absence and presence of KI. The adsorption of the studied dyes on mild steel surface, with and without KI, obeys the Langmuir adsorption isotherm and involves physical adsorption mechanism. Quantum chemical calculations revealed that the most likely sites in the dye molecules for interactions with mild steel are the S, O, and N heteroatoms.

  13. Stress corrosion cracking of Alloy 600 in primary water of PWR: study of chromium diffusion

    International Nuclear Information System (INIS)

    Chetroiu, Bogdan-Adrian

    2015-01-01

    Alloy 600 (Ni-15%Cr-10%Fe) is known to be susceptible to Stress Corrosion Cracking (SCC) in primary water of Pressurized Water Reactors (PWR). Recent studies have shown that chromium diffusion is a controlling rate step in the comprehension of SCC mechanism. In order to improve the understanding and the modelling of SCC of Alloy 600 in PWR primary medium the aim of this study was to collect data on kinetics diffusion of chromium. Volume and grain boundary diffusion of chromium in pure nickel and Alloy 600 (mono and poly-crystals) has been measured in the temperature range 678 K to 1060 K by using Secondary Ions Mass Spectroscopy (SIMS) and Glow Discharge-Optical Spectrometry (GD-OES) techniques. A particular emphasis has been dedicated to the influence of plastic deformation on chromium diffusion in nickel single crystals (orientated <101>) for different metallurgical states. The experimental tests were carried out in order to compare the chromium diffusion coefficients in free lattice (not deformed), in pre-hardening specimens (4% and 20%) and in dynamic deformed tensile specimens at 773 K. It has been found that chromium diffusivity measured in dynamic plastic deformed creep specimens were six orders of magnitude greater than those obtained in not deformed or pre-hardening specimens. The enhancement of chromium diffusivity can be attributed to the presence of moving dislocations generated during plastic deformation. (author)

  14. SEM corrosion-casts study of the microcirculation of the flat bones in the rat.

    Science.gov (United States)

    Pannarale, L; Morini, S; D'Ubaldo, E; Gaudio, E; Marinozzi, G

    1997-04-01

    Little is known about the organization of microcirculation in flat bones in comparison with long bones. This study, therefore, helps us to determine the design of this vascular system in flat bones in relation to their structure and function. The organization of microvasculature in parietal, scapula, and ileum bones of 15 young sexually mature rats, aged 6-7 weeks, was studied by light and scanning electron microscopy (SEM) from vascular corrosion cast (vcc), a resin-cast obtained material. Our observations show that the pattern of the microcirculation in flat bones is different in the thick and thin parts of such bones. Where the bone is thinner than 0.4 mm, only periosteal and dural network exist. Larger vessels which do not form a real network connect the two tables of the bones in these regions. In thicker areas, the organization of the microvasculature is similar to that in long bones, with distinct periosteal, cortical and bone marrow networks. Moreover, in different bones, outer networks show slightly different characteristics according to the different adjacent structures (dura mater, muscles etc.). Different types of vessels were recognized by comparing their different diameter, course and endothelial imprints. The microvascular patterns of the flat bones are strongly influenced by the bone thickness. The different microvascular systems can interact both with the bone modelling and remodeling and with the variable metabolic needs, modifying the microvascular pattern and the blood flow. This is even more important in view of the reciprocal influence of the different networks within the same bone.

  15. A Theoretical Model for Metal Corrosion Degradation

    Directory of Open Access Journals (Sweden)

    David V. Svintradze

    2010-01-01

    Full Text Available Many aluminum and stainless steel alloys contain thin oxide layers on the metal surface which greatly reduce the corrosion rate. Pitting corrosion, a result of localized breakdown of such films, results in accelerated dissolution of the underlying metal through pits. Many researchers have studied pitting corrosion for several decades and the exact governing equation for corrosion pit degradation has not been obtained. In this study, the governing equation for corrosion degradation due to pitting corrosion behavior was derived from solid-state physics and some solutions and simulations are presented and discussed.

  16. Corrosion study on high power feeding of telecomunication copper cable in 5 wt.% CaSO4.2H2O solution

    Science.gov (United States)

    Shamsudin, Shaiful Rizam; Hashim, Nabihah; Ibrahim, Mohd Saiful Bahri; Rahman, Muhammad Sayuzi Abdul; Idrus, Muhammad Amin; Hassan, Mohd Rezadzudin; Abdullah, Wan Razli Wan

    2016-07-01

    The studies were carried out to find out the best powering scheme over the copper telephone line. It was expected that the application of the higher power feeding could increase the data transfer and capable of providing the customer's satisfaction. To realize the application of higher remote power feeding, the potential of corrosion problem on Cu cables was studied. The natural corrosion behaviour of copper cable in the 0.5% CaSO4.2H2O solution was studied in term of open circuit potential for 30 days. The corrosion behaviour of higher power feeding was studied by the immersion and the planned interval test to determine the corrosion rate as well as the effect of voltage magnitudes and the current scheme i.e. positive direct (DC+) and alternating current (AC) at about 0.40 ± 0.01 mA/ cm2 current density. In the immersion test, both DC+ and AC scheme showed the increasing of feeding voltage magnitude has increased the corrosion rate of Cu samples starting from 60 to 100 volts. It was then reduced at about 100 - 120 volts which may due to the passive and transpassive mechanism. The corrosion rate was slowly reduced further from 120 to 200 volts. Visually, the positively charged of Cu cable was seems susceptible to severe corrosion, while AC scheme exhibited a slight corrosion reaction on the surface. However, the planned interval test and XRD results showed the corrosion activity of the copper cable in the studied solution was a relatively slow process and considered not to be corroded as a partially protective scale of copper oxide formed on the surface.

  17. In situ synchrotron X-ray diffraction study of the effect of microstructure and boundary layer conditions on CO2 corrosion of pipeline steels

    International Nuclear Information System (INIS)

    Ko, M.; Ingham, B.; Laycock, N.; Williams, D.E.

    2015-01-01

    Highlights: • We studied the effects of steel microstructures and local conditions on CO 2 corrosion. • Microstructure influences the development of surface roughness during corrosion. • The effects of Cr alloying, on average, dominate over the effects of microstructure. • Spatial segregation of Cr between the phases in the steel may result in localised corrosion. - Abstract: This study demonstrates that the nucleation of crystalline scales of siderite and chukanovite onto the surface of low-alloy steels under CO 2 corrosion at elevated temperature is critically dependent on initial surface roughness, on microstructure-related surface roughness developed during corrosion, and on stirring in the solution. This study confirms that effects due to chromium micro-alloying in the steel are extremely important for siderite nucleation. On average, these effects dominate over the effects of microstructure. However, spatial variation of the corrosion deposit thickness indicates an interdependence between microstructure and chromium-enhanced siderite nucleation with the possibility of localised corrosion developing as a result

  18. Synergy effect of naphthenic acid corrosion and sulfur corrosion in crude oil distillation unit

    Science.gov (United States)

    Huang, B. S.; Yin, W. F.; Sang, D. H.; Jiang, Z. Y.

    2012-10-01

    The synergy effect of naphthenic acid corrosion and sulfur corrosion at high temperature in crude oil distillation unit was studied using Q235 carbon-manganese steel and 316 stainless steel. The corrosion of Q235 and 316 in corrosion media containing sulfur and/or naphthenic acid at 280 °C was investigated by weight loss, scanning electron microscope (SEM), EDS and X-ray diffractometer (XRD) analysis. The results showed that in corrosion media containing only sulfur, the corrosion rate of Q235 and 316 first increased and then decreased with the increase of sulfur content. In corrosion media containing naphthenic acid and sulfur, with the variations of acid value or sulfur content, the synergy effect of naphthenic acid corrosion and sulfur corrosion has a great influence on the corrosion rate of Q235 and 316. It was indicated that the sulfur accelerated naphthenic acid corrosion below a certain sulfur content but prevented naphthenic acid corrosion above that. The corrosion products on two steels after exposure to corrosion media were investigated. The stable Cr5S8 phases detected in the corrosion products film of 316 were considered as the reason why 316 has greater corrosion resistance to that of Q235.

  19. Study of alloy 600`S stress corrosion cracking mechanisms in high temperature water; Etude des mecanismes de corrosion sous contrainte de l`alliage 600 dans l`eau a haute temperature

    Energy Technology Data Exchange (ETDEWEB)

    Rios, R

    1994-06-01

    In order to better understand the mechanisms involved in Alloy 600`s stress corrosion cracking in PWR environment, laboratory tests were performed. The influence of parameters pertinent to the mechanisms was studies : hydrogen and oxygen overpressures, local chemical composition, microstructure. The results show that neither hydrogen nor dissolution/oxidation, despite their respective roles in the process, are sufficient to account for experimental facts. SEM observation of micro-cleavage facets on specimens` fracture surfaces leads to pay attention to a new mechanism of corrosion/plasticity interactions. (author). 113 refs., 73 figs., 15 tabs., 4 annexes.

  20. Study of the localized corrosion of over-aged aeronautical 2024 aluminum alloy. Kelvin probe Force Microscopy (KFM) application

    OpenAIRE

    Radutoiu , Nicoleta; Lacroix , Loïc; Alexis , Joël; Abrudeanu , Marioara; Petit , Jacques-Alain

    2012-01-01

    International audience; The 2xxx serie aluminum alloys are characterized by good mechanical performances and low density, however they are susceptible to different forms of localized corrosion: pitting corrosion, intergranular corrosion and stress corrosion cracking. The 2024-T351 aluminum alloy is used in the aircraft industry for numerous applications such as fuselage and door skin. Corrosion damage of the material is also very detrimental for the structural integrity of the aircraft. The p...

  1. SERS and DFT study of copper surfaces coated with corrosion inhibitor

    Directory of Open Access Journals (Sweden)

    Maurizio Muniz-Miranda

    2014-12-01

    Full Text Available Azole derivatives are common inhibitors of copper corrosion due to the chemical adsorption occurring on the metal surface that gives rise to a protective film. In particular, 1,2,4-triazole performs comparable to benzotriazole, which is much more widely used, but is by no means an environmentally friendly agent. In this study, we have analyzed the adsorption of 1,2,4-triazole on copper by taking advantage of the surface-enhanced Raman scattering (SERS effect, which highlights the vibrational features of organic ligand monolayers adhering to rough surfaces of some metals such as gold, silver and copper. To ensure the necessary SERS activation, a roughening procedure was implemented on the copper substrates, resulting in nanoscale surface structures, as evidenced by microscopic investigation. To obtain sufficient information on the molecule–metal interaction and the formation of an anticorrosive thin film, the SERS spectra were interpreted with the aid of theoretical calculations based on the density functional theory (DFT approach.

  2. Stress-corrosion-cracking studies on candidate container alloys for the Tuff Repository

    International Nuclear Information System (INIS)

    Beavers, J.A.; Durr, C.L.

    1992-05-01

    Cortest Columbus Technologies, Inc. (CC Technologies) investigated the long-term performance of container materials used for high-level waste package as part of the information needed by the Nuclear Regulatory Commission (NRC) to assess the Department of Energy's application to construct to geologic repository for high-level radioactive waste. At the direction of the NRC, the program focused on the Tuff Repository. This report summarizes the results of Stress-Corrosion-Cracking (SCC) studies performed in Tasks 3, 5, and 7 of the program. Two test techniques were used; U-bend exposures and Slow-Strain-Rate (SSR) tests. The testing was performed on two copper-base alloys (Alloy CDA 102 and Alloy CDA 175) and two Fe-Cr-Ni alloys (Alloy 304L and Alloy 825) in simulated J-13 groundwater and other simulated solutions for the Tuff Repository. These solutions were designed to simulate the effects of concentration and irradiation on the groundwater composition. All SCC testing on the Fe-Cr-Ni Alloys was performed on solution-annealed specimens and thus issues such as the effect of sensitization on SCC were not addressed

  3. Electrochemical Studies of Monoterpenic Thiosemicarbazones as Corrosion Inhibitor for Steel in 1 M HCl

    Directory of Open Access Journals (Sweden)

    R. Idouhli

    2018-01-01

    Full Text Available We have studied the inhibitory effect of some Monoterpenic Thiosemicarbazones on steel corrosion in 1 M HCl solution. The potentiodynamic polarization and electrochemical impedance spectroscopy were used. The Monoterpenic Thiosemicarbazones have inhibited significantly the dissolution of steel. The inhibition efficiency increased with increasing inhibitor concentration and also with the increase in temperature (293–323 K. Furthermore, the results obtained revealed that the adsorption of inhibitor on steel surface obeys Langmuir adsorption model and the thermodynamic parameters such as enthalpy and activation energy were determined. The scanning electron microscopy combined with dispersive X-ray spectroscopy examinations were used to see the shape of the surface morphology and to determine the elemental composition. Scanning electron microscope (SEM images show that the surface damage decreases when the inhibitor is added. The quantum chemical calculations using density functional theory (DFT were performed in order to provide some insights into the electronic density distribution as well as the nature of inhibitor-steel interaction.

  4. Electrochemical and conversion electron Moessbauer study of corrosion induced by acid rain

    International Nuclear Information System (INIS)

    Vertes, C.; Lakatos-Varsanyi, M.; Vertes, A.; Meisel, W.; Guetlich, P.

    1993-01-01

    The passivation of low carbon steel was studied in aqueous solution of 0.5M Na 2 SO 4 +0.001M NaHSO 3 (pH 3.5, 6.5 and 8.5) which can be considered as a model of acid rain. The used conversion electron Moessbauer spectroscopy (CEMS) with the complementary electrochemical investigations proved that the sulfite ions induce pitting corrosion at pH 3.5 and 6.5, while the measurements showed much weaker pitting at pH 8.5. The compositions and thicknesses of the passive films formed during the electrochemical treatments are determined from the CEM spectra. Only γ-FeOOH was found on the surface of the samples at pH 6.5 and 8.5. Nevertheless, at pH 3.5 the sextet belonging to Fe 3 C appears in the spectra, and also FeSO 4 .H 2 O could be detected in low concentration. (orig.)

  5. Study on Corrosion Inhibition Efficiency of Stem Alkaloid Extract of Different Varieties of Holy Basil on Aluminium in HCl Solution

    Energy Technology Data Exchange (ETDEWEB)

    Kumpawat, Nutan; Chaturvedi, Alok; Upadhyay, R. K. [Synthetic and Surface Science Laboratory, Ajmer (India)

    2012-08-15

    Corrosion inhibition efficiencies of holy basil on Al in HCl solution were studied by weight loss and thermometric methods in presence and in absence of stem extract of three different varieties of holy basil viz. ocimum basilicum (E{sub B}), ocimum canum (E{sub C}) and ocimum sanctum (E{sub S}). Inhibition efficiency increases with the increasing concentration of stem extract and decreases with increases in acid strength. Results show that all varieties under study are good corrosion inhibitors, among which, E{sub B} is most effective. Maximum inhibition efficiency was found 97.09% in 0.5N HCl solution with 0.6% stem extract. The Langmuir adsorption isotherm indicates that surface coverage also increases with increasing in the concentration of extract of stem in HCl solution.

  6. Study on Corrosion Inhibition Efficiency of Stem Alkaloid Extract of Different Varieties of Holy Basil on Aluminium in HCl Solution

    International Nuclear Information System (INIS)

    Kumpawat, Nutan; Chaturvedi, Alok; Upadhyay, R. K.

    2012-01-01

    Corrosion inhibition efficiencies of holy basil on Al in HCl solution were studied by weight loss and thermometric methods in presence and in absence of stem extract of three different varieties of holy basil viz. ocimum basilicum (E B ), ocimum canum (E C ) and ocimum sanctum (E S ). Inhibition efficiency increases with the increasing concentration of stem extract and decreases with increases in acid strength. Results show that all varieties under study are good corrosion inhibitors, among which, E B is most effective. Maximum inhibition efficiency was found 97.09% in 0.5N HCl solution with 0.6% stem extract. The Langmuir adsorption isotherm indicates that surface coverage also increases with increasing in the concentration of extract of stem in HCl solution

  7. A Study of Magnesium-Base Metallic Systems and Development of Principles for Creation of Corrosion-Resistant Magnesium Alloys

    Science.gov (United States)

    Mukhina, I. Yu.

    2014-11-01

    The effect of 26 alloying elements on the corrosion resistance of high-purity magnesium in a 0.5-n solution of sodium chloride and in a humid atmosphere (0.005 n) is studied. The Mg - Li, Mg - Ag, Mg - Zn, Mg - Cu, Mg - Gd, Mg - Al, Mg - Zr, Mg - Mn and other binary systems, which present interest as a base for commercial or perspective castable magnesium alloys, are studied. The characteristics of corrosion resistance of the binary alloys are analyzed in accordance with the group and period of the Mendeleev's periodic law. The roles of the electrochemical and volume factors and of the factor of the valence of the dissolved element are determined.

  8. High temperature corrosion studies on friction welded low alloy steel and stainless steel in air and molten salt environment at 650 oC

    International Nuclear Information System (INIS)

    Arivazhagan, N.; Narayanan, S.; Singh, Surendra; Prakash, Satya; Reddy, G.M.

    2012-01-01

    Highlights: → Thermogravimetric analysis on friction welded AISI 304 with AISI 4140 exposed in air and molten salt environment. → Comparative study on friction welded AISI 4140 with AISI 304 exposed in air, Na 2 SO 4 -60%V 2 O 5 and NaCl-50%Na 2 SO 4 at 650 o C. → SEM/EDAX, XRD analysis on corroded dissimilar AISI 304 and AISI 4140 materials. -- Abstract: The investigation on high-temperature corrosion resistance of the weldments is necessary for prolonged service lifetime of the components used in corrosive environments. This paper reports on the performance of friction welded low alloy steel AISI 4140 and stainless steel AISI 304 in air as well as molten salt environment of Na 2 SO 4 -60%V 2 O 5 and NaCl-50%Na 2 SO 4 at 650 o C. This paper reports several studies carried out for characterizing the weldments corrosion behavior. Initially thermogravimetric technique was used to establish the kinetics of corrosion. For analyzing the corrosion products, X-ray diffraction, scanning electron microscopy/energy-dispersive analysis and electron probe micro analysis techniques were used. From the results of the experiments, it is observed that the weldments suffered accelerated corrosion in NaCl-Na 2 SO 4 environment and showed spalling/sputtering of the oxide scale. Furthermore, corrosion resistance of weld interface was found to be lower than that of parent metals in molten salt environment. Weight gain kinetics in air oxidation studies reveals a steady-state parabolic rate law while the kinetics with salt deposits displays multi-stage growth rates. Moreover NaCl is the main corrosive species in high temperature corrosion, involving mixtures of NaCl and Na 2 SO 4 which is responsible for formation of internal attack.

  9. Design and fabrication of an apparatus to study stress corrosion cracking

    International Nuclear Information System (INIS)

    Buscarlet, Carol

    1977-01-01

    In this research thesis, the author first gives a large overview of tests methods of stress corrosion cracking: definition and generalities, stress corrosion cracking in the laboratory (test methods with imposed deformation, load or strain rate, theories of hydrogen embrittlement, of adsorption, of film breaking, and electrochemical theories), stress corrosion cracking in alkaline environment (in light water reactors, of austenitic stainless steels), and conventional tests on polycrystals and monocrystals of stainless steels in sodium hydroxide. The next parts address the core of this research, i.e. the design of an autoclave containing a tensile apparatus, the fabrication of this apparatus, the stress application device, the sample environment, pressurization, control and command, preliminary tests in a melt salt, and the first cracking tests [fr

  10. Study of chelating agent as a surface modifier for retarding corrosion attack on ferrous metal

    International Nuclear Information System (INIS)

    Nur Ubaidah Saidin; Muhamad Daud; Siti Radiah Mohd Kamarudin; Zaifol Samsu; Azali Muhamad; Rusni Rejab; Mohd Saari Ripin; Mohd Shariff Sattar

    2010-01-01

    A different concentration of chelating agents in electrolyte of 3.5 % NaCl was applied to bare ferrous metal and tested for their effectiveness as a corrosion retardant. The performance of the samples was measured using corrosion measurement system. The results indicated that the contribution of chelating agent was expediting the reduction of the passive film. The anodic behavior was clearly found to be influenced by the concentration of the chelating agent. It was also found that some of the corrosion was apparently converted to protective layer over a period of time. Excessive moisture caused breakdown of film by removing the unreacted chelating agent and causing regrowth of the existing rust. (author)

  11. Electrochemical studies of novel corrosion inhibitor for mild steel in 1 M hydrochloric acid

    Directory of Open Access Journals (Sweden)

    Ahmed A. Al-Amiery

    2018-06-01

    Full Text Available The electrochemical performance of a novel organic corrosion inhibitor 6-(4-hydroxyphenyl-3-mercapto-7,8-dihydro-[1,2,4]triazolo[4,3-b][1,2,4,5]tetrazine [HT3], for mild steel in 1 M hydrochloric acid is evaluated by potentiodynamic curves. The experimental results show that the investigated inhibitor [HT3], which can effectively retard the corrosion process that occurs to mild steel with a hydrochloric acid solution by providing a protective coating for the mild steel that, can be weakened by increasing the temperature. Furthermore, the inhibition efficiency of [HT3] increased with increasing the concentrations of the inhibitors and decreased with increasing temperature. Keywords: Corrosion, Inhibitor, Mild steel, Potentiodynamic polarization, HT3, NMR, FT-IR

  12. Teaching the concepts of oxidation and reduction contextualized in the study of corrosion

    Directory of Open Access Journals (Sweden)

    Lazo Santibáñez, Leontina

    2013-01-01

    Full Text Available The contextualization of chemistry is of great importance to our society as it allows to bring this science to students of secondary education thus facilitating the learning process, so that students can identify and explain the phenomena that occur around. As a way to improve student learning, driven redox processes are contextualized through the process of corrosion of metals, which can place them in real contexts, for which there were two experiences, one on corrosion reactions that occur over an extended time due to constant contact of the coins one hundred Chilean pesos, the old and current human sweat by verifying which of the two alloys are most affected. The other experience is to determine qualitatively the degree of corrosion experienced by coins of the same value mentioned above, through two media, a dry and moist soil, respectively. Both activities were used with chemical reagents readily available..

  13. Laboratory studies of the corrosion and mechanical properties of titanium grade-12 under WIPP repository conditions

    International Nuclear Information System (INIS)

    Sorensen, N.R.

    1990-01-01

    The author reviews laboratory work done at the Sandia Laboratories on the properties of titanium grade 12. The effect of gamma radiation on corrosion and mechanical properties has been investigated; no real effect has been detected on corrosion rate, Charpy impact energy, or tensile properties at 90 degrees and 10 4 rad/h. No structural changes are evident under examination by SEM or TEM. There is also no evidence of crevice corrosion after five years of exposure. The effect of radiation on hydrogen uptake was also investigated. Radiation appears to reduce the extent of uptake. The microstructure of titanium-12 changes with the addition of hydrogen to a structure with alternating layers of alpha and beta phase. A decrease in mechanical properties is associated with this change

  14. Study of localized corrosion in aluminum alloys by the scanning reference electrode technique

    Science.gov (United States)

    Danford, M. D.

    1995-01-01

    Localized corrosion in 2219-T87 aluminum (Al) alloy, 2195 aluminum-lithium (Al-Li) alloy, and welded 2195 Al-Li alloy (4043 filler) have been investigated using the relatively new scanning reference electrode technique (SRET). Anodic sites are more frequent and of greater strength in the 2195 Al-Li alloy than in the 2219-T87 Al alloy, indicating a greater tendency toward pitting for the latter. However, the overall corrosion rates are about the same for these two alloys, as determined using the polarization resistance technique. In the welded 2195 Al-Li alloy, the weld bean is entirely cathodic, with rather strongly anodic heat affected zones (HAZ) bordering both sides, indicating a high probability of corrosion in the HAZ parallel to the weld bead.

  15. CORROSION STUDY FOR THE EFFLUENT TREATMENT FACILITY CHROME (VI) REDUCTANT SOLUTION USING 304 AND 316L STAINLESS STEEL

    Energy Technology Data Exchange (ETDEWEB)

    DUNCAN JB; WYRAS RB

    2007-10-08

    This report documents the laboratory testing and analyses as directed under the test plan, RPP PLAN-34065, and documented in laboratory notebooks HNF 2742 and HNF-N-473-1. The purpose of this study was to evaluate and compare the electrochemical corrosion and pitting susceptibility of the 304 and 316L stainless steel in the acidified reducing solution that will be contained in either the secondary waste receiving tank or concentrate tank.

  16. Moessbauer study of the composition and corrosion behaviour of electrodeposited and cast brass containing 1-4 m% tin

    International Nuclear Information System (INIS)

    Vertes, A.; Suba, M.; Varsanyi-Lakatos, M.; Czako-Nagy, I.; Pchelnikov, A.P.; Losev, V.V.

    1982-01-01

    Moessbauer measurements on electrodeposited and cast brass containing 1-4 m% tin were carried out using conversion electron detector. It was found that the tin formed phases with copper but not with zinc. The identified phases were β, γ, epsilon and eta and their ratio depended on the tin concentration and on the preparation process of the brass. The corrosion behaviour of the samples was also studied. (author)

  17. A multi-analytical approach to gold in Ancient Egypt: Studies on provenance and corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Tissot, I., E-mail: isabeltissot@gmail.com [LIBPhys – UNL, Faculty of Science and Technology, 2829-516 Caparica (Portugal); Department of Physics, Faculty of Sciences, University of Lisbon, Campo Grande, 1649-004 Lisbon (Portugal); Troalen, L.G. [National Museums Scotland, Collections Services Department, 242 West Granton Road, Edinburgh EH5 1JA (United Kingdom); Manso, M. [LIBPhys – UNL, Faculty of Science and Technology, 2829-516 Caparica (Portugal); Faculdade de Belas-Artes da Universidade de Lisboa, Largo da Academia Nacional de Belas-Artes, 1249-058 Lisbon (Portugal); Ponting, M. [Archaeology, Classics and Egyptology, University of Liverpool, 12-14 Abercromby Square, Liverpool L69 7WZ (United Kingdom); Radtke, M.; Reinholz, U. [BAM Federal Institute for Materials Research and Testing, Richard-Willstaetter-Strasse 11, 12489 Berlin (Germany); Barreiros, M.A. [LNEG, I.P., Estrada do Paço do Lumiar, 22, 1649-038 Lisbon (Portugal); Shaw, I. [Archaeology, Classics and Egyptology, University of Liverpool, 12-14 Abercromby Square, Liverpool L69 7WZ (United Kingdom); Carvalho, M.L. [LIBPhys – UNL, Faculty of Science and Technology, 2829-516 Caparica (Portugal); Guerra, M.F. [ArchAm, UMR 8096 CNRS - Université Paris Sorbonne, MAE, 21 allée de l' Université, 92023 Nanterre (France)

    2015-06-01

    Recent results from a three-year multi-disciplinary project on Ancient Egyptian gold jewellery revealed that items of jewellery from the Middle Kingdom to the New Kingdom were manufactured using a variety of alluvial gold alloys. These alloys cover a wide range of colours and the majority contain Platinum Group Elements inclusions. However, in all the gold foils analysed, these inclusions were found to be absent. In this work a selection of gilded wood and leather items and gold foil fragments, all from the excavations by John Garstang at Abydos (primarily from Middle Kingdom graves), were examined using Scanning Electron Microscopy-Energy Disperse Spectroscopy (SEM-EDS), X-Ray Fluorescence (μXRF), Particle Induced X-Ray Emission (µPIXE) and Double Dispersive X-Ray Fluorescence (D{sup 2}XRF). The work allowed us to characterise the composition of the base-alloys and also to reveal the presence of Pt at trace levels, confirming the use of alluvial gold deposits. Corrosion products were also investigated in the foils where surface tarnish was visually observed. Results showed that the differences in the colour of corrosion observed for the foils are related not only to the thickness of the corrosion layer but also to a multi-layer structure containing the various corrosion products. - Highlights: • Multi-analytical protocol based on techniques with different MDLs and spatial resolution • Application of D{sup 2}XRF developed at synchrotron BESSY II for determination of Pt in Au with a MDL of 1 ppm • Egyptian gold alloys have nanoporous corrosion layers where distinct corrosion phases could be identified. • Egyptian gold foils are made with different gold base alloys, but all containing alluvial gold.

  18. Microstructure and corrosion study of porous Mg-Zn-Ca alloy in simulated body fluid

    Science.gov (United States)

    Annur, Dhyah; Erryani, Aprilia; Lestari, Franciska P.; Nyoman Putrayasa, I.; Gede, P. A.; Kartika, Ika

    2017-03-01

    Magnesium alloys had been considered as promising biomedical devices due to their biocompatibility and biodegradability. In this present work, microstructure and corrosion properties of Mg-Zn-Ca-CaCO3 porous magnesium alloy were examined. Porous metals were fabricated through powder metallurgy process with CaCO3 addition as a foaming agent. CaCO3 content was varied (1, 5, and 10%wt) followed by sintering process in 650 °C in Argon atmosphere for 10 and 15 h. The microstructure of the resulted alloys was analyzed by scanning electron microscopy (SEM) equipped with energy dispersive spectrometry data (EDS). Further, to examine corrosion properties, electrochemical test were conducted using G750 Gamry Instrument in accordance with ASTM standard G5-94 in simulated body fluid (Hank’s solution). As it was predicted, increasing content of foaming agent was in line with the increasing of pore formation. The electrochemical testing indicated corrosion rate would increase along with the increasing of foaming agent. The porous Mg-Zn-Ca alloy which has more porosity and connecting area will corrode much faster because it can transport the solution containing chloride ion which accelerated the chemical reaction. Highest corrosion resistance was given by Mg-Zn-Ca-1CaCO3-10 h sintering with potential corrosion of  -1.59 VSCE and corrosion rate of 1.01 mmpy. From the microstructure after electrochemical testing, it was revealed that volcano shaped structure and crack would occur after exposure to Hank’s solution

  19. A Study on the Effect of Electrolyte Thickness on Atmospheric Corrosion of Carbon Steel

    International Nuclear Information System (INIS)

    Chung, Kyeong Woo; Kim, Kwang Bum

    1998-01-01

    Effect of electrolyte layer thickness and increase in concentration of electrolyte during electrolyte thining on the atmospheric corrosion of carbon steel were investigated using EIS and cathodic polarization technique. The electrolyte layer thickness was controlled via two methods : one is mechanical method with microsyringe applying a different amount of electrolyte onto the metal surface to give different electrolyte thickness with the same electrolyte concentration. The other is drying method in which water layer thickness decreases through drying, causing increase in concentration of electrolyte during electrolyte thinning. In the region whose corrosion rate is controlled by cathodic reaction, corrosion rate for mechanical method is larger than that for drying method. However, for the electrolyte layers thinner than 20 ∼ 30 m, increase in concentration of electrolyte cause a higher corrosion rate for the case of the mechanical method compared with that of drying method. For a carbon steel covered with 0.1M Na 2 SO 4 , maximum corrosion rate is found at an electrolyte thickness of 45 ∼ 55 μm for mechanical method. However, maximum corrosion rate is found at an electrolyte thickness of 20 ∼ 35 μm for drying method. The limiting current is inversely proportional to electrolyte thickness for electrolyte thicker than 20 ∼ 30 μm. However, further decrease of the electrolyte thickness leads to an electrolyte thickness-independent limiting current reagion, where the oxygen rate is controlled by the solvation of oxygen at the electrolyte/gas interface. Diffusion limiting current for drying method is smaller compared with that for mechanica control. This can be attributed to decreasing in O 2 solubility caused by increase in concentration of electrolyte during electrolyte thining

  20. A multi-analytical approach to gold in Ancient Egypt: Studies on provenance and corrosion

    International Nuclear Information System (INIS)

    Tissot, I.; Troalen, L.G.; Manso, M.; Ponting, M.; Radtke, M.; Reinholz, U.; Barreiros, M.A.; Shaw, I.; Carvalho, M.L.; Guerra, M.F.

    2015-01-01

    Recent results from a three-year multi-disciplinary project on Ancient Egyptian gold jewellery revealed that items of jewellery from the Middle Kingdom to the New Kingdom were manufactured using a variety of alluvial gold alloys. These alloys cover a wide range of colours and the majority contain Platinum Group Elements inclusions. However, in all the gold foils analysed, these inclusions were found to be absent. In this work a selection of gilded wood and leather items and gold foil fragments, all from the excavations by John Garstang at Abydos (primarily from Middle Kingdom graves), were examined using Scanning Electron Microscopy-Energy Disperse Spectroscopy (SEM-EDS), X-Ray Fluorescence (μXRF), Particle Induced X-Ray Emission (µPIXE) and Double Dispersive X-Ray Fluorescence (D 2 XRF). The work allowed us to characterise the composition of the base-alloys and also to reveal the presence of Pt at trace levels, confirming the use of alluvial gold deposits. Corrosion products were also investigated in the foils where surface tarnish was visually observed. Results showed that the differences in the colour of corrosion observed for the foils are related not only to the thickness of the corrosion layer but also to a multi-layer structure containing the various corrosion products. - Highlights: • Multi-analytical protocol based on techniques with different MDLs and spatial resolution • Application of D 2 XRF developed at synchrotron BESSY II for determination of Pt in Au with a MDL of 1 ppm • Egyptian gold alloys have nanoporous corrosion layers where distinct corrosion phases could be identified. • Egyptian gold foils are made with different gold base alloys, but all containing alluvial gold

  1. Corrosion in airframes

    OpenAIRE

    PETROVIC ZORAN C.

    2016-01-01

    The introductory chapter provides a brief reference to the issue of corrosion and corrosion damage to aircraft structures. Depending on the nature and dimensions of this non uniformity, three different categories of corrosion are defined: uniform, selective and localized corrosion. The following chapters present the forms of corrosion that can occur in three defined categories of corrosion. Conditions that cause certain types of corrosion in various corrosive environments are discussed. Examp...

  2. Influence of geometry of pipe on flow accelerated corrosion - a study under neutral pH condition

    International Nuclear Information System (INIS)

    Madasamy, P.; Mukunthan, M.; Chandramohan, P.; Krishna Mohan, T.V.; Velmurugan, S.; Sylvanus, Andrews; Natarajan, E.

    2015-01-01

    The carbon steel piping material's degradation due to flow accelerated corrosion (FAC) is one of the problems in nuclear power plant. FAC impacts plant operation and maintenance significantly. Wall thinning of structural materials should be predictable based on combined hydrodynamics analyses and experimental corrosion data. Such predictive tools help to take preventive measures before loss of material becomes a serious issue for plant operation. In order to develop predictive tools, data on the effect of various parameters that control FAC are required. As per existing literature, one of the important parameters that affect FAC is piping configuration (Geometry of flow path). Hence, experiments were carried out to assess the role played by the geometry of the piping in the FAC of carbon steel. In this study, experiments were conducted in simulation loop under neutral pH condition while varying the geometry parameter of bend such as bend angle and bend radius. Therefore, pipe specimen holder 15 NB bend with 58 °, 73 ° as bend angle and 4D, 2D bend radius was designed and fabricated. The experiments were carried out in order to quantify the wear rate (wall thickness measurement was by ultrasonic method) with a single phase flow velocity (7 m/s) under neutral pH conditions With the pipe specimen four experiments were conducted under neutral pH condition and at 120 DC. Wall thickness mapping was carried out by ultrasonic thickness gauge using a template before and after the experiment. High wall thickness reduction under neutral water chemistry enables easy measurement by ultrasonic thickness gauge. It was observed from the first two sets (2D 58°, 4D 58°) that the corrosion rate with 4D, 58 ° was 50% less than the corrosion with 2D 58°. Subsequently, another two sets of experiments (2D 73° and 4D 73°) was carried out in SIM loop at 7 m/s under neutral pH conditions for two months. Thus, this method of experiments enables us to understand the geometrical

  3. Comparative study of the microbiological corrosion among an AISI 304L and an API X65

    International Nuclear Information System (INIS)

    Diaz S, A.; Arganis J, C.; Luna C, P.; Carapia M, L.; Gonzalez F, E.

    2004-01-01

    Metallic samples of AISI 304L sensitized and API X65, were subjected to the action of an inoculated media with reductive sulphate microorganisms (SBR), carrying out electrochemical evaluations by means of the techniques of Polarization Resistance (RP), Tafel extrapolation (ET) and Electrochemical Noise (RE). The generated information was complemented with the analysis and diagnostic of the present damage in the surfaces exposed in both metals. The used electrochemical techniques allow to determine the corrosion velocities associated to each system, establishing that the uniform corrosion is not affected by the effect of the microorganisms; however, electrochemical noise, evidenced the formation of stings associated to the presence of bacteria. (Author)

  4. Utilization of the molecular dynamic to study the effect of hydrogen in the stress corrosion

    International Nuclear Information System (INIS)

    Arnoux, P.

    2007-01-01

    Many microscopic and theoretical models of stress corrosion have been proposed, in particularly to explain the grain boundary cracking of stainless steels and nickel base. In this work calculus of molecular dynamic have been used to propose a mechanism of stress corrosion at the atomic scale. The author aims to reproduce, by molecular dynamic, the mechanism of an open crack in irradiated stainless steel in PWR reactor and show that the growth of the oxide at the crack back produce hydrogen. (A.L.B.)

  5. Studying titanium-molybdenum-zirconium alloys of increased corrosion resistance in acid solutions

    International Nuclear Information System (INIS)

    Tomashov, N.D.; Kazarin, V.I.; Mikheev, V.S.; Goncharenko, B.A.; Sigalovskaya, T.M.; Kalyanova, M.P.

    1977-01-01

    New promising Ti-Mo-Nb-Zr system alloys, possessing good workability and a high corrosion resistance in non-oxidizing solutions of acids, have been developed. The alloys may be recommended as structural materials for equipment operating in severely agressive acid media, such as hydrochloric, sulphuric and phosphoric acids. The corrosion resistance of alloys of the above system in solutions of H 2 SO 4 , HCl and H 3 PO 4 acids may be maximized by increasing the overall alloying to 42% (keeping the ratio of the alloying components Mo/Nb/Zr=4/1/1 unchanged), while retaining sufficiently good plasticity and workability

  6. Studies on corrosion inhibitors for the cooling water system at the Heavy Water Project, Kota

    International Nuclear Information System (INIS)

    Pillai, B.P.; Mehta, C.T.; Abubacker, K.M.

    1986-01-01

    The Heavy Water Project at Kota uses the water from the Rana Pratap Sagar Lake as coolant in the open recirculation system. In order to find suitable corrosion inhibitors for the above system, a series of laboratory experiments on corrosion inhibitors were carried out using the constructional materials of the cooling water system and a number of proprietary formulations and the results are tabulated. From the data thus generated through various laboratory experiments, the most useful ones have been recommended for application in practice. (author)

  7. Fire-Side Corrosion: A Case Study of Failed Tubes of a Fossil Fuel Boiler

    OpenAIRE

    Asnavandi, Majid; Kahram, Mohaddeseh; Rezaei, Milad; Rezakhani, Davar

    2017-01-01

    The failures of superheater and reheater boiler tubes operating in a power plant utilizing natural gas or mazut as a fuel have been analysed and the fire-side corrosion has been suggested as the main reason for the failure in boiler tubes. The tubes have been provided by a fossil fuel power plant in Iran and optical and electron microscopy investigations have been performed on the tubes as well as the corrosion products on their surfaces. The results showed that the thickness of the failed tu...

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

    International Nuclear Information System (INIS)

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

    2001-01-01

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

  9. Corrosion behavior of Haynes {sup registered} 230 {sup registered} nickel-based super-alloys for integrated coal gasification combined cycle syngas plants. A plant exposure study

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sungkyu; Lee, Jieun; Kang, Suk-Hwan; Lee, Seung-Jong; Yun, Yongseung [Institute for Advanced Engineering (IAE), Gyeonggi-do (Korea, Republic of). Plant Engineering Center; Kim, Min Jung [Sungkyunkwan Univ, Gyeonggi-do (Korea, Republic of). Advanced Materials Technology Research Center

    2015-07-01

    The corrosion behavior of commercially available Haynes {sup registered} 230 {sup registered} nickel-based alloy samples was investigated by exposure to coal-gasifying integrated coal gasification combined cycle pilot plant facilities affiliated with the Institute for Advanced Engineering (2.005 MPa and 160-300 C). The morphological and microstructural analyses of the exposed samples were conducted using scanning electron microscopy and energy-dispersive X-ray spectroscopy analysis on the external surface of the recovered corrosion test samples to obtain information of the corrosion scale. These analyses based on the pre- and post-exposure corrosion test samples combined with thermodynamic Ellingham-Pourbaix stability diagrams provided preliminary insight into the mechanism of the observed corrosion behavior prevailing in the piping materials that connected the particulate removal unit and water scrubber of the integrated coal gasification combined cycle pilot plant. Uniform material wastage was observed after 46 hours of operation, and a preliminary corrosion mechanism was suggested: the observed material waste and corrosion behavior of the Haynes {sup registered} 230 {sup registered} nickel-based alloy samples cut off from the coal syngas integrated coal gasification combined cycle plant were explained by the formation of discontinuous (complex) oxide phases and subsequent chlorine-induced active oxidation under the predominantly reducing environment encountered. This contribution continues the already published studies of the Fe-Ni-Cr-Co alloy Haynes {sup registered} 556 {sup registered}.

  10. Corrosion behavior of Haynes registered 230 registered nickel-based super-alloys for integrated coal gasification combined cycle syngas plants. A plant exposure study

    International Nuclear Information System (INIS)

    Lee, Sungkyu; Lee, Jieun; Kang, Suk-Hwan; Lee, Seung-Jong; Yun, Yongseung; Kim, Min Jung

    2015-01-01

    The corrosion behavior of commercially available Haynes registered 230 registered nickel-based alloy samples was investigated by exposure to coal-gasifying integrated coal gasification combined cycle pilot plant facilities affiliated with the Institute for Advanced Engineering (2.005 MPa and 160-300 C). The morphological and microstructural analyses of the exposed samples were conducted using scanning electron microscopy and energy-dispersive X-ray spectroscopy analysis on the external surface of the recovered corrosion test samples to obtain information of the corrosion scale. These analyses based on the pre- and post-exposure corrosion test samples combined with thermodynamic Ellingham-Pourbaix stability diagrams provided preliminary insight into the mechanism of the observed corrosion behavior prevailing in the piping materials that connected the particulate removal unit and water scrubber of the integrated coal gasification combined cycle pilot plant. Uniform material wastage was observed after 46 hours of operation, and a preliminary corrosion mechanism was suggested: the observed material waste and corrosion behavior of the Haynes registered 230 registered nickel-based alloy samples cut off from the coal syngas integrated coal gasification combined cycle plant were explained by the formation of discontinuous (complex) oxide phases and subsequent chlorine-induced active oxidation under the predominantly reducing environment encountered. This contribution continues the already published studies of the Fe-Ni-Cr-Co alloy Haynes registered 556 registered .

  11. Report on the studies on the corrosion behaviour of the constructional materials for the gate cooling system

    International Nuclear Information System (INIS)

    Elayathu, N.S.D.; Balachandra, J.

    1974-01-01

    The gate cooling system of the Trombay R-5 reactor, now under construction, is proposed to be a laminated gate designed to operate with 50 % KBO 2 solution within the temperature limits 30 deg C and 50 deg C. With a view to find suitable constructional materials for the gate, the corrosion behaviour of stainless steel 304 L(ASTM 240-69), lead (ASTM B-29), aluminium (as Boral), neoprene, perspex and carbon steel (ASTM A 302 grade B) has been investigated in 50 % KBO 2 solution at 45 deg C. After definite periods of exposure, their coupons were examined metallographically at different magnifications to assess the nature and extent of sub-surface attack. The results show that out of the materials studied, carbon steel, lead and aluminium are more liable to corrosion in the borate solution and hence their use should be avoided. (M.G.B.)

  12. Events as Power Source: Wireless Sustainable Corrosion Monitoring

    OpenAIRE

    Sun, Guodong; Qiao, Guofu; Zhao, Lin; Chen, Zhibo

    2013-01-01

    This study presents and implements a corrosion-monitoring wireless sensor platform, EPS (Events as Power Source), which monitors the corrosion events in reinforced concrete (RC) structures, while being powered by the micro-energy released from the corrosion process. In EPS, the proposed corrosion-sensing device serves both as the signal source for identifying corrosion and as the power source for driving the sensor mote, because the corrosion process (event) releases electric energy; this is ...

  13. Towards lightweight nanocomposite coatings for corrosion inhibition: Graphene, carbon nanotubes, and nanostructured magnesium as case studies

    Science.gov (United States)

    Dennis, Robert Vincent, III

    The field of nanocomposites is a burgeoning area of research due to the interest in the remarkable properties which can be achieved through their use in a variety of applications, including corrosion resistant coatings. Lightweighting is of increasing importance in the world today due to the ever growing push towards energy efficiency and the green movement and in recent years there has been a vast amount of research performed in the area of developing lightweight nanocomposites for corrosion inhibition. Many new composite materials have been developed through the use of newly developed nanomaterials (including carbonaceous and metallic constituents) and their specialized incorporation in the coating matrix materials. We start with a general review on the development of hybrid nanostructured composites for corrosion protection of base metals from a sustainability perspective in Chapter 1. This review demonstrates the ever swelling requirements for a paradigm shift in the way that we protect metals against corrosion due to the costs and environmental concerns that exist with currently used technology. In Chapter 2, we delve into the much required understanding of graphene oxide and reduced graphene oxide through near-edge X-ray absorption fine structure (NEXAFS) spectroscopy measurements to elucidate information about the electronic structure upon incorporation of nitrogen within the structure. For successful integration of the carbonaceous nanomaterials into a composite coating, a full swath of knowledge is necessary. Within this work we have shown that upon chemical defunctionalization of graphene oxide to reduced graphene oxide by means of hydrazine treatment, nitrogen is incorporated into the structure in the form of a pyrazole ring. In Chapter 3, we demonstrate that by way of in situ polymerization, graphene and multiwalled carbon nanotubes can be incorporated within a polymer (polyetherimide, PEI) matrix. Two systems have been developed including graphene and

  14. Some observations about the Incoloy 800 corrosion

    International Nuclear Information System (INIS)

    Baptista, W.; Sathler, L.; Mattos, O.R.

    1985-01-01

    The chemical and electrochemical characteristics of synthetic solutions similar to those inside the occluded cell corrosion - OCC (pitting, cracks from stress corrosion) of incoloy 800, 25 0 C are studied. (E.G.) [pt

  15. Rail base corrosion and cracking prevention

    Science.gov (United States)

    2014-07-01

    Rail base corrosion combined with fatigue or damage can significantly reduce rail life. Studies were done to examine the relative contribution of damage, corrosion, and fatigue on rail life. The combined effects can be separated into constituent fact...

  16. Experimental and numerical study of hydrodynamics of flow-accelerated corrosion in CANDU primary coolant

    Energy Technology Data Exchange (ETDEWEB)

    Supa-Amornkul, S

    2006-07-01

    In CANDU-6 reactors, the pressurised high-temperature coolant flows through 380 fuel channels passing horizontally through the core. Each end of a fuel channel has a stainless steel annular end-fitting connected to a carbon steel feeder pipe. The outlet coolant, which is at 310{sup o}C with up to 0.30 steam voidage, turns through 90{sup o} as it passes from flow in the annular end-fitting to pipe flow in the feeder via a Grayloc connector. Since 1996, several CANDU stations reported excessive corrosion of their outlet feeder pipes, especially over the first metre, which consists of single or double bends. Early studies related the attack to the hydrodynamics of the coolant and verified that it was a type of flow-accelerated corrosion (FAC). Local shear stress, which is believed to be one of the important factors contributing to FAC, was approximated in the studies with standard empirical correlations. In order to understand the hydrodynamics of the coolant in the outlet feeders, flow-visualisation studies were done at AECL and UNB. At AECL, the observations were confined to a transparent simulation of an outlet feeder bend but at UNB a full-scale transparent test section simulating the geometry and orientation of an outlet feeder bend with its upstream annular end-fitting was fabricated. The feeder consisted of a 54 mm (inside diameter) acrylic pipe with a 73{sup o} bend, connected to an acrylic simulation of a Grayloc flanged fitting and annular end-fitting. The annular end-fitting consisted of an inner pipe, 110 mm outside diameter, and an outer pipe, 150 mm inside diameter, both 1.907 m long. The tests were performed with water and air at atmospheric pressure and room temperature. The maximum water volumetric flow rate was 0.019 m{sup 3}/s and the volume fraction of air varied from 0.05 to 0.56. In characterizing the flow in the UNB study, particular attention was paid to the patterns at the inside of the bend, where a CFD (computational fluid dynamics) code

  17. Experimental and numerical study of hydrodynamics of flow-accelerated corrosion in CANDU primary coolant

    International Nuclear Information System (INIS)

    Supa-Amornkul, S.

    2006-01-01

    In CANDU-6 reactors, the pressurised high-temperature coolant flows through 380 fuel channels passing horizontally through the core. Each end of a fuel channel has a stainless steel annular end-fitting connected to a carbon steel feeder pipe. The outlet coolant, which is at 310 o C with up to 0.30 steam voidage, turns through 90 o as it passes from flow in the annular end-fitting to pipe flow in the feeder via a Grayloc connector. Since 1996, several CANDU stations reported excessive corrosion of their outlet feeder pipes, especially over the first metre, which consists of single or double bends. Early studies related the attack to the hydrodynamics of the coolant and verified that it was a type of flow-accelerated corrosion (FAC). Local shear stress, which is believed to be one of the important factors contributing to FAC, was approximated in the studies with standard empirical correlations. In order to understand the hydrodynamics of the coolant in the outlet feeders, flow-visualisation studies were done at AECL and UNB. At AECL, the observations were confined to a transparent simulation of an outlet feeder bend but at UNB a full-scale transparent test section simulating the geometry and orientation of an outlet feeder bend with its upstream annular end-fitting was fabricated. The feeder consisted of a 54 mm (inside diameter) acrylic pipe with a 73 o bend, connected to an acrylic simulation of a Grayloc flanged fitting and annular end-fitting. The annular end-fitting consisted of an inner pipe, 110 mm outside diameter, and an outer pipe, 150 mm inside diameter, both 1.907 m long. The tests were performed with water and air at atmospheric pressure and room temperature. The maximum water volumetric flow rate was 0.019 m 3 /s and the volume fraction of air varied from 0.05 to 0.56. In characterizing the flow in the UNB study, particular attention was paid to the patterns at the inside of the bend, where a CFD (computational fluid dynamics) code - Fluent 6.1- had

  18. Synergy effect of naphthenic acid corrosion and sulfur corrosion in crude oil distillation unit

    Energy Technology Data Exchange (ETDEWEB)

    Huang, B.S., E-mail: yinwenfeng2010@163.com [College of Materials Science and Engineering, Southwest Petroleum University, Sichuan, Chengdu, 610500 (China); Yin, W.F. [College of Mechatronic Engineering, Southwest Petroleum University, Sichuan, Chengdu, 610500 (China); Sang, D.H. [Sheng Li Construction Group International Engineering Department, Shandong, Dongying, 257000 (China); Jiang, Z.Y. [College of Materials Science and Engineering, Southwest Petroleum University, Sichuan, Chengdu, 610500 (China)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer The corrosion of a carbon-manganese steel and a stainless steel in sulfur and/or naphthenic acid media was investigated. Black-Right-Pointing-Pointer The corrosion rate of the carbon-manganese steel increased with the increase of the acid value and sulfur content. Black-Right-Pointing-Pointer The critical values of the concentration of sulfur and acid for corrosion rate of the stainless steel were ascertained respectively. Black-Right-Pointing-Pointer The stainless steel is superior to the carbon-manganese steel in corrosion resistance because of the presence of stable Cr{sub 5}S{sub 8} phases. - Abstract: The synergy effect of naphthenic acid corrosion and sulfur corrosion at high temperature in crude oil distillation unit was studied using Q235 carbon-manganese steel and 316 stainless steel. The corrosion of Q235 and 316 in corrosion media containing sulfur and/or naphthenic acid at 280 Degree-Sign C was investigated by weight loss, scanning electron microscope (SEM), EDS and X-ray diffractometer (XRD) analysis. The results showed that in corrosion media containing only sulfur, the corrosion rate of Q235 and 316 first increased and then decreased with the increase of sulfur content. In corrosion media containing naphthenic acid and sulfur, with the variations of acid value or sulfur content, the synergy effect of naphthenic acid corrosion and sulfur corrosion has a great influence on the corrosion rate of Q235 and 316. It was indicated that the sulfur accelerated naphthenic acid corrosion below a certain sulfur content but prevented naphthenic acid corrosion above that. The corrosion products on two steels after exposure to corrosion media were investigated. The stable Cr{sub 5}S{sub 8} phases detected in the corrosion products film of 316 were considered as the reason why 316 has greater corrosion resistance to that of Q235.

  19. Corrosion studies using potentiodynamic and EIS electrochemical techniques of welded lean duplex stainless steel UNS S82441

    Science.gov (United States)

    Brytan, Z.; Niagaj, J.; Reiman, Ł.

    2016-12-01

    The corrosion characterisation of lean duplex stainless steel (1.4662) UNS S82441 welded joints using the potentiodynamic test and electrochemical impedance spectroscopy in 1 M NaCl solution are discussed. The influence of autogenous TIG welding parameters (amount of heat input and composition of shielding gases like Ar and Ar-N2 and an Ar-He mixture), as well as A-TIG welding was studied. The influence of welding parameters on phase balance, microstructural changes and the protective properties of passive oxide films formed at the open circuit potential or during the anodic polarisation were studied. From the results of the potentiodynamic test and electrochemical impedance spectroscopy of TIG and A-TiG, welded joints show a lower corrosion resistance compared to non-welded parent metal, but introducing heat input properly during welding and applying shielding gases rich in nitrogen or helium can increase austenitic phase content, which is beneficial for corrosion resistance, and improves surface oxide layer resistance in 1 M NaCl solution.

  20. An ac impedance study of the corrosion behaviour of mild steel coated with electrochemically synthesized polyoxyphenylenes

    Energy Technology Data Exchange (ETDEWEB)

    Musiani, M.M.; Mengoli, G.; Pagura, C.

    1985-04-01

    Electrochemically synthesized polyoxphenylene coatings on mild steel exposed to NaCl or H2SO4 solutions were investigated by ac impedance measurements. The influence of coating cohesion, adhesion to substrate, and surface pretreatment on the corrosion behaviour of the samples is clarified.