WorldWideScience

Sample records for corrosive effects

  1. Assessing Level and Effectiveness of Corrosion Education in the UAE

    Directory of Open Access Journals (Sweden)

    Hwee Ling Lim

    2012-01-01

    Full Text Available The consequences of corrosion can be minimized by an engineering workforce well trained in corrosion fundamentals and management. Since the United Arab Emirates incurs the second highest cost of corrosion after Saudi Arabia, this paper examined the quality of corrosion education in the UAE. Surveys with academia and industry respondents showed that dedicated corrosion courses and engineering courses that integrated corrosion into the curricula were available in UAE universities, but graduates had insufficient knowledge of corrosion engineering and superficial understanding of corrosion in real-life design contexts. The effectiveness of corrosion education is determined by both competence in corrosion knowledge/skills and availability of resources (faculty and research. Though most departments would not hire new corrosion-specialist faculty, department research efforts and industry partnerships in corrosion research were present. The paper concluded with recommendations for improving knowledge and skills of future engineers in corrosion and enhancing corrosion instruction to better meet industry needs.

  2. Corrosion effects on soda lime glass

    NARCIS (Netherlands)

    Veer, F.A.; Rodichev, Y.M.

    2010-01-01

    Although soda lime glass is the most common used transparent material in architecture, little is known about the corrosion effects on long term strength and the interaction between corrosion and defects. Extensive testing on soda lime bars under different environmental conditions and different

  3. 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.

  4. 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.

  5. Corrosion effects on friction factors

    International Nuclear Information System (INIS)

    Magleby, H.L.; Shaffer, S.J.

    1996-01-01

    This paper presents the results of NRC-sponsored material specimen tests that were performed to determine if corrosion increases the friction factors of sliding surfaces of motor-operated gate valves, which could require higher forces to close and open safety-related valves when subjected to their design basis differential pressures. Friction tests were performed with uncorroded specimens and specimens subjected to accelerated corrosion. Preliminary tests at ambient conditions showed that corrosion increased the friction factors, indicating the need for additional tests duplicating valve operating parameters at hot conditions. The additional tests showed friction factors of corroded specimens were 0.1 to 0.2 higher than for uncorroded specimens, and that the friction factors of the corroded specimens were not very dependent on contact stress or corrosion film thickness. The measured values of friction factors for the three corrosion films tested (simulating three operating times) were in the range of 0.3 to 0.4. The friction factor for even the shortest simulated operating time was essentially the same as the others, indicating that the friction factors appear to reach a plateau and that the plateau is reached quickly

  6. 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)

  7. Strain rate effects in stress corrosion cracking

    Energy Technology Data Exchange (ETDEWEB)

    Parkins, R.N. (Newcastle upon Tyne Univ. (UK). Dept. of Metallurgy and Engineering Materials)

    1990-03-01

    Slow strain rate testing (SSRT) was initially developed as a rapid, ad hoc laboratory method for assessing the propensity for metals an environments to promote stress corrosion cracking. It is now clear, however, that there are good theoretical reasons why strain rate, as opposed to stress per se, will often be the controlling parameter in determining whether or not cracks are nucleated and, if so, are propagated. The synergistic effects of the time dependence of corrosion-related reactions and microplastic strain provide the basis for mechanistic understanding of stress corrosion cracking in high-pressure pipelines and other structures. However, while this may be readily comprehended in the context of laboratory slow strain tests, its extension to service situations may be less apparent. Laboratory work involving realistic stressing conditions, including low-frequency cyclic loading, shows that strain or creep rates give good correlation with thresholds for cracking and with crack growth kinetics.

  8. Effect of Flow Velocity on Corrosion Rate and Corrosion Protection Current of Marine Material

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seong Jong [Kunsan National University, Kunsan (Korea, Republic of); Han, Min Su; Jang, Seok Ki; Kim, Seong Jong [Mokpo National Maritime University, Mokpo (Korea, Republic of)

    2015-10-15

    In spite of highly advanced paint coating techniques, corrosion damage of marine metal and alloys increase more and more due to inherent micro-cracks and porosities in coatings formed during the coating process. Furthermore, flowing seawater conditions promote the breakdown of the protective oxide of the materials introducing more oxygen into marine environments, leading to the acceleration of corrosion. Various corrosion protection methods are available to prevent steel from marine corrosion. Cathodic protection is one of the useful corrosion protection methods by which the potential of the corroded metal is intentionally lowered to an immune state having the advantage of providing additional protection barriers to steel exposed to aqueous corrosion or soil corrosion, in addition to the coating. In the present investigation, the effect of flow velocity was examined for the determination of the optimum corrosion protection current density in cathodic protection as well as the corrosion rate of the steel. It is demonstrated from the result that the material corrosion under dynamic flowing conditions seems more prone to corrosion than under static conditions.

  9. The effects of corrosion conditions and cold work on the nodular corrosion of zircaloy-4

    International Nuclear Information System (INIS)

    You, Gil Sung

    1992-02-01

    The nodular corrosion of Zircaloy-4 was investigated on the effects of corrosion conditions and cold work. Variation of steam pressures, heat-up environments and prefilms were considered and cold work effects were also studied. The corrosion rate of Zircaloy-4 was dependent on pressure between 1 and 100 atm and it followed the cubic law as W=16.85 x P 0.31 for plate specimens and W=12.69 x P 0.27 for tube specimens, where W is weight gain (mg/dm 2 ) and P is the steam pressure (atm). The environment variation in autoclave during heat-up period did not affect the early stage of nodular corrosion. The prefilm, which was formed at 500 .deg. C under 1 atm steam for 4 hours, restrained the formation of the initial small nodules. The oxide film formed under 1 atm steam showed no difference of electrical resistivity from the oxides formed under 100 atm steam pressure. Cold work specimens showed the higher resistivity against nodular corrosion than as-received specimens. The corrosion resistance arising from cold work seems to be due to the texture changes by the cold work. The results showed that cold work can affect the later stage of uniform corrosion and the early stage of nodular corrosion, namely, the nodule initiation stage

  10. Atmospheric corrosion effects on copper

    International Nuclear Information System (INIS)

    Franey, J.P.

    1985-01-01

    Studies have been performed on the naturally formed patina on various copper samples. Samples have been obtained from structures at AT and T Bell Laboratories, Murray Hill, NJ (40,2,1 and <1 yr) and the Statue of Liberty (100 yr). The samples show a distinct layering effect, that is, the copper base material shows separate oxide and basic sulfate layers on all samples, indicating that patina is not a homogeneous mixture of oxides and basic sulfates

  11. The effect of recasting on corrosion of DUCINOX prosthetic alloy

    Directory of Open Access Journals (Sweden)

    L. Klimek

    2009-07-01

    Full Text Available The effect of recasting, up to two times, Ni-Cr (DUCINOX prosthetic alloy on its corrosion properties was carried out. The corrosion measurements were done in deoxygenated Fusayama Meyer artificial saliva solution at temperature of 37°C. In the study following electrochemical methods were used: measurement of free corrosion potential Ecor in open circuit, measurement of polarization resistance according to Stern-Geary's method and measurement of potentiodynamic characteristic in wide range of anodic polarization. In general, it can be stated that casting number weakly influence on corrosion properties of investigated alloy. At free corrosion potential there is no monotonic dependence of corrosion parameters versus casting number. However, at extreme anodic potentials monotonic changes of corrosion parameters with increasing casting number is observed. Obtained results and drawn conclusions are partially compatible with literature data.

  12. Surface layer effects on waste glass corrosion

    International Nuclear Information System (INIS)

    Feng, X.

    1993-01-01

    Water contact subjects waste glass to chemical attack that results in the formation of surface alteration layers. Two principal hypotheses have been advanced concerning the effect of surface alteration layers on continued glass corrosion: (1) they act as a mass transport barrier and (2) they influence the chemical affinity of the glass reaction. In general, transport barrier effects have been found to be less important than affinity effects in the corrosion of most high-level nuclear waste glasses. However, they can be important under some circumstances, for example, in a very alkaline solution, in leachants containing Mg ions, or under conditions where the matrix dissolution rate is very low. The latter suggests that physical barrier effect may affect the long-term glass dissolution rate. Surface layers influence glass reaction affinity through the effects of the altered glass and secondary phases on the solution chemistry. The reaction affinity may be controlled by various precipitates and crystalline phases, amorphous silica phases, gel layer, or all the components of the glass. The surface alteration layers influence radionuclide release mainly through colloid formation, crystalline phase incorporation, and gel layer retention. This paper reviews current understanding and uncertainties

  13. Corrosion of X65 Pipeline Steel Under Deposit and Effect of Corrosion Inhibitor

    Directory of Open Access Journals (Sweden)

    XU Yun-ze

    2016-10-01

    Full Text Available Effect of the deposit on the electrochemical parameters of X65 pipeline steel in oxygen contained sodium chloride solution was studied by EIS and PDS methods. The galvanic corrosion behavior under deposit and effect of different concentration of corrosion inhibitor PBTCA were studied by electrical resistance (ER method combined with ZRA. The results show that the corrosion potential of X65 steel shifts negatively as SiO2 covering its surface and the corrosion rate becomes lower. When the galvanic couple specimen with deposit is electrically connected with the specimen without deposit, anodic polarization occurs on X65 steel under deposit and the galvanic current density decreases from 120μA/cm2 to 50μA/cm2 and keeps stable. As 5×10-5, 8×10-5 and 3×10-4 PBTCA were introduced into the solution, the galvanic current density reaches the highest 1300μA/cm2 and then decreases to 610μA/cm2 keeping stable around 610μA/cm2, corrosion rate of X65 steel under deposit reaches 6.11mm/a. PBTCA accelerates the corrosion of X65 steel under deposit in oxygen contained solution. Through the investigation on the surface of the specimens, serious local corrosion occurs on the X65 steel surface under deposit.

  14. Effect of flow on corrosion in catenary risers and its corrosion inhibitor performance

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Pedro Altoe; Magalhaes, Alvaro Augusto Oliveira; Silva, Jussara de Mello [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil); Kang, Cheolho; More, Parimal P. [Det Norske Veritas (DNV), Oslo (Norway)

    2009-07-01

    In oil and gas production, multiphase flow is often encountered and a range of different flow patterns can be experienced in pipelines. The flow regime transition and flow characteristics can be changed with the change of pipeline topography, which affects the corrosion and the performance of corrosion inhibitor in these multiphase pipelines. This paper outlines on the effect of inclination on the flow characteristics and their subsequent effect on corrosion rates. Also, this paper presents on the performance of three candidate corrosion inhibitors under severe slugging conditions at low water cut. For the simulation of offshore flow lines and risers, the experiments were carried out in a 44 m long, 10 cm diameter, three different pipeline inclinations of 0, 3 and 45 degrees. Light condensate oil with a viscosity of 2.5 cP at room temperature was used and water cut was 20%. The results indicated that the baseline corrosion rate in 45 degrees showed higher than other inclinations. Each corrosion inhibitor showed a different inhibitor performance. (author)

  15. Effect of Acidic Water on Strength, Durability and Corrosion of ...

    African Journals Online (AJOL)

    In this study, specimens of 108 cubes (150 mm x 150 mm x 150 mm), 36 cylinders (300 mm x 150 mm), and 72 cylinders (102 mm x 51 mm) were cast and cured in percentages of NaCl added water to find the workability, strength, durability and corrosion resistance characteristics concrete. The effect of corrosion of steel in ...

  16. Economic effects of full corrosion surveys for aging concrete structures

    NARCIS (Netherlands)

    Polder, R.B.; Peelen, W.H.A.; Raupach, M.; Reichling, K.

    2013-01-01

    This paper investigates the economic effects of full corrosion surveys of concrete structures. The background is that the existing concrete infrastructure is aging, while being exposed to aggressive influences, which increases the occurrence of corrosion and related concrete damage over time. The

  17. Effect of municipal liquid waste on corrosion susceptibility of ...

    African Journals Online (AJOL)

    This investigation studied the effect of municipal liquid waste discharged into the environment within Kano municipal area on the corrosion susceptibility of galvanized steel pipe burial underground. Six stagnant and six moving municipal liquid waste samples were used for the investigation. The corrosion rate of the ...

  18. Corrosion behaviors and effects of corrosion products of plasma electrolytic oxidation coated AZ31 magnesium alloy under the salt spray corrosion test

    International Nuclear Information System (INIS)

    Wang, Yan; Huang, Zhiquan; Yan, Qin; Liu, Chen; Liu, Peng; Zhang, Yi; Guo, Changhong; Jiang, Guirong; Shen, Dejiu

    2016-01-01

    Highlights: • Corrosion behaviors of a PEO coating was investigated after the salt spray test. • Corrosion products have significant effects on corrosion behaviors of the coating. • An electrochemical corrosion model is proposed. - Abstract: The effects of corrosion products on corrosion behaviors of AZ31 magnesium alloy with a plasma electrolytic oxidation (PEO) coating were investigated under the salt spray corrosion test (SSCT). The surface morphology, cross-sectional microstructure, chemical and phase compositions of the PEO coating were determined using scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction analysis (XRD), respectively. Further, the corrosion process of the samples under the SSCT was examined in a non-aqueous electrolyte (methanol) using electrochemical impedance spectroscopy (EIS) coupled with equivalent circuit. The results show that the inner layer of the coating was destroyed firstly and the corrosion products have significant effects on the corrosion behaviors of the coating. The results above are discussed and an electrochemical corrosion model is proposed in the paper.

  19. Corrosion behaviors and effects of corrosion products of plasma electrolytic oxidation coated AZ31 magnesium alloy under the salt spray corrosion test

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yan; Huang, Zhiquan; Yan, Qin; Liu, Chen; Liu, Peng; Zhang, Yi [State Key Laboratory of Metastable Materials Science and Technology, College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004 (China); Guo, Changhong; Jiang, Guirong [College of Mechanical Engineering, Yanshan University, Qinhuangdao 066004 (China); Shen, Dejiu, E-mail: DejiuShen@163.com [State Key Laboratory of Metastable Materials Science and Technology, College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004 (China)

    2016-08-15

    Highlights: • Corrosion behaviors of a PEO coating was investigated after the salt spray test. • Corrosion products have significant effects on corrosion behaviors of the coating. • An electrochemical corrosion model is proposed. - Abstract: The effects of corrosion products on corrosion behaviors of AZ31 magnesium alloy with a plasma electrolytic oxidation (PEO) coating were investigated under the salt spray corrosion test (SSCT). The surface morphology, cross-sectional microstructure, chemical and phase compositions of the PEO coating were determined using scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction analysis (XRD), respectively. Further, the corrosion process of the samples under the SSCT was examined in a non-aqueous electrolyte (methanol) using electrochemical impedance spectroscopy (EIS) coupled with equivalent circuit. The results show that the inner layer of the coating was destroyed firstly and the corrosion products have significant effects on the corrosion behaviors of the coating. The results above are discussed and an electrochemical corrosion model is proposed in the paper.

  20. Corrosion behaviors and effects of corrosion products of plasma electrolytic oxidation coated AZ31 magnesium alloy under the salt spray corrosion test

    Science.gov (United States)

    Wang, Yan; Huang, Zhiquan; Yan, Qin; Liu, Chen; Liu, Peng; Zhang, Yi; Guo, Changhong; Jiang, Guirong; Shen, Dejiu

    2016-08-01

    The effects of corrosion products on corrosion behaviors of AZ31 magnesium alloy with a plasma electrolytic oxidation (PEO) coating were investigated under the salt spray corrosion test (SSCT). The surface morphology, cross-sectional microstructure, chemical and phase compositions of the PEO coating were determined using scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction analysis (XRD), respectively. Further, the corrosion process of the samples under the SSCT was examined in a non-aqueous electrolyte (methanol) using electrochemical impedance spectroscopy (EIS) coupled with equivalent circuit. The results show that the inner layer of the coating was destroyed firstly and the corrosion products have significant effects on the corrosion behaviors of the coating. The results above are discussed and an electrochemical corrosion model is proposed in the paper.

  1. Structural Effects of Reinforced Concrete Beam Due to Corrosion

    Science.gov (United States)

    Noh, Hamidun Mohd; Idris, Nur'ain; Noor, Nurazuwa Md; Sarpin, Norliana; Zainal, Rozlin; Kasim, Narimah

    2018-03-01

    Corrosion of steel in reinforced concrete is one of the main issues among construction stakeholders. The main consequences of steel corrosion include loss of cross section of steel area, generation of expansive pressure which caused cracking of concrete, spalling and delaminating of the concrete cover. Thus, it reduces the bond strength between the steel reinforcing bar and concrete, and deteriorating the strength of the structure. The objective of this study is to investigate the structural effects of corrosion damage on the performance of reinforced concrete beam. A series of corroded reinforced concrete beam with a corrosion rate of 0%, 20% and 40% of rebar corrosion is used in parametric study to assess the influence of different level of corrosion rate to the structural performance. As a result, the used of interface element in the finite element modelling predicted the worst case of corrosion analysis since cracks is induced and generate at this surface. On the other hand, a positive linear relationship was sketched between the increase of expansive pressure and the corrosion rate. Meanwhile, the gradient of the graph is decreased with the increase of steel bar diameter. Furthermore, the analysis shows that there is a significant effect on the load bearing capacity of the structure where the higher corrosion rate generates a higher stress concentration at the mid span of the beam. This study could predict the residual strength of reinforced concrete beam under the corrosion using the finite element analysis. The experimental validation is needed on the next stage to investigate the quantitative relation between the corrosion rate and its influence on the mechanical properties.

  2. Effect of menthol coated craft paper on corrosion of copper in HCl ...

    Indian Academy of Sciences (India)

    Administrator

    The effect of menthol on copper corrosion was studied by gravimetric and ... lable for temporary protection of metals and alloys from corrosion, the use of volatile .... The corrosion kinetic parameters were obtained from the anodic and cathodic.

  3. Corrosion in marine atmospheres. Effect of distance from the coast

    International Nuclear Information System (INIS)

    Chico, B.; Otero, E.; Morcillos, M.; Mariaca, L.

    1998-01-01

    In marine atmospheres the deposition of saline particles on the surface of metals intensifies the metallic corrosion process. However, quantitative information about the effect of atmospheric salinity on metallic corrosion is very scarce. This paper reports the relationship between salinity and metallic corrosion, where a clear linear relation (r=0.97) has been found for a broad interval of salinities (4-500 mg Cl''-/m''2.d), as well as the relationship between salinity (or metallic corrosion) and distance from the coast. A hyperbolic function seems to be established both variables; there is an exponential drop in salinity (or corrosion) as shoreline distance increases tending towards and asymptotic value. The study has been based on information obtained from field research conducted at a marine atmosphere in Tarragona (Spain) and data compiled from the literature. (Author) 14 refs

  4. Effects of climate and corrosion on concrete behaviour

    Science.gov (United States)

    Ismail, Mohammad; Egba, Ernest Ituma

    2017-11-01

    Corrosion of steel is a damaging agent that reduces the functional and structural responsibilities of reinforced concrete structures. Accordingly, reinforced concrete members in the environments that are prone to concrete carbonation or chloride attack coupled with high temperature and relative humidity suffer from accelerated corrosion of reinforcing material. Also, literature proves that climate influences corrosion of concrete, and suggests investigation of impact of corrosion on concrete based on climate zone. Therefore, this paper presents the effects of climate and corrosion on concrete behavior, using bond strength of concrete as a case study. Concrete specimens were prepared form concrete mix that was infested with 3.5 kgm-3 of sodium chloride to accelerate corrosion. The specimens were cured sodium chloride solution 3.5% by weight of water for 28 days before placing them in the exposure conditions. Pull-out tests were conducted at time intervals for one year to measure the impact of exposure condition and corrosion on bond strength of concrete. The results show reduction of bond strength of concrete by 32%, 28% and 8% after one year of subjection of the specimens to the unsheltered natural climate, sheltered natural climate, and laboratory ambient environment respectively. The findings indicate that the climate influences corrosion, which reduces the interlocking bond between the reinforcing bar and the adjacent concrete.

  5. EFFECT OF RATIO OF SURFACE AREA ON THE CORROSION RATE

    OpenAIRE

    Dody Prayitno; M. Irsyad

    2018-01-01

    Aluminum and steel are used to be a construction for a building outdoor panel. Aluminum and steel are connected by bolt and nut. An atmosphere due to a corrosion of the aluminum. The corrosion possibly to cause the hole diameter of bolt and nut to become larger. Thus the bolt and nut can not enough strong to hold the panel. The panel may collapse. The aim of the research is first to answer a question where does the corrosion starts. The second is to know the effect of ratio surface area of st...

  6. Effect of aging on the corrosion of aluminum alloy 6061

    International Nuclear Information System (INIS)

    EL-Bedawy, M.E.M.

    2010-01-01

    Not only alloying additions may affect the corrosion resistance of aluminum alloys, but also practices that result in a nonuniform microstructure may introduce susceptibility to some forms of corrosion, especially if the microstructural effect is localized. This work was intended to study the effect of aging time at 225, 185 and 140 degree C and the effect of constant aging time ( 24 hrs ) in the temperature range 100 - 450 degree C as well as the influence of the solution ph on the corrosion characteristics of 6061 aluminum alloy, (Al-Mg-Si alloy) containing 0.22 wt% Cu. The investigation was performed by standard immersion corrosion test according to the British Standard BS 11846 method B and by applying potentiodynamic polarization technique in neutral deaerated 0.5 % M NaCl solution as well as in alkaline NaOH solution (ph = 10). The susceptibility to corrosion and the dominant corrosion type was evaluated by examination of transverse cross sections of corroded samples after the immersion test and examination of the corroded surfaces after potentiodynamic polarization using optical microscope. Analysis of the polarization curves was used to determine the effect of different aging parameters on corrosion characteristics such as the corrosion current density I (corr), the corrosion potential E (corr), the cathodic current densities and the passivation behavior.Results of the immersion test showed susceptibility to intergranular corrosion in the under aged tempers while pitting was the dominant corrosion mode for the over aged tempers after aging at 225 and 185 degree C.Analysis of the potentiodynamic polarization curves showed similar dependence of I (corr) and cathodic current densities on the aging treatment in the neutral 0.5 %M NaCl solution and in the alkaline NaOH solution. It was observed that E(corr) values in the NaCl solution were shifted in the more noble direction for the specimens aged before peak aging while it decreased again with aging time for

  7. Effect of Wall Shear Stress on Corrosion Inhibitor Film Performance

    Science.gov (United States)

    Canto Maya, Christian M.

    In oil and gas production, internal corrosion of pipelines causes the highest incidence of recurring failures. Ensuring the integrity of ageing pipeline infrastructure is an increasingly important requirement. One of the most widely applied methods to reduce internal corrosion rates is the continuous injection of chemicals in very small quantities, called corrosion inhibitors. These chemical substances form thin films at the pipeline internal surface that reduce the magnitude of the cathodic and/or anodic reactions. However, the efficacy of such corrosion inhibitor films can be reduced by different factors such as multiphase flow, due to enhanced shear stress and mass transfer effects, loss of inhibitor due to adsorption on other interfaces such as solid particles, bubbles and droplets entrained by the bulk phase, and due to chemical interaction with other incompatible substances present in the stream. The first part of the present project investigated the electrochemical behavior of two organic corrosion inhibitors (a TOFA/DETA imidazolinium, and an alkylbenzyl dimethyl ammonium chloride), with and without an inorganic salt (sodium thiosulfate), and the resulting enhancement. The second part of the work explored the performance of corrosion inhibitor under multiphase (gas/liquid, solid/liquid) flow. The effect of gas/liquid multiphase flow was investigated using small and large scale apparatus. The small scale tests were conducted using a glass cell and a submersed jet impingement attachment with three different hydrodynamic patterns (water jet, CO 2 bubbles impact, and water vapor cavitation). The large scale experiments were conducted applying different flow loops (hilly terrain and standing slug systems). Measurements of weight loss, linear polarization resistance (LPR), and adsorption mass (using an electrochemical quartz crystal microbalance, EQCM) were used to quantify the effect of wall shear stress on the performance and integrity of corrosion inhibitor

  8. Effects of prior cold work on corrosion and corrosive wear of copper in HNO3 and NaCl solutions

    International Nuclear Information System (INIS)

    Yin Songbo; Li, D.Y.

    2005-01-01

    Effects of prior cold work on corrosion and corrosive wear behavior of copper in 0.1 M HNO 3 and 3.5% NaCl solutions, respectively, were investigated using electrochemical tests, electron work function measurements, and sliding corrosive wear tests with and without cathodic protection. Optical microscope and SEM were employed to examine the microstructure and worn surfaces. It was shown that, in general, the prior cold work raised the corrosion rate, but the effect differed in different corrosive media. In both the solutions, pure mechanical wear decreased with an increase in cold work. The prior cold work had a significant influence on the corrosive wear of copper, depending on the corrosive solution and the applied load. In the 0.1 M HNO 3 solution, the ratio of the wear loss caused by corrosion-wear synergism to the total wear loss increased with the cold work and became saturated when the cold work reached a certain level. In the 3.5% NaCl solution, however, this ratio decreased initially and then became relatively stable with respect to the cold work. It was observed that wear of copper in the 3.5% NaCl solution was larger than that in 0.1 M HNO 3 solution, although copper showed lower corrosion rate in the former solution. The experimental observations and the possible mechanisms involved are discussed

  9. The corrosion effect on the conduit systems

    International Nuclear Information System (INIS)

    Laaidi, Naouar; Belattar, Sougratti

    2009-01-01

    The conduits in the buildings require a regular and permanent control, in order to avoid the risks of deterioration caused by the corrosion or the escape of water. In this work, we present a thermal nondestructive testing method of concrete structures containing water conduits, based on numerical modeling in three dimensions. The goal is to study the detectability of these conduits in different situations and to give a thermal characterization of the rust behaviour in the steel conduits. (author)

  10. 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)

  11. 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

  12. Effective flow-accelerated corrosion programs in nuclear facilities

    International Nuclear Information System (INIS)

    Esselman, Thomas C.; McBrine, William J.

    2004-01-01

    Piping Flow-Accelerated Corrosion Programs in nuclear power generation facilities are classically comprised of the selection of inspection locations with the assistance of a predictive methodology such as the Electric Power Research Institute computer codes CHECMATE or CHECWORKS, performing inspections, conducting structural evaluations on the inspected components, and implementing the appropriate sample expansion and corrective actions. Performing such a sequence of steps can be effective in identifying thinned components and implementing appropriate short term and long term actions necessary to resolve flow-accelerated corrosion related problems. A maximally effective flow-accelerated corrosion (FAC) program requires an understanding of many programmatic details. These include the procedural control of the program, effective use of historical information, managing the activities performed during a limited duration outage, allocating resources based on risk allocation, having an acute awareness of how the plant is operated, investigating components removed from the plant, and several others. This paper will describe such details and methods that will lead to a flow-accelerated corrosion program that effectively minimizes the risk of failure due to flow-accelerated corrosion and provide full and complete documentation of the program. (author)

  13. 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

  14. Effect of Bi on the corrosion resistance of zirconium alloys

    International Nuclear Information System (INIS)

    Yao Meiyi; Zhou Bangxin; Li Qiang; Zhang Weipeng; Zhu Li; Zou Linghong; Zhang Jinlong; Peng Jianchao

    2014-01-01

    In order to investigate systematically the effect of Bi addition on the corrosion resistance of zirconium alloys, different zirconium-based alloys, including Zr-4 (Zr-l.5Sn-0.2Fe-0.1Cr), S5 (Zr-0.8Sn-0.35Nb-0.4Fe-0.1Cr), T5 (Zr-0.7Sn-l.0Nb-0.3Fe-0.1Cr) and Zr-1Nb, were adopted to prepare the zirconium alloys containing Bi of 0∼0.5% in mass fraction. These alloys were denoted as Zr-4 + xBi, S5 + xBi, T5 + xBi and Zr-1Nb + xBi, respectively. The corrosion behavior of these specimens was investigated by autoclave testing in lithiated water with 0.01 M LiOH or deionized water at 360 ℃/18.6 MPa and in superheated steam at 400 ℃/10.3 MPa. The microstructure of the alloys was examined by TEM and the second phase particles (SPPs) were analyzed by EDS. Microstructure observation shows that the addition of Bi promotes the precipitation of Sn as second phase particles (SPPs) because Sn is in solid solution in α-Zr matrix in Zr-4, S5 and T5 alloys. The concentration of Bi dissolved in α-Zr matrix increase with the increase of Nb in the alloys, and the excess Bi precipitates as Bi-containing SPPs. The corrosion results show that the effect of Bi addition on the corrosion behavior of different zirconium-based alloys is very complicated, depending on their compositions and corrosion conditions. In the case of higher Bi concentration in α-Zr, the zirconium alloys exhibit better corrosion resistance. However, in the case of precipitation of Bi-containing SPPs, the corrosion resistance gets worse. This indicates that the solid solution of Bi in α-Zr matrix can improve the corrosion resistance, while the precipitation of the Bi-containing SPPs is harmful to the corrosion resistance. (authors)

  15. Effect of microcrystallization on pitting corrosion of pure aluminium

    International Nuclear Information System (INIS)

    Meng Guozhe; Wei Liyan; Zhang Tao; Shao Yawei; Wang Fuhui; Dong Chaofang; Li Xiaogang

    2009-01-01

    A microcrystalline aluminium film with grain size of about 400 nm was prepared by magnetron sputtering technique. Its corrosion behaviour was investigated in NaCl containing acidic solution by means of potentiodynamic polarization curves and electrochemical noise (EN). The polarization results indicated that the corrosion potential of the sample shifted towards more positive direction, while its corrosion current density decreased compared with that of pure coarse-grain Al. The EN analysis based on stochastic model demonstrated that there existed two kinds of effect of microcrystallization on the pitting behaviour of pure aluminium: (1) the rate of pit initiation is accelerated, (2) the pit growth process was impeded. This leads to the enhancement of pitting resistance for the microcrystallized aluminium.

  16. Effect of radiation on anaerobic corrosion of iron

    International Nuclear Information System (INIS)

    Smart, N.R.; Rance, A.P.

    2005-01-01

    To ensure the safe encapsulation of spent nuclear fuel elements for geological disposal, SKB of Sweden are considering using the Advanced Cold Process Canister, which consists of an outer copper canister and a cast iron insert. A programme of work has been carried out to investigate a range of corrosion issues associated with the canister, including measurements of gas generation due to the anaerobic corrosion of ferrous materials (carbon steel and cast iron) over a range of conditions. To date, all this work has been conducted in the absence of a radiation field. SKB asked Serco Assurance to carry out a set of experiments designed to investigate the effect of radiation on the corrosion of steel in repository environments. This report describes the experimental programme and presents the results that were obtained. The measurements were carried out in the type of gas cell used previously, in which the change in gas pressure was measured using a liquid-filled manometer. The test cells were placed in a radiation cell and positioned so that the received radiation dose was equivalent to that expected in the repository. Control cells were used to allow for any gas generation caused by radiolytic breakdown of the construction materials and the water. Tests were carried out at two temperatures (30 deg C and 50 deg C), two dose rates (11 Gray/hr and 300 Gray/hr), and in two different artificial groundwaters. A total of four tests were carried out, using carbon steel wires as the test material. The cells were exposed for a period of several months, after which they were dismantled and the corrosion product on one wire from each test cell was analysed using Raman spectroscopy. The report presents the results from the gas generation tests and compares the results obtained under irradiated conditions to results obtained previously in the absence of radiation. Radiation was found to enhance the corrosion rate at both dose rates but the greatest enhancement occurred at the

  17. Effects of chemical composition on the corrosion of dental alloys.

    Science.gov (United States)

    Galo, Rodrigo; Ribeiro, Ricardo Faria; Rodrigues, Renata Cristina Silveira; Rocha, Luís Augusto; de Mattos, Maria da Glória Chiarello

    2012-01-01

    The aim of this study was to determine the effect of the oral environment on the corrosion of dental alloys with different compositions, using electrochemical methods. The corrosion rates were obtained from the current-potential curves and electrochemical impedance spectroscopy (EIS). The effect of artificial saliva on the corrosion of dental alloys was dependent on alloy composition. Dissolution of the ions occurred in all tested dental alloys and the results were strongly dependent on the general alloy composition. Regarding the alloys containing nickel, the Ni-Cr and Ni-Cr-Ti alloys released 0.62 mg/L of Ni on average, while the Co-Cr dental alloy released ions between 0.01 and 0.03 mg/L of Co and Cr, respectively.The open-circuit potential stabilized at a higher level with lower deviation (standard deviation: Ni-Cr-6Ti = 32 mV/SCE and Co-Cr = 54 mV/SCE). The potenciodynamic curves of the dental alloys showed that the Ni-based dental alloy with >70 wt% of Ni had a similar curve and the Co-Cr dental alloy showed a low current density and hence a high resistance to corrosion compared with the Ni-based dental alloys. Some changes in microstructure were observed and this fact influenced the corrosion behavior for the alloys. The lower corrosion resistance also led to greater release of nickel ions to the medium. The quantity of Co ions released from the Co-Cr-Mo alloy was relatively small in the solutions. In addition, the quantity of Cr ions released into the artificial saliva from the Co-Cr alloy was lower than Cr release from the Ni-based dental alloys.

  18. Effect of temperature on structure and corrosion resistance for ...

    Indian Academy of Sciences (India)

    The effect of plating temperatures between 60 and 90◦C on structure and corrosion resistance for elec- troless NiWP coatings ..... which helps to form fine grain. At 80 .... [23] Zhang W X, Jiang Z H, Li G Y and Jiang Q 2008 Surf. Coat. Technol.

  19. Effects of glacial meltwater on corrosion of copper canisters

    International Nuclear Information System (INIS)

    Ahonen, L.; Vieno, T.

    1994-08-01

    The composition of glacial meltwater and its reactions in the bedrock are examined. The evidences that there are or should be from past intrusions of glacial meltwater and oxygen deep in the bedrock are also considered. The study is concluded with an evaluation of the potential effects of oxygenated meltwater on the corrosion of copper canisters. (46 refs., 3 figs., 2 tabs.)

  20. Synergetic effect of sulphur and nitrogen oxides on corrosion of ...

    African Journals Online (AJOL)

    The synergetic effect of nitrogen dioxide (NO2) and sulphur dioxide (SO2) on corrosion of galvanized iron roofing sheets has been investigated. The field studies were conducted in Ibeno and Ebocha (Niger Delta, Nigeria). Specimens of the roofing sheets were exposed for one year to outdoor environment to record the ...

  1. Galvanic corrosion -- Effect of environmental and experimental variables

    International Nuclear Information System (INIS)

    Roy, A.K.; Fleming, D.L.; Lum, B.Y.

    1999-01-01

    Galvanic corrosion behavior of A 516 steel (UNS K01800) coupled to UNS N06022 and UNS R53400, respectively was evaluated in an acidic brine (pH ∼ 2.75) at 30 C, 60 C and 80 C using zero resistance ammeter method. A limited number of experiments were also performed in a neutral brine involving A 516 steel/UNS N06022 couple. The steady-state galvanic current and galvanic potential were measured as functions of anode-to-cathode (A/C) area ratio and electrode distance. Results indicate that the galvanic current was gradually reduced as the A/C area ratio was increased. No systematic trend on the effect of A/C area ratio on the galvanic potential was observed. Also, no significant effect of electrode distance on the galvanic current and galvanic potential was evident. In general, increased galvanic current was noticed with increasing temperature. The limited data obtained in the neutral brine indicate that the galvanic current was reduced in this environment compared to that in the acidic brine. Optical microscopic examination was performed on all tested specimens to evaluate the extent of surface damage resulting from galvanic interaction. A 516 steel suffered from general corrosion and crevice corrosion in all environments tested. Very light crevice corrosion mark was observed with UNS N06022 and R53400 in the acidic brine at 60 C and 80 C. However, this mark appears to be a surface discoloration and no actual crevice was detected

  2. An Experimental Investigation of the Effect of Corrosion on Dry Friction Noise

    International Nuclear Information System (INIS)

    Baek, Jongsu; Kang, Jaeyoung

    2015-01-01

    This study investigates the friction noise characteristic in relation to the corrosion of metal by using the frictional reciprocating and pin-on-disk system. From the experiments, it is found that the corrosion of metal advances the onset time and increases the magnitude of friction noise. Further, it is observed that the effect of corrosion on friction noise stems from the alteration of tribo-surface during repetitive frictional motion. The alteration of the corrosive contact surface induces a negative friction-velocity slope, by which the corrosion of metal can generate dynamic instability faster than non-corrosion of metal

  3. The Effects of Corrosive Chemicals on Corrosion Rate of Steel Reinforcement Bars: II. Swamp Sludges

    Directory of Open Access Journals (Sweden)

    Henki Ashadi

    2010-10-01

    Full Text Available A polluted environment will influence the building age. The objective of this research was to find out the influence of corrosive chemicals within the sludge swamp area with the corrosion rate of steel concrete. Corrosion in steel concrete usually occur in acid area which contain of SO42-, Cl- and NO3-. The research treatment used by emerging ST 37 andST 60 within 60 days in 'polluted' sludge swamp area. Three variation of 'polluted' swamp sludge were made by increasing the concentration a corrosive unsure up to 1X, 5X and 10X. The corrosion rate measured by using an Immersion Method. The result of Immersion test showed that sulphate had a greatest influence to corrosion rate of ST 37 and ST 60 and followed by chloride and nitrate. Corrosion rate value for ST 37 was 17.58 mpy and for ST 60 was 12.47 mpy.

  4. The Effect of Homogenization on the Corrosion Behavior of Al-Mg Alloy

    Science.gov (United States)

    Li, Yin; Hung, Yuanchun; Du, Zhiyong; Xiao, Zhengbing; Jia, Guangze

    2018-04-01

    The effect of homogenization on the corrosion behavior of 5083-O aluminum alloy is presented in this paper. The intergranular corrosion and exfoliation corrosion were used to characterize the discussed corrosion behavior of 5083-O aluminum alloy. The variations in the morphology, the kind and distribution of the precipitates, and the dislocation configurations in the samples after the homogenization were evaluated using optical microscopy (OM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The effects of the highly active grain boundary character distribution and the types of constituent particles on the corrosion are discussed on the basis of experimental observations. The results indicated that the corrosion behavior of 5083-O alloy was closely related to the microstructure obtained by the heat treatment. Homogenization carried out after casting had the optimal effect on the overall corrosion resistance of the material. Nevertheless, all samples could satisfy the requirements of corrosion resistance in marine applications.

  5. Radionuclide decay effects on waste glass corrosion and weathering

    International Nuclear Information System (INIS)

    Wronkiewicz, D.J.

    1993-01-01

    The release of glass components into solution, including radionuclides, may be influenced by the presence of radiolytically produced nitric acid, carboxylic acid, and transient water dissociation products such as ·OH and O 2 - . Under batch test conditions, glass corrosion has been shown to increase up to a maximum of three-to five-fold in irradiated tests relative to nonirradiated tests, while in other studies the presence of radiolytic products has actually decreased glass corrosion rates. Bicarbonate groundwaters will buffer against pH decreases and changes in corrosion rates. Under high surface area-to-solution volume (S/V) conditions, the bicarbonate buffering reservoir may be quickly overwhelmed by radiolytic acids that are concentrated in the thin films of water contacting the samples. Glass reaction rates have been shown to increase up to 10-to-15-fold due to radiation exposure under high S/V conditions. Radiation damage to solid glass materials results in bond damage and atomic displacements. This type of damage has been shown to increase the release rates of glass components up to four-fold during subsequent corrosion tests, although under actual disposal conditions, glass annealing processes may negate the solid radiation damage effects

  6. The effect of single overloading on stress corrosion cracking

    International Nuclear Information System (INIS)

    Ito, Yuzuru; Saito, Masahiro

    2008-01-01

    In the normal course of nuclear power plant operation in Japan, proof testing has been performed after periodic plant inspections. In this proof test procedure, the reactor pressure vessel and pipes of the primary coolant loop are subjected to a specified overload with a slightly higher hydraulic pressure than during normal operation. This specified overload is so called a single overload' in material testing. It is well known that the fatigue crack growth rate is decreased after a single overload has been applied to the specimen. However, it is not clear whether the stress corrosion cracking rate is also decreased after a single overload. In this study, the effect of a single overload on the stress corrosion cracking rate under simulated boiling water reactor environment was evaluated by examining a singly overloaded WOL (wedge opening load) specimen. The WOL specimen for the stress corrosion cracking test was machined from sensitized 304 type austenitic stainless steel. Since the crack extension length was 3.2% longer in the case of a more severely overloaded specimen, it was observed than the stress corrosion cracking rate is also decreased after the single overload has been applied to the specimen. (author)

  7. Assessing Level and Effectiveness of Corrosion Education in the UAE

    OpenAIRE

    Lim, Hwee Ling

    2012-01-01

    The consequences of corrosion can be minimized by an engineering workforce well trained in corrosion fundamentals and management. Since the United Arab Emirates incurs the second highest cost of corrosion after Saudi Arabia, this paper examined the quality of corrosion education in the UAE. Surveys with academia and industry respondents showed that dedicated corrosion courses and engineering courses that integrated corrosion into the curricula were available in UAE universities, but graduates...

  8. The effects of Nitinol phases on corrosion and fatigue behavior

    Science.gov (United States)

    Denton, Melissa

    The purpose of these studies was to provide a detailed understanding of Nitinol phases and their effects on corrosion and fatigue life. The two primary phases, austenite and martensite, were carefully evaluated with respect to material geometry, corrosion behavior, wear, and fatigue life. Material characterization was performed using several techniques that include metallography, scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), x-ray photoelectron spectrum (XPS), and Auger electron spectroscopy (AES). Uniaxial tensile tests were conducted to determine the mechanical properties such as elongation, ultimate tensile strength, modulus, transformation strain, and plateau stress. In addition, accelerated wear testing and four point bend fatigue testing were completed to study the fatigue life and durability of the material. The corrosion of Nitinol was found to be dependent on various surface conditions. Electrochemical corrosion behavior of each phase was investigated using cyclic potentiodyamic polarization testing. The corrosion response of electropolished Nitinol was found to be acceptable, even after durability testing. Stress-induced martensite had a lower breakdown potential due to a rougher surface morphology, while thermally induced martensite and austenite performed similarly well. The surface conditioning also had a significant effect on Nitinol mechanical properties. Electropolishing provided a smooth mirror finish that reduced localized texture and enhanced the ductility of the material. Quasi-static mechanical properties can be good indicators of fatigue life, but further fatigue testing revealed that phase transformations had an important role as well. The governing mechanisms for the fatigue life of Nitinol were determined to be both martesitic phase transformations and surface defects. A new ultimate dislocation strain model was proposed based on specific accelerated step-strain testing.

  9. Adsorption and corrosion inhibiting effect of riboflavin on Q235 mild steel corrosion in acidic environments

    Energy Technology Data Exchange (ETDEWEB)

    Chidiebere, Maduabuchi A. [Institute of Metal Research, Chinese Academy of Sciences, 62 Wencui Rd, Shenyang 110016 (China); Electrochemistry and Materials Science Research Laboratory, Department of Chemistry, Federal University of Technology Owerri, PMB 1526 Owerri (Nigeria); Oguzie, Emeka E. [Electrochemistry and Materials Science Research Laboratory, Department of Chemistry, Federal University of Technology Owerri, PMB 1526 Owerri (Nigeria); Liu, Li [Institute of Metal Research, Chinese Academy of Sciences, 62 Wencui Rd, Shenyang 110016 (China); Li, Ying, E-mail: liying@imr.ac.cn [Institute of Metal Research, Chinese Academy of Sciences, 62 Wencui Rd, Shenyang 110016 (China); Wang, Fuhui [Institute of Metal Research, Chinese Academy of Sciences, 62 Wencui Rd, Shenyang 110016 (China)

    2015-04-15

    The inhibiting effect of Riboflavin (RF) on Q235 mild steel corrosion in 1 M HCl and 0.5 M H{sub 2}SO{sub 4} at 30 °C temperature was investigated using electrochemical techniques (electrochemical impedance spectroscopy and potentiodynamic polarization). The obtained results revealed that RF inhibited the corrosion reaction in both acidic solutions. Maximum inhibition efficiency values in 1 M HCl and 0.5 M H{sub 2}SO{sub 4} were 83.9% and 71.4%, respectively, obtained for 0.0012 M RF. Polarization data showed RF to be a mixed-type inhibitor, while EIS results revealed that the RF species adsorbed on the metal surface. The adsorption of RF followed Langmuir adsorption isotherm. Atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) studies confirmed the formation of a protective layer adsorbed on the steel surface. Quantum chemical calculations were used to correlate the inhibition ability of RF with its electronic structural parameters. - Highlights: • The inhibitory mechanism was influenced by the nature of acid anions. • RF has reasonable inhibition effect especially in 1 M HCl solution. • Polarization studies showed that RF functioned as a mixed type inhibitor. • Improved surface morphology was observed in the presence of RF.

  10. The effect of notches and pits on corrosion fatigue strength

    Science.gov (United States)

    Tatner, Ian

    An investigation has been undertaken to examine the fatigue behaviour of two martensitic steels in air and aggressive environments. The steels studied are, 18% Ni marageing steel and FV520B, the later being a stainless steel turbine blade material and the former being a marageing steel that suffers general corrosion in mild environments. Both steels were heat treated to give similar tensile strength.The design and manufacture of an autoclave allowed push-pull fatigue tests to be conducted in aggressive environments at elevated temperatures.Corrosion potential was monitored using a three electrode cell and was controlled during testing. Base-line fatigue tests were conducted with a range of constant corrosion potentials, using both notched and plain FV520B specimens. In addition fatigue tests with pulsed corrosion potential were performed to asses the effect of transient corrosion conditions on the corrosion fatigue strength. The pulsed tests were designed to simulate service transients in the oxygen content and general chemical hostility in the condensing steam environment during start-up and shut down of the steam turbine.Post test examination of fractured samples was performed using Scanning Electron Microscopy (SEM) and optical microscope techniques. The fractography results were used to quantify microstructural and fracture features of the steels.A model based on the size and geometry of the initial corrosion pitting has been proposed to asses the fatigue life of FV520B in an aggressive environment.The effect of pitting on the corrosion fatigue strength of FV520B has been modelled using linear elastic fracture mechanics (LEFM) type approach. The model has shown a good correlation between predicted fatigue lives with experimental results.The results suggest that the fatigue life is governed by the mechanical stress concentrating effect of the pits rather than the electrochemical damage caused by the environment.Finite Element Analysis (FEA) of the notch allowed

  11. Effects of Chemical Treatments on Microbiologically Influenced Corrosion

    Science.gov (United States)

    Friedman, E. S.; Strom, M.; Dexter, S. C.

    2008-12-01

    Biofilms are known to have an effect on galvanic corrosion of alloys in seawater systems. In the Delaware Bay, biofilm formation on surface of cathodes has been shown to cause galvanic corrosion to occur up to 100 times more rapidly. Given the impacts that corrosion can have on structures, it is important to study how we can affect corrosion rates. One way of doing this is the application of chemical treatments to biofilms on metal samples. To investigate this, natural marine biofilms were grown on alloy 6XN stainless steel samples, and various chemical treatments were applied to discover their effects on open circuit potentials and corrosion currents. Another objective of this study was to determine if there was a threshold molecular weight above which molecules were unable to penetrate the biofilm. It was discovered that chemicals with molecular weights as high as 741.6 g/mol were able to penetrate at least some parts of the heterogeneous biofilm and reach the metal surface. No upper threshold value was found in this study. It was found that the reducing agents sodium L-ascorbate and NADH as well as the chelate ferizene caused a drop in open circuit potential of biofilmed 6XN samples. Also, glutaraldahyde, which is used as a fixative for bacteria, shifted the open circuit potential of biofilm samples in the noble direction but had no effect on the corrosion current. Sodium L- ascorbate was found to reach the metal surface, but in concentrations lower than those present in the bulk fluid. It was not determined in this study whether this was due to physical or chemical processes within the biofilm. A synergistic effect was observed when applying a mixture of ferizene and glutaraldahyde. It is thought that this was due to the death of the bacteria as well as the disruption of iron cycling in the biofilm. Finally, it was observed that NADH caused a reduction in current at potentials associated with iron reduction, leading us to believe that the iron was being reduced

  12. Chemical effects in the Corrosion of Aluminum and Aluminum Alloys. A Bibliography

    Science.gov (United States)

    1976-10-01

    tances.II. Effect Of Pomegranate Juice And The Aqueous Extract Of Pomegranate Fruits And Tea leaves On The Corrosion Of Aluminum" The effect of the juices...T7651 tempers to exfoliation and stress- corrosion cracking . 1968-8 D.P. Doyle and H.P. Godard ,a) Tr. Mezhdunar. Kongr. Korroz. Metal, 4, 439-48, (1968...Tapper Brit. Corros. J., 3, 285-87, (1968) "Corrosion Of Aluminum" Summary of the literature of Al corrosion which includes stress- corrosion cracking

  13. The effects of corrosion product colloids on actinide transport

    International Nuclear Information System (INIS)

    Gardiner, M.P.; Smith, A.J.; Williams, S.J.

    1991-11-01

    This report assesses the possible effects of colloidal corrosion products on the transport of actinides from the near field of radioactive waste repositories. The desorption of plutonium and americium from colloidal corrosion products of iron and zirconium was studied under conditions simulating a transition from near-field to far-field environmental conditions. Desorption of actinides occurred slowly from the colloids under far-field conditions. Measurements of particle stability showed all the colloids to be unstable in the near field. Stability increased under far-field conditions or as a result of the evolution of the near field. Migration of colloids from the near field is unlikely except in the presence of organic materials. (Author)

  14. Effects of amalgam corrosion products on human cells

    Energy Technology Data Exchange (ETDEWEB)

    Goldschmidt, P R; Cogen, R B; Taubman, S B [Departments of Periodontics and Pathology, University of Connecticut Health Center, Farmington, Connecticut, U.S.A.

    1976-01-01

    Using three independent criteria, we have found that 10/sup -4/,10/sup -6/M concentrations of ions presumably liberated from the corrosion of dental amalgam produce injurious effects on either human gingival fibroblasts or HeLa cells when the cells are grown in culture. Release of /sup 51/Cr and uptake of trypan blue dye were seen with 10/sup -5/M Hg/sup + +/ and Ag/sup +/. Inhibition of amino acid incorporation into protein-like material was seen with eluates of amalgam and with ionic solutions of most metals comprising dental amalgam. Stannous ion showed little if any cytotoxic potential. These results suggest that corrosion products of amalgam are capable of causing cellular injury or destruction.

  15. Corrosion and inhibition of stainless steel pitting corrosion in alkaline medium and the effect of Cl- and Br- anions

    International Nuclear Information System (INIS)

    Refaey, S.A.M.; Taha, F.; El-Malak, A.M. Abd

    2005-01-01

    The effect of carbonate anion on the pitting corrosion and inhibition behavior of stainless steel samples (304L SS and 316L SS) has been studied using potentiodynamic and scanning electron microscope (SEM) techniques. The effect of concentration of CO 3 2- ions, pH, potential scanning rate and the composition of stainless steel are discussed. Additions of Cl - and Br - ions into the carbonate solution increase the anodic dissolution of stainless steel and decrease its pitting corrosion resistance. The effect of CO 3 2- anion on the inhibition of chloride and bromide pitting corrosion of the two stainless steel types has been studied also. Pitting corrosion decrease with the increasing of sodium carbonate concentration, i.e. increases the resistance of stainless steels towards the chloride and bromide pitting corrosion. This inhibition effect argued to formation of [Fe,Cr]CO 3 film caused by preferential adsorption of the CO 3 2- ion, leading to instantaneous repair of weak sites for pit nucleation

  16. Effect of ageing time and temperature on corrosion behaviour of aluminum alloy 2014

    Science.gov (United States)

    Gadpale, Vikas; Banjare, Pragya N.; Manoj, Manoranjan Kumar

    2018-03-01

    In this paper, the effect of corrosion behaviour of aluminium alloy 2014 were studied by potentiodynamic polarization in 1 mole of NaCl solution of aged sample. The experimental testing results concluded that, corrosion resistance of Aluminum alloy 2014 degraded with the increasing the temperature (150°C & 200°C) and time of ageing. Corroded surface of the aged specimens was tested under optical microscopes for microstructures for phase analysis. Optical micrographs of corroded surfaces showed general corrosion and pitting corrosion. The corrosion resistance of lower ageing temperature and lower ageing time is higher because of its fine distribution of precipitates in matrix phase.

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

    International Nuclear Information System (INIS)

    Hyun, Youngmin; Kim, Heesan

    2016-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-02-15

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

  19. Effect of molybdate on phosphating of Nd-Fe-B magnets for corrosion protection

    Directory of Open Access Journals (Sweden)

    Adonis Marcelo Saliba-Silva

    2005-06-01

    Full Text Available Nd-Fe-B magnets are highly susceptible to corrosion and need protection against environment attack. The use of organic coatings is one of the main methods of corrosion protection of these materials. Data related to the effect of conversion coatings, such as phosphating, on corrosion performance of these magnets is still scarce. Studies about the effect of phosphating on the corrosion resistance of a commercial Nd-Fe-B sintered magnet indicated that it increases the corrosion resistance of these magnets, compared to non-phosphated magnets. In this study, the solution chemistry of a phosphating bath was altered with the addition of molybdate and its effect on the corrosion resistance of magnets investigated. Sintered magnet specimens were phosphated in solutions of 10 g/L NaH2PO4 (pH 3.8, either with or without molybdate [10-3 M MoO4(2-], to improve their corrosion resistance. The effect of phosphating time was also evaluated, and specimens were phosphated for 4 and 18 hours. To evaluate the corrosion performance of phosphated and unphosphated specimens, a corrosion test based on monitoring hydrogen evolution on the surface of the magnets was used. This technique revealed that the addition of molybdate to the phosphating solution improved the corrosion resistance of the magnets phosphated by immersion for short periods but had no beneficial effect if phosphated by immersion for longer periods.

  20. Corrosion of conductive polypyrrole: Effects of environmental factors, electrochemical stimulation, and doping anions

    International Nuclear Information System (INIS)

    Qi Kai; Qiu Yubing; Chen Zhenyu; Guo Xingpeng

    2012-01-01

    Highlights: ► Corrosive galvanic cells form on PPy film with the electrochemical reduction of O 2. ► Suitable electrochemical stimulation can inhibit the PPy’s corrosion. ► PPy film doped with larger sized anions has better corrosion resistance performance. - Abstract: The effects of environmental factors, electrochemical stimulation, and doping anions on the corrosion behaviour of conductive polypyrrole (PPy) films in alkaline aqueous media were studied with cyclic voltammetry, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. High concentrations of electrolyte, low dissolved oxygen and low temperatures enhance the stability of PPy. Polarising PPy at a negative potential inhibits its corrosion obviously. PPy doped with large counter anions shows better corrosion resistance than PPy doped with small counter ions. The possible mechanism involved in PPy corrosion process is discussed.

  1. Effects of Cations on Corrosion of Inconel 625 in Molten Chloride Salts

    Science.gov (United States)

    Zhu, Ming; Ma, Hongfang; Wang, Mingjing; Wang, Zhihua; Sharif, Adel

    2016-04-01

    Hot corrosion of Inconel 625 in sodium chloride, potassium chloride, magnesium chloride, calcium chloride and their mixtures with different compositions is conducted at 900°C to investigate the effects of cations in chloride salts on corrosion behavior of the alloy. XRD, SEM/EDS were used to analyze the compositions, phases, and morphologies of the corrosion products. The results showed that Inconel 625 suffers more severe corrosion in alkaline earth metal chloride molten salts than alkaline metal chloride molten salts. For corrosion in mixture salts, the corrosion rate increased with increasing alkaline earth metal chloride salt content in the mixture. Cations in the chloride molten salts mainly affect the thermal and chemical properties of the salts such as vapor pressure and hydroscopicities, which can affect the basicity of the molten salt. Corrosion of Inconel 625 in alkaline earth metal chloride salts is accelerated with increasing basicity.

  2. Effects of crystalline growth on corrosion behaviour of ...

    Indian Academy of Sciences (India)

    tron microscopy and transmission electron microscopy. The corrosion behaviours ... sity and high melting point.7,8 This compound often shows good corrosion and .... Figure 4. TEM image of as-deposited nanocrystalline NiAl coating. Figure 5.

  3. The Effects of Corrosive Chemicals on Corrosion Rate of Steel Reinforcement Bars: I. Swamp Water

    Directory of Open Access Journals (Sweden)

    Sulistyoweni Widanarko

    2010-10-01

    Full Text Available Most of infrastructures using steel concrete to reinforce the strength of concrete. Steel concrete is so vulnerable to chemical compounds that can cause corrosion. It can happen due to the presence of chemical compounds in acid environment in low pH level. These chemical compounds are SO42-, Cl-, NO3-. There are many swamp area in Indonesia. The acid contents and the concentration of ion sulphate, chlorides, and nitrate are higher in the swamp water than in the ground water .The objective of this research was to find out the influence of corrosive chemicals in the swamp water to the steel concrete corrosion rate. There were two treatment used: (1 emerging ST 37 and ST 60 within 60 days in the 'polluted' swamp water, (2 moving the ST 37 up and down periodically in the ' polluted' swamp water. Three variation of 'polluted' swamp water were made by increasing the concentration of corrosive chemical up to 1X, 5X and 10X respectively. The corrosion rate was measured by using an Immersion Method. The result of Immersion test showed that chloride had the greatest influence to corrosion rate of ST 37 and ST 60 and followed by sulphate and Nitrate. Corrosion rate value for ST 37 is 24.29 mpy and for ST 60 is 22.76 mpy. By moving the sample up and down, the corrosion rate of ST 37 increase up to 37.59 mpy, and chloride still having the greatest influence, followed by sulphate and nitrate.

  4. Synergistic Effect of Potassium Iodide on Corrosion Inhibition of Mild ...

    African Journals Online (AJOL)

    MICHAEL

    fruticans' wurmb extract on corrosion of mild steel in 0.1M and 0.5M HCl have been investigated using weight loss methods. ... efficient ways of combating the corrosion of metals. Among other ..... chloride ion on cold rolled steel corrosion.

  5. Effect of Adenine Concentration on the Corrosion Inhibition of Aisi ...

    African Journals Online (AJOL)

    This gave a surface coverage of 0.8956 and corrosion penetration rate of 0.022132mm/yr. Hence, the best adenine concentration for the corrosion inhibition of alloys 304L in 1.0M sulphuric acid solution to obtain optimum inhibition efficiency is 0.011M. Keywords: Corrosion, AISI 304L Steel, Inhibition efficiency, Degree of ...

  6. Temperature effect on Zircaloy-4 stress corrosion cracking

    International Nuclear Information System (INIS)

    Farina, Silvia B.; Duffo, Gustavo S.; Galvele, Jose R.

    1999-01-01

    Stress corrosion cracking (SCC) susceptibility of Zircaloy-4 alloy in chloride, bromide and iodide solutions with variables as applied electrode potential, deformation rate and temperature have been studied. In those three halide solutions the susceptibility to SCC is only observed at potentials close to pitting potential, the crack propagation rate increases with the increase of deformation rate, and that the temperature has a notable effect only for iodide solutions. For chloride and bromide solutions and temperatures ranging between 20 to 90 C degrees it was not found measurable changes in crack propagation rates. (author)

  7. Corrosion/95 conference papers

    International Nuclear Information System (INIS)

    Anon.

    1995-01-01

    The papers in this conference represent the latest technological advances in corrosion control and prevention. The following subject areas are covered: cathodic protection in natural waters; materials for fossil fuel combustion and conversion systems; modern problems in atmospheric corrosion; innovative ideas for controlling the decaying infrastructure; deposits and their effects on corrosion in industry; volatile high temperature and non aqueous corrosion inhibitors; corrosion of light-weight and precoated metals for automotive application; refining industry corrosion; corrosion in pulp and paper industry; arctic/cold weather corrosion; materials selection for waste incinerators and associated equipment; corrosion measurement technology; environmental cracking of materials; advancing technology in the coating industry; corrosion in gas treating; green inhibition; recent advances in corrosion control of rail equipment; velocity effects and erosion corrosion in oil and gas production; marine corrosion; corrosion of materials in nuclear systems; underground corrosion control; corrosion in potable and industrial water systems in buildings and its impact on environmental compliance; deposit related boiler tube failures; boiler systems monitoring and control; recent developments and experiences in reactive metals; microbiologically influenced corrosion; corrosion and corrosion control for steel reinforced concrete; international symposium on the use of 12 and 13 Cr stainless steels in oil and gas production environments; subsea corrosion /erosion monitoring in production facilities; fiberglass reinforced pipe and tubulars in oilfield service; corrosion control technology in power transmission and distribution; mechanisms and methods of scale and deposit control; closing the loop -- results oriented cooling system monitoring and control; and minimization of aqueous discharge

  8. Effects of alpha-decay on spent fuel corrosion behaviour

    International Nuclear Information System (INIS)

    Wiss, T.; Rondinella, V.V.; Cobos, J.; Wegen, D.H.; Amme, M.; Ronchi, C.

    2004-01-01

    An overview of results in the area of spent fuel characterization as nuclear waste is presented. These studies are focused on primary aspects of spent fuel corrosion, by considering different fuel compositions and burn ups, as well as a wide set of environmental conditions. The key parameter is the storage time of the fuel e.g. in view of spent fuel retrieval or in view of its final disposal. To extrapolate data obtainable from a laboratory-acceptable timescale to those expected after storage periods of interest have elapsed (amounting in the extreme case to geological ages) is a tough challenge. Emphasis is put on key aspects of fuel corrosion related to fuel properties at a given age and environmental conditions expected in the repository: e.g. the fuel activity (radiolysis effects), the effects of helium build-up and of groundwater composition. A wide range of techniques, from traditional leaching experiments to advanced electrochemistry, and of materials, including spent fuel with different compositions/burnups and analogues like the so-called alpha-doped UO 2 , are employed for these studies. The results confirm the safety of European underground repository concepts. (authors)

  9. Effect of mechanical treatment on intergranular corrosion of 6064 alloy bars

    Science.gov (United States)

    Sláma, P.; Nacházel, J.

    2017-02-01

    Aluminium Al-Mg-Si-type alloys (6xxx-series) exhibit good mechanical properties, formability, weldability and good corrosion resistance in various environments. They often find use in automotive industry and other applications. Some alloys, however, particularly those with higher copper levels, show increased susceptibility to intergranular corrosion. Intergranular corrosion (IGC) is typically related to the formation of microgalvanic cells between cathodic, more noble phases and depleted (precipitate-free) zones along grain boundaries. It is encountered mainly in AlMgSi alloys containing Cu, where it is thought to be related to the formation Q-phase precipitates (Al4Mg8Si7Cu2) along grain boundaries. The present paper describes the effects of mechanical working (extrusion, drawing and straightening) and artificial aging on intergranular corrosion in rods of the 6064 alloy. The resistance to intergranular corrosion was mapped using corrosion tests according to EN ISO 11846, method B. Corrosion tests showed dependence of corrosion type on mechanical processing of the material. Intergranular, pitting and transgranular corrosion was observed. Artificial ageing influenced mainly the depth of the corrosion.

  10. Effect of Inhibitors on Weld Corrosion under Sweet Conditions Using Flow Channel

    OpenAIRE

    Khaled Alawadhi; Abdulkareem Aloraier; Suraj Joshi; Jalal Alsarraf

    2014-01-01

    The aim of this paper is to compare the effectiveness and electrochemical behavior of typical oilfield corrosion inhibitors with previous oilfield corrosion inhibitors under the same electrochemical techniques to control preferential weld corrosion of X65 pipeline steel in artificial seawater saturated with carbon dioxide at a pressure of one bar. A secondary aim is to investigate the conditions under which current reversal takes place. A flow channel apparatus was used in the laboratory to s...

  11. The Effects of Alloy Chemistry on Localized Corrosion of Austenitic Stainless Steels

    Science.gov (United States)

    Sapiro, David O.

    This study investigated localized corrosion behavior of austenitic stainless steels under stressed and unstressed conditions, as well as corrosion of metallic thin films. While austenitic stainless steels are widely used in corrosive environments, they are vulnerable to pitting and stress corrosion cracking (SCC), particularly in chloride-containing environments. The corrosion resistance of austenitic stainless steels is closely tied to the alloying elements chromium, nickel, and molybdenum. Polarization curves were measured for five commercially available austenitic stainless steels of varying chromium, nickel, and molybdenum content in 3.5 wt.% and 25 wt.% NaCl solutions. The alloys were also tested in tension at slow strain rates in air and in a chloride environment under different polarization conditions to explore the relationship between the extent of pitting corrosion and SCC over a range of alloy content and environment. The influence of alloy composition on corrosion resistance was found to be consistent with the pitting resistance equivalent number (PREN) under some conditions, but there were also conditions under which the model did not hold for certain commercial alloy compositions. Monotonic loading was used to generate SCC in in 300 series stainless steels, and it was possible to control the failure mode through adjusting environmental and polarization conditions. Metallic thin film systems of thickness 10-200 nm are being investigated for use as corrosion sensors and protective coatings, however the corrosion properties of ferrous thin films have not been widely studied. The effects of film thickness and substrate conductivity were examined using potentiodynamic polarization and scanning vibrating electrode technique (SVET) on iron thin films. Thicker films undergo more corrosion than thinner films in the same environment, though the corrosion mechanism is the same. Conductive substrates encourage general corrosion, similar to that of bulk iron

  12. Effect of chlorides on the corrosion behaviour of mild steel

    International Nuclear Information System (INIS)

    Harada, Kazuyuki; Shimada, Minoru

    1980-01-01

    In PWR's steam generators, ''denting'' resulted from corrosion of support plate material, carbon steel is an important problem. The role of chlorides in corrosion acceleration of mild steel was studied. Corrosion tests were conducted at temperature from 100 0 C to 280 0 C in deaerated solutions of NaCl and MgCl 2 which are main content of sea water. 1) Solution of MgCl 2 was more corrosive than that of NaCl. The more increased in concentration of each chloride solution, the more corrosive in MgCl 2 soln. but the less corrosive in NaCl soln. 2) The rate of corrosion in the mixed solution of NaCl and MgCl 2 was governed by the concentration of MgCl 2 soln. The corrosion behaviour in sea water was suggested to be not controlled by NaCl but by MgCl 2 . 3) Acidification of MgCl 2 soln. could be evaluated by experiment at 100 0 C, the degree of acidification increased with increasing the concentration. However, the value of pH during corrosion was kept constant by the concentration of dissolved Fe 2+ ions. 4) The corrosion acceleration by MgCl 2 soln. was arised not only from acidification by the solution itself but from continuous supplementation of H + ions with the hydrolysis of dissolved Fe 2+ ions. This autocatalytic corrosion process not exhausting acid was characterized with the corrosion in closed system such as in crevice. In addition to acidification of MgCl 2 soln., the formation of non-protective magnetite film by Mg 2+ ion was estimated to be a reason of accelerated corrosion. (author)

  13. The Effect of Corrosive Environment on Geopolymer Concrete Tensile Strength

    Directory of Open Access Journals (Sweden)

    Bayuaji Ridho

    2017-01-01

    Full Text Available This study has the purpose to explore the potential of geopolymer concrete tensile strength in particular on the effects of corrosive environments. Geopolymer concrete, concrete technology used no OPC that has advantages, one of which is durability, especially for corrosive seawater environment. In addition, geopolymer concrete with polymerization mechanism does not require large energy consumption or an environmentally friendly concept. Geopolymer concrete in this study is using a type C fly ash from PT. International Power Mitsui Operation & Maintenence Indonesia (IPMOMI Paiton. The type of alkaline activator used NaOH (14 molar and Na2SiO3. Coarse and fine aggregate used are local aggregate. Geopolymer concrete molded test specimen with dimensions of (10 × 20 cm cylinder, further heating and without heating, then maintained at room temperature and seawater up to 28 days. Then to determine the mechanical properties, the tensile strength testing is done with reference. This result of study indicates the curing of geopolymer concrete at 60 ° C for 24 hours to raise the tensile strength of geopolymer concrete.

  14. Effect of Copper on Passivity and Corrosion Behavior of Fe-xC-5Cu ...

    African Journals Online (AJOL)

    ... copper/microstructure is discussed. Alloying Cu showed a beneficial effect on hypoeutectoid steel and harmful effect on hypereutectoid steel. The improved corrosion resistance is related to cementite morphology and by a copper dissolution/re-deposition process. Keywords: Corrosion; Copper; cementite; EIS; Passivation ...

  15. Effects of annealing on tensile property and corrosion behavior of Ti-Al-Zr alloy

    International Nuclear Information System (INIS)

    Kim, Tae-Kyu; Choi, Byung-Seon; Jeong, Yong-Hwan; Lee, Doo-Jeong; Chang, Moon-Hee

    2002-01-01

    The effects of annealing on the tensile property and corrosion behavior of Ti-Al-Zr alloy were evaluated. The annealing in the temperature range from 500 to 800 deg. C for 1 h induced the growth of the grain and the precipitate sizes. The results of tensile tests at room temperature showed that the strengths and the ductility were almost independent of the annealing temperature. However, the results of corrosion test in an ammonia aqueous solution of pH 9.98 at 360 deg. C showed that the corrosion resistance depended on the annealing temperature, and the corrosion rate was accelerated with increasing annealing temperature. Hydrogen contents absorbed during the corrosion test of 220 days also increased with the annealing temperature. It could be attributed to the growth of Fe-rich precipitates by annealing. It is thus suggested that the lower annealing temperatures provide the better corrosion properties without degrading the tensile properties

  16. Effects of annealing on the corrosion behavior and mechanical properties of Ti-Al-V alloy

    International Nuclear Information System (INIS)

    Kim, T. K.; Choi, B. S.; Baek, J. H.; Choi, B. K.; Jeong, Y. H.; Lee, D. J.; Jang, M. H.; Jeong, Y. H.

    2002-01-01

    In order to determine the annealing condition after cold rolling, the effects of annealing on the corrosion behavior and mechanical properties of Ti-Al-V alloy were evaluated. The results of tensile tests at room temperature showed that the strengths and the ductility were almost independent of the annealing temperature. The results of hardness test also revealed that the hardness was independent of the annealing, However, the results of corrosion test in an ammoniated water of pH 9.98 at 360 .deg. C showed that the corrosion resistance depended on the annealing temperature, and the corrosion rate was accelerated with increasing annealing temperature. Hydrogen contents absorbed during the corrosion test of 120 days also increased with the annealing temperature. It may be attributed to the growth of α' precipitates by annealing. It is thus suggested that the lower annealing temperatures provide the better corrosion properties without degrading the tensile properties

  17. Effect of Biodiesel Concentration on Corrosion of Carbon Steel by Serratia marcescens

    Directory of Open Access Journals (Sweden)

    Pusparizkita Yustina M

    2018-01-01

    Full Text Available Biodiesel come into being used as an alternative source of energy as the diminishing of petroleum reserves. This fuel is typically stored in tanks that are commonly made from carbon steel, which is easily corroded by microorganisms. Recent studies have shown that bacteria aside from SRB may also be involved in corrosion. Therefore, this research was aimed to evaluate the effect of biodiesel concentration (15%, 20% and 30% v/v mixed in diesel oil on the corrosion of carbon steel by S. marcescens that dominate biocorrosion on hydrocarbon products. In this study, the corrosion process was investigated by evaluation of biofilm morphology and composition, the rate of corrosion and the corrosion product of carbon steel which was exposed in the mixture of hydrocarbons and the presence of S. marcescens. It can be concluded that higher concentration of biodiesel in diesel oil leads to higher growth of bacteria in the biofilm and higher corrosion rate.

  18. Effect of Surface Precipitate on the Crevice Corrosion in HYBRID and Oxalic Acid Solution

    International Nuclear Information System (INIS)

    Park, S. Y.; Jung, J. Y.; Won, H. J.; Kim, S. B.; Choi, W. K.; Moon, J. K.; Park, S. J.

    2015-01-01

    In this study, we investigated the characteristics of the crevice corrosion for Inconel-600 and 304SS in OA solution according to the change in pH. The evaluation of the crevice corrosion with the chemical thermodynamic analysis identified the effect of the residual chemicals such as iron-oxalate and nickeloxalate to the crevice corrosion behavior. Test results were compared with those of HYBRID (HYdrizine Base Reductive metal Ion Decontamination). The crevice corrosion properties of 304 SS and Inconel-600 in HYBRID and oxalic acid solution were evaluated. In case of oxalic acid solution, the corrosion rate on 304SS was rapidly increased with a pH decrease of around 2, but there was no increase in the corrosion rate on Inconel-600

  19. The effect of urea on the corrosion behavior of different dental alloys.

    Science.gov (United States)

    Geckili, Onur; Bilhan, Hakan; Bilgin, Tayfun; Anthony von Fraunhofer, J

    2012-01-01

    Intraoral corrosion of dental alloys has biological, functional, and esthetic consequences. Since it is well known that the salivary urea concentrations undergo changes with various diseases, the present study was undertaken to determine the effect of salivary urea concentrations on the corrosion behavior of commonly used dental casting alloys. Three casting alloys were subjected to polarization scans in synthetic saliva with three different urea concentrations. Cyclic polarization clearly showed that urea levels above 20 mg/100 ml decreased corrosion current densities, increased the corrosion potentials and, at much higher urea levels, the breakdown potentials. The data indicate that elevated urea levels reduced the corrosion susceptibility of all alloys, possibly through adsorption of organics onto the metal surface. This study indicates that corrosion testing performed in sterile saline or synthetic saliva without organic components could be misleading.

  20. Effect of chloride concentration and pH on pitting corrosion of waste package container materials

    International Nuclear Information System (INIS)

    Roy, A.K.; Fleming, D.L.; Gordon, S.R.

    1996-12-01

    Electrochemical cyclic potentiodynamic polarization experiments were performed on several candidate waste package container materials to evaluate their susceptibility to pitting corrosion at 90 degrees C in aqueous environments relevant to the potential underground high-level nuclear waste repository. Results indicate that of all the materials tested, Alloy C-22 and Ti Grade-12 exhibited the maximum corrosion resistance, showing no pitting or observable corrosion in any environment tested. Efforts were also made to study the effect of chloride ion concentration and pH on the measured corrosion potential (Ecorr), critical pitting and protection potential values

  1. Effect of nitrogen alloying of stainless steels on their corrosion stability

    International Nuclear Information System (INIS)

    Chigal, V.; Knyazheva, V.M.; Pitter, Ya.; Babich, S.G.; Bogolyubskij, S.D.

    1986-01-01

    Results of corrosion tests and structural investigations of 03Cr18Ni10 and 03Cr18Ni10Mo3 steels without nitrogen and with nitrogen content of 0.15-0.3% are presented. Corrosion-electrochemical behaviour of Cr20Ni20 steel with ultralow carbon content (0.004-0.006%) and nitrogen content with 0-0.5% as well as Cr 2 N nitride behaviour are investigated. A conclusion is made on nitrogen and excessive nitride phase effect on corrosion stability of steel in corrosive media with different reduction-oxidation properties

  2. Effect of heating rate on caustic stress corrosion cracking

    International Nuclear Information System (INIS)

    Indig, M.E.; Hoffman, N.J.

    1977-01-01

    To evaluate effects of a large water leak into the sodium side of a steam generator in a Liquid Metal Fast Breeder Reactor the Liquid Metal Engineering Center (LMEC) at Canoga Park, California, is performing a series of tests in a Large Leak Test Rig (LLTR). This test series involves heating a large steam generator that possibly contains localized pockets of aqueous caustic retained from a previous sodium-water reaction. Such pockets of caustic solution could be in contact with welds and other components that contain residual stresses up to the yield point. The LMEC and General Electric (GE) ran a series of tests to evaluate the effect of heating rate on caustic stress corrosion cracking (SCC) for alloys either used or considered for the LLTR. A summary of the temperatures and caustic concentration ranges that can result in caustic SCC for carbon steel and Type-304 stainless steel is given

  3. The effect of zinc addition on PWR corrosion product deposition on zircaloy-4

    International Nuclear Information System (INIS)

    Walters, W.S.; Page, J.D.; Gaffka, A.P.; Kingsbury, A.F.; Foster, J.; Anderson, A.; Wickenden, D.; Henshaw, J.; Zmitko, M.; Masarik, V.; Svarc, V.

    2002-01-01

    During the period 1995 to 2001 a programme of loop irradiation tests have been performed to confirm the effectiveness of zinc additions on PWR circuit chemistry and corrosion. The programme included two loop irradiation experiments, and subsequent PIE; the experiments were a baseline test (no added zinc) and a test with added zinc (10 ppb). This paper addresses the findings regarding corrosion product deposition and activation on irradiated Zircaloy-4 surfaces. The findings are relevant to overall corrosion of the reactor primary circuit, the use of zinc as a corrosion inhibitor, and activation and transport of corrosion products. The irradiation experience provides information on the equilibration of the loop chemistry, with deliberate injection of zinc. The PIE used novel and innovative techniques (described below) to obtain samples of the oxide from the irradiated Zircaloy. The results of the PIE, under normal chemistry and zinc chemistry, indicate the effect of zinc on the deposition and activation of corrosion products on Zircaloy. It was found that corrosion product deposition on Zircaloy is enhanced by the addition of zinc (but corrosion product deposition on other materials was reduced in the presence of zinc). Chemical analysis and radioisotope gamma counting results are presented, to interpret the findings. A computer model has also been used to simulate the corrosion product deposition and activation, to assist in the interpretation of the results. (authors)

  4. Evaluation of the flow-accelerated corrosion downstream of an orifice. 2. Measurement of corrosion rate and evaluation on the effects of the flow field

    International Nuclear Information System (INIS)

    Nagaya, Yukinori; Utanohara, Yoichi; Nakamura, Akira; Murase, Michio

    2008-01-01

    In this study, in order to evaluate the effects of flow field on corrosion rate due to flow accelerated corrosion (FAC), a corrosion rate downstream of an orifice was measured using the electric resistance method. The diameter of the pipe is 50 mm and that of the orifice is 24.3 mm, and flow velocity of the experimental loop was set at 5m/s, and the temperature of water was controlled within ±1 at 150deg-C. There were no significant circumferential difference in measured corrosion rate, and the maximum corrosion rate was observed at 1D or 2D downstream from the orifice. The ratios of the measured corrosion rate and the calculated wall shear stress at the 1D downstream from the orifice to the value at upstream under well developed flow agreed well. (author)

  5. Microbial exopolysaccharides: Effect on corrosion and partial chemical characterization

    Digital Repository Service at National Institute of Oceanography (India)

    Majumdar, I; DeSouza, F.P.; Bhosle, N.B.

    gas chromatograph MICROBIAL EXOPOLYSACCHARIDES 543 Fig. I. Changes in the biofilm organic carbon (a) and EPS (b) associated with corrosion products and corrosion rate (c) of mild steel. Fig. 2. Linear correlation coeffiient (r) between EPS and organic... carbon (a), corrosion rate and organic carbon (b). and corrosion rate and EPS (c). (Chrompack model CP-9002) equipped with a fused silica capillary column coated with CP Sil-88 (25 m, i.d. = 0.32 mm) and flame ionization detector (FID) was used...

  6. Effect of grain size on corrosion of nanocrystalline copper in NaOH solution

    International Nuclear Information System (INIS)

    Luo Wei; Xu Yimin; Wang Qiming; Shi Peizhen; Yan Mi

    2010-01-01

    Research highlights: → Coppers display an active-passive-transpassive behaviour with duplex passive film. → Grain size variation has little effect on the overall corrosion behaviour of Cu. → Little effect on corrosion may be due to duplex passivation in NaOH solution. → Bulk nanocrystalline Cu show bamboo-like flake corrosion structure. - Abstract: Effect of grain size on corrosion of bulk nanocrystalline copper was investigated using potentiodynamic polarization measurements in 0.1 M NaOH solution. Bulk nanocrystalline copper was prepared by inert gas condensation and in situ warm compress (IGCWC) method. The grain sizes of all bulk nanocrystalline samples were determined to be 48, 68 and 92 nm using X-ray diffraction (XRD). Results showed that bulk coppers displayed an active-passive-transpassive behaviour with duplex passive films. From polycrystalline to nanocrystalline, grain size variation showed little effect on the overall corrosion resistance of copper samples.

  7. Zinc corrosion after loss-of-coolant accidents in pressurized water reactors – Physicochemical effects

    Energy Technology Data Exchange (ETDEWEB)

    Kryk, Holger, E-mail: h.kryk@hzdr.de [Helmholtz-Zentrum Dresden-Rossendorf, Institute of Fluid Dynamics, P.O. Box 510119, D-01314 Dresden (Germany); Hoffmann, Wolfgang [Helmholtz-Zentrum Dresden-Rossendorf, Institute of Fluid Dynamics, P.O. Box 510119, D-01314 Dresden (Germany); Kästner, Wolfgang; Alt, Sören; Seeliger, André; Renger, Stefan [Hochschule Zittau/Görlitz, Institute of Process Technology, Process Automation and Measuring Technology, Theodor-Körner-Allee 16, D-02763 Zittau (Germany)

    2014-12-15

    Highlights: • Physicochemical effects due to post-LOCA zinc corrosion in PWR were elucidated. • Decreasing solubility of corrosion products with increasing temperature was found. • Solid corrosion products may be deposited on hot surfaces and/or within hot-spots. • Corrosion products precipitating from coolant were identified as zinc borates. • Depending on coolant temperature, different types of zinc borate are formed. - Abstract: Within the framework of the reactor safety research, generic experimental investigations were carried out aiming at the physicochemical background of possible zinc corrosion product formation, which may occur inside the reactor pressure vessel during the sump circulation operation after loss-of-coolant accidents in pressurized water reactors. The contact of the boric acid containing coolant with hot-dip galvanized steel containment internals causes corrosion of the corresponding materials resulting in dissolution of the zinc coat. A retrograde solubility of zinc corrosion products with increasing temperature was observed during batch experiments of zinc corrosion in boric acid containing coolants. Thus, the formation and deposition of solid corrosion products cannot be ruled out if the coolant containing dissolved zinc is heated up during its recirculation into hot regions within the emergency cooling circuit (e.g. hot-spots in the core). Corrosion experiments at a lab-scale test facility, which included formation of corrosion products at a single heated cladding tube, proved that dissolved zinc, formed at low temperatures in boric acid solution by zinc corrosion, turns into solid deposits of zinc borates when contacting heated zircaloy surfaces during the heating of the coolant. Moreover, the temperature of formation influences the chemical composition of the zinc borates and thus the deposition and mobilization behavior of the products.

  8. Zinc corrosion after loss-of-coolant accidents in pressurized water reactors – Physicochemical effects

    International Nuclear Information System (INIS)

    Kryk, Holger; Hoffmann, Wolfgang; Kästner, Wolfgang; Alt, Sören; Seeliger, André; Renger, Stefan

    2014-01-01

    Highlights: • Physicochemical effects due to post-LOCA zinc corrosion in PWR were elucidated. • Decreasing solubility of corrosion products with increasing temperature was found. • Solid corrosion products may be deposited on hot surfaces and/or within hot-spots. • Corrosion products precipitating from coolant were identified as zinc borates. • Depending on coolant temperature, different types of zinc borate are formed. - Abstract: Within the framework of the reactor safety research, generic experimental investigations were carried out aiming at the physicochemical background of possible zinc corrosion product formation, which may occur inside the reactor pressure vessel during the sump circulation operation after loss-of-coolant accidents in pressurized water reactors. The contact of the boric acid containing coolant with hot-dip galvanized steel containment internals causes corrosion of the corresponding materials resulting in dissolution of the zinc coat. A retrograde solubility of zinc corrosion products with increasing temperature was observed during batch experiments of zinc corrosion in boric acid containing coolants. Thus, the formation and deposition of solid corrosion products cannot be ruled out if the coolant containing dissolved zinc is heated up during its recirculation into hot regions within the emergency cooling circuit (e.g. hot-spots in the core). Corrosion experiments at a lab-scale test facility, which included formation of corrosion products at a single heated cladding tube, proved that dissolved zinc, formed at low temperatures in boric acid solution by zinc corrosion, turns into solid deposits of zinc borates when contacting heated zircaloy surfaces during the heating of the coolant. Moreover, the temperature of formation influences the chemical composition of the zinc borates and thus the deposition and mobilization behavior of the products

  9. The effect of conditioning agents on the corrosive properties of molten urea

    Energy Technology Data Exchange (ETDEWEB)

    Nichols, D E; Nguyen, D T; Norton, M M; Parker, B R; Daniels, L E

    1991-01-01

    From the process case histories of the failure of several heat exchanger tube bundles, it was revealed that molten urea containing lignosulfonate as a granulation conditioning-hardening agent (Urea LS[trademark]) is corrosive to Types 304 and 316 stainless steel. The results of field and laboratory immersion corrosion tests indicated that the corrosivity of molten urea is strongly dependent on the process temperature rather than the conditioner composition. At temperatures below 295F, molten Urea LS[trademark] is not aggressive to these stainless steels. However, at temperatures above 300F, the corrosion of these stainless steels is extremely severe. The corrosion rate of Types 304, 304L, 316, and 316L is as high as hundreds of mils per year. The corrosion mechanism tends to be more general than localized. The results of the laboratory corrosion test also revealed that among alloying elements, copper is detrimental to corrosion resistance of stainless steel exposed to molten Urea LS[trademark], chromium is the most beneficial, and nickel has only a minor effect. Thus, copper-free and chromium stainless steels have superior corrosion resistance to the molten Urea LS[trademark] at a wide range of temperatures up to 345F.

  10. Area effect on galvanic corrosion of condenser materials with titanium tubes in nuclear power plants

    International Nuclear Information System (INIS)

    Hwang, Seong Sik; Kim, Joung Soo; Kim, Uh Chul

    1993-01-01

    Titanium tubes have recently been used in condensers of nuclear power plants since titanium has very good corrosion resistance to seawater. However, when it is connected to Cu alloys as tube sheet materials and these Cu alloys are connected to carbon steels as water box materials, it makes significant galvanic corrosion on connected materials. It is expected from electrochemical tests that the corrosion rate of carbon steel will increase when it is galvanically coupled with Ti or Cu in sea water and the corrosion rate of Cu will increase when it is coupled with Ti, of this couple is exposed to sea water for a long time. It is also expected that the surface area ratios, R 1 (surface area of carbon steel/surface area of Ti) and R 2 (surface area of carbon steel/surface area of Cu) are very improtant for the galvanic corrosion of carbon steel and that these should not be kept to low values in order to minimize the galvanic corrosion on the carbon steel of the water box. Immersed galvanic corrosion tests show that the corrosion rate of carbon steel is 4.4 mpy when this ratio is 10 -2 . The galvanic corrosion rate of this carbon steel is increased from 4.4 mpy to 13 mpy at this area ratio, 1, when this connected galvanic specimen is galvanically coupled with a Ti tube. This can be rationalized by the combined effects of R 1 and R 2 on the polarization curve. (Author)

  11. Corrosion and protection in reinforced concrete : Pulse cathodic protection: an improved cost-effective alternative

    NARCIS (Netherlands)

    Koleva, D.A.

    2007-01-01

    Corrosion and protection in reinforced concrete. Pulse cathodic protection: an improved cost-effective alternative. The aim of the research project was to study the possibilities for establishing a new or improved electrochemical method for corrosion prevention/protection for reinforced concrete.

  12. Effectiveness of resins/exudates of trees in corrosion prevention of ...

    African Journals Online (AJOL)

    Corrosion of steel reinforcement is one of the important factors that are responsible for the short service life of reinforced concrete members, in marine structures like bridges, piers and jetties. This study, investigated the effectiveness of resin/exuda tes in corrosion prevention of reinforcement in reinforced concrete cubes.

  13. Evaluation of austenitic stainless steels for transpassive corrosion by metal purification technology. Synergistic effect of Si and P on intergranular corrosion of Fe-18Cr-14Ni alloys

    International Nuclear Information System (INIS)

    Mayuzumi, Masami; Ohta, Joji; Kako, Kenji; Kawakami, Eishi

    2001-01-01

    The synergistic effect of Si, Mn, C, P, and S on the transpassive corrosion of HP18Cr-14Ni alloys was studied in 13N nitric acid. The specimens were fabricated using a cold crucible method in a high-vacuum chamber to reduce contamination. The additions of Si<1% and Mn<2% had no effect on the corrosion behavior of HP18Cr-14Ni alloys, and the addition of Si<1% also had no effect on the corrosion behavior of HP18Cr-14Ni-1Mn alloys, although 1% Si induced intergranular corrosion in both the alloys. Thus, HP18Cr-14Ni-1Mn-0.5Si alloys were selected to evaluate the effects of C, P and S (100 ppm each). The addition of P, and the co-addition of C, P, and S to HP18Cr-14Ni-1Mn-0.5Si induced intergranular corrosion of the same degree in the solution annealed condition. This result suggests the synergistic effect of Si and P to induce intergranular corrosion, since the single addition of Si or P to this level did not lead to intergranular corrosion of HP18Cr-14Ni alloys. HP18Cr-14Ni-1Mn-0.5Si alloys containing C, P, and S at the 100 ppm level each showed superior corrosion resistance compared to a commercial Type 304L in 13N nitric acid. (author)

  14. Corrosion behavior of Zircaloy 4 cladding material. Evaluation of the hydriding effect

    International Nuclear Information System (INIS)

    Blat, M.

    1997-04-01

    In this work, particular attention has been paid to the hydriding effect in PIE and laboratory test to validate a detrimental hydrogen contribution on Zircaloy 4 corrosion behavior at high burnup. Laboratory corrosion tests results confirm that hydrides have a detrimental role on corrosion kinetics. This effect is particularly significant for cathodic charged samples with a massive hydride outer layer before corrosion test. PIE show that at high burnup a hydride layer is formed underneath the metal/oxide interface. The results of the metallurgical examinations are discussed with respect to the possible mechanisms involved in this detrimental effect of hydrogen. Therefore, according to the laboratory tests results and PIE, hydrogen could be a strong contributor to explain the increase in corrosion rate at high burnup. (author)

  15. Effects of alloying elements on nodular and uniform corrosion resistance of zirconium-based alloys

    International Nuclear Information System (INIS)

    Abe, Katsuhiro

    1992-01-01

    The effects of alloying and impurity elements (tin, iron, chromium, nickel, niobium, tantalum, oxygen, aluminum, carbon, nitrogen, silicon, and phosphorus) on the nodular and uniform corrosion resistance of zirconium-based alloys were studied. The improving effect of iron, nickel and niobium in nodular corrosion resistance were observed. The uniform corrosion resistance was also improved by nickel, niobium and tantalum. The effects of impurity elements, nitrogen, aluminum and phosphorus were negligibly small but increasing the silicon content seemed to improve slightly the uniform corrosion resistance. Hydrogen pick-up fraction were not changed by alloying and impurity elements except nickel. Nickel addition increased remarkably hydrogen pick-up fraction. Although the composition of secondary precipitates changed with contents of alloying elements, the correlation of composition of secondary precipitates to corrosion resistance was not observed. (author)

  16. 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.)

  17. effect of municipal liquid waste on corrosion susceptibility

    African Journals Online (AJOL)

    DR. AMINU

    Kogo, A. A.. Department of Integrated Science, Federal College of Education, Kano, Nigeria. ... The corrosion rate of the galvanized steel pipe was measured using the gravimetric ... Key words: Liquid waste, galvanized steel, weight loss, gravimetric, corrosion, leaking ... the side of the test tubes, so that each side would be.

  18. Inhibition Effect of Deanol on Mild Steel Corrosion in Dilute ...

    African Journals Online (AJOL)

    NICOLAAS

    2014-06-23

    Jun 23, 2014 ... The influence of deanol on the corrosion behaviour of mild steel in dilute sulphuric acid with sodium ... the formation of a complex precipitate of protective film, which ... silicon carbide abrasive papers of 80, 120, 220, 800 and 1000 grit ...... ions in sulphuric acid on the corrosion behaviour of stainless steel,.

  19. Effects of microbial redox cycling of iron on cast iron pipe corrosion in drinking water distribution systems.

    Science.gov (United States)

    Wang, Haibo; Hu, Chun; Zhang, Lili; Li, Xiaoxiao; Zhang, Yu; Yang, Min

    2014-11-15

    Bacterial characteristics in corrosion products and their effect on the formation of dense corrosion scales on cast iron coupons were studied in drinking water, with sterile water acting as a reference. The corrosion process and corrosion scales were characterized by electrochemical and physico-chemical measurements. The results indicated that the corrosion was more rapidly inhibited and iron release was lower due to formation of more dense protective corrosion scales in drinking water than in sterile water. The microbial community and denitrifying functional genes were analyzed by pyrosequencing and quantitative polymerase chain reactions (qPCR), respectively. Principal component analysis (PCA) showed that the bacteria in corrosion products played an important role in the corrosion process in drinking water. Nitrate-reducing bacteria (NRB) Acidovorax and Hydrogenophaga enhanced iron corrosion before 6 days. After 20 days, the dominant bacteria became NRB Dechloromonas (40.08%) with the protective corrosion layer formation. The Dechloromonas exhibited the stronger corrosion inhibition by inducing the redox cycling of iron, to enhance the precipitation of iron oxides and formation of Fe3O4. Subsequently, other minor bacteria appeared in the corrosion scales, including iron-respiring bacteria and Rhizobium which captured iron by the produced siderophores, having a weaker corrosion-inhibition effect. Therefore, the microbially-driven redox cycling of iron with associated microbial capture of iron caused more compact corrosion scales formation and lower iron release. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Effect of Ti3+ ion on the Corrosion Behavior of Alloy 600

    International Nuclear Information System (INIS)

    Lee, Chang Bong; Lim, Han Gwi; Kim, Bok Hee; Kim, Ki Ju

    1999-01-01

    Alloy 600 has been widely used as a steam generator tubing material in pressurized water reactors(PWRs) nuclear power plants. Corrosion of steam generator tubing mainly occurs on the secondary water side. The purpose of this work is primarily concerned with examining the effect of Ti 3+ ion concentrations on the corrosion behavior of the Alloy 600 steam generator tubing material. Corrosion behavior of the Alloy 600 steam generator tubing material was studied in aqueous solutions with varying Ti 3+ ion concentration at room temperature. Potentiodynamic and potentiostatic polarization techniques were used to determine the corrosion and pitting potentials for the Alloy 600 test material. The addition of Ti 3+ ion to 1000ppm, showed inhibition effect on the corrosion of Alloy 600. But the corrosion of Alloy 600 was accelerated when the concentration of Ti 3+ ion exceeded 1000ppm, it is assumed that the effect of general corrosion of Alloy 600 is more sensitive than pitting corrosion. It is considered that the passive film which was formed on the Alloy 600 surface in the 100ppm Ti 3+ ion containing solution is mainly consisted of TiO 2

  1. Corrosion of alloy 22 in phosphate ions effect and chloride containing solutions

    International Nuclear Information System (INIS)

    Carranza, Ricardo M.

    2009-01-01

    Alloy 22 belongs to Ni-Cr-Mo family. This alloy resists the most aggressive environments for industrial applications, in oxidizing as well as reducing conditions, because exhibits an excellent uniform and localized corrosion resistance in aqueous solution. Because of its outstanding corrosion resistant, this alloy is one of the candidate to be considered for the outer shell of the canister that would contain high level radioactive nuclear wastes in a geological repository. The aim of this work is to study ion phosphate influence over Alloy 22 corrosion behavior under aggressive conditions, such as high temperature and high ion chloride concentration, where this material might be susceptible to crevice corrosion. Two different types of samples were used: cylinder specimens for uniform corrosion behavior studies and Prismatic Crevice Assembly (PCA) specimens for localized corrosion studies. Electrochemical tests were performed in deaerated aqueous solution of 1 M NaCl and 1 M NaCl with different phosphate additions at 90 C degrees and pH near neutral. The anodic film and corrosion products obtained were studied by SEM/EDS. Cyclic Potentiodynamic Polarization (CPP) curves obtained for uniform corrosion studies, showed an increase of the passivity range in phosphate containing solutions. The passive current value was 1 μA/cm 2 approximately in all the tests. PCA electrochemical tests, that combined a CPP with a potentiostatic polarization step for 2 hours in between the forward and reverse scan, showed crevice corrosion development in some cases. The repassivation potential value, determined by the intersection of the forward and the reverse scan, increased with phosphate addition. A complete crevice corrosion inhibition effect was found for phosphate concentration higher than 0.3 M. These results indicate that the passivity potential range depend on phosphate presence and might be related with the incorporation of the anion in the passive film. Results of the tests

  2. The effects of heat treatment and environment on corrosion fatigue

    International Nuclear Information System (INIS)

    Ballinger, R.G.; Hwang, I.S.; Elliott, C.K.

    1993-05-01

    Alloy X-750 is a nickel-base alloy used extensively in Light Water Reactor (LWR) nuclear power systems due to its excellent corrosion resistance and high temperature strength. In spite of alloy X-750's exceptional high temperature properties, it has been found to be susceptible to environmentally assisted fatigue and stress corrosion cracking in relatively low temperature aqueous environments such as those that exist in LWR systems. In order to develop a better understanding of the role that microstructure plays in the fatigue behavior of alloy X-750, three thermal treatments were studied. The treatments used were as hot worked + : (1) 24 h at 885 degree C + 20 h at 704 degree C (AH), (2) lh at 982 degree C + 20 h at 704 degree C (BH), and (3) 1 h at 1093 degree C + 20 h at 704 degree C (HTH). Fatigue crack growth tests were conducted at frequencies of 0.1 and 10 Hz in the following aqueous environments: (1) high purity, air saturated water (8 ppM O 2 ) at 93 degree C and 288 degree C, (2) high purity, deoxygenated water (5 ppb O 2 ) at 93 degree C, and (3) simulated BWR water chemistry with hydrogen additions at 288 degree C. Crack growth rate data was collected at constant values of stress intensity factor range (ΔK). The results show that crack growth rates and morphology are a function of ΔK, frequency, thermal treatment and environment. Frequency effects were most significant for the AH material. Crack growth rates generally decrease, for a given value of ΔK, in the BH and HTH materials with the HTH material showing the lowest growth rate

  3. The effect of corrosion on the structural reliability of steel offshore structures

    International Nuclear Information System (INIS)

    Melchers, Robert E.

    2005-01-01

    This paper considers essential theoretical concepts and data requirements for engineering structural reliability assessment suitable for the estimation of the safety and reliability of corroding ships, offshore structures and pipelines. Such infrastructure operates in a harsh environment. Allowance must be made for structural deterioration since protective measures such as paint coatings, galvanizing or cathodic protection may be ineffective. Reliability analysis requires accurate engineering models for the description and prediction of material corrosion loss and for the maximum depth of pitting. New probability-based models for both these forms of corrosion have been proposed recently and calibrated against a wide range of data. The effects of water velocity and of water pollution are reviewed and compared with recently reported field data for a corrosion at an offshore oil platform. The data interpreted according to the model show good correlation when allowance is made for the season of first immersion and the adverse effects of seawater velocity and of water pollution. An example is given to illustrate the application of reliability analysis to a pipeline subject to pitting corrosion. An important outcome is that good quality estimation of the longer-term probability of loss of structural integrity requires good modelling of the longer-term corrosion behaviour. This is usually associated with anaerobic corrosion. As a result, it cannot be extrapolated from data for short-term corrosion as this is associated with aerobic corrosion conditions

  4. The effect of corrosion on the structural reliability of steel offshore structures

    Energy Technology Data Exchange (ETDEWEB)

    Melchers, Robert E. [Centre for Infrastructure Performance and Reliability, Department of Civil, Surveying and Environmental Engineering, School of Engineering, University of Newcastle, University Drive, Callaghan NSW 2300 (Australia)]. E-mail: rob.melchers@newcastle.edu.au

    2005-10-01

    This paper considers essential theoretical concepts and data requirements for engineering structural reliability assessment suitable for the estimation of the safety and reliability of corroding ships, offshore structures and pipelines. Such infrastructure operates in a harsh environment. Allowance must be made for structural deterioration since protective measures such as paint coatings, galvanizing or cathodic protection may be ineffective. Reliability analysis requires accurate engineering models for the description and prediction of material corrosion loss and for the maximum depth of pitting. New probability-based models for both these forms of corrosion have been proposed recently and calibrated against a wide range of data. The effects of water velocity and of water pollution are reviewed and compared with recently reported field data for a corrosion at an offshore oil platform. The data interpreted according to the model show good correlation when allowance is made for the season of first immersion and the adverse effects of seawater velocity and of water pollution. An example is given to illustrate the application of reliability analysis to a pipeline subject to pitting corrosion. An important outcome is that good quality estimation of the longer-term probability of loss of structural integrity requires good modelling of the longer-term corrosion behaviour. This is usually associated with anaerobic corrosion. As a result, it cannot be extrapolated from data for short-term corrosion as this is associated with aerobic corrosion conditions.

  5. The effects of argon ion bombardment on the corrosion resistance of tantalum

    Science.gov (United States)

    Ramezani, A. H.; Sari, A. H.; Shokouhy, A.

    2017-02-01

    Application of ion beam has been widely used as a surface modification method to improve surface properties. This paper investigates the effect of argon ion implantation on surface structure as well as resistance against tantalum corrosion. In this experiment, argon ions with energy of 30 keV and in doses of 1 × 1017-10 × 1017 ions/cm2 were used. The surface bombardment with inert gases mainly produces modified topography and morphology of the surface. Atomic Force Microscopy was also used to patterned the roughness variations prior to and after the implantation phase. Additionally, the corrosion investigation apparatus wear was applied to compare resistance against tantalum corrosion both before and after ion implantation. The results show that argon ion implantation has a substantial impact on increasing resistance against tantalum corrosion. After the corrosion test, scanning electron microscopy (SEM) analyzed the samples' surface morphologies. In addition, the elemental composition is characterized by energy-dispersive X-ray (EDX) analysis. The purpose of this paper was to obtain the perfect condition for the formation of tantalum corrosion resistance. In order to evaluate the effect of the ion implantation on the corrosion behavior, potentiodynamic tests were performed. The results show that the corrosion resistance of the samples strongly depends on the implantation doses.

  6. The effects of water radiolysis on the corrosion and stress corrosion behavior of type 316 stainless steel in pure water

    International Nuclear Information System (INIS)

    Wyllie, W.E. II; Duquette, D.J.; Steiner, D.

    1994-11-01

    In the ITER Conceptual Design Activity, water will be used as coolant for the major reactor components, which will be made of solution-annealed 316 SS. A concern is that the radiolysis products may increase the stress corrosion cracking (SCC) susceptibility of 316 SS. The corrosion and stress corrosion of 316 SS was observed under irradiated and nonirradiated conditions. Gamma irradiation produced a 100 mV potential shift in the active direction, probably from the polarizing effect of reducing radiolysis products. The irradiation also resulted in nearly an order of magnitude increase in the passive current density of 316 SS, probably from increased surface reaction rates involving radiolysis products as well as increased corrosion rates; however the latter was considered insignificant. Computer simulations of pure water radiolysis at 50, 90, and 130 C and dose rates of 10 18 -10 24 were performed; effects of hydrogen, argon, and argon + 20% oxygen deaeration were also studied. Slow strain rate suggest that annealed and sensitized 316 SS was not suscepible to SCC in hydrogen- or argon-deaerated water at 50 C. Modeling of irradiated water chemistry was performed. Open circuit potential of senstizied and annealed 316 SS had a shift of 800 mV in the noble (positive) direction. Steady-state potentials of -0.180 V for sensitized 316 SS wire and -0.096 V vs Hg/HgSO 4 for annealed 316 SS wire were independent of oxygen presence. The -0.180 V shift is likely to promote SCC

  7. Effect of water chemistry on corrosion of stainless steel and deposition of corrosion products in high temperature pressurised water

    International Nuclear Information System (INIS)

    Morrison, Jonathan; Cooper, Christopher; Ponton, Clive; Connolly, Brian; Banks, Andrew

    2012-09-01

    In any water-cooled nuclear reactor, the corrosion of the structural materials in contact with the coolant and the deposition of the resulting oxidised species has long been an operational concern within the power generation industry. Corrosion of the structural materials at all points in the reactor leads to low concentrations of oxidised metal species in the coolant water. The oxidised metal species can subsequently be deposited out as CRUD deposits at various points around the reactor's primary and secondary loops. The deposition of soluble oxidised material at any location in the reactor cooling system is undesirable due to several effects; deposits have a porous structure, capable of incorporating radiologically active material (forming out of core radiation fields) and concentrating aggressively corrosive chemicals, which exacerbate environmental degradation of structural and fuel-cladding materials. Deposits on heat transfer surfaces also limit efficiency of the system as a whole. The work in this programme is an attempt to determine and understand the fundamental corrosion and deposition behaviour under controlled, simulated reactor conditions. The rates of corrosion of structural materials within pressurised water reactors are heavily dependent on the condition of the exposed surface. The effect of mechanical grinding and of electropolishing on the corrosion rate and structure of the resultant oxide film formed on grade 316L stainless steel exposed to high purity water, modified to pH 9.5 and 10.5 at temperatures between 200 and 300 deg. C and pressures of up to 100 bar will be investigated. The corrosion of stainless steel in water via electrochemical oxidation leads to the formation of surface iron, nickel and chromium based spinels. Low concentrations of these spinels can be found dissolved in the coolant water. The solubility of magnetite, stainless steels' major corrosion product, in high purity water will be studied at pH 9.5 to 10.5 at

  8. 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.

  9. The effect of recrystallization on corrosion and electrochemical behavior of 7150 Al alloy

    Energy Technology Data Exchange (ETDEWEB)

    Peng, G.S.; Chen, K.H.; Fang, H.C.; Chen, S.Y.; Chao, H. [State Key Laboratory for Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China)

    2011-01-15

    By weight loss, potentiodynamic polarization, cyclic voltammetry, and electrochemical impedance spectroscopy (EIS) techniques complemented by optical and scanning electron microscopy observations, the effect of recrystallization on the corrosion, and electrochemical behavior of 7150 Al alloy was studied. The results indicated that the high recrystallization fraction 7150-1 was worse than the low recrystallization fraction 7150-2 on corrosion resistance. The analysis of EIS indicated that 7150-1 exhibited obvious pitting corrosion at 5 h immersion time, whereas 7150-2 showed no obvious pitting corrosion even at 33 h. The corrosion route developed along the grain boundary of recrystallization grains, not along the grain boundary of unrecrystallization grains. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. Mechanism and degree of chemical elements effect on atmosphere corrosion resistance of steels

    International Nuclear Information System (INIS)

    Vu Din' Vuj

    1991-01-01

    It follows from the proposed regression equations that falourable effect of chemical elements on steel resistance to atmospheric corrosion is determined by their ability to increase interatom bond stability in iron crystal lattice and form corrosion products with high protection properties. Element positive influence on steel corrosion resistance decreases in the following order: S, P, Si, Mn, Cu, Cr, Ni, C in semiurban tropical atmosphere and S, Mn, Sr, Cu, Ni, Cr in coastal atmosphere. In the latter case C increases corrosion in a greater degree as compared to P. Small ammounts of Mo decrease steel resistance in semiurban atmosphere and almost do not influence it in the coastal one. Possible mechanisms of individual element influence on steel corrosion resistance are considered

  11. Effect of ion implantation on the corrosion behavior of lead and a lead-antimony alloy

    International Nuclear Information System (INIS)

    Zhang, S.T.; Kong, F.P.; Muller, R.H.

    1994-01-01

    Ion implantation of different metals in Pb and Pb-4% Sb has been found to improve the open-circuit corrosion resistance of the two metals in 5M H 2 SO 4 . Titanium ions were implanted under different conditions of ion dose and ion energy. Optimum implantation conditions resulted in an up to 72-fold reduction of corrosion currents. The implantation of V, Cr, Ni, and W has been investigated for one implantation condition and has also resulted in decreased corrosion currents. The corrosion behavior was characterized by the current response to small anodic potential steps. Surface analysis and depth profiles have shown the importance of the spatial distribution of the implanted ions for their effects on the anodic and cathodic parts of the corrosion reactions

  12. Effect of cold working on the stress corrosion cracking resistance of nickel-chromium-iron alloys

    International Nuclear Information System (INIS)

    Yonezawa, T.; Onimura, K.

    1987-01-01

    In order to grasp the stress corrosion cracking resistance of cold worked nickel base alloys in PWR primary water, the effect of cold working on the stress corrosion cracking resistance of alloys 600, X-750 and 690, in high temperature water, have been studied. Stress corrosion cracking tests were conducted at 360 0 C (633K) in a simulated PWR primary water for about 12,000 hours (43.2Ms). From the test results, it is concluded that the stress corrosion cracking resistance in the cold worked Alloy 600 at the same applied stress level increases with an increase in cold working ratio, and the cold worked alloys of thermally treated 690 and X-750 have excellent stress corrosion cracking resistance. (Author)

  13. The effect of heat treatments on the corrosion behavior of Zircaloy-4

    International Nuclear Information System (INIS)

    Zhou Bangxin; Zhao Wenjin; Miao Zhi; Pan Shufang; Li Cong; Jiang Yourong

    1996-06-01

    The effect of penultimate annealing temperature and cooling rate on the corrosion behavior of Zircaloy-4 cladding tube has been investigated. Both nodular corrosion and uniform corrosion resistance can be improved obviously after changing the heat treatment from the original annealing at 650 degree C to quenching from 830 degree C (upper temperature of alpha phase region or lower temperature of beta phase region). Although the nodular corrosion resistance can be improved obviously after quenching from beta phase, there was a second transition in the variation between weight gain and exposure time, which shows a poor uniform corrosion resistance after a long exposure time during the autoclave tests. The main factor of affecting corrosion behavior is the solid solution contents of Fe and Cr in alpha zirconium rather than the size of second phase particles. About 200 μg/g Fe and Cr super saturated solid solution in alpha zirconium could get good uniform and nodular corrosion resistance, but much more solid solution contents of Fe and Cr in alpha zirconium could bring about a trend toward poor uniform corrosion resistance for long-term exposure time. (14 refs., 10 figs., 1 tab.)

  14. Effects of pH and chloride concentration on pitting corrosion of AA6061 aluminum alloy

    International Nuclear Information System (INIS)

    Zaid, B.; Saidi, D.; Benzaid, A.; Hadji, S.

    2008-01-01

    Effects of pH solution and chloride (Cl - ) ion concentration on the corrosion behaviour of alloy AA6061 immersed in aqueous solutions of NaCl have been investigated using measurements of weight loss, potentiodynamic polarisation, linear polarisation, cyclic polarisation experiment combined with open circuit potential transient technique and optical or scanning electron microscopy. The corrosion behaviour of the AA6061 aluminum alloy was found to be dependant on the pH and chloride concentration [NaCl] of solution. In acidic or slightly neutral solutions, general and pitting corrosion occurred simultaneously. In contrast, exposure to alkaline solutions results in general corrosion. Experience revealed that the alloy AA6061 was susceptible to pitting corrosion in all chloride solution of concentration ranging between 0.003 wt% and 5.5 wt% NaCl and an increase in the chloride concentration slightly shifted both the pitting E pit and corrosion E cor potentials to more active values. In function of the conditions of treatment, the sheets of the alloy AA6061 undergo two types of localised corrosion process, leading to the formation of hemispherical and crystallographic pits. Polarisation resistance measurements in acidic (pH = 2) and alkaline chloride solutions (pH = 12) which are in good agreement with those of weight loss, show that the corrosion kinetic is minimised in slightly neutral solutions (pH = 6)

  15. Effects of chloride ions on corrosion of ductile iron and carbon steel in soil environments.

    Science.gov (United States)

    Song, Yarong; Jiang, Guangming; Chen, Ying; Zhao, Peng; Tian, Yimei

    2017-07-31

    Chloride is reported to play a significant role in corrosion reactions, products and kinetics of ferrous metals. To enhance the understanding of the effects of soil environments, especially the saline soils with high levels of chloride, on the corrosion of ductile iron and carbon steel, a 3-month corrosion test was carried out by exposing ferrous metals to soils of six chloride concentrations. The surface morphology, rust compositions and corrosion kinetics were comprehensively studied by visual observation, scanning electron microscopy (SEM), X-Ray diffraction (XRD), weight loss, pit depth measurement, linear polarization and electrochemical impedance spectroscopy (EIS) measurements. It showed that chloride ions influenced the characteristics and compositions of rust layers by diverting and participating in corrosion reactions. α-FeOOH, γ-FeOOH and iron oxides were major corrosion products, while β-Fe 8 O 8 (OH) 8 Cl 1.35 rather than β-FeOOH was formed when high chloride concentrations were provided. Chloride also suppressed the decreasing of corrosion rates, whereas increased the difficulty in the diffusion process by thickening the rust layers and transforming the rust compositions. Carbon steel is more susceptible to chloride attacks than ductile iron. The corrosion kinetics of ductile iron and carbon steel corresponded with the probabilistic and bilinear model respectively.

  16. Effect of Additional Sulfide and Thiosulfate on Corrosion of Q235 Carbon Steel in Alkaline Solutions

    Directory of Open Access Journals (Sweden)

    Bian Li Quan

    2016-01-01

    Full Text Available This paper investigated the effect of additional sulfide and thiosulfate on Q235 carbon steel corrosion in alkaline solutions. Weight loss method, scanning electron microscopy (SEM equipped with EDS, X-ray photoelectron spectroscopy (XPS, and electrochemical measurements were used in this study to show the corrosion behavior and electrochemistry of Q235 carbon steel. Results indicate that the synergistic corrosion rate of Q235 carbon steel in alkaline solution containing sulfide and thiosulfate is larger than that of sulfide and thiosulfate alone, which could be due to redox reaction of sulfide and thiosulfate. The surface cracks and pitting characteristics of the specimens after corrosion were carefully examined and the corrosion products film is flake grains and defective. The main corrosion products of specimen induced by S2− and S2O32- are FeS, FeS2, Fe3O4, and FeOOH. The present study shows that the corrosion mechanism of S2− and S2O32- is different for the corrosion of Q235 carbon steel.

  17. Effects of cold working on the pitting corrosion behavior s of AISI 304 stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Kee Min; Kim, Jong Soo; Kim, Young Jun; Kwon, Houk Sang [KAIST, Daejon (Korea, Republic of)

    2015-12-15

    These microstructural changes by cold working can lead improvement of mechanical properties, however from a corrosion resistant point of view, the effects of cold working on the corrosion resistance of stainless steel have been argued. Several studies has been focused on the influence of cold working on the localized corrosion resistance of stainless steels. However, the opinions about the role of cold working on the localized corrosion resistance are highly in consistence. Some studies report that the pitting potential of austenitic stainless steels decreased with cold working level, on the other hands, other studies claimed that the pitting resistance was increased by cold working. Therefore it is necessary to verify how cold working affects pitting corrosion behavior of austenitic stainless steels. In the present work, the influence of cold working on the localized corrosion of AISI 304stainless steel in the neutral chloride solution was studied based on point defect model (PDM). The fraction of deformation-induced martensite was linearly increased with cold rolling level. Through cold rolling, the pitting potential was decreased, the metastable pitting event density was significantly increased and the repassivation potential was decreased. The overall localized corrosion resistance was decreased with cold working, however cold working level increased from 30 % to 50 %, localized corrosion resistance was recovered. The accumulated cation vacancy generates a void at metal/film interface, therefore film breakdown accelerates for cold worked alloys.

  18. Effects of cold working on the pitting corrosion behavior s of AISI 304 stainless steels

    International Nuclear Information System (INIS)

    Jung, Kee Min; Kim, Jong Soo; Kim, Young Jun; Kwon, Houk Sang

    2015-01-01

    These microstructural changes by cold working can lead improvement of mechanical properties, however from a corrosion resistant point of view, the effects of cold working on the corrosion resistance of stainless steel have been argued. Several studies has been focused on the influence of cold working on the localized corrosion resistance of stainless steels. However, the opinions about the role of cold working on the localized corrosion resistance are highly in consistence. Some studies report that the pitting potential of austenitic stainless steels decreased with cold working level, on the other hands, other studies claimed that the pitting resistance was increased by cold working. Therefore it is necessary to verify how cold working affects pitting corrosion behavior of austenitic stainless steels. In the present work, the influence of cold working on the localized corrosion of AISI 304stainless steel in the neutral chloride solution was studied based on point defect model (PDM). The fraction of deformation-induced martensite was linearly increased with cold rolling level. Through cold rolling, the pitting potential was decreased, the metastable pitting event density was significantly increased and the repassivation potential was decreased. The overall localized corrosion resistance was decreased with cold working, however cold working level increased from 30 % to 50 %, localized corrosion resistance was recovered. The accumulated cation vacancy generates a void at metal/film interface, therefore film breakdown accelerates for cold worked alloys

  19. Overview of Corrosion, Erosion, and Synergistic Effects of Erosion and Corrosion in the WTP Pre-treatment Facility

    Energy Technology Data Exchange (ETDEWEB)

    Imrich, K. J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-03-27

    Corrosion is an extremely complex process that is affected by numerous factors. Addition of a flowing multi-phase solution further complicates the analysis. The synergistic effects of the multiple corrosive species as well as the flow-induced synergistic effects from erosion and corrosion must be thoroughly evaluated in order to predict material degradation responses. Public domain data can help guide the analysis, but cannot reliably provide the design basis especially when the process is one-of-a-kind, designed for 40 plus years of service, and has no viable means for repair or replacement. Testing in representative simulants and environmental conditions with prototypic components will provide a stronger technical basis for design. This philosophy was exemplified by the Defense Waste Processing Facility (DWPF) at the Savannah River Site and only after 15 plus years of successful operation has it been validated. There have been “hiccups”, some identified during the cold commissioning phase and some during radioactive operations, but they were minor and overcome. In addition, the system is robust enough to tolerate most flowsheet changes and the DWPF design allows minor modifications and replacements – approaches not available with the Hanford Waste Treatment Plant (WTP) “Black Cell” design methodology. Based on the available data, the synergistic effect between erosion and corrosion is a credible – virtually certain – degradation mechanism and must be considered for the design of the WTP process systems. Testing is recommended due to the number of variables (e.g., material properties, process parameters, and component design) that can affect synergy between erosion and corrosion and because the available literature is of limited applicability for the complex process chemistries anticipated in the WTP. Applicable testing will provide a reasonable and defensible path forward for design of the WTP Black Cell and Hard-to-Reach process equipment. These

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

    International Nuclear Information System (INIS)

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

    2002-01-01

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

  1. Inhibition Effect of Deanol on Mild Steel Corrosion in Dilute ...

    African Journals Online (AJOL)

    NICOLAAS

    2014-06-23

    Jun 23, 2014 ... allows for extensive use as the material of construction in petro- leum industries .... steel specimens was investigated after mass-loss analysis ..... Ogbuliec, Inhibition of pseudo-anaerobic corrosion of oil pipeline steel in ...

  2. Effect of corrosion on the buckling capacity of tubular members

    Science.gov (United States)

    Øyasæter, F. H.; Aeran, A.; Siriwardane, S. C.; Mikkelsen, O.

    2017-12-01

    Offshore installations are subjected to harsh marine environment and often have damages from corrosion. Several experimental and numerical studies were performed in the past to estimate buckling capacity of corroded tubular members. However, these studies were either based on limited experimental tests or numerical analyses of few cases resulting in semi-empirical relations. Also, there are no guidelines and recommendations in the currently available design standards. To fulfil this research gap, a new formula is proposed to estimate the residual strength of tubular members considering corrosion and initial geometrical imperfections. The proposed formula is verified with results from finite element analyses performed on several members and for varying corrosion patch parameters. The members are selected to represent the most relevant Eurocode buckling curve for tubular members. It is concluded that corrosion reduces the buckling capacity significantly and the proposed formula can be easily applied by practicing engineers without performing detailed numerical analyses.

  3. Effect of tempering on corrosion resistance of cast aluminium bronzes

    International Nuclear Information System (INIS)

    Aaltonen, P.; Klemetti, K.; Haenninen, H.

    1985-01-01

    The subject of this study is corrosion resistance of aluminium bronzes, which are copper base alloys containing aluminium up to 12% with additions of nickel, iron and manganese. The main conclutions that can be drawn are: (1) The dealloying corrosion resistance of nickel-aluminium bronze is much better than that of aluminium bronze with iron and manganese additions, but it is not immune; (2) The dealloying corrosion resistance of aluminium bronzes can be improved by appropiate heat treatments. The best properties were obtained by temperering between 600 and 800 deg C, depending on the initial microstructure; (3) In crevice conditions, where local acidification can occur, dealloying of aluminium bronzes is a consequence of the preferential attack of aluminium-rich phases. By appropriate tempering, a uniform distribution of aluminium-rich phases is obtained and the continous path for selective corrosion is not formed

  4. Effects of Alloyed Carbon on the General Corrosion and the Pitting Corrosion Behavior of FeCrMnN Stainless Steels

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Heon-Young; Lee, Tae-Ho; Kim, Sung-Joon [Korea Institute of Materials Science, Changwon (Korea, Republic of)

    2011-10-15

    The effects of alloyed carbon on the pitting corrosion, the general corrosion, and the passivity behavior of Fe{sub 1}8Cr{sub 1}0Mn{sub 0}.4Nx{sub C} (x=0 ⁓ 0.38 wt%) alloys were investigated by various electrochemical methods and XPS analysis. The alloyed carbon increased the general corrosion resistance of the FeCrMnN matrix. Carbon enhanced the corrosion potential, reduced the metal dissolution rate, and accelerated the hydrogen evolution reaction rate in various acidic solutions. In addition, carbon promoted the pitting corrosion resistance of the matrix in a chloride solution. The alloyed carbon in the matrix increased the chromium content in the passive film, and thus the passive film became more protective.

  5. AC-Induced Bias Potential Effect on Corrosion of Steels

    Science.gov (United States)

    2009-02-05

    induction, variable conduction Experimental Setup Super- martensitic stainless steel composition Analysis: C Mn Si Cr Ni Mo Cu N Typical 13 Cr ɘ.01 0.6... stainless steel used in pipelines. •Low carbon (ɘ.01): allows the formation of a “soft” martensite that is more resistant than standard martensitic ...Proposed AC Corrosion Models  AC Simulated Corrosion testing  Stainless steel pipe and coating  Cathodic protection  Experimental Setup  Preliminary

  6. Water vapor effects on the corrosion of steel

    International Nuclear Information System (INIS)

    Estill, J.C.; Gdowski, G.E.

    1995-01-01

    Critical relative humidity for AISI 1020 carbon steel is 75-85% RH at 65 C. Aggressive electrochemical corrosion occurs above 85% RH, while dry oxidation occurs below 75% RH. The reddish-brown product is probably Fe2O3 or its hydrate; the black oxide layer, Fe3O4. The face surfaces had little or no corrosion, while the mill-machined edges were corroded with nonuniform reddish-brown areas

  7. Multilayer graphene as an effective corrosion protection coating for copper

    Science.gov (United States)

    Ravishankar, Vasumathy; Ramaprabhu, S.; Jaiswal, Manu

    2018-04-01

    Graphene grown by chemical vapor deposition (CVD) has been studied as a protective layer against corrosion of copper. The layer number dependence on the protective nature of graphene has been investigated using techniques such as Tafel analysis and Electroimpedance Spectroscopy. Multiple layers of graphene were achieved by wet transfer above CVD grown graphene. Though this might cause grain boundaries, the sites where corrosion is initiated, to be staggered, wet transfer inherently carries the disadvantage of tearing of graphene, as confirmed by Raman spectroscopy measurements. However, Electroimpedance Spectroscopy (EIS) reflects that graphene protected copper has a layer dependent resistance to corrosion. Decrease in corrosion current (Icorr) for graphene protected copper is presented. There is only small dependence of corrosion current on the layer number, Tafel plots clearly indicate passivation in the presence of graphene, whether it be single layer or multiple layers. Notwithstanding the crystallite size, defect free layers of graphene with staggered grain boundaries combined with passivation could offer good corrosion protection for metals.

  8. Effect of Pseudomonas fluorescens on Buried Steel Pipeline Corrosion.

    Science.gov (United States)

    Spark, Amy J; Law, David W; Ward, Liam P; Cole, Ivan S; Best, Adam S

    2017-08-01

    Buried steel infrastructure can be a source of iron ions for bacterial species, leading to microbiologically influenced corrosion (MIC). Localized corrosion of pipelines due to MIC is one of the key failure mechanisms of buried steel pipelines. In order to better understand the mechanisms of localized corrosion in soil, semisolid agar has been developed as an analogue for soil. Here, Pseudomonas fluorescens has been introduced to the system to understand how bacteria interact with steel. Through electrochemical testing including open circuit potentials, potentiodynamic scans, anodic potential holds, and electrochemical impedance spectroscopy it has been shown that P. fluorescens increases the rate of corrosion. Time for oxide and biofilms to develop was shown to not impact on the rate of corrosion but did alter the consistency of biofilm present and the viability of P. fluorescens following electrochemical testing. The proposed mechanism for increased corrosion rates of carbon steel involves the interactions of pyoverdine with the steel, preventing the formation of a cohesive passive layer, after initial cell attachment, followed by the formation of a metal concentration gradient on the steel surface.

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

    International Nuclear Information System (INIS)

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

    1996-01-01

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

  10. Zinc Addition Effects on General Corrosion of Austenitic Stainless Steels in PWR Primary Conditions

    International Nuclear Information System (INIS)

    Qiao Peipeng; Zhang Lefu; Liu Ruiqin; Jiang Suqing; Zhu Fawen

    2010-01-01

    Zinc addition effects on general corrosion of austenitic stainless steel 316 and 304 were investigated in simulated PWR primary coolant without zinc or with 50 ppb zinc addition at 315 degree C for 500 h. The results show that with the addition of zinc, the corrosion rate of austenitic stainless steel is effectively reduced, the surface oxide film is thinner, the morphology and chemical composition of surface oxide scales are evidently different from those without zinc. There are needle-like corrosion products on the surface of stainless steel 304. (authors)

  11. Effect of flow velocity on erosion-corrosion behaviour of QSn6 alloy

    Science.gov (United States)

    Huang, Weijiu; Zhou, Yongtao; Wang, Zhenguo; Li, Zhijun; Zheng, Ziqing

    2018-05-01

    The erosion-corrosion behaviour of QSn6 alloy used as propellers in marine environment was evaluated by erosion-corrosion experiments with/without cathodic protection, electrochemical tests and scanning electron microscope (SEM) observations. The analysis was focused on the effect of flow velocity. The dynamic polarization curves showed that the corrosion rate of the QSn6 alloy increased as the flow velocity increased, due to the protective surface film removal at higher velocities. The lowest corrosion current densities of 1.26 × 10‑4 A cm‑2 was obtained at the flow velocity of 7 m s‑1. Because of the higher particle kinetic energies at higher flow velocity, the mass loss rate of the QSn6 alloy increased as the flow velocity increased. The mass loss rate with cathodic protection was lower than that without cathodic protection under the same conditions. Also, the lowest mass loss rate of 0.7 g m‑2 · h‑1 was acquired at the flow velocity of 7 m s‑1 with cathodic protection. However, the increase rate of corrosion rate and mass loss were decreased with increasing the flow velocity. Through observation the SEM morphologies of the worn surfaces, the main wear mechanism was ploughing with/without cathodic protection. The removal rates of the QSn6 alloy increased as the flow velocity increased in both pure erosion and erosion-corrosion, whereas the erosion and corrosion intensified each other. At the flow velocity of 7 m s‑1, the synergy rate (ΔW) exceeded by 5 times the erosion rate (Wwear). Through establishment and observation the erosion-corrosion mechanism map, the erosion-corrosion was the dominant regime in the study due to the contribution of erosion on the mass loss rate exceeded the corrosion contribution. The QSn6 alloy with cathodic protection is feasible as propellers, there are higher security at lower flow velocity, such as the flow velocity of 7 m s‑1 in the paper.

  12. Effects of partial crystallinity and quenched-in defects on corrosion of ...

    Indian Academy of Sciences (India)

    Unknown

    Rapid solidification by planar flow casting has been found to have introduced deficiencies, viz. ... alloy. In order to investigate the effects of these deficiencies on the corrosion of rapidly ... Partial crystallinity (Dutta et al 1995; Savalia et al 1996),.

  13. Effect of niobium element on the electrochemical corrosion behavior of depleted uranium

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Yanping, E-mail: wuyanping-2@126.com; Wu, Quanwen; Zhu, Shengfa, E-mail: zhushf-306@163.com; Pu, Zhen; Zhang, Yanzhi; Wang, Qinguo; Lang, Dingmu; Zhang, Yuping

    2016-09-15

    Depleted uranium (DU) has many military and civilian uses. However, its high chemical reactivity limits its application. The effect of Nb content on corrosion behavior of DU is evaluated by scanning Kelvin probe and electrochemical corrosion measurements. The Volta potential value of DU and U-2.5 wt% Nb is about the same level, the Volta potential value of U-5.7 wt% Nb has a rise of 370mV{sub SHE} in comparison with DU. The polarization current of U-5.7 wt% Nb alloy is about an order of magnitude of that of DU. The Nb{sub 2}O{sub 5} is the protective layer for the U-Nb alloys. The negative potential of Nb-depleted α phase is the main reason of the poor corrosion resistance of DU and U-2.5 wt% Nb alloy. - Highlights: • New method (scanning Kelvin probe) was used to study the corrosion property. • Three types of corrosion morphologies were found after potentiodynamic polarization. • The effect of impurity elements on corrosion property was mentioned. • The corrosion mechanism of DU and U-Nb alloys was discussed.

  14. The effect of organic matter associated with the corrosion products on the corrosion of mild steel in the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Bhosle, N.B.; Wagh, A.B.

    The corrosion of mild steel immersed at various depths (0-100 m) from three stations of the Arabian Sea was investigated. The corrosion of mild steel decreased with increasing immersion depth. Significant positive relationships were observed between...

  15. Environmental effects on corrosion in the Tuff repository

    International Nuclear Information System (INIS)

    Beavers, J.A.; Thompson, N.G.

    1990-02-01

    Cortest Columbus is investigating the long-term performance of container materials used for high-level waste packages as part of the information needed by the Nuclear Regulatory Commission to assess the Department of Energy's application to construct a geologic repository for high-level radioactive waste. The scope of work consists of employing short-term techniques, to examine a wide range of possible failure modes. Long-term tests are being used to verify and further examine specific failure modes identified as important by the short-term studies. The original focus of the program was on the salt repository but the emphasis was shifted to the Tuff repository. This report summarizes the results of a literature survey performed under Task 1 of the program. The survey focuses on the influence of environmental variables on the corrosion behavior of candidate container materials for the Tuff repository. Environmental variables considered include: radiation, thermal and microbial effects. 80 refs., 44 figs., 44 tabs

  16. Effect of Sensitization on Corrosion-Fatigue Cracking in Al 5083 Alloy

    Science.gov (United States)

    2015-01-21

    immediately ahead of the fatigue precrack in 0.001 and 0.01% NaCl solutions are transgranular ductile void coalescences. This observation suggests the 9...Naval Research Laboratory Washington, DC 20375-5320 NRL/MR/6355--15-9581 Effect of Sensitization on Corrosion- Fatigue Cracking in Al 5083 Alloy...area code) b. ABSTRACT c. THIS PAGE 18. NUMBER OF PAGES 17. LIMITATION OF ABSTRACT Effect of Sensitization on Corrosion- Fatigue Cracking in Al 5083

  17. The precious metal effect in high temperature corrosion

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-01-01

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

  18. Grain size effect in corrosion behavior of electrodeposited nanocrystalline Ni coatings in alkaline solution

    International Nuclear Information System (INIS)

    Wang Liping; Zhang Junyan; Gao Yan; Xue Qunji; Hu Litian; Xu Tao

    2006-01-01

    Effects of grain size reduction on the electrochemical corrosion behavior of nanocrystalline Ni produced by pulse electrodeposition were characterized using potentiodynamic polarization testing and electrochemical impedance spectroscopy; X-ray photoelectron spectroscopy were used to confirm the electrochemical measurements and the suggested mechanisms. The corrosion resistance of Ni coatings in alkaline solutions considerably increased as the grain size decreased from microcrystalline to nanocrystalline. The higher corrosion resistance of NC Ni may be due to the more rapid formation of continuous Ni(OH) 2 passive films compared with coarse-grained Ni coatings

  19. Evaluation of microstructural effects on the corrosion behaviour of AZ91D magnesium alloy

    DEFF Research Database (Denmark)

    Ambat, Rajan; Aung, Naing Naing; Zhou, W.

    2000-01-01

    The effect of microconstituents on the corrosion and electrochemical behaviour of AZ91D alloy prepared by die-casting and ingot casting route has been investigated in 3.5% NaCl solution at pH 7.25. The experimental techniques used include constant immersion technique, in-situ corrosion monitoring....... The corrosion products for ingot consisted of Mg(OH)(2) with small amounts beta phase, magnesium-aluminum oxide and MgH2 while for die-cast, the product showed a highly amorphous structure. (C) 2000 Elsevier Science Ltd. All rights reserved....

  20. Effects of organic acid pickling on the corrosion resistance of magnesium alloy AZ31 sheet

    DEFF Research Database (Denmark)

    Nwaogu, Ugochukwu Chibuzoh; Blawert, C.; Scharnagl, N.

    2010-01-01

    mu m of the contaminated surface was required to reach corrosion rates less than 1 mm/year in salt spray condition. Among the three organic acids examined, acetic acid is the best choice. Oxalic acid can be an alternative while citric acid is not suitable for cleaning AZ31 sheet, because......Organic acids were used to clean AZ31 magnesium alloy sheet and the effect of the cleaning processes on the surface condition and corrosion performance of the alloy was investigated. Organic acid cleanings reduced the surface impurities and enhanced the corrosion resistance. Removal of at least 4...

  1. The effect of ion implantation on the resistance of 316L stainless steel to crevice corrosion

    International Nuclear Information System (INIS)

    Bombara, G.; Cavallini, M.

    1983-01-01

    The results of an investigation of the influence of aluminium, titanium and scandium implantation on the electrochemical and chemical crevice corrosion behaviour of 316L stainless steel are presented and discussed. Ion implantation, in addition to improving markedly the protective quality of the passive film at the free corrosion potential, greatly increases the resistance of 316L stainless steel to crevice corrosion in both neutral NaCl and acidic FeCl 3 solutions. A moderate decrease in pitting resistance is possibly due to coverage effect of implanted species on the surface molybdenum constituent. (Auth.)

  2. Effects of nitrogen and nitrogen getters in lithium on the corrosion of type 316 stainless steel

    International Nuclear Information System (INIS)

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

    1979-01-01

    This paper presents preliminary results on the corrosion of type 316 stainless steel in nitrogen-contaminated lithium. Nitrogen is a principal interstitial impurity in lithium and has a significant detrimental effect on compatibility, while O, H, and C in lithium do not enhance corrosion of type 316 stainless steel. Because of this, there is a need to understand the corrosion mechanisms and kinetics associated with nitrogen-induced attack in lithium. Results from experiments with getters in nitrogen-contaminated lithium are also reported

  3. Effect of Nitrite Inhibitor on the Macrocell Corrosion Behavior of Reinforcing Steel

    Directory of Open Access Journals (Sweden)

    Zhonglu Cao

    2015-01-01

    Full Text Available The effect of nitrite ions on the macrocell corrosion behavior of reinforcing steel embedded in cement mortar was investigated by comparing and analyzing the macrocell corrosion current, macrocell polarization ratios, and slopes of anodic and cathodic steels. Based on the experimental results, the relationship between macrocell potential difference and macrocell current density was analyzed, and the mechanism of macrocell corrosion affected by nitrite ions was proposed. The results indicated that nitrite ions had significant impact on the macrocell polarization ratios of cathode and anode. The presence of nitrite could reduce the macrocell current by decreasing the macrocell potential difference and increasing the macrocell polarization resistance of the anode.

  4. Effect of microstructure on corrosion behavior of Ag-30Cu-27Sn alloy in vitro media

    International Nuclear Information System (INIS)

    Salehisaki, Mehdi; Aryana, Maryam

    2014-01-01

    Highlights: • High cooling rates decrease the number of Ag intermetallic particles in Cu-rich phase. • Increasing cooling rate improves corrosion behavior of Ag-30Cu-27Sn dental alloy. • Cathode/anode ratio in Cu-rich phases determines the corrosion behavior of alloy. - Abstract: In the present work, three simple heat treatment cycles were used to study the effects of microstructure on electrochemical corrosion behavior of Ag-30Cu-27Sn dental alloy. The electrochemical impedance spectroscopy (EIS) measurements and potentiodynamic polarization tests were carried out to investigate the corrosion behavior of as-cast and heat treated samples in synthetic saliva solution. The presence of intermetallic compounds were studied by X-ray diffraction method (XRD) and scanning electron microscopy (SEM) with energy dispersive X-ray detector (EDAX). The microstructural observations and electrochemical corrosion results revealed that, increasing the cooling rate improves the corrosion behavior of under investigation samples. Improvement of the corrosion behavior is attributed to reducing the area of fine distributed Ag 3 Sn islands in the Cu-rich matrix which decrease the cathode/anode ratio of microgalvanic cells

  5. Effects of chitosan inhibitor on the electrochemical corrosion behavior of 2205 duplex stainless steel

    Science.gov (United States)

    Yang, Se-fei; Wen, Ying; Yi, Pan; Xiao, Kui; Dong, Chao-fang

    2017-11-01

    The effects of chitosan inhibitor on the corrosion behavior of 2205 duplex stainless steel were studied by electrochemical measurements, immersion tests, and stereology microscopy. The influences of immersion time, temperature, and chitosan concentration on the corrosion inhibition performance of chitosan were investigated. The optimum parameters of water-soluble chitosan on the corrosion inhibition performance of 2205 duplex stainless steel were also determined. The water-soluble chitosan showed excellent corrosion inhibition performance on the 2205 duplex stainless steel. Polarization curves demonstrated that chitosan acted as a mixed-type inhibitor. When the stainless steel specimen was immersed in the 0.2 g/L chitosan solution for 4 h, a dense and uniform adsorption film covered the sample surface and the inhibition efficiency (IE) reached its maximum value. Moreover, temperature was found to strongly influence the corrosion inhibition of chitosan; the inhibition efficiency gradually decreased with increasing temperature. The 2205 duplex stainless steel specimen immersed in 0.4 g/L water-soluble chitosan at 30°C displayed the best corrosion inhibition among the investigated specimens. Moreover, chitosan decreased the corrosion rate of the 2205 duplex stainless steel in an FeCl3 solution.

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

    Science.gov (United States)

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

    2014-01-01

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

  7. The composition effect on the long-term corrosion of high-level waste glass

    Energy Technology Data Exchange (ETDEWEB)

    Hrma, P. [Pacific Northwest National Laboratory, Richland, Washington (United States)

    1997-07-01

    Waste glass can be optimized for long-term corrosion behavior if the key parameters that control the rate of corrosion are identified, measured, and modeled as functions of glass composition. Second-order polynomial models have been used to optimize glass with respect to a set of requirements on glass properties, such as viscosity and outcomes of standard corrosion tests. Extensive databases exist for the 7-day Product Consistency Test and the 28-day Materials Characterization Center tests, which have been used for nuclear waste glasses in the United States. Models based on these tests are reviewed and discussed to demonstrate the compositional effects on the extent of corrosion under specified conditions. However, modeling the rate of corrosion is potentially more useful for predicting long-term behavior than modeling the extent of corrosion measured by standard tests. Based on an experimental study of two glasses, it is shown that the rate of corrosion can be characterized by simple functions with physically meaningful coefficients. (author)

  8. Effect of fluoride additives on the corrosion of aluminum for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Tsuyoshi, Nakajima; Mitsuhiro, Mori; Vinay, Gupta; Yoshimi, Ohzawa [Aichi Institute of Technology, Dept. of Applied Chemistry, Toyota-shi (Japan); Hiroyuki, Iwata [Aichi Institute of Technology, Technical Research Center, Toyata-shi (Japan)

    2002-12-01

    Effect of fluoride additives was investigated in organic solvents containing LiCF{sub 3}SO{sub 3} to prevent the corrosion of aluminum current collector for lithium ion batteries. LiClO{sub 4} was also examined for comparison. Among examined LiBF{sub 4}, LiPF{sub 6}, LiAsF{sub 6}, LiSbF{sub 6} and LiClO{sub 4}, LiBF{sub 4} was the best additive to suppress the corrosion of aluminum because its oxidation potential is close to that of CF{sub 3}SO{sub 3}{sup -} anion. Corrosion currents for aluminum in a complex fluoride- or LiClO{sub 4}-added solvents became smaller in the order, LiSbF{sub 6}>LiAsF{sub 6}>LiClO{sub 4}>LiPF{sub 6}>LiBF{sub 4}. Oxidation potential of ClO{sub 4}{sup -} is nearly the same as that of CF{sub 3}SO{sub 3}{sup -}. However, the corrosion currents were similar to or slightly larger than those observed in LiPF{sub 6}-added solvents. SEM images of electrochemically oxidized aluminum samples indicated that the level of corrosion well coincided with the observed corrosion currents. The corrosion mechanism of aluminum was also proposed. (authors)

  9. Quantitative assessment of the effect of corrosion product buildup on occupational exposure

    International Nuclear Information System (INIS)

    Divine, J.R.

    1982-10-01

    The program was developed to provide a method for predicting occupational exposures caused by the deposition of radioactive corrosion products outside the core of the primary system of an operating power reactor. This predictive capability will be useful in forecasting total occupational doses during maintenance, inspection, decontamination, waste treatment, and disposal. In developing a reliable predictive model, a better understanding of the parameters important to corrosion product film formation, corrosion product transport, and corrosion product film removal will be developed. This understanding can lead to new concepts in reactor design to minimize the buildup and transport of radioactive corrosion products or to improve methods of operation. To achieve this goal, three objectives were established to provide: (1) criteria for acceptable coolant sampling procedures and sampling equipment that will provide data which will be used in the model development; (2) a quantitative assessment of the effect of corrosion product deposits on occupational exposure; and (3) a model which describes the influence of flow, temperature, coolant chemistry, construction materials, radiation, and other operating parameters on the transport and buildup of corrosion products

  10. Effect of noble metals on the corrosion of AISI 316L stainless steel in nitric acid

    International Nuclear Information System (INIS)

    Robin, R.; Andreoletti, G.; Fauvet, P.; Terlain, A.

    2004-01-01

    In the spent fuel treatment, the solutions of fission products contain dissolution fines, in particular platinoids. These solutions are stored into AISI 316L stainless steel tanks, and the contact of noble metallic particles such as platinoids with austenitic stainless steels may induce a shift of the steel corrosion potential towards the trans-passive domain by galvanic coupling. In that case, the steel may be polarized up to a potential value above the range of passive domain, that induces an increase of the corrosion current. The galvanic corrosion of AISI 316L stainless steel in contact with different platinoids has been investigated by electrochemical and gravimetric techniques. Two types of tests were conducted in 1 mol/L nitric acid media at 80 deg C: (1) polarization curves and (2) immersion tests with either platinoid powders (Ru, Rh, Pd) or true insoluble dissolution fines (radioactive laboratory test). The results of the study have shown that even if galvanic coupling enhances the corrosion rate by about a factor 10 in these conditions, the corrosion behavior of AISI 316L remains low (a corrosion rate below 6 μm/year, few small intergranular indentations). No specific effect of irradiation and of elements contained in radioactive fines (other than Ru, Rh and Pd) was observed on corrosion behavior. A platinoids-ranking has also been established according to their coupling potential: Ru > Pd > Rh. (authors)

  11. Effect of nanograin-boundary networks generation on corrosion of carburized martensitic stainless steel.

    Science.gov (United States)

    Boonruang, Chatdanai; Thong-On, Atcharawadi; Kidkhunthod, Pinit

    2018-02-02

    Martensitic stainless steel parts used in carbonaceous atmosphere at high temperature are subject to corrosion which results in a large amount of lost energy and high repair and maintenance costs. This work therefore proposes a model for surface development and corrosion mechanism as a solution to reduce corrosion costs. The morphology, phase, and corrosion behavior of steel are investigated using GIXRD, XANES, and EIS. The results show formation of nanograin-boundary networks in the protective layer of martensitic stainless steel. This Cr 2 O 3 -Cr 7 C 3 nanograin mixture on the FeCr 2 O 4 layer causes ion transport which is the main reason for the corrosion reaction during carburizing of the steel. The results reveal the rate determining steps in the corrosion mechanism during carburizing of steel. These steps are the diffusion of uncharged active gases in the stagnant-gas layer over the steel surface followed by the conversion of C into C 4- and O into O 2- at the gas-oxide interface simultaneously with the migration of Cr 3+ from the metal-oxide interface to the gas-oxide interface. It is proposed that previous research on Al 2 O 3 coatings may be the solution to producing effective coatings that overcome the corrosion challenges discussed in this work.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-07-15

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

  13. The effect of Electro Discharge Machining (EDM) on the corrosion resistance of dental alloys.

    Science.gov (United States)

    Ntasi, Argyro; Mueller, Wolf Dieter; Eliades, George; Zinelis, Spiros

    2010-12-01

    The aim of the present study was to evaluate the effect of Electro Discharge Machining (EDM) on the corrosion resistance of two types of dental alloys used for fabrication of implant retained superstructures. Two groups of specimens were prepared from a Co-Cr (Okta-C) and a grade II cpTi (Biotan) alloys respectively. Half of the specimens were subjected to EDM with Cu electrodes and the rest were conventionally finished (CF). The corrosion resistance of the alloys was evaluated by anodic polarization in Ringer's solution. Morphological and elemental alterations before and after corrosion testing were studied by SEM/EDX. Six regions were analyzed on each surface before and after corrosion testing and the results were statistically analyzed by paired t-test (a=0.05). EDM demonstrated inferior corrosion resistance compared to CF surfaces, the latter being passive in a wider range of potential demonstrating higher polarization resistance and lower I(corr) values. Morphological alterations were found before and after corrosion testing for both materials tested after SEM analysis. EDX showed a significant decrease in Mo, Cr, Co, Cu (Co-Cr) and Ti, Cu (cpTi) after electrochemical testing plus an increase in C. According to the results of this study the EDM procedure decreases the corrosion resistance of both the alloys tested, increasing thus the risk of possible adverse biological reactions. Copyright © 2010 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  14. Effect of high temperature filtration on out-core corrosion product activity

    International Nuclear Information System (INIS)

    Horvath, G.L.; Bogancs, J.

    1983-01-01

    Investigation of the effect of high temperature filtration on corrosion product transport and out-core corrosion product activity has been carried out for VVER-440 plants. In the physico-chemical model applied particulate and dissolved corrosion products were taken into account. We supposed 100% effectivity for the particulate filter. It was found that about 0,5% 160 t/h/ of the main flow would result in an approx.50% reduction of the out-core corrosion product activity. Investigation of the details of the physico-chemical model in Nuclear Power Plant Paks showed a particle deposition rate measured during power transients fairly agreeing with other measurements and data used in the calculations. (author)

  15. The Effect of Fly Ash on the Corrosion Behaviour of Galvanised Steel Rebarsin Concrete

    Science.gov (United States)

    Tittarelli, Francesca; Mobili, Alessandra; Bellezze, Tiziano

    2017-08-01

    The effect of fly ash on the corrosion behaviour of galvanised steel rebars in cracked concrete specimens exposed to wet-dry cycles in a chloride solution has been investigated. The obtained results show that the use of fly ash, replacing either cement or aggregate, always improves the corrosion behaviour of galvanised steel reinforcements. In particular, the addition of fly ash, even in the presence of concrete cracks, decreases the corrosion rate monitored in very porous concretes, as those with w/c = 0.80, to values comparable with those obtained in good quality concretes, as those with w/c = 0.45. Therefore, fly ash cancels the negative effect, at least from the corrosion point of view, of a great porosity of the cement matrix.

  16. Effect of hydrogen on the corrosion behavior of the Mg–xZn alloys

    Directory of Open Access Journals (Sweden)

    Yingwei Song

    2014-09-01

    Full Text Available Hydrogen evolution reaction is inevitable during the corrosion of Mg alloys. The effect of hydrogen on the corrosion behavior of the Mg–2Zn and Mg–5Zn alloys is investigated by charging hydrogen treatment. The surface morphologies of the samples after charging hydrogen were observed using a scanning electron microscopy (SEM and the corrosion resistance was evaluated by polarization curves. It is found that there are oxide films formed on the surface of the charged hydrogen samples. The low hydrogen evolution rate is helpful to improve the corrosion resistance of Mg alloys, while the high hydrogen evolution rate can increases the defects in the films and further deteriorates their protection ability. Also, the charging hydrogen effect is greatly associated with the microstructure of Mg substrate.

  17. Effect of soil compositions on the electrochemical corrosion behavior of carbon steel in simulated soil solution

    Energy Technology Data Exchange (ETDEWEB)

    Liu, T.M. [College of Materials Science and Engineering, Chongqing University (China); Luo, S.X. [Department of Chemistry, Zunyi Normal College, Zunyi (China); Sun, C. [State Key Laboratory for Corrosion and Protection, Institute of Metal Research, Chinese Academy of Sciences, Shenyang (China); Wu, Y.H.

    2010-04-15

    In this study, effect of cations, Ca{sup 2+}, Mg{sup 2+}, K{sup +}, and anions, SO{sub 4}{sup 2-}, HCO{sub 3}{sup -}, NO{sub 3}{sup -} on electrochemical corrosion behavior of carbon steel in simulated soil solution was investigated through potentiodynamic polarization curves and electrochemical impedance spectroscopy. The results indicate that the Ca{sup 2+}and Mg{sup 2+} can decrease the corrosion current density of carbon steel in simulated soil solution, and K{sup +}, SO{sub 4}{sup 2-}, HCO{sub 3}{sup -}, and NO{sub 3}{sup -} can increase the corrosion density. All the above ions in the simulated soil solution can decrease its resistivity, but they have different effect on the charge transfer resistivity. This finding can be useful in evaluating the corrosivity of certain soil through chemical analysis, and provide data for construction engineers. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  18. Effect of H2O2 on the corrosion behavior of 304L stainless steel

    International Nuclear Information System (INIS)

    Song, Taek Hoh; Kim, In Sub; Noh, Sung Kee

    1995-01-01

    In connection with the safe storage of high level nuclear waste, effect of H 2 O 2 on the corrosion behavior of 304L stainless steel was examined. Open circuit potentials and polarization curves were measured with and without H 2 O 2 . The experimental results show that H 2 O 2 increased corrosion potential and decreased pitting potential. The passive range, therefore, decreased as H 2 O 2 concentration increased, indicating that pitting resistance was decreased by the existence of H 2 O 2 in the electrolyte. These effects of H 2 O 2 on corrosion of 304L stainless steel are considered to be similar to those of γ-irradiation. To compare the effects of H 2 O 2 with those of O 2 , cathodic and anodic polarization curves were made in three types of electrolyte such as aerated, deaerated, and stirred electrolyte. The experimental results show that the effects of H 2 O 2 on the corrosion behavior were very similar to those of O 2 such as increase of corrosion potential, decrease of pitting resistance, and increase of repassivation potential. In acid and alkaline media, the corrosion potential shifts by H 2 O 2 were restricted by the large current density of proton reduction and by the le Chatelier's principle respectively. 13 figs., 1 tabs., 17 refs. (Author)

  19. Inhibition of Aluminium Corrosion in Hydrochloric Acid Using Nizoral and the Effect of Iodide Ion Addition

    OpenAIRE

    I. B. Obot; N. O. Obi-Egbedi

    2010-01-01

    The effect of nizoral (NZR) on the corrosion inhibition of aluminium alloy AA 1060 in 2 M HCl solution was investigated using the mylius thermometric technique. Results of the study revealed that nizoral acts as corrosion inhibitor for aluminium in the acidic medium. In general, at constant acid concentration, the inhibition efficiency increases with increase in the inhibitor concentration. The addition of KI to the inhibitor enhanced the inhibition efficiency to a considerable extent. The ad...

  20. Radiometric investigation of effect of decontamination agents on corrosion behavior of structural materials for nuclear power engineering

    International Nuclear Information System (INIS)

    Silber, R.; Ecksteinova, A.

    1987-01-01

    The tracer technique is used in monitoring corrosion behaviour of high-alloy steels used as structural materials in nuclear power engineering. Radioisotopes 59 Fe, 51 Cr, 58 Co and 60 Co produced by neutron irradiation of steel are mainly used for labelling steel components. The actual corrosion test proceeds in a facility whose description is given. The facility allows automatic sampling of corrosion medium fractions in preset intervals. The fractions are evaluated using a multi-channel analyzer with a Ge(Li) detector. The method can be applied in, e.g., monitoring extraction corrosion, the effect of decontamination agents on the corrosion of alloy steels and the effect of heat treatment of steels of their corrosion resistance in a model corrosion environment. (Z.M.). 2 fig., 1 tab., 5 refs

  1. Investigations into the corrosion resistance of copper aluminium alloys. Effect of phosphorus as corrosion resistant third alloying element in the ternary system CuAl20P1

    International Nuclear Information System (INIS)

    Allwardt, A.

    1997-01-01

    The effect of phosphorus on the corrosion resistance of Al-bronzes is studied in detail in this work. A literature review showed that there are a lot of things known about the microstructure and the mechanical properties of Al-bronzes. In spite of their corrosion resistance the corrosion properties and the structure of the protective oxide films of Al-bronzes were seldom a matter of interest. Systematic studies of the influence of different alloying elements on the oxide film and the corrosion properties are rare. Therefore, it is not possible to predict the corrosion resistance of Al-bronzes, made by alloying particular elements. The high corrosion resistance of the new alloy CuAl 20 P 1 was the reason to investigate the influence of phosphorus on the corrosion properties of Al-bronzes in more detail. A systematic study of the microstructure and the corrosion properties of Cu, CuP x , CuAl 20 and CuAl 20 P x offers an insight into the effect of aluminium and phosphorus on the formation of the oxide film on Al-bronzes. It was found that there exists a critical amount of 1 at.-% of phosphorus. Above and below this amount the corrosion resistance becomes worse. This behaviour could be explained by XPS-and electrochemical measurements. Although there are still some questions about the influence of phosphorus on the corrosion resistance of Al-bronzes, this work has produced some important results, which in the future may be helpful to develop new high corrosion resistant Al-bronzes more efficiently: - on clean surface Al-bronze, the oxidation of Al and Cu takes place simultaneously, - Al promotes the formation of Cu 2 O but impedes the formation of Cu(II)-oxide/-hydride in neutral solutions, - P impedes the formation of Cu 2 O and as a consequence promotes the formation of aluminium oxide. This results in a higher amount of Al in the oxide film on the surface of the alloy, which leads to a better corrosion resistance. (author) figs., tabs., 106 refs

  2. Effects of porosity on corrosion resistance of Mg alloy foam produced by powder metallurgy technology

    Energy Technology Data Exchange (ETDEWEB)

    Aghion, E., E-mail: egyon@bgu.ac.il; Perez, Y.

    2014-10-15

    Magnesium alloy foams have the potential to serve as structural material for regular light-weight applications as well as for biodegradable scaffold implants. However, their main disadvantage relates to the high reactivity of magnesium and consequently their natural tendency to corrode in regular service conditions and in physiological environments. The present study aims at evaluating the effect of porosity on the corrosion resistance of MRI 201S magnesium alloy foams in 0.9% NaCl solution and in phosphate buffer saline solution as a simulated physiological electrolyte. The magnesium foams were produced by powder metallurgy technology using space-holding particles to control the porosity content. Machined chips were used as raw material for the production of Mg alloy powder by milling process. The microstructure of the foams was examined using optical and scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy analysis. The corrosion behavior was evaluated by immersion test and potentiodynamic polarization analysis. The results obtained clearly demonstrate that the porosity has a significant effect on the corrosion resistance of the tested foams. Foams with 14–19% porosity have a corrosion rate of 4–10 mcd and 7–15 mcd in NaCl and phosphate buffer saline solution, respectively, compared to only 0.10 mcd for the same alloy in as cast conditions. This increased corrosion degradation of the Mg foams by more than one order of magnitude compared to the cast alloy may limit their potential application in regular and physiological environments. - Highlights: • Porosity has a detrimental effect on corrosion resistance of MRI 201S Mg foams. • 14–19% porosity increases the corrosion rate by more than one order of magnitude. • Accelerated corrosion limits the use of foams in regular/physiological environments.

  3. Physico-chemical analyses and corrosion effect of produced water ...

    African Journals Online (AJOL)

    Physico-chemical characteristics of the composite produced water sample used for the study has a higher concentration compared with DPR standard for discharge of produced formation water into surface environment. It was assumed that the corrosion of the coupons was due to presence of high chemical matters in the ...

  4. effect of municipal liquid waste on corrosion susceptibility

    African Journals Online (AJOL)

    DR. AMINU

    categories: complete immersion in seawater or exposure to an environment charged with salts particles or solutions, both categories are subjected to many variables and pollutants (Kareem, 2006). Also the corrosion behaviour of galvanized steel in industrial effluents discharged into the environment, was found to corrode ...

  5. Effect of acid corrosion on crack propagation of concrete beams

    Indian Academy of Sciences (India)

    HU SHAOWEI

    2018-03-10

    Mar 10, 2018 ... sive strength, low price, convenient construction modelling and workability, as well as corrosion ... These test results showed that the elastic modulus and fracture parameters of concrete structures reduced ... due to nonlinear characteristics of concrete materials, the classical linear elastic fracture mechanics.

  6. Effect of piperidones on hydrogen permeation and corrosion ...

    Indian Academy of Sciences (India)

    corrosion inhibition. 3.5 Hydrogen permeation measurements. Hydrogen can enter into the metal during various industrial operations like melting, heat treatment, or pickling and electrochemical processes such as cathodic cleaning and electrolytic machining. Of the various sources of entry of hydrogen into the metal,.

  7. Inhibition Effect of Deanol on Mild Steel Corrosion in Dilute ...

    African Journals Online (AJOL)

    The influence of deanol on the corrosion behaviour of mild steel in dilute sulphuric acid with sodium chloride addition was studied by means of mass-loss, potentiodynamic polarization, electrode potential monitoring, scanning electron microscopy and statistical analysis. Results show that deanol performed excellently with ...

  8. The effect of flow and chemical corrosion in reverse osmosis over desalinated water

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Jae [Chunnam National Univ., Gwangju (Korea, Republic of); Pak, Byung Gu [Doosan Heavy Industry Co., Tongyoung (Korea, Republic of)

    2015-12-15

    Desalinated water produced by a reverse osmosis (RO) filtering method forms about 22% of total production of desalinated water in the world. However, the RO environment is very corrosive due to the presence of various chemicals for water treatment and the flow of sand particles leading to corrosion. Recently, there has been much effort to substitute cheaper and more corrosion resistant stainless steels for copper based alloys as a valve material in RO. Nevertheless, the effects of chemicals and particles on the corrosion of stainless steels have rarely been studied. Erosion phenomenon was detected under the condition with the flow rate of more than 8ms{sup -1} in spite of the absence of sand particles. In seawater containing sand particles, the erosion in stainless steels was accelerated further.

  9. Effect of Zr on the Corrosion Properties of Mg-Li-Al Alloy

    International Nuclear Information System (INIS)

    Kim, Soon Ho; Choi, Sang Hyun; Kim, In Bae; Kim, Kyung Hyun

    1994-01-01

    Effect of Zr on the electrochemical corrosion characteristics of Mg-Li-Al alloy has been investigated by means of potentiodynamic polarization study. The electrochemical behaviors were evaluated in 0.03% NaCl solution and the solution buffered with KH 2 PO 5 · NaOH at room temperature. It was found that the addition of very small quantity of Zr (0.03wt%) in Mg-Li-Al alloy increased corrosion rates and amount of corrosion products and decreased the pitting resistance of the alloy. From the results it was concluded that Zr which is added to increase the strength of Mg-Li-Al alloy is harmful to corrosion properties of the alloy

  10. Radiolysis effects on fuel corrosion within a failed nuclear waste container

    International Nuclear Information System (INIS)

    Sunder, S.; Shoeshmith, D.W.; Christensen, H.C.

    2003-01-01

    The concept of geological disposal of used nuclear fuel in corrosion resistant containers is being investigated in several countries. In the Canadian Nuclear Fuel Waste Management Program (CNFWMP), it is assumed that the used fuel will be disposed of in copper containers. Since the predicted lifetimes of these containers are very long (>106 years), only those containers emplaced with an undetected defect will fail within the period for which radionuclide release from the fuel must be considered. Early failure could lead to the entry of water into the container and subsequent release of radionuclides. The release rate of radionuclides from the used fuel will depend upon its dissolution rate. The primary mechanism for release will be the corrosion of the fuel driven by radiolytically-produced oxidants. The studies carried out to determine the effects of water radiolysis on fuel corrosion are reviewed, and some of the procedures used to predict corrosion rates of used fuel in failed nuclear waste containers described. (author)

  11. Reliability assessment of underground pipelines under the combined effect of active corrosion and residual stress

    International Nuclear Information System (INIS)

    Amirat, A.; Mohamed-Chateauneuf, A.; Chaoui, K.

    2006-01-01

    Lifetime management of underground pipelines is mandatory for safe hydrocarbon transmission and distribution systems. Reliability analysis is recognized as a powerful decision-making tool for risk-based design and maintenance. Both the residual stresses generated during the manufacturing process and in-service corrosion reduce the ability to resist internal and external loading. In this study, the residual stress distribution in large diameter pipes has been characterized experimentally in order to be coupled with the corrosion model. During the pipe lifetime, residual stress relaxation occurs due to the loss of pipe thickness as material layers are consumed by corrosion. The reliability-based assessment of residual stress effects is applied to underground pipelines under a roadway, with and without active corrosion. It has been found that the residual stress greatly increases the failure probability, especially in the early stage of the pipe lifetime

  12. A review on the effect of welding on the corrosion of magnesium alloys

    Science.gov (United States)

    Mohamed, N. S.; Alias, J.

    2017-10-01

    Welding is an important joining technique for lightweight alloys with their increasing applications in aerospace, aircraft, automotive, electronics and other industries. The applications of lightweight alloys particularly magnesium alloys increased rapidly due to their beneficial properties such as low density, high strength-to-mass ratio, good dimensional stability, electromagnetic shielding and good recyclability. The effect of welding on the corrosion of magnesium alloys are reviewed in this paper, which closely related to the developed microstructure by the welding process. The paper focuses particularly on friction stir and laser welding. The basic principles of friction stir and laser welding are discussed, to present the likelihood of defects which significantly affect the corrosion of magnesium alloy. The finding in corrosion demonstrated the morphology of corrosion occurrence on each welded region, and observation on the potential and current values are also included.

  13. Effect of red mud addition on the corrosion parameters of reinforced concrete evaluated by electrochemical methods

    Directory of Open Access Journals (Sweden)

    D.V. Ribeiro

    Full Text Available Red mud, the main waste generated in aluminum and alumina production from bauxite ore by the Bayer process, is considered "hazardous" due to its high pH. The high pH also provides greater protection of rebars, which is reflected in the low corrosion potential and high electrical resistivity (filler effect of concrete. The corrosion potential was monitored by electrochemical measurements and the electrical resistivity was evaluated using sensors embedded in concrete test specimens. The results showed that the addition of red mud is beneficial to concrete, reducing its corrosion potential and increasing its electrical resistivity. Red mud proved to be a promising additive for concrete to inhibit the corrosion process.

  14. Effect of Secondary Phase Precipitation on the Corrosion Behavior of Duplex Stainless Steels

    Directory of Open Access Journals (Sweden)

    Kai Wang Chan

    2014-07-01

    Full Text Available Duplex stainless steels (DSSs with austenitic and ferritic phases have been increasingly used for many industrial applications due to their good mechanical properties and corrosion resistance in acidic, caustic and marine environments. However, DSSs are susceptible to intergranular, pitting and stress corrosion in corrosive environments due to the formation of secondary phases. Such phases are induced in DSSs during the fabrication, improper heat treatment, welding process and prolonged exposure to high temperatures during their service lives. These include the precipitation of sigma and chi phases at 700–900 °C and spinodal decomposition of ferritic grains into Cr-rich and Cr-poor phases at 350–550 °C, respectively. This article gives the state-of the-art review on the microstructural evolution of secondary phase formation and their effects on the corrosion behavior of DSSs.

  15. Effect of Secondary Phase Precipitation on the Corrosion Behavior of Duplex Stainless Steels.

    Science.gov (United States)

    Chan, Kai Wang; Tjong, Sie Chin

    2014-07-22

    Duplex stainless steels (DSSs) with austenitic and ferritic phases have been increasingly used for many industrial applications due to their good mechanical properties and corrosion resistance in acidic, caustic and marine environments. However, DSSs are susceptible to intergranular, pitting and stress corrosion in corrosive environments due to the formation of secondary phases. Such phases are induced in DSSs during the fabrication, improper heat treatment, welding process and prolonged exposure to high temperatures during their service lives. These include the precipitation of sigma and chi phases at 700-900 °C and spinodal decomposition of ferritic grains into Cr-rich and Cr-poor phases at 350-550 °C, respectively. This article gives the state-of the-art review on the microstructural evolution of secondary phase formation and their effects on the corrosion behavior of DSSs.

  16. Effect of load deflection on corrosion behavior of NiTi wire.

    Science.gov (United States)

    Liu, I H; Lee, T M; Chang, C Y; Liu, C K

    2007-06-01

    For dental orthodontic applications, NiTi wires are used under bending conditions in the oral environment for a long period. The purpose of this study was to investigate the effect of bending stress on the corrosion of NiTi wires using potentiodynamic and potentiostatic tests in artificial saliva. The results indicated that bending stress induces a higher corrosion rate of NiTi wires in passive regions. It is suggested that the passive oxide film of specimens would be damaged under bending conditions. Auger electron spectroscopic analysis showed a lower thickness of passive films on stressed NiTi wires compared with unstressed specimens in the passive region. By scanning electron microscopy, localized corrosion was observed on stressed Sentalloy specimens after a potentiodynamic test at pH 2. In conclusion, this study indicated that bending stress changed the corrosion properties and surface characteristics of NiTi wires in a simulated intra-oral environment.

  17. Effect of forging process on microstructure, mechanical and corrosion properties of biodegradable Mg-1Ca alloy

    International Nuclear Information System (INIS)

    Harandi, Shervin Eslami; Hasbullah Idris, Mohd; Jafari, Hassan

    2011-01-01

    Research highlights: → Forging temperature demonstrates more pronounced effect compared to forging speed. → Precipitation of Mg 2 Ca phase at grain boundaries accelerates corrosion rate. → Forging process doesn't provide the corrosion resistance required for bone healing. -- Abstract: The performance of Mg-1Ca alloy, a biodegradable metallic material, may be improved by hot working in order that it may be of use in bone implant applications. In this study, Mg-1Ca cast alloy was preheated to different temperatures before undergoing forging process with various forging speeds. Macro- and microstructure of the samples were examined by stereo and scanning electron microscopes (SEM) equipped with energy dispersive X-ray spectroscopy (EDS), respectively. To determine the mechanical properties of the alloy, hardness value and plastic deformation ability of the samples were measured. To investigate the corrosion behaviour of the alloy, immersion and electrochemical tests were performed on the samples in simulated body fluid and the corrosion products were characterized by SEM/EDS. The results showed that increasing forging temperature decreased grain size led to improved hardness value and plastic deformation ability of the alloy, whereas no significant effect was observed by changing forging speed. Moreover, forging at higher temperatures led to an increase in the amount of Mg 2 Ca phase at grain boundaries resulted in higher corrosion rates. It can be concluded that although forging process improved the mechanical properties of the alloy, it does not satisfy the corrosion resistance criteria required for bone healing.

  18. Effect of compression deformation on the microstructure and corrosion behavior of magnesium alloys

    International Nuclear Information System (INIS)

    Snir, Y.; Ben-Hamu, G.; Eliezer, D.; Abramov, E.

    2012-01-01

    Highlights: ► Metallurgical features (mainly twinning, dislocation accumulation, and dynamic recrystallization). ► The thermo-mechanical state (amount of deformation and its temperature). ► The corrosion behavior of wrought Mg-alloys. This correlation was emphasized by the mechanical behavior measured through micro-hardness. ► Microstructural changes during deformation, and potentio-dynamic corrosion tests were correlated. - Abstract: The effect of deformation on the corrosion and mechanical behavior of wrought Mg-alloys AZ31, AM50, and ZK60 was investigated. The materials’ behavior was correlated to the changes in metallurgical features, during compression, into different amounts of deformation at three temperatures: 250° C, 280° C, and 350° C. The metallurgical features were monitored by optical microscope, scanning electron microscope (SEM), and transmission electron microscopy (TEM). It was observed that there is a very strong correlation between three features: 1. metallurgical features (mainly twinning, dislocation accumulation, and dynamic recrystallization); 2. The thermo-mechanical state (amount of deformation and its temperature); and 3. The corrosion behavior of wrought Mg-alloys. This correlation was emphasized by the mechanical behavior measured through micro-hardness. Microstructural changes during deformation, and potentio-dynamic corrosion tests were correlated. These results show that studies on the effect of thermo-mechanical state (related to the microstructure) on the corrosion behavior of wrought Mg-alloys are essential in order to optimize their applicability to plastic forming processes.

  19. Effect of mixed alloy combinations on fretting corrosion performance of spinal screw and rod implants.

    Science.gov (United States)

    Mali, Sachin A; Singh, Vaneet; Gilbert, Jeremy L

    2017-07-01

    Spinal implants are made from a variety of materials to meet the unique mechanical demands of each application. However, the medical device community has raised concern about mixing dissimilar metals in an implant because of fear of inducing corrosion. There is a lack of systematic studies on the effects of mixing metals on performance of spinal implants, especially in fretting corrosion conditions. Hence, the goal was to determine whether mixing stainless steel (SS316L), titanium alloy (Ti6Al4V) and cobalt chromium (CoCrMo) alloy components in a spinal implant leads to any increased risk of corrosion degradation. Spinal constructs consisting of single assembly screw-connector-rod components were tested using a novel short-term cyclic fretting corrosion test method. A total of 17 alloy component combinations (comprised of SS316L, Ti6Al4V-anodized and CoCrMo alloy for rod, screws and connectors) were tested under three anatomic orientations. Spinal constructs having all SS316L were most susceptible to fretting-initiated crevice corrosion attack and showed higher average fretting currents (∼25 - 30 µA), whereas constructs containing all Ti6Al4V components were less susceptible to fretting corrosion with average fretting currents in the range of 1 - 6 µA. Mixed groups showed evidence of fretting corrosion but they were not as severe as all SS316L group. SEM results showed evidence of severe corrosion attack in constructs having SS316L components. There also did not appear to be any galvanic effects of combining alloys together. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1169-1177, 2017. © 2016 Wiley Periodicals, Inc.

  20. Effect of temperature, of oxygen content and the downstream effect on corrosion rate of structural materials in liquid sodium

    International Nuclear Information System (INIS)

    Ilincev, G.

    1988-01-01

    The effects were experimentally tested of temperature and of oxygen content on the corrosion rate of structural materials in liquid sodium and on reducing the corrosion rate down the sodium stream. The results of the experiments are shown in graphs and tables and are discussed in detail. The duration of all tests was standard 1,000 hours. The test parameters were set such as to determine the effect of temperature on corrosion of a quantity of various materials in sodium with a low oxygen content (1.2 to 2 ppm) at temperatures of 500 to 800 degC and in sodium with a high oxygen content (345 ppm) at temperatures of 500 to 700 degC. More experiments served the determination of the effect of a different oxygen content varying between 1.2 and 2 ppm at a constant temperature of 600 degC. The materials being tested included main structural materials used for fast reactor construction and materials allowing to establish the effect of main alloying elements on their corrosion in liquid sodium of different temperatures and purity grades. The relationships showing the effects of temperature and oxygen content in sodium on the rate of corrosion of various structural materials in hot parts of the installation and on the reduction in the rate of corrosion downstream due to sodium saturation with corrosion products were constructed using the experimental results. (Z.M.). 15 figs., 2 tabs., 7 refs

  1. Effect Mo Addition on Corrosion Property and Sulfide Stress Cracking Susceptibility of High Strength Low Alloy Steels

    International Nuclear Information System (INIS)

    Lee, Woo Yong; Koh, Seong Ung; Kim, Kyoo Young

    2005-01-01

    The purpose of this work is to understand the effect of Mo addition on SSC susceptibility of high strength low alloy steels in terms of microstructure and corrosion property. Materials used in this study are high strength low alloy (HSLA) steels with carbon content of 0.04wt% and Mo content varying from 0.1 to 0.3wt%. The corrosion property of steels was evaluated by immersion test in NACE-TM01-77 solution A and by analyzing the growth behavior of surface corrosion products. SSC resistance of steels was evaluated using constant load test. Electrochemical test was performed to investigate initial corrosion rate. Addition of Mo increased corrosion rate of steels by enhancing the porosity of surface corrosion products. however, corrosion rate was not directly related to SSC susceptibility of steels

  2. The effect of corrosion on stained glass windows

    Directory of Open Access Journals (Sweden)

    Laissner, Johanna

    1996-06-01

    Full Text Available Stained glass windows belong to the most important cultural heritage of Europe. Within the last decades a disastrous deterioration took place. The wonderful stained glass windows and their glass paintings as pieces of art are acutely menaced by environmental corrosive influences. This corrosion process is a very complex reaction which is not only influenced by temperature and humidity changes but also by gaseous pollutants like sulfur dioxide, nitrogen oxides or ozone, by dust and air, microorganisms as well as synergetic interactions. Strongly affected by these environmental attacks are medieval stained glasses due to their chemical composition. They have a low content in silica and high contents of modifier ions (e.g. potassium and calcium. The corrosion phenomena can range from predominantly pitting on the surface to the formation of thick corrosion crusts which are turning the panel opaque and thus reducing strongly the transparency of the windows. In order to set up a conservation and restoration concept, it is necessary to know about the environmental conditions to which the stained glass windows are exposed. For this purpose very corrosion sensitive model glasses (so called glass sensors were developed which have a similar chemical composition as historic stained glasses. They exhibit the same corrosion reactions but react much faster, and are now widely used to estimate corrosive stresses on stained glass windows to give basic information about the corrosive impacts which work on the historic glasses. In this paper principle corrosion mechanisms of stained glass windows and their enhancing factors are discussed. For the evaluation of the environmental impact, the application of glass sensors is demonstrated.

    Las vidrieras coloreadas pertenecen al legado cultural más importante de Europa. En las últimas décadas se ha producido en ellas un desastroso deterioro. Las maravillosas vidrieras coloreadas y sus policromías est

  3. Corrosion resistance of Ni-Cr-Mo alloys. Chemical composition and metallurgical condition's effects

    International Nuclear Information System (INIS)

    Zadorozne, N.S.; Rebak, Raul B.

    2009-01-01

    Ni-Cr-Mo alloys offer an outstanding corrosion resistance in a wide variety of highly-corrosive environments. This versatility is due to the excellent performance of nickel in hot alkaline solutions and the beneficial effect of chromium and molybdenum in oxidizing and reducing conditions, respectively. Alloy C-22 (22 % Cr-13 % Mo-3% W) is a well known versatile member of this family. Due to its excellent corrosion resistance in a wide variety of environments, Alloy C-22 has been selected for the fabrication of the corrosion-resistant outer shell of the high-level nuclear waste container. The increasing demand of the industry for corrosion resistant alloys with particular properties of corrosion and mechanical resistance has led to the development of new alloys. Alloy C-22HS (Ni-21 % Cr-17 % Mo) is a new high-strength corrosion resistant material recently developed and introduced into the market. This alloy provides a corrosion resistance comparable with that of other C-type alloys, and it can also be age hardened to effectively double its yield strength. HASTELLOY HYBRID-BC1 (Ni-22 % Mo-15 % Cr) is a new development intended for filling the gap between Ni-Mo and Ni-Cr-Mo alloys. This novel alloy is able to withstand HCl and H 2 SO 4 , even in the presence of dissolved oxygen and other oxidizing species. Its resistance to chloride-induced pitting corrosion, crevice corrosion and stress corrosion cracking is also remarkable. Thermal aging of Ni-Cr-Mo alloys leads to microstructure changes depending on the temperature range and exposure time at temperature. A Long Range Ordering (LRO) reaction can occur in the range of 350 C degrees to 600 C degrees, producing an ordered Ni 2 (Cr,Mo) phase. This ordering reaction does not seem to affect the corrosion resistance and produces only a slight loss in ductility. LRO transformation is homogeneous and has proven to be useful to fabricate the age-hard enable Alloy C22-HS. Tetrahedral Close Packed (TCP) phases, like μ, σ and

  4. Effect of acidity upon attrition-corrosion of human dental enamel.

    Science.gov (United States)

    Wu, Yun-Qi; Arsecularatne, Joseph A; Hoffman, Mark

    2015-04-01

    Attrition-corrosion is a synthesized human enamel wear process combined mechanical effects (attrition) with corrosion. With the rising consumption of acidic food and beverages, attrition-corrosion is becoming increasingly common. Yet, research is limited and the underlying mechanism remains unclear. In this study, in vitro wear loss of human enamel was investigated and the attrition-corrosion process and wear mechanism were elucidated by the analysis of the wear scar and its subsurface using focused ion beam (FIB) sectioning and scanning electron microscopy (SEM). Human enamel flat-surface samples were prepared with enamel cusps as the wear antagonists. Reciprocating wear testing was undertaken under load of 5N at the speed of 66 cycle/min for 2250 cycles with lubricants including citric acid (at pH 3.2 and 5.5), acetic acid (at pH 3.2 and 5.5) and distilled water. All lubricants were used at 37°C. Similar human enamel flat-surface samples were also exposed to the same solutions as a control group. The substance loss of enamel during wear can be linked to the corrosion potential of a lubricant used. Using a lubricant with very low corrosion potential (such as distilled water), the wear mechanism was dominated by delamination with high wear loss. Conversely, the wear mechanism changed to shaving of the softened layer with less material loss in an environment with medium corrosion potential such as citric acid at pH 3.2 and 5.5 and acetic acid at pH 5.5. However, a highly corrosive environment (e.g., acetic acid at pH 3.2) caused the greatest loss of substance during wear. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Effects of Copper and Sulfur Additions on Corrosion Resistance and Machinability of Austenitic Stainless Steel

    International Nuclear Information System (INIS)

    Kim, Soon Tae; Park, Yong Soo; Kim, Hyung Joon

    1999-01-01

    Effects of Cu and S on corrosion resistance and machinability of austenitic stainless steel were investigated using immersion test, metallographic examination, Auger surface analysis and tool life test with single point turning tools. Corrosion resistance of the experimental Cu containing alloys in 18.4N H 2 SO 4 at 80 ∼ 120 .deg. C and 3N HCl at 40 .deg. C decreased as S content increased. However, one of the experimental alloys (Fe- 18%Cr- 21%Ni-3.2%Mo- 1.6%W- 0.2%N- 3.1%Cu- 0.091%S) showed general and pitting corrosion resistance equivalent to that of CW12MW in highly concentrated SO 4 2- environment. The alloy also showed pitting corrosion resistance superior to super stainless steel such as 654SMO in Cl - environment. The reasons why the increase in S content deteriorated the corrosion resistance were first, that the number and size of (Mn, Cr)S sulfides having corrosion resistance lower than that of matrix increased, leading to pitting corrosion and second, that rapid dissolution of the matrix around the pits was caused by adsorbed S. However, the alloy containing 3.1 %Cu and 0.091 % S maintained high general and pitting corrosion resistance due to heavily enriched noble Cu through selective dissolution of active Fe and Ni. The tool life for 3.1 % Cu + 0.091 % S added alloy was about four times that of 0.06%Cu + 0.005% S added alloy due to high shear strain rate generated by Cu addition giving easy cross slip of dislocation, lubrication of ductile (Mn, Cr)S sulfides adhering to tool crater surface and low cutting force resulting from thin continuous sulfides formed in chips during machining

  6. Synergistic Effect on Corrosion Inhibition Efficiency of Ginger Affinale Extract in Controlling Corrosion of Mild Steel in Acid Medium

    International Nuclear Information System (INIS)

    Subramanian, Ananth Kumar; Arumugam, Sankar; Mallaiya, Kumaravel; Subramaniam, Rameshkumar

    2013-01-01

    The corrosion inhibition nature of Ginger affinale extract for the corrosion of mild steel in 0.5N H 2 SO 4 was investigated using weight loss, electrochemical impedance and potentiodynamic polarization methods. The results revealed that Ginger affinale extract acts as a good corrosion inhibitor in 0.5N H 2 SO 4 medium. The inhibition efficiency increased with an increase in inhibitor concentration. The inhibition could be attributed to the adsorption of the inhibitor on the steel surface

  7. Characterizing Corrosion Effects of Weak Organic Acids Using a Modified Bono Test

    Science.gov (United States)

    Zhou, Yuqin; Turbini, Laura J.; Ramjattan, Deepchand; Christian, Bev; Pritzker, Mark

    2013-12-01

    To meet environmental requirements and achieve benefits of cost-effective manufacturing, no-clean fluxes (NCFs) or low-solids fluxes have become popular in present electronic manufacturing processes. Weak organic acids (WOAs) as the activation ingredients in NCFs play an important role, especially in the current lead-free and halogen-free soldering technology era. However, no standard or uniform method exists to characterize the corrosion effects of WOAs on actual metallic circuits of printed wiring boards (PWBs). Hence, the development of an effective quantitative test method for evaluating the corrosion effects of WOAs on the PWB's metallic circuits is imperative. In this paper, the modified Bono test, which was developed to quantitatively examine the corrosion properties of flux residues, is used to characterize the corrosion effects of five WOAs (i.e., abietic acid, succinic acid, glutaric acid, adipic acid, and malic acid) on PWB metallic circuits. Experiments were performed under three temperature/humidity conditions (85°C/85% RH, 60°C/93% RH, and 40°C/93% RH) using two WOA solution concentrations. The different corrosion effects among the various WOAs were best reflected in the testing results at 40°C and 60°C. Optical microscopy was used to observe the morphology of the corroded copper tracks, and scanning electron microscopy (SEM) energy-dispersive x-ray (EDX) characterization was performed to determine the dendrite composition.

  8. The effects of bacteria on the corrosion behavior of carbon steel in compacted bentonite

    International Nuclear Information System (INIS)

    Nishimura, T.; Wada, R.; Nishimoto, H.; Fujiwara, K.; Taniguchi, N.; Honda, A.

    1999-10-01

    As a part of evaluation of corrosion life of carbon steel overpack, the experimental studies have been performed on the effects of bacteria on the corrosion behavior of carbon steel in compacted bentonite using iron bacteria (IB) as a representative oxidizing bacteria and sulphur reducing bacteria (SRB) as a representative reducing bacteria. The results of the experimental studies showed that; The activity of SRB was low in compacted bentonite in spite of applying suitable condition for the action of bacteria such as temperature and nutritious solution. Although the corrosion behavior of carbon steel was affected by the existence of bacteria in simple solution, the corrosion rates of carbon steel in compacted bentonite were several μ m/year -10 μ m/year irrespective of coexistence of bacteria and that the corrosion behavior was not affected by the existence of bacteria. According to these results, it was concluded that the bacteria would not affect the corrosion behavior of carbon steel overpack under repository condition. (author)

  9. 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

  10. Effect of Heat Treatment on Corrosion Behaviors of Mg-5Y-1.5Nd Alloys

    Directory of Open Access Journals (Sweden)

    Xiumin Ma

    2016-01-01

    Full Text Available Corrosion behavior of Mg-5Y-1.5Nd alloy was investigated after heat treatment. The microstructure and precipitation were studied by scanning electron microscope (SEM and energy dispersive spectrometer (EDS. The weight loss rates of different samples were arranged as T6-24 h>T6-6 h>T6-14 h>as-cast>T4. The open circuit potential (OCP showed that T4 sample had a more positive potential than that of other samples. The potentiodynamic polarization curves showed that the T6-24 h sample had the highest corrosion current density of 245.362 μA·cm−2, whereas the T4 sample had the lowest at 52.164 μA·cm−2. The EIS results confirmed that the heat treatment reduced the corrosion resistance for Mg-5Y-1.5Nd alloy, because the precipitations acted as the cathode of electrochemical reactions to accelerate the corrosion process. The corrosion rates of different samples were mainly determined by the amount and distribution of the precipitations. The precipitations played dual roles that depended on the amount and distribution. The presence of the phase in the alloys could deteriorate the corrosion performance as it could act as an effective galvanic cathode. Otherwise, a fine and homogeneous phase appeared to be a better anticorrosion barrier.

  11. 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

  12. The effect of Ti(CN/TiNb(CN coating on erosion–corrosion resistance

    Directory of Open Access Journals (Sweden)

    William Aperador Chaparro

    2012-05-01

    Full Text Available The goal of this work was to study electrochemical behaviour in corrosion-erosion conditions for Ti(CN/TiNb(CN multilayer coatings having 1, 50, 100, 150 and 200 bilayer periods on AISI 4140 steel substrates by using a multi-target magnetron reactive sputtering device, with an r.f. source (13.56 MHz, two cylindrical magnetron cathodes and two stoichiometric TiC and Nb targets. The multi-layers were evaluated by comparing them to corrosion, erosion and erosion corrosion for a 30º impact angle in a solution of 0.5 M NaCl and silica, analysing the effect of impact angle and the number of bilayers on these coatings’ corrosion resistance. The electrochemical characterisation was performed using electrochemical impedance spectroscopy for analysing corrosion surface; surface morphology was characterised by using a high-resolution scanning electron microscope (SEM. The results showed a de-creased corrosion rate for multilayer systems tested at 30°.

  13. Lithuanian Quarry Aggregates Concrete Effects of Alkaline Corrosion Tests

    Directory of Open Access Journals (Sweden)

    Aurimas Rutkauskas

    2016-02-01

    Full Text Available Aggregate alkaline corrosion of cement in concrete is going to respond in sodium and potassium hydroxide (lye with active SiO2 found in some aggregates. During this reaction, the concrete has resulted in significant internal stresses which cause deformation of the concrete, cracking and disintegration. The reaction is slow and concrete signs of decomposition appear only after a few months or years. The study used two different aggregates quarries. Studies show that Lithuania gravel contaminated with reactive particles having amorphous silicon dioxide reacting with cement in sodium and potassium hydroxide and the resulting alkaline concrete corrosion. It was found that, according to AAR 2 large aggregates include Group II – potentially reactive because of their expansion after 14 days, higher than 0.1%.

  14. Effect of Solder Flux Residues on Corrosion of Electronics

    DEFF Research Database (Denmark)

    Hansen, Kirsten Stentoft; Jellesen, Morten Stendahl; Møller, Per

    2009-01-01

    Flux from ‘No Clean’ solder processes can cause reliability problems in the field due to aggressive residues, which may be electrical conducting or corrosive in humid environments. The solder temperature during a wave solder process is of great importance to the amount of residues left on a PCBA...... testing and use in the field, consequences and recommendations are given. Failures, caused by harsh[1] customer environments, are not covered in this paper....

  15. Synergistic Effect of Molybdate and Monoethanolamine on Corrosion Inhibition of Ductile Cast Iron in Tap Water

    Energy Technology Data Exchange (ETDEWEB)

    Kim, K. T.; Kim, Y. S. [Andong National University, Andong (Korea, Republic of); Chang, H. Y.; Lim, B. T.; Park, H. B. [KEPCO Engineering and Construction Company, Gimcheon (Korea, Republic of)

    2017-02-15

    A synergistic effect was observed in the combination of nitrite and ethanolamines. Ethanolamine is one of the representative organic corrosion inhibitors and can be categorized as adsorption type. However, nitrosamines can form when amines mix with sodium nitrite. Since nitrosamine is a carcinogen, the co-addition of nitrite and ethanolamine will be not practical, and thus, a non-toxic combination of inhibitors shall be needed. In order to maximize the effect of monoethanolamine, we focused on the addition of molybdate. Molybdate has been used to alternate the addition of chromate, but it showed insufficient oxidizing power relative to corrosion inhibitors. This work evaluated the synergistic effect of the co-addition of molybdate and monoethanolamine, and its corrosion mechanism was elucidated. A high concentration of molybdate or monoethanolamine was needed to inhibit the corrosion of ductile cast iron in tap water, but in the case of the co-addition of molybdate and monoethanolamine, a synergistic effect was observed. This synergistic effect could be attributed to the molybdate that partly oxidizes the metallic surface and the monoethanolamine that is simultaneously adsorbed on the graphite surface. This adsorbed layer then acts as the barrier layer that mitigates galvanic corrosion between the graphite and the matrix.

  16. Astrakhan-Mangyshlak water main (pipeline): corrosion state of the inner surface, and methods for its corrosion protection. Part III. The effects of KW2353 inhibitor. Part IV. Microbiological corrosion

    International Nuclear Information System (INIS)

    Reformatskaya, I.I.; Ashcheulova, I.I.; Barinova, M.A.; Kostin, D.V.; Prutchenko, S.G.; Ivleva, G.A.; Taubaldiev, T.S.; Murinov, K.S.; Tastanov, K.Kh.

    2003-01-01

    The effect of the KW2353 corrosion inhibitor, applied on the Astrakhan-Mangyshlak water main (pipeline) since 1997, on the corrosion processes, occurring on the 17G1S steel surface, is considered. The properties of the surface sediments are also considered. The role of the microbiological processes in the corrosion behavior of the water main (pipeline) inner surface is studied. It is shown, that application of the polyphosphate-type inhibitors, including the KW2353 one, for the anticorrosive protection of the inner surface of the extended water main (pipelines) is inadmissible: at the temperature of ∼20 deg C this corrosion inhibitor facilitates the development of the local corrosion processes on the water main (pipeline) inner surface. At the temperature of ∼8 deg C the above inhibitor discontinues to effect the corrosive stability of the 17G1S steel. The optimal way of the anticorrosive protection of the steel equipment, contacting with the water media, is the increase in the oxygen content therein [ru

  17. Current state of knowledge in radiolysis effects on spent fuel corrosion

    International Nuclear Information System (INIS)

    Christensen, H.; Sunder, S.

    1998-09-01

    Literature data on the effect of water radiolysis products on spent fuel oxidation and dissolution have been reviewed. Effects of γ-radiolysis, α-radiolysis and dissolved O 2 or H 2 O 2 in unirradiated solutions have been discussed separately. Also the effect of carbonate in γ-irradiated solutions and radiolysis effects on leaching of spent fuels have been reviewed. In addition a radiolysis model for calculation of corrosion rates of UO 2 , presented previously, has been discussed. The model has been shown to give a good agreement between calculated and measured corrosion rates in the case of γ-radiolysis and in unirradiated solutions of dissolved oxygen or hydrogen peroxide. The model has failed to predict the results of α-radiolysis. In a recent study it was shown that the model gave a good agreement with measured corrosion rates of spent fuel exposed in deionized water

  18. Current state of knowledge of water radiolysis effects on spent nuclear fuel corrosion

    International Nuclear Information System (INIS)

    Christensen, H.; Sunder, S.

    2000-07-01

    Literature data on the effect of water radiolysis products on spent-fuel oxidation and dissolution are reviewed. Effects of gamma radiolysis, alpha radiolysis, and dissolved O 2 or H 2 O 2 in unirradiated solutions are discussed separately. Also, the effect of carbonate in gamma-irradiated solutions and radiolysis effects on leaching of spent fuel are reviewed. In addition, a kinetic model for calculating the corrosion rates of UO 2 in solutions undergoing radiolysis is discussed. The model gives good agreement between calculated and measured corrosion rates in the case of gamma radiolysis and in unirradiated solutions containing dissolved oxygen or hydrogen peroxide. However, the model fails to predict the results of alpha radiolysis. In a recent study , it was shown that the model gave good agreement with measured corrosion rates of spent fuel exposed in deionized water. The applications of radiolysis studies for geologic disposal of used nuclear fuel are discussed. (author)

  19. Effect of H2O2 on the corrosion behavior of 304L stainless steel

    International Nuclear Information System (INIS)

    Song, Taek Ho

    1994-02-01

    In connection with the safe storage of high level nuclear waste, effect of H 2 O 2 on the corrosion behavior of 304L stainless steel was examined. Open circuit potentials and polarization curves were measured with and without H 2 O 2 . The experimental results show that H 2 O 2 increased corrosion potential and decreased pitting potential. The passive range, therefore, decreased as H 2 O 2 concentration increased, indicating that pitting resistance was decreased by the existence of H 2 O 2 in the electrolyte. These effects of H 2 O 2 on corrosion of 304L stainless steel are considered to be similar to those of γ-irradiation. To compare the effects of H 2 O 2 with those of O 2 , cathodic and anodic polarization curves were made in three types of electrolyte such as aerated, deaerated, and stirred electrolyte. The experimental results show that the effects of H 2 O 2 on the corrosion behavior were very similar to those of O 2 such as increase of corrosion potential, decrease of pitting resistance, and increase of repassivation potential. Further, H 2 O 2 played much greater role in controlling cathodic reaction rate in neutral water environment. In acid and alkaline media, potential shifts by H 2 O 2 were restricted by the large current density of proton reduction and by the le Chatelier's principle respectively

  20. Effect Of Age And Concrete Cover Thickness On Steel Reinforcement Corrosion At Splash Zone In Reinforced Concrete Hydraulic Structures

    Directory of Open Access Journals (Sweden)

    Nada M. Al- Galawi

    2015-08-01

    Full Text Available Corrosion of reinforcing steel bars in reinforced concrete is considered as one of the biggest problems that face countries overlooking to the Arabian Gulf including Iraq. The research aims to study the effect of the corrosion of steel bars in concrete structures that are exposed to wetting and drying via waves. Reinforced concrete samples were exposed to marine simulated environment for 90 days using prepared system for this purpose. At the end of exposure period polarization test was implemented to measure the actual corrosion rate in each sample. After that the corrosion process was accelerated using impressed current technique by applying a constant electric current DC to the reinforcing bars. Depending on the corrosion current in natural conditions which was measured in polarization test periods of exposing samples to accelerated corrosion current so as to maintain virtual exposure ages of 5 and 25 years of exposure to natural corrosion were calculated. The results showed a remarkable increase in the corrosion current of steel bars in samples that had lower concrete cover thickness. The increase in the cover thickness from 20mm to 40 and 65 mm had a significant effect on reducing the corrosion current at the age of 90 days to about 70 of its original value in both cases. At the virtual exposure age of 5 years the reduction percentage in the corrosion current resulted from increasing cover thickness from 20mm to 40 and 65 mm were 43 and 79 respectively.

  1. Effect of Rice Straw Extract and Alkali Lignin on the Corrosion Inhibition of Carbon Steel

    International Nuclear Information System (INIS)

    Rabiahtul Zulkafli; Norinsan Kamil Othman; Irman Abdul Rahman; Azman Jalar

    2014-01-01

    A paddy residue based corrosion inhibitor was prepared by treating finely powdered rice straw with aqueous ethanol under acid catalyst (0.01 M H 2 SO 4 ). Commercial alkali lignin was obtained from Sigma-Aldrich. Prior to the corrosion test, the extraction yield and alkali lignin was characterized via FTIR to determine the functional group. The effect of paddy residue extract and commercial alkali lignin on the corrosion inhibition of carbon steel in 1 M HCl was investigated through the weight loss method, potentiodynamic polarization technique and scanning electron microscopy (SEM). The corrosion inhibition efficiency of the extract and alkali lignin at different immersion times (3 h, 24 h and 42 h) was evaluated. The results show that the paddy waste extract exhibited lesser weight loss of carbon steel in the acidic medium in comparison to the commercial alkali lignin, suggesting that the paddy residue extract is more effective than the commercial alkali lignin in terms of its corrosion inhibition properties. The results obtained proves that the extract from paddy residue could serve as an effective inhibitor for carbon steel in acidic mediums. (author)

  2. The size effect in corrosion greatly influences the predicted life span of concrete infrastructures.

    Science.gov (United States)

    Angst, Ueli M; Elsener, Bernhard

    2017-08-01

    Forecasting the life of concrete infrastructures in corrosive environments presents a long-standing and socially relevant challenge in science and engineering. Chloride-induced corrosion of reinforcing steel in concrete is the main cause for premature degradation of concrete infrastructures worldwide. Since the middle of the past century, this challenge has been tackled by using a conceptual approach relying on a threshold chloride concentration for corrosion initiation ( C crit ). All state-of-the-art models for forecasting chloride-induced steel corrosion in concrete are based on this concept. We present an experiment that shows that C crit depends strongly on the exposed steel surface area. The smaller the tested specimen is, the higher and the more variable C crit becomes. This size effect in the ability of reinforced concrete to withstand corrosion can be explained by the local conditions at the steel-concrete interface, which exhibit pronounced spatial variability. The size effect has major implications for the future use of the common concept of C crit . It questions the applicability of laboratory results to engineering structures and the reproducibility of typically small-scale laboratory testing. Finally, we show that the weakest link theory is suitable to transform C crit from small to large dimensions, which lays the basis for taking the size effect into account in the science and engineering of forecasting the durability of infrastructures.

  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. Effects of ion implantation on corrosion of zirconium and zirconium base alloys

    International Nuclear Information System (INIS)

    Zelenskij, V.F.; Petel'guzov, I.A.; Rekova, L.P.; Rodak, A.G.

    1989-01-01

    The influence of He and Ar ion bombardment on the corrosion of Zr and Zr-1%Nb and Zr-2.5%Nb alloys is investigated with the aims of finding the irradiation influence laws, obtaining the dependences of the effect of increasing the corrosiuon resistance on the type and dose of bombarding ions and of finding the conditions for the maximum effect. The prolonged corrosion test of specimens (3500 hours) have shown that the strongest effect is obtained for the irradiation with Ar ions up to the dose 1x10 16 ion/cm 2 . The kinetics of ion thermosorption after corrosion of irradiated materials is studied, the temperature threshold of implanted ion stability in zirconium and its alloys is found to be 400 deg C

  5. The effect of surface treatment and gaseous rust protection paper on the atmospheric corrosion stability of aluminium alloy

    International Nuclear Information System (INIS)

    Gao Guizhong

    1992-03-01

    The experimental results of atmospheric corrosion of 166 aluminium alloy of Al-Mg-Si-Cu system and 167 aluminium alloy of Al-Mg-Si-Cu-Fe-Ni system for different surface treatment and different wrapping papers used are introduced. The results show: 1. The composition of aluminium alloy has some effect on the performance of atmospheric corrosion stability and the local corrosion depth for 167 aluminium alloy specimen is considerable. 2. After 8 years storage, the 167 aluminium alloy tubular specimen, which was treated with surface treatment in deionized water at 100 ∼ 230 C degree, has no spot of atmospheric corrosion found. 3. Within the test period, the performance of atmospheric corrosion stability by sulphuric-acid anodization film is remarkable. 4. The No. 19 gaseous rust protection paper has no effect of atmospheric corrosion stability on the 166 and 167 aluminium alloys which were treated with quenching and natural ageing method

  6. Multifrequency Eddy Current Inspection of Corrosion in Clad Aluminum Riveted Lap Joints and Its Effect on Fatigue Life

    Science.gov (United States)

    Okafor, A. C.; Natarajan, S.

    2007-03-01

    Aging aircraft are prone to corrosion damage and fatigue cracks in riveted lap joints of fuselage skin panels. This can cause catastrophic failure if not detected and repaired. Hence detection of corrosion damage and monitoring its effect on structural integrity are essential. This paper presents multifrequency eddy current (EC) inspection of corrosion damage and machined material loss defect in clad A1 2024-T3 riveted lap joints and its effect on fatigue life. Results of eddy current inspection, corrosion product removal and fatigue testing are presented.

  7. Multifrequency Eddy Current Inspection of Corrosion in Clad Aluminum Riveted Lap Joints and Its Effect on Fatigue Life

    International Nuclear Information System (INIS)

    Okafor, A. C.; Natarajan, S.

    2007-01-01

    Aging aircraft are prone to corrosion damage and fatigue cracks in riveted lap joints of fuselage skin panels. This can cause catastrophic failure if not detected and repaired. Hence detection of corrosion damage and monitoring its effect on structural integrity are essential. This paper presents multifrequency eddy current (EC) inspection of corrosion damage and machined material loss defect in clad A1 2024-T3 riveted lap joints and its effect on fatigue life. Results of eddy current inspection, corrosion product removal and fatigue testing are presented

  8. Investigation of Non-Uniform Rust Distribution and Its Effects on Corrosion Induced Cracking in Reinforced Concrete

    Directory of Open Access Journals (Sweden)

    Sutrisno Wahyuniarsih

    2017-01-01

    Full Text Available Uniform corrosion still widely used by a lot of researchers and engineers to analyze the corrosion induced cracking. However, in practice, corrosion process occurred non-uniformly. The part nearest to the exposed surface is more likely to have faster corrosion initiation compared with other regions. This research is mainly focused on investigating the effect of non-uniform rust distribution to cover cracking in reinforced concrete. An experimental test performed using accelerated corrosion test by using 5% NaCl solution and applied a constant electric current to the concrete samples. The rust distribution and measurement were observed by using a digital microscope. Based on the experimental result, it was found that the rust was distributed in a non-uniform pattern. As a result, the cracks also formed non-uniformly along the perimeter of steel bar. At the last part of this paper, a simulation result of concrete cracking induced by non-uniform corrosion is presented. The result compared with a simulation using uniform corrosion assumption to investigate the damage pattern of each model. The simulation result reveals stress evolution due to rust expansion which leads to concrete cracking. Furthermore, a comparison of stresses induced by non-uniform corrosion and uniform corrosion indicates that non-uniform corrosion could lead to earlier damage to the structure which is specified by the formation and propagation of the crack.

  9. Effect of Calcium Nitrate and Sodium Nitrite on the Rebar Corrosion of Medium Carbon Steel in Seawater and Cassava Fluid

    OpenAIRE

    Adamu, M; Umoru, LE; Ige, OO

    2014-01-01

    Inhibitors are regularly used as one of the principal prevention and control techniques in reinforcement corrosion. Hence this study investigates the effect of calcium nitrate and sodium nitrite inhibitors on the rebar corrosion of medium carbon steel in seawater and cassava fluid with a view to determining inhibitive potentials of the different inhibitors in the two media. Gravimetric and voltametric techniques were employed in this study and a total of forty-five corrosion coupons of differ...

  10. The effects of RE and Si on the microstructure and corrosion resistance of Zn–6Al–3Mg hot dip coating

    International Nuclear Information System (INIS)

    Li, Shiwei; Gao, Bo; Yin, Shaohua; Tu, Ganfeng; Zhu, Guanglin; Sun, Shuchen; Zhu, Xiaoping

    2015-01-01

    Highlights: • ZAM coating has been prepared by using an experimental hot-dip galvanizing simulator. • The corrosion resistance of ZAM coating can be improved by additions of Si and RE. • Zn–6Al–3Mg–Si–RE coating forms a dense and stabilized corrosion product layer. • Zn–6Al–3Mg–Si–RE coating shows uniform corrosion. - Abstract: The effects of Si and RE on the microstructure and corrosion resistance of Zn–6Al–3Mg coating (ZAM) have been investigated. Surface morphology observations of the coating and corrosion products reveal that the additions of Si and rare earth metals (RES) improve the microstructural homogeneity of ZAMSR coating and stability of corrosion products formed on ZAMSR coating. Moreover, only uniform corrosion occurs in ZAMSR coating during the corrosion test, while intergranular corrosion and pitting occur in ZAM. As a result, the corrosion resistance of ZAM coating is improved by the additions of Si and RES.

  11. The effects of RE and Si on the microstructure and corrosion resistance of Zn–6Al–3Mg hot dip coating

    Energy Technology Data Exchange (ETDEWEB)

    Li, Shiwei [State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming 650093 (China); School of Materials and Metallurgy, Northeastern University, Shenyang 110819 (China); Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093 (China); Gao, Bo, E-mail: surfgao@aliyun.com [School of Materials and Metallurgy, Northeastern University, Shenyang 110819 (China); Yin, Shaohua [State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming 650093 (China); School of Materials and Metallurgy, Northeastern University, Shenyang 110819 (China); Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093 (China); Tu, Ganfeng; Zhu, Guanglin; Sun, Shuchen; Zhu, Xiaoping [School of Materials and Metallurgy, Northeastern University, Shenyang 110819 (China)

    2015-12-01

    Highlights: • ZAM coating has been prepared by using an experimental hot-dip galvanizing simulator. • The corrosion resistance of ZAM coating can be improved by additions of Si and RE. • Zn–6Al–3Mg–Si–RE coating forms a dense and stabilized corrosion product layer. • Zn–6Al–3Mg–Si–RE coating shows uniform corrosion. - Abstract: The effects of Si and RE on the microstructure and corrosion resistance of Zn–6Al–3Mg coating (ZAM) have been investigated. Surface morphology observations of the coating and corrosion products reveal that the additions of Si and rare earth metals (RES) improve the microstructural homogeneity of ZAMSR coating and stability of corrosion products formed on ZAMSR coating. Moreover, only uniform corrosion occurs in ZAMSR coating during the corrosion test, while intergranular corrosion and pitting occur in ZAM. As a result, the corrosion resistance of ZAM coating is improved by the additions of Si and RES.

  12. Possible effects of external electrical fields on the corrosion of copper in bentonite

    Energy Technology Data Exchange (ETDEWEB)

    Taxen, Claes (Swerea KIMAB (Sweden))

    2011-12-15

    External potentials that develop across a repository may interact with the copper canister. A study was undertaken to investigate the potential corrosion effects of voltage differences in a repository. A set of experiments was performed to study the tendency of copper in bentonite to corrode under influence of an externally applied electrical field. A model study was made to estimate possible corrosion effects of an external electrical field on a full-scale canister in the KBS-3 concept. The interaction between the repository represented by a copper canister in bentonite, and an external electrical field is illustrated with an example

  13. Effect of reactor chemistry and operating variables on fuel cladding corrosion in PWRs

    International Nuclear Information System (INIS)

    Park, Moon Ghu; Lee, Sang Hee

    1997-01-01

    As the nuclear industry extends the fuel cycle length, waterside corrosion of zircaloy cladding has become a limiting factor in PWR fuel design. Many plant chemistry factors such as, higher lithium/boron concentration in the primary coolant can influence the corrosion behavior of zircaloy cladding. The chemistry effect can be amplified in higher duty fuel, particularlywhen surface boiling occurs. Local boiling can result in increased crud deposition on fuel cladding which may induce axial power offset anomalies (AOA), recently reported in several PWR units. In this study, the effect of reactor chemistry and operating variables on Zircaloy cladding corrosion is investigated and simulation studies are performed to evaluate the optimal primary chemistry condition for extended cycle operation. (author). 8 refs., 3 tabs., 16 figs

  14. 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

  15. The effect of corrosion product colloids on actinide transport

    International Nuclear Information System (INIS)

    Gardiner, M.P.; Smith, A.J.; Williams, S.J.

    1992-01-01

    The near field of the proposed UK repository for ILW/LLW will contain containers of conditioned waste in contact with a cementious backfill. It will contain significant quantities of iron and steel, Magnox and Zircaloy. Colloids deriving from their corrosion products may possess significant sorption capacity for radioelements. If the colloids are mobile in the groundwater flow, they could act as a significant vector for activity transport into the far field. The desorption of plutonium and americium from colloidal corrosion products of iron and zirconium has been studied under chemical conditions representing the transition from the near field to the far field. Desorption R d values of ≥ 5 x 10 6 ml g -1 were measured for both actinides on these oxides and hydroxides when actinide sorption took place under the near-field conditions and desorption took place under the far-field conditions. Desorption of the actinides occurred slowly from the colloids under far-field conditions when the colloids had low loadings of actinide and more quickly at high loadings of actinide. Desorbed actinide was lost to the walls of the experimental vessel. (author)

  16. 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

  17. 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.

  18. New understanding of the effect of hydrostatic pressure on the corrosion of Ni–Cr–Mo–V high strength steel

    International Nuclear Information System (INIS)

    Yang, Yange; Zhang, Tao; Shao, Yawei; Meng, Guozhe; Wang, Fuhui

    2013-01-01

    Highlights: •Stress distributions of pits under different hydrostatic pressures are simulated. •Corrosion model of Ni–Cr–Mo–V steel under hydrostatic pressure is established. •A novel understanding of the effect of hydrostatic pressure is proposed. -- Abstract: Corrosion of Ni–Cr–Mo–V high strength steel at different hydrostatic pressures is investigated by scanning electron microscopy (SEM) and finite element analysis (FEA). The results indicate that corrosion pits of Ni–Cr–Mo–V high strength steel originate from inclusions in the steel and high hydrostatic pressures accelerate pit growth rate parallel to steel and the coalescence rate of neighbouring pits, which lead to the fast formation of uniform corrosion. Corrosion of Ni–Cr–Mo–V high strength steel under high hydrostatic pressure is the interaction result between electrochemical corrosion and elastic stress

  19. Effect of HCl pre-treatment on corrosion resistance of cerium-based conversion coatings on magnesium and magnesium alloys

    International Nuclear Information System (INIS)

    Brunelli, Katya; Dabala, Manuele; Calliari, Irene; Magrini, Maurizio

    2005-01-01

    The corrosion protection afforded by a cerium conversion coating, formed by immersion in a solution containing rare earth salt and hydrogen peroxide, on pure magnesium and two magnesium alloys, AZ91 and AM50, has been studied. The effect of HCl pre-treatments on the morphology and on the corrosion resistance of the cerium conversion layer was investigated. A thicker and more homogeneous distribution of the conversion coating was obtained when the sample surface was pre-treated with acid. Higher amounts of cerium on the surface of the pre-treated samples were detected. The cerium conversion coating increased the corrosion resistance of the alloys because it ennobled the corrosion potential and decreased both the anodic and cathodic current. The acid pre-treatment further increased the corrosion resistance of the coated alloys. After five days of immersion in chloride environment the untreated samples showed localized corrosion while the chemical conversion coated samples appeared unaffected

  20. EFFECTS OF CHEMISTRY AND OTHER VARIABLES ON CORROSION AND STRESS CORROSION CRACKING IN HANFORD DOUBLE SHELL TANKS

    Energy Technology Data Exchange (ETDEWEB)

    BROWN MH

    2008-11-13

    Laboratory testing was performed to develop a comprehensive understanding of the corrosivity of the tank wastes stored in Double-Shell Tanks using simulants primarily from Tanks 241-AP-105, 241-SY-103 and 241-AW-105. Additional tests were conducted using simulants of the waste stored in 241-AZ-102, 241-SY-101, 241-AN-107, and 241-AY-101. This test program placed particular emphasis on defining the range of tank waste chemistries that do not induce the onset of localized forms of corrosion, particularly pitting and stress corrosion cracking. This document summarizes the key findings of the research program.

  1. EFFECTS OF CHEMISTRY AND OTHER VARIABLES ON CORROSION AND STRESS CORROSION CRACKING IN HANFORD DOUBLE-SHELL TANKS

    International Nuclear Information System (INIS)

    Brown, M.H.

    2008-01-01

    Laboratory testing was performed to develop a comprehensive understanding of the corrosivity of the tank wastes stored in Double-Shell Tanks using simulants primarily from Tanks 241-AP-105, 241-SY-103 and 241-AW-105. Additional tests were conducted using simulants of the waste stored in 241-AZ-102, 241-SY-101, 241-AN-107, and 241-AY-101. This test program placed particular emphasis on defining the range of tank waste chemistries that do not induce the onset of localized forms of corrosion, particularly pitting and stress corrosion cracking. This document summarizes the key findings of the research program

  2. Synergistic Effect on Corrosion Inhibition Efficiency of Ginger Affinale Extract in Controlling Corrosion of Mild Steel in Acid Medium

    Energy Technology Data Exchange (ETDEWEB)

    Subramanian, Ananth Kumar; Arumugam, Sankar [Kandaswami Kandar' s College, Namakkal (India); Mallaiya, Kumaravel; Subramaniam, Rameshkumar [PSG College of Technology Peelamedu, Coimbatore (India)

    2013-12-15

    The corrosion inhibition nature of Ginger affinale extract for the corrosion of mild steel in 0.5N H{sub 2}SO{sub 4} was investigated using weight loss, electrochemical impedance and potentiodynamic polarization methods. The results revealed that Ginger affinale extract acts as a good corrosion inhibitor in 0.5N H{sub 2}SO{sub 4} medium. The inhibition efficiency increased with an increase in inhibitor concentration. The inhibition could be attributed to the adsorption of the inhibitor on the steel surface.

  3. The effect of zinc thickness on corrosion film breakdown of Colombian galvanized steel

    Science.gov (United States)

    Sandoval-Amador, A.; E Torres Ramirez, J.; Cabrales-Villamizar, P. A.; Laverde Cataño, D.; Y Peña-Ballesteros, D.

    2017-12-01

    This work studies the corrosion behaviour of Colombian galvanized steel in solutions of chloride and sulphate ions. The effect of the thickness and exposure time on the film’s breakdown susceptibility and protectiveness of the corrosion products were studied using potentiodynamic polarization curves and electrochemical impedance spectroscopy. The corrosion products were analysed using SEM-EDS and XRD. The samples with a higher thickness level in the zinc film (Z180) have the lowest corrosion rate. In this case, one of the products that was formed by the chemical reactions that occurred was Zinc hydroxide, which exhibits a passive behaviour as observed in the Pourbaix curves of the obtained potentials and in how the different Ph levels of the solutions worked. The sheets with the highest thickness (Z180) had the best performance, since at the end of the study they showed the least amount of damage on the surface of the zinc layer. This is because the thickness of the zinc layer favours the formation of simonkolleite, which is the corrosion product that protects the material under the conditions of the study.

  4. Effects of porosity in a model of corrosion and passive layer growth

    Directory of Open Access Journals (Sweden)

    F.D.A. Aarão Reis

    2017-12-01

    Full Text Available We introduce a stochastic lattice model to investigate the effects of pore formation in a passive layer grown with products of metal corrosion. It considers that an anionic species diffuses across that layer and reacts at the corrosion front (metal-oxide interface, producing a random distribution of compact regions and large pores, respectively represented by O (oxide and P (pore sites. O sites are assumed to have very small pores, so that the fraction Φ of P sites is an estimate of the porosity, and the ratio between anion diffusion coefficients in those regions is D_r0 and D_r≪1, significant changes are observed in passive layer growth and corrosion front roughness. For small Φ, a slowdown of the growth rate is observed, which is interpreted as a consequence of the confinement of anions in isolated pores for long times. However, the presence of large pores near the corrosion front increases the frequency of reactions at those regions, which leads to an increase in the roughness of that front. This model may be a first step to represent defects in a passive layer which favor pitting corrosion.

  5. Effect of Water Chemistry Factors on Flow Accelerated Corrosion : pH, DO, Hydrazine

    International Nuclear Information System (INIS)

    Lee, Eun Hee; Kim, Kyung Mo; Kim, Hong Pyo

    2013-01-01

    Flow accelerated corrosion(FAC) of the carbon steel piping in pressurized water reactors(PWRs) has been major issue in nuclear industry. Severe accident at Surry Unit 2 in 1986 initiated the worldwide interest in this area. Major parameters influencing FAC are material composition, microstructure, water chemistry, and hydrodynamics. Qualitative behaviors of FAC have been well understood but quantitative data about FAC have not been published for proprietary reason. In order to minimize the FAC in PWRs, the optimal method is to control water chemistry factors. Chemistry factors influencing FAC such as pH, corrosion potential, and hydrazine contents were reviewed in this paper. FAC rate decreased with pH up to 10 because magnetite solubility decreased with pH. Corrosion potential is generally controlled dissolved oxygen (DO) and hydrazine in secondary water. DO increased corrosion potential. FAC rate decreased with DO by stabilizing magnetite at low DO concentration or by formation of hematite at high DO concentration. Even though hydrazine is generally used to remove DO, hydrazine itself thermally decomposed to ammonia, nitrogen, and hydrogen raising pH. Hydrazine could react with iron and increased FAC rate. Effect of hydrazine on FAC is rather complex and should be careful in FAC analysis. FAC could be managed by adequate combination of pH, corrosion potential, and hydrazine

  6. Effect of Equal-Channel Angular Pressing on Pitting Corrosion of Pure Aluminum

    Directory of Open Access Journals (Sweden)

    Injoon Son

    2012-01-01

    Full Text Available The effect of equal-channel angular pressing (ECAP on the pitting corrosion of pure Al was investigated using electrochemical techniques in solutions containing 0.1 m mol·dm−3 of Na2SO4 and 8.46 mol·dm−3 of NaCl (300 ppm Cl− and followed by surface analysis. The potential for pitting corrosion of pure Al was clearly shifted in the noble direction by the ECAP process indicating that this process improves resistance to pitting corrosion. The time dependence of corrosion potential and the anodic potential at 1 A·m−2 revealed that the rate of formation of Al oxide films increased due to a decrease in the grain size of the Al after ECAP. Since there exists a negligible amount of impurity precipitates in pure Al, the improvement in pitting corrosion resistance of pure Al by ECAP appears to be attributable to an increase in the rate of formation of Al oxide films.

  7. Effects of molybdenum additions on the corrosion resistance of stainless steels in inorganic aqueous solutions and organic media (A review)

    International Nuclear Information System (INIS)

    Charbonnier, J.-C.

    1975-01-01

    The effects of molybdenum additions on the corrosion resistance of austenitic and ferritic stainless steels are reviewed. The following types of corrosion are considered: uniform attack in inorganic and organic acids, pitting and crevice corrosion in chloride media. The survey has been conducted with particular emphasis on the recent works. The different hypotheses which have been suggested in order to clarify the role of the molybdenum additions on the improvement of the corrosion resistance of stainless steels are analyzed and discussed. A synthesis is given [fr

  8. Effects of surface condition on aqueous corrosion and environmental embrittlement of iron aluminides

    Energy Technology Data Exchange (ETDEWEB)

    Perrin, R.L.; Buchanan, R.A. [Univ. of Tennessee, Knoxville, TN (United States)

    1996-08-01

    Effects of retained high-temperature surface oxides, produced during thermomechanical processing and/or heat treatment, on the aqueous-corrosion and environmental-embrittlement characteristics of Fe{sub 3}Al-based iron aluminides (FA-84, FA-129 and FAL-Mo), a FeAl-based iron aluminide (FA-385), and a disordered low-aluminum Fe-Al alloy (FAPY) were evaluated. All tests were conducted at room temperature in a mild acid-chloride solution. In cyclic-anodic-polarization testing for aqueous-corrosion behavior, the surface conditions examined were: as-received (i.e., with the retained high-temperature oxides), mechanically cleaned and chemically cleaned. For all materials, the polarization tests showed the critical pitting potentials to be significantly lower in the as-received condition than in the mechanically-cleaned and chemically-cleaned conditions. These results indicate detrimental effects of the retained high-temperature oxides in terms of increased susceptibilities to localized corrosion. In 200-hour U-bend stress-corrosion-cracking tests for environmental-embrittlement behavior, conducted at open-circuit corrosion potentials and at a hydrogen-charging potential of {minus}1500 mV (SHE), the above materials (except FA-385) were examined with retained oxides and with mechanically cleaned surfaces. At the open-circuit corrosion potentials, none of the materials in either surface condition underwent cracking. At the hydrogen-charging potential, none of the materials with retained oxides underwent cracking, but FA-84, FA-129 and FAL-Mo in the mechanically cleaned condition did undergo cracking. These results suggest beneficial effects of the retained high-temperature oxides in terms of increased resistance to environmental hydrogen embrittlement.

  9. Effect of cryogenic cooling on corrosion of friction stir welded AA7010-T7651

    DEFF Research Database (Denmark)

    Jariyaboon, Manthana; Davenport, A. J.; Ambat, Rajan

    2010-01-01

    Purpose - The purpose of this paper is to study how cryogenic CO2 cooling during the welding process affects corrosion behaviour of friction stir welding (FSW) AA7010-T7651. Design/methodology/approach - Friction stir welded AA7010-17651 was produced with a rotation speed of 288 rpm and a travel...... speed of 58 mm/min. The liquid CO2 was sprayed onto the weld centre line immediately after the toolpiece. The microstructures of welds in different regions were observed using Field Emission Gun Scanning Electron Microscope (FEG-SEM). The effect on the corrosion susceptibility was investigated using...... a gel visualisation test and potentiodynamic polarisation measurements using a micro-electrochemical technique. Findings - The main corrosion region for both FSWs AA7010-T7651 produced with and without cryogenic CO2 cooling is in the HAZ region, which exhibited intergranular attack. Cryogenic cooling...

  10. Inhibiting Effect of Nicotinic Acid Hydrazide on Corrosion of Aluminum and Mild Steel in Acidic Medium

    Energy Technology Data Exchange (ETDEWEB)

    Bhat, J. Ishwara [Mangalore Univ., Karnataka (India); Alva, Vijaya D. P. [Shree Devi Institute of Technology, Karnataka (India)

    2014-02-15

    The corrosion behavior of aluminum and mild steel in hydrochloric acid medium was studied using a nicotinic acid hydrazide as inhibitor by potentiodynamic polarization, electrochemical impedance spectroscopy technique and gravimetric methods. The effects of inhibitor concentration and temperature were investigated. The experimental results suggested, nicotinic acid hydrazide is a good corrosion inhibitor for both aluminum and mild steel in hydrochloric acid medium and the inhibition efficiency increased with increase in the inhibitor concentration. The polarization studies revealed that nicotinic acid hydrazide exhibits mixed type of inhibition. The inhibition was assumed to occur via adsorption of the inhibitor molecules on the aluminum and mild steel surface and inhibits corrosion by blocking the reaction sites on the surface of aluminum.

  11. Annealing Effect on Corrosion Behavior of the Beta-Quenched HANA Alloy

    International Nuclear Information System (INIS)

    Kim, Hyun Gil; Kim, Il Hyun; Choi, Byung Kwan; Park, Sang Yoon; Park, Jeong Yong; Jeong, Yong Hwan

    2009-01-01

    The advanced fuel cladding materials named as HANA cladding have been developed at KAERI for application of high burn-up and that cladding showed an improved performance in both in-pile and out-of-pile conditions. However, the cladding performance could be changed by the annealing conditions during the tube manufacturing process. Especially, the corrosion resistance is considerably sensitive to their microstructure which is determined by a manufacturing process in the high Nb-containing zirconium alloys. They reported that the corrosion properties of the Nb-containing Zr alloys were considerably affected by the microstructure conditions such as the Nb concentration in the matrix and the second phase types. Therefore, the corrosion behavior of HANA cladding having the high Nb could be considerably affected by the annealing time and temperatures. The purpose of this study is focused on the annealing effect of the beta quenched HANA alloy to obtain the optimum annealing conditions

  12. Effect of Sulfide Concentration on Copper Corrosion in Anoxic Chloride-Containing Solutions

    Science.gov (United States)

    Kong, Decheng; Dong, Chaofang; Xu, Aoni; Man, Cheng; He, Chang; Li, Xiaogang

    2017-04-01

    The structure and property of passive film on copper are strongly dependent on the sulfide concentration; based on this, a series of electrochemical methods were applied to investigate the effect of sulfide concentration on copper corrosion in anaerobic chloride-containing solutions. The cyclic voltammetry and x-ray photoelectron spectroscopy analysis demonstrated that the corrosion products formed on copper in anaerobic sulfide solutions comprise Cu2S and CuS. And the corrosion resistance of copper decreased with increasing sulfide concentration and faster sulfide addition, owing to the various structures of the passive films observed by the atomic force microscope and scanning electron microscope. A p-type semiconductor character was obtained under all experimental conditions, and the defect concentration, which had a magnitude of 1022-1023 cm-3, increased with increasing sulfide concentration, resulting in a higher rate of both film growth and dissolution.

  13. Effect of some pyrimidinic Schiff bases on the corrosion of mild steel in hydrochloric acid solution

    International Nuclear Information System (INIS)

    Ashassi-Sorkhabi, H.; Shaabani, B.; Seifzadeh, D.

    2005-01-01

    The efficiency of benzylidene-pyrimidin-2-yl-amine (A) (4-methyl-benzylidene)-pyrimidine-2-yl-amine (B) and (4-chloro-benzylidene)-pyrimidine-2-yl-amine, as corrosion inhibitors for mild steel in 1 M HCl have been determined by weight loss measurements and electrochemical polarization method. The results showed that these inhibitors revealed a good corrosion inhibition even at very low concentrations. Polarization curves indicate that all compounds are mixed type inhibitors. The effect of various parameters such as temperature and inhibitor concentration on the efficiency of the inhibitors has been studied. Activation energies of corrosion reaction in the presence and absence of inhibitors have been calculated. The adsorption of used compounds on the steel surface obeys Langmuir's isotherm. It appears that an efficient inhibition is characterized by a relatively greater decrease in free energy of adsorption. Significant correlations are obtained between inhibition efficiency and quantum chemical parameters using quantitative structure-activity relationship (QSAR) method

  14. Boron effect on fabrication properties and service behaviour of complex corrosion-resistant steels

    International Nuclear Information System (INIS)

    Gol'dshtejn, Ya.E.; Piskunova, A.I.; Shmatko, M.N.

    1978-01-01

    In order to determine the optimum boron admixtures for the improvement of the technological plasticity without the considerable reduction in the corrosion resistance of the complex alloy Cr-Ni-Mo steels, industrial heats of the 03KH16N15M3, 03KH17N14M3 and other steels, containing 0.0005-0.003% boron, have been researched. The plasticity, corrosion resistance and microstructure of certain steels have been determined. It is shown that small additions of boron enhance the technological plasticity during the ingot rolling. In order to prevent a sharp reduction in the corrosion resistance, the boron content should be confined to 0.0015% and the quenching temperature raised to 1,120-1,150 deg C. The positive effect of the quenching temperature increase is accounted for by the solution of the excess phases and by the reduction of the dislocation density in the near-the-boundary zones

  15. Inhibiting Effect of Nicotinic Acid Hydrazide on Corrosion of Aluminum and Mild Steel in Acidic Medium

    International Nuclear Information System (INIS)

    Bhat, J. Ishwara; Alva, Vijaya D. P.

    2014-01-01

    The corrosion behavior of aluminum and mild steel in hydrochloric acid medium was studied using a nicotinic acid hydrazide as inhibitor by potentiodynamic polarization, electrochemical impedance spectroscopy technique and gravimetric methods. The effects of inhibitor concentration and temperature were investigated. The experimental results suggested, nicotinic acid hydrazide is a good corrosion inhibitor for both aluminum and mild steel in hydrochloric acid medium and the inhibition efficiency increased with increase in the inhibitor concentration. The polarization studies revealed that nicotinic acid hydrazide exhibits mixed type of inhibition. The inhibition was assumed to occur via adsorption of the inhibitor molecules on the aluminum and mild steel surface and inhibits corrosion by blocking the reaction sites on the surface of aluminum

  16. Characterizing the effect of carbon steel exposure in sulfide containing solutions to microbially induced corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Sherar, B.W.A. [Department of Chemistry, University of Western Ontario, London, ON, N6A 5B7 (Canada); Power, I.M. [Department of Earth Sciences, University of Western Ontario, London, ON, N6A 5B7 (Canada); Keech, P.G.; Mitlin, S. [Department of Chemistry, University of Western Ontario, London, ON, N6A 5B7 (Canada); Southam, G. [Department of Earth Sciences, University of Western Ontario, London, ON, N6A 5B7 (Canada); Shoesmith, D.W., E-mail: dwshoesm@uwo.c [Department of Chemistry, University of Western Ontario, London, ON, N6A 5B7 (Canada)

    2011-03-15

    Research highlights: Compares inorganic sulfide and sulfate reducing bacteria (SRB) on steel corrosion. Mackinawite was the dominant iron sulfide phase. SRBs can form nanowires, presumably grown to acquire energy. - Abstract: This article compares the electrochemical effects induced by inorganic sulfide and sulfate reducing bacteria on the corrosion of carbon steel - a subject of concern for pipelines. Biological microcosms, containing varying concentrations of bioorganic content, were studied to investigate changes to the morphology of biofilms and corrosion product deposits. Raman analysis indicated mackinawite (FeS{sub 1-x}) was the dominant iron sulfide phase grown both abiotically and biotically. A fascinating feature of biological media, void of an organic electron donor, was the formation of putative nanowires that may be grown to acquire energy from carbon steel by promoting the measured cathodic reaction.

  17. Effects of laser shock peening on stress corrosion behavior of 7075 aluminum alloy laser welded joints

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J.T., E-mail: jiasqq1225@126.com [School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013 (China); School of Materials Engineering, Jiangsu University of Technology, Changzhou 213001 (China); Zhang, Y.K. [School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013 (China); School of Mechanical Engineering, Southeast University, Nanjing 211189 (China); Chen, J.F.; Zhou, J.Y.; Ge, M.Z.; Lu, Y.L.; Li, X.L. [School of Materials Engineering, Jiangsu University of Technology, Changzhou 213001 (China)

    2015-10-28

    7075 aluminum alloy weldments were processed by an intensive process known as laser shock peening (LSP), meanwhile its stress corrosion behaviors were observed by scanning electron microscopy (SEM) and slow strain rate tensile (SSRT) tests. Results showed that the effect of LSP on corrosion behavior of the joint was fairly useful and obvious. With LSP, the elongation, time of fracture and static toughness after the SSRT test were improved by 11.13%, 20% and 100%, respectively. At the same time, the location of the fracture also changed. LSP led to a transition of the fracture type from transgranular to intergranular The reasons for these enhancements of the joint on corrosion behavior were caused by microstructure, residual stress, micro-hardness, and fracture appearance.

  18. Electrochemical analysis of the corrosion inhibition effect of trypsin complex on the pitting corrosion of 420 martensitic stainless steel in 2M H2SO4 solution.

    Science.gov (United States)

    Loto, Roland Tolulope

    2018-01-01

    Inhibition effect of trypsin complex (TC) on the pitting corrosion of martensitic stainless steel (type 420) in 1M H2SO4 solution was studied with potentiodynamic polarization, open circuit potential measurement and optical microscopy. TC reduced the corrosion rate of the steel with maximum inhibition efficiency of 80.75%. Corrosion potential shifted anodically due to the electrochemical action of TC. The pitting potential increased from 1.088VAg/AgCl (3M) at 0% TC to 1.365VAg/AgCl(3M) at 4% TC. TC shifts the open circuit corrosion potential from -0.270s at 0% TC concentration to -0.255V at 5% TC. The compound completely adsorbed onto the steel according to Langmuir, Frumkin and Temkin isotherms. ATF-FTIR spectroscopy confirmed the inhibition mode to be through surface coverage. Thermodynamic calculations showed physisorption molecular interaction. Corrosion pits are present on the uninhibited 420 morphology in comparison to TC inhibited surface which slightly deteriorated.

  19. Effect of iron ions on corrosion of lithium in a thionyl chloride electrolytes

    International Nuclear Information System (INIS)

    Shirokov, A.V.; Churikov, A.V.

    1999-01-01

    The effect of the iron electrolyte addition on the growth rate of the passivating layer on lithium in the LiAlCl 4 1 M solution in thionyl chloride is experimentally studied. It is established, that kinetic curved in the first 10 hours of the Li-electrode contact with electrolyte are described by the equation, assuming mixed diffusion kinetic control over the corrosion process. It is shown that introduction of Fe 3+ into electrolyte causes increase in both ionic and electron conductivity constituents. Increase in the electron carrier concentration is the cause of lithium corrosion in the iron-containing thionyl chloride solutions [ru

  20. The effects of strain induced martensite on stress corrosion cracking in AISI 304 stainless steel

    International Nuclear Information System (INIS)

    Lee, W. S.; Kwon, S. I.

    1989-01-01

    The effects of strain induced martensite on stress corrosion cracking behavior in AISI 304 stainless steel in boiling 42 wt% MgCl 2 solution were investigated using monotonic SSRT and cyclic SSRT with R=0.1 stress ratio. As the amount of pre-strain increased, the failure time of the specimens in monotonic SSRT test decreased independent of the existence of strain induced martensite. The strain induced martensite seems to promote the crack initiation but to retard the crack propagation during stress corrosion cracking

  1. Inhibition of Aluminium Corrosion in Hydrochloric Acid Using Nizoral and the Effect of Iodide Ion Addition

    Directory of Open Access Journals (Sweden)

    I. B. Obot

    2010-01-01

    Full Text Available The effect of nizoral (NZR on the corrosion inhibition of aluminium alloy AA 1060 in 2 M HCl solution was investigated using the mylius thermometric technique. Results of the study revealed that nizoral acts as corrosion inhibitor for aluminium in the acidic medium. In general, at constant acid concentration, the inhibition efficiency increases with increase in the inhibitor concentration. The addition of KI to the inhibitor enhanced the inhibition efficiency to a considerable extent. The adsorption of nizoral onto the aluminium surface was found to obey the Fruendlich adsorption isotherm. The value of the free energy for the adsorption process shows that the process is spontaneous.

  2. Corrosion effect of fast reactor fuel claddings on their mechanical properties

    International Nuclear Information System (INIS)

    Davydov, E.F.; Krykov, F.N.; Shamardin, V.K.

    1985-01-01

    Fast reactor fuel cladding corrosion effect on its mechanical properties was investigated. UO 2 fuel elements were irradiated in the BOP-60 reactor at the linear heat rate of 42 kw/m. Fuel cladding is made of stainless steel OKh16N15M3BR. Calculated maximum cladding temperature is 920 K. Neutron fluence in the central part of fuel elements is 6.3x10 26 m+H- 2 . To investigate the strength changes temperature dependence of corrossion depth, cladding strength reduction factors was determined. Samples plasticity reduction with corrosion layer increase is considered to be a characteristic feature

  3. Contribution of local probes in the understanding of mechanical effect on localized corrosion

    International Nuclear Information System (INIS)

    Vignal, Vincent; Oltra, Roland; Mary, Nicolas

    2004-01-01

    Understanding the actual effects of mechanical stresses on the processes leading to pitting corrosion necessitates to develop both a mechanical approach and electrochemical experiments at a microscopic scale. Typical embrittlement can be observed after straining around MnS inclusions on a re-sulfurized 316 stainless steels and their corrosion sensitivity have been classified using the micro-capillary electrochemical cell technique. It has been shown that the numerical simulation of the location of stress gradients is possible before the local electrochemical analysis and could be a very interesting way to define the pitting susceptibility of micro-cracked areas during straining. (authors)

  4. The effect of fatigue on the corrosion resistance of common medical alloys.

    Science.gov (United States)

    Di Prima, Matthew; Gutierrez, Erick; Weaver, Jason D

    2017-10-01

    The effect of mechanical fatigue on the corrosion resistance of medical devices has been a concern for devices that experience significant fatigue during their lifespan and devices made from metallic alloys. The Food and Drug Administration had recommended in some instances for corrosion testing to be performed on post-fatigued devices [Non-clinical tests and recommended labeling for intravascular stents and associated delivery systems: guidance for industry and FDA staff. 2005: Food and Drug Administration, Center for Devices and Radiological Health], although the need for this has been debated [Nagaraja S, et al., J Biomed Mater Res Part B: Appl Biomater 2016, 8.] This study seeks to evaluate the effect of fatigue on the corrosion resistance of 5 different materials commonly used in medical devices: 316 LVM stainless steel, MP35N cobalt chromium, electropolished nitinol, mechanically polished nitinol, and black oxide nitinol. Prior to corrosion testing per ASTM F2129, wires of each alloy were split into subgroups and subjected to either nothing (that is, as received); high strain fatigue for less than 8 min; short-term phosphate buffered saline (PBS) soak for less than 8 min; low strain fatigue for 8 days; or long-term PBS soak for 8 days. Results from corrosion testing showed that the rest potential trended to an equilibrium potential with increasing time in PBS and that there was no statistical (p > 0.05) difference in breakdown potential between the fatigued and matching PBS soak groups for 9 out of 10 test conditions. Our results suggest that under these nonfretting conditions, corrosion susceptibility as measured by breakdown potential per ASTM F2129 was unaffected by the fatigue condition. 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2019-2026, 2017. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

  5. Laboratory testing of waste glass aqueous corrosion; effects of experimental parameters

    International Nuclear Information System (INIS)

    Ebert, W.L.; Mazer, J.J.

    1993-01-01

    A literature survey has been performed to assess the effects of the temperature, glass surface area/leachate volume ratio, leachant composition, leachant flow rate, and glass composition (actual radioactive vs. simulated glass) used in laboratory tests on the measured glass reaction rate. The effects of these parameters must be accounted for in mechanistic models used to project glass durability over long times. Test parameters can also be utilized to highlight particular processes in laboratory tests. Waste glass corrosion results as water diffusion, ion-exchange, and hydrolysis reactions occur simultaneously to devitrify the glass and release soluble glass components into solution. The rates of these processes are interrelated by the affects of the solution chemistry and glass alteration phases on each process, and the dominant (fastest) process may change as the reaction progresses. Transport of components from the release sites into solution may also affect the observed corrosion rate. The reaction temperature will affect the rate of each process, while other parameters will affect the solution chemistry and which processes are observed during the test. The early stages of corrosion will be observed under test conditions which maintain dilute leachates and the later stages will be observed under conditions that generate more concentrated leachate solutions. Typically, water diffusion and ion-exchange reactions dominate the observed glass corrosion in dilute solutions while hydrolysis reactions dominant in more concentrated solutions. Which process(es) controls the long-term glass corrosion is not fully understood, and the long-term corrosion rate may be either transport- or reaction-limited

  6. New Mechanism on Synergistic Effect of Nitrite and Triethanolamine Addition on the Corrosion of Ductile Cast Iron

    Directory of Open Access Journals (Sweden)

    K. T. Kim

    2016-01-01

    Full Text Available In general, we compared the different inhibition mechanisms of organic inhibitor with that of anodic inhibitor. When triethanolamine or nitrite was added separately to tap water for inhibiting the corrosion of ductile cast iron, large amounts of inhibitor were needed. This is because the corrosion inhibitors had to overcome the galvanic corrosion that occurs between graphite and matrix. In this work, we investigated the corrosion of ductile cast iron in tap water with/without inhibitors. The corrosion rate was measured using chemical immersion test and electrochemical methods, including anodic polarization test. The inhibited surface was analyzed using EPMA and XPS. Test solutions were analyzed by performing FT-IR measurement. When triethanolamine and nitrite coexisted in tap water, synergistic effect built up, and the inhibition effect was ca. 30 times more effective than witnessed with single addition. This work focused on the synergistic effect brought about by nitrite and triethanolamine and its novel mechanism was also proposed.

  7. Local effects in flow-accelerated corrosion wall thinning

    International Nuclear Information System (INIS)

    Pietralik, J.

    2006-01-01

    'Full text:' There is enough evidence that flow conditions play the dominant role locally in Flow-Accelerated Corrosion (FAC) under certain conditions, e.g., in CANDU feeders. While chemistry and materials set the overall potential for FAC, which can be low or high, flow conditions determine the local distribution of wall thinning. This relationship is not new and recent accurate measurements of FAC rate of a plant feeder bend confirm that the relationship between flow local conditions expressed by local mass transfer coefficient and FAC rate in CANDU feeder bends is close. There is also a lot of other direct and indirect, experimental and laboratory evidence about this relationship. This knowledge can be useful for minimizing inspection, predicting new locations for inspection, predicting the location with the highest FAC rate for a given piping component, e.g., feeder element, and determining what components or feeders and to what extent they should be replaced. It applies also to heat exchangers and steam generators. The objective of this paper is to examine the relationship between FAC rate and local flow parameters. For FAC, the most important flow parameter is mass transfer coefficient. The mass transfer coefficient describes the intensity of the transport of corrosion products from the oxide-water interface into the bulk water. Therefore, this parameter can be used for predicting the local distribution of FAC rate. It could also be used in planning experiments because time-varying surface roughness can explain the time-dependence of FAC rates. The paper presents plant and laboratory evidence about the relationship. In addition, it shows correlations for mass transfer coefficient in components that are highly susceptible to FAC. The role of surface roughness, wall shear stress, and local turbulence is also discussed. (author)

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

    International Nuclear Information System (INIS)

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

    2007-01-01

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

  9. Effect of boron control of environment on corrosion and resistance to low-cycle corrosion fatigue in structural steels

    International Nuclear Information System (INIS)

    Babej, Yu.I.; Zhitkov, V.V.; Zvezdin, Yu.I.; Liskevich, I.Yu.; Nazarov, A.A.

    1982-01-01

    Tests of the specimens on total, contact and crevice corrosion, corrosion cracking and low-cycle fatigue are conducted for determination of corrosion and corrosion-fatigue characteristics in the 15Kh3NMFA, 10N3MFA, 10Kh16N4B, 05Kh13N6M2 structural steels, used in energetics. The environment is subjected to boron control and contacting with atmosphere for simulation of stop and operation modes of the facility. The experiments are carried out in the distilled water with 12g/l H 3 BO 3 and 10 mg/l Cl' at 25, 60, 100 deg C under contacting with atmosphere. It is established, that the pearlitic steels 15Kh3NMFA, 10N3MFA, as well as transition and martensitic 05Kh13N6M2 and 10Kh16N4B steels are highly stable to total, crevice and contact corrosion at the high parameters of aqueous boron-containing medium. Steel resistance to low-cycle fracture decreases slightly under the conditions similar to the operation ones, in the water with 12 g/l H 3 BO 3 . Durability of the pearlitic steels at the simulation of stop conditions decreases more noticeably, crack formation as a rule, initiating from corrosion spots

  10. 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

  11. Catastrophes caused by corrosion

    OpenAIRE

    PETROVIC ZORAN C.

    2016-01-01

    For many years, huge attention has been paid to the problem of corrosion damage and destruction of metallic materials. Experience shows that failures due to corrosion problems are very important, and statistics at the world level shows that the damage resulting from the effects of various forms of corrosion is substantial and that, for example, in industrialized countries it reaches 4-5% of national incomes. Significant funds are determined annually for the prevention and control of corrosion...

  12. Effects of Cr, Mo, and W on Na2SO4 induced high temperature corrosion of Ni

    International Nuclear Information System (INIS)

    Reising, R.F.

    1975-01-01

    Operating gas turbine engines are susceptible to a phenomenon called hot corrosion. Hot corrosion is generally attributed to the interaction of nickel-base turbine blade alloys with ingested sodium sulfate. Two mechanism were presented previously to account for the surface and grain boundary corrosion of nickel metal. The effects of chromium, molybdenum, or tungsten, or their corrosion products on the corrosion of nickel metal were studied. The corrosion products considered are the oxides and sodium-oxygen compounds. The corrosion products of molybdenum and tungsten enhance the sodium sulfate-induced corrosion of nickel to the same degree as the metals themselves while those of chromium do not. The enhanced corrosion caused by sodium molybdate or tungstate suggests that more than a simple acid-base phenomenon is involved. The formation of a triable, porous film caused by the presence of nickel molybdate or tungstate is proposed as the mechanism responsible for this enhancement. This mechanism is consistent with that proposed by Lashka and Glezer who associated the intensified oxidation of molybdenum-containing nickel alloys with a sub-layer oxide scale containing nickel molybdate. (U.S.)

  13. Effects of partial crystallinity and quenched-in defects on corrosion of ...

    Indian Academy of Sciences (India)

    Rapid solidification by planar flow casting has been found to have introduced deficiencies, viz. partial crystallinity, air pockets and compositional difference in the ribbons of rapidly solidified Ti42.9-Cu57.1 alloy. In order to investigate the effects of these deficiencies on the corrosion of rapidly solidified Ti42.9-Cu57.1 alloy ...

  14. 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

  15. Effect of chemical composition on corrosion resistance of Zircaloy fuel cladding tube for BWR

    International Nuclear Information System (INIS)

    Inagaki, Masahisa; Akahori, Kimihiko; Kuniya, Jirou; Masaoka, Isao; Suwa, Masateru; Maru, Akira; Yasuda, Teturou; Maki, Hideo.

    1990-01-01

    Effects of Fe and Ni contents on nodular corrosion susceptibility and hydrogen pick-up of Zircaloy were investigated. Total number of 31 Zr alloys having different chemical compositions; five Zr-Sn-Fe-Cr alloys, eight Zr-Sn-Fe-Ni alloys and eighteen Zr-Sn-Fe-Ni-Cr alloys, were melted and processed to thin plates for the corrosion tests in the environments of a high temperature (510degC) steam and a high temperature (288degC) water. In addition, four 450 kg ingots of Zr-Sn-Fe-Ni-Cr alloys were industrially melted and BWR fuel cladding tubes were manufactured through a current material processing sequence to study their producibility, tensile properties and corrosion resistance. Nodular corrosion susceptibility decreased with increasing Fe and Ni contents of Zircaloys. It was seen that the improved Zircaloys having Fe and Ni contents in the range of 0.30 [Ni]+0.15[Fe]≥0.045 (w%) showed no susceptibility to nodular corrosion. An increase of Fe content resulted in a decrease of hydrogen pick-up fraction in both steam and water environments. An increase of Fe and Ni content of Zircaloys in the range of Fe≤0.25 w% and Ni≤0.1 w% did not cause the changes in tensile properties and fabricabilities of fuel cladding tube. The fuel cladding tube of improved Zircaloy, containing more amount of Fe and Ni than the upper limit of Zircaloy-2 specification showed no susceptibility to nodular corrosion even in the 530degC steam test. (author)

  16. The effect of functionalized polycarboxylate structures as corrosion inhibitors in a simulated concrete pore solution

    Science.gov (United States)

    Fazayel, A. S.; Khorasani, M.; Sarabi, A. A.

    2018-05-01

    In this study, the effects of polycarboxylate derivatives with different comonomers and functional groups on the control or reduction of corrosion in steel specimens were evaluated through electrochemical impedance spectroscopy (EIS) and potentiodynamic analysis. A highly alkaline contaminated concrete pore solution (CPS) containing chlorides was used to simulate the pitting corrosion, and according to the results, the mechanism of inhibitive action was determined. Both the inhibition efficiency and pitting corrosion inhibition of methacrylate-copolymers were in the order of poly methacrylate-co acrylamide > poly methacrylate-co-2-acrylamido-2 methylpropane sulfonic acid > poly methacrylate-co-hydroxyethyl methacrylate. In addition, the corrosion potential of steel specimens in all studied concentrations of NaCl with different concentrations of polymethacrylate-co acrylamide (as the best inhibitor in this study) in saturated Ca(OH)2 solution showed almost an identical trend. Polymethacrylic acid-co-acrylamide showed a 92.35% inhibitor efficiency in the saturated Ca(OH)2 solution containing 1.8 wt.% chlorides and could effectively reduce the corrosion rate. Even at 3.5 wt.% of NaCl, this inhibitor could remarkably reduce the destructive effect of chloride ion attacks on the steel surface and passive film. The inhibition effect of these polymeric inhibitors seemed to be due to the formation of a barrier layer on the metal surface, approved by the well-known adsorption mechanism of organic molecules at the metal/solution interface. The results of SEM, EDS and AFM investigations were also in agreement with the outcomes of electrochemical studies.

  17. Effect of sulfur on the SCC and corrosion fatigue performance of stainless steel

    International Nuclear Information System (INIS)

    West, E.; Nolan, T.; Lucente, A.; Morton, D.; Lewis, N.; Morris, R.; Mullen, J.; Newsome, G.

    2015-01-01

    Stress corrosion cracking and corrosion fatigue experiments were conducted on model heats of 304/304L stainless steel with systematically controlled sulfur content to isolate the influence of sulfur on crack growth behavior. The results of the SCC experiments conducted in 338 C. degrees deaerated water on 20% cold worked model heats with 0.006 and 0.012 wt% sulfur showed an order of magnitude or more reduction in the crack growth rate relative to a model heat with <0.001 wt% sulfur. Corrosion fatigue crack growth rates revealed a reduction in the crack growth rates of the elevated sulfur heats relative to model predicted steady state crack growth rates with increasing rise time for nominal loading conditions of a stress ratio of 0.7 and a stress intensity factor range of 6.6 MPa√m. At the longest rise time of 5.330 sec, the corrosion fatigue crack growth rate of the 0.006 wt% sulfur model heat was only 13% of model predictions and the crack growth of the 0.012 wt% sulfur heat completely stalled. Experiments conducted in anion faulted aerated water on stainless steel heats with moderate to high sulfur and variable carbon and boron contents showed that any detrimental effect of sulfur in this environment was secondary to the effect of sensitization in promoting SCC growth. (authors)

  18. Effects of iron content on microstructure and crevice corrosion of titanium Grade-2

    International Nuclear Information System (INIS)

    He, X.; Noel, J.J.; Shoesmith, D.W.

    2003-01-01

    The effects of iron content on microstructure and crevice corrosion of titanium Grade-2 (Ti-2) were studied using a galvanic coupling technique combined with optical microscopy and secondary ion mass spectrometry (SIMS) imaging. The study reveals that iron content has a significant effect on the microstructure and crevice corrosion behavior of Ti-2. The grain size decreases significantly with the increasing iron content. For Ti-2 material of medium iron content, crevice corrosion was readily initiated and exhibited extensive intergranular attack which could be associated with the more reactive iron-stabilized β-phase within the α-phase matrix as revealed by SIMS imaging. By contrast, Ti-2 materials with low and high iron content showed suppressed crevice attack. The small surface area of available grain boundaries in Ti-2 of low iron content accounted for this limited attack. For the material with high iron content, SIMS imaging suggest that some Ti x Fe intermetallic particles were formed. These particles may act as proton reduction catalysts and enhance crevice corrosion resistance. (author)

  19. Effect of temperature on corrosion of steels in high purity water

    International Nuclear Information System (INIS)

    Honda, Takashi; Kashimura, Eiji; Ohashi, Kenya; Furutani, Yasumasa; Ohsumi, Katsumi; Aizawa, Motohiro; Matsubayashi, Hideo.

    1987-01-01

    Effect of temperature on corrosion behavior of steels was evaluated in the range of 150 - 300 deg C in high purity water containing about 200 ppb oxygen. The exposure tests were carried out in actual and simulated reactor water of BWR plants. Through X-ray diffractometry, SIMS, XPS and chemical analyses, it was clarified that the chemical composition and morphology of oxide films formed on austenitic stainless steel changed above about 250 deg C. Chromium dissolved easily through corrosion above this temperature, and the oxide films primarily consisted of spinel type oxides containing high concentration of nickel. Further, as the protectivety of oxide films increased with temperature, the corrosion rate had a peak around 250 deg C after a long exposure period. A major phase of oxide films on carbon steel was magnetite in the whole temperature range. However, as the oxide films formed at high temperatures had very compact structures, the effect of temperature on the corrosion rate was similar to that observed on stainless steel. (author)

  20. The effects of the glass surface area/solution volume ratio on glass corrosion: A critical review

    International Nuclear Information System (INIS)

    Ebert, W.L.

    1995-03-01

    This report reviews and summarizes the present state of knowledge regarding the effects of the glass surface area/solution volume (SA/V) ratio on the corrosion behavior of borosilicate waste glasses. The SA/V ratio affects the rate of glass corrosion through the extent of dilution of corrosion products released from the glass into the leachate solution: glass corrosion products are diluted more in tests conducted at low SA/V ratios than they are in tests conducted at high SA/V ratios. Differences in the solution chemistries generated in tests conducted at different SA/V ratios then affect the observed glass corrosion behavior. Therefore, any testing parameter that affects the solution chemistry will also affect the glass corrosion rate. The results of static leach tests conducted to assess the effects of the SA/V are discussed with regard to the effects of SA/V on the solution chemistry. Test results show several remaining issues with regard to the long-term glass corrosion behavior: can the SA/V ratio be used as an accelerating parameter to characterize the advanced stages of glass corrosion relevant to long disposal times; is the alteration of the glass surface the same in tests conducted at different SA/V, and in tests conducted with monolithic and crushed glass samples; what are the effects of the SA/V and the extent of glass corrosion on the disposition of released radionuclides? These issues will bear on the prediction of the long-term performance of waste glasses during storage. The results of an experimental program conducted at ANL to address these and other remaining issues regarding the effects of SA/V on glass corrosion are described. 288 refs., 59 figs., 16 tabs

  1. The effects of the glass surface area/solution volume ratio on glass corrosion: A critical review

    Energy Technology Data Exchange (ETDEWEB)

    Ebert, W.L. [Argonne National Lab., IL (United States). Chemical Technology Div.

    1995-03-01

    This report reviews and summarizes the present state of knowledge regarding the effects of the glass surface area/solution volume (SA/V) ratio on the corrosion behavior of borosilicate waste glasses. The SA/V ratio affects the rate of glass corrosion through the extent of dilution of corrosion products released from the glass into the leachate solution: glass corrosion products are diluted more in tests conducted at low SA/V ratios than they are in tests conducted at high SA/V ratios. Differences in the solution chemistries generated in tests conducted at different SA/V ratios then affect the observed glass corrosion behavior. Therefore, any testing parameter that affects the solution chemistry will also affect the glass corrosion rate. The results of static leach tests conducted to assess the effects of the SA/V are discussed with regard to the effects of SA/V on the solution chemistry. Test results show several remaining issues with regard to the long-term glass corrosion behavior: can the SA/V ratio be used as an accelerating parameter to characterize the advanced stages of glass corrosion relevant to long disposal times; is the alteration of the glass surface the same in tests conducted at different SA/V, and in tests conducted with monolithic and crushed glass samples; what are the effects of the SA/V and the extent of glass corrosion on the disposition of released radionuclides? These issues will bear on the prediction of the long-term performance of waste glasses during storage. The results of an experimental program conducted at ANL to address these and other remaining issues regarding the effects of SA/V on glass corrosion are described. 288 refs., 59 figs., 16 tabs.

  2. Effect of antimony, bismuth and calcium addition on corrosion and electrochemical behaviour of AZ91 magnesium alloy

    International Nuclear Information System (INIS)

    Zhou Wei; Aung, Naing Naing; Sun Yangshan

    2009-01-01

    This study investigated the effect of antimony, bismuth and calcium addition on the corrosion and electrochemical behaviour of AZ91 magnesium alloy in 3.5% NaCl solution. Techniques including constant immersion, electrochemical potentiodynamic polarisation, scanning electron microscopy (SEM), energy dispersed spectroscopy (EDS) and X-ray diffraction (XRD) were used to characterise electrochemical and corrosion properties and surface topography. It was found that corrosion attack occurred preferentially on Mg 3 Bi 2 and Mg 3 Sb 2 particles while Mg 17 Al 8 Ca 0.5 and Mg 2 Ca phases showed no detrimental effect on corrosion. Combined addition of small amounts of bismuth and antimony to the AZ91 alloy resulted in significant increase in corrosion rate

  3. 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

  4. Flow Accelerated Corrosion: Effect of Water Chemistry and Database Construction

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eun Hee; Kim, Kyung Mo; Lee, Gyeong Geun; Kim, Dong Jin [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    Flow accelerated corrosion (FAC) of carbon steel piping in pressurized water reactors (PWRs) has been a major issue in nuclear industry. Severe accidents at Surry Unit 2 in 1986 and Mihama Unit 3 in 2004 initiated the world wide interest in this area. FAC is a dissolution process of the protective oxide layer on carbon steel or low-alloy steel when these parts are exposed to flowing water (single-phase) or wet steam (two-phase). In a single-phase flow, a scalloped, wavy, or orange peel and in a two-phase flow, tiger striping is observed, respectively. FAC is affected by many parameters, like material composition, pH, dissolved oxygen (DO), flow velocity, system pressure, and steam quality. This paper describes the water chemistry factors influencing on FAC and the database is then constructed using literature data. In order to minimize FAC in NPPs, the optimal method is to control water chemistry parameters. However, quantitative data about FAC have not been published for proprietary reason even though qualitative behaviors of FAC have been well understood. A database was constructed using experimental data in literature. Accurate statistical analysis will be performed using this database to identify the relationship between the FAC rate and test environment.

  5. Anti-corrosive Effects of Multi-Walled Carbon Nano Tube and Zinc Particle Shapes on Zinc Ethyl Silicate Coated Carbon Steel

    Energy Technology Data Exchange (ETDEWEB)

    Jang, JiMan; Shon, MinYoung; Kwak, SamTak [Pukyong National University, Busan (Korea, Republic of)

    2016-01-15

    Zinc ethyl silicate coatings containing multi walled carbon nanotubes (MWCNTs) were prepared, to which we added spherical and flake shaped zinc particles. The anti-corrosive effects of MWCNTs and zinc shapes on the zinc ethyl silicate coated carbon steel was examined, using electrochemical impedance spectroscopy and corrosion potential measurement. The results of EIS and corrosion potential measurement showed that the zinc ethyl silicate coated with flake shaped zinc particles and MWCNT showed lesser protection to corrosion. These outcomes were in agreement with previous results of corrosion potential and corrosion occurrence.

  6. Effects of cold work, sensitization treatment, and the combination on corrosion behavior of stainless steels in nitric acid

    International Nuclear Information System (INIS)

    Mayuzumi, M.; Ohta, J.; Arai, T.

    1998-01-01

    In a reprocessing process, spent nuclear fuels from light-water reactors are dissolved in nitric acid (HNO 3 ) to separate and recover the fissile materials such as uranium and plutonium from the radioactive fission products. Corrosion behavior of two stainless steels (SS) was investigated in nitric acid (HNO 3 ) for the effect of cold work (CW), sensitization heat treatment (Sens.), and a combination (CW + Sens.). The corrosion rate of the solution-treated type 304 SS (UNS S30400) with extra-low carbon (type 304ELC SS (UNS S30403)) increased with time and reached constant values after 1,000 h of immersion. However, constant corrosion rates were obtained for 25% Cr-20% Ni-Nb (type 310Nb SS [UNS S31040]) from the initial stage of immersion. CW mitigated corrosion of the solution-treated SS. The effect of CW was different on the two types of SS, with the sensitization heat-treated type 304 ELC SS showing higher corrosion rates and type 310Nb SS lower corrosion rates by CW. Corrosion resistance of type 310Nb SS was superior to type 304 ELC SS after all treatments. Chromium concentration of the sensitization-treated type 304 ELC SS was lower in the grain-boundary region than of the solution-treated one, although no chromium carbide precipitation was observed. This may have been the cause of intergranular corrosion enhancement by sensitization treatment

  7. Effect of cerium addition on the corrosion behaviour of carbon-alloyed iron aluminides

    International Nuclear Information System (INIS)

    Sriram, S.; Balasubramaniam, R.; Mungole, M.N.; Bharagava, S.; Baligidad, R.G.

    2006-01-01

    The effect of Ce addition on the microstructure and corrosion behavior of carbon-alloyed iron aluminides Fe-20.0Al-2.0C, Fe-18.5Al-3.6C and Fe-19.2Al-3.3C-0.07Ce (in at.%) has been studied. The potentiodynamic polarization behaviour of the alloys was evaluated in freely aerated 0.25 mol/l H 2 SO 4 . A 0.05% C steel was used for comparison purposes. All the alloys exhibited active-passive behaviour in the acidic solution. The addition of Ce destroyed passivity as indicated by lower breakdown potentials in polarization studies. This has been related to the finer distribution of the carbides in the microstructure. Corrosion rates were evaluated by immersion testing. The iron aluminide with Ce addition exhibited a lower corrosion rate compared to the aluminides without Ce addition. This has been attributed to modifications in surface film with Ce addition. Scanning electron microscopy of corroded surfaces indicated that the carbon-alloyed intermetallics were susceptible to localized galvanic corrosion due to the presence of carbides in the microstructure

  8. Effect of microstructure on the localized corrosion of Fe-Cr-Mn-N stainless steels

    International Nuclear Information System (INIS)

    Kim, Jae Young; Park, Yong Soo; Kim, Young Sik

    1998-01-01

    This paper dealt with the effect of microstructure on the localized corrosion of Fe-Cr-Mn-N stainless steels. The experimental alloys were made by vacuum induction melting and then hot rolled. The alloys were designed by controlling Cr eq /Ni eq ratio. Two alloys had austenitic phase and one alloy showed (austenite+ferrite) du-plex phase. High nitrogen addition in austenitic alloys stabilized the austenitic structure and then suppressed the formations of ferrite and α martensite, but martensite was formed in the case of large Cr eq /Ni eq ratio and low nitrogen addition. Pitting initiation site was grain boundary in austenitic alloys and was ferrite/austenite phase boundary in duplex alloy in the HCl solution. In sulfuric acids, austenitic alloys showed uniform corrosion, but ferrite phase was preferentially corroded in duplex alloy. The preferential dissolution seems to be related with the distribution of alloying elements between ferrite and austenite. Intergranular corrosion test showed that corrosion rate by immersion Huey test had a linear relation with degree of sensitization by EPR test

  9. Investigation of processing effects on the corrosion resistance of Ti20Mo alloy in saline solutions

    International Nuclear Information System (INIS)

    Bolat, G.; Izquierdo, J.; Gloriant, T.; Chelariu, R.; Mareci, D.; Souto, R.M.

    2015-01-01

    Graphical abstract: - Highlights: • Alloy fabrication method affects both surface finish and corrosion resistance. • More porous surface finish and higher wettability produced by powder sintering. • Passive layer formed on sintered alloy breaks down in saline solution. • Increase in surface porosity facilitated electron transfer through the oxide film. • More corrosion resistant alloy produced by cold crucible levitation melting. - Abstract: The electrochemical properties of Ti20Mo alloys prepared using different fabrication procedures, namely cold crucible levitation melting (CCLM) and powder sintering, were investigated using linear potentiodynamic polarization and EIS measurements. The surface condition was established using AFM, with the observation of a more porous surface finish in the case of powder sintering. A major effect of surface conditioning on the corrosion resistance of Ti20Mo alloys was observed, where the compact finish exhibits a superior corrosion resistance in chloride-containing saline solutions. Less insulating surfaces towards electron exchange resulted for the more porous finish as revealed by scanning electrochemical microscopy (SECM)

  10. Effect of Plastic Deformation on the Corrosion Behavior of a Super-Duplex Stainless Steel

    Science.gov (United States)

    Renton, Neill C.; Elhoud, Abdu M.; Deans, William F.

    2011-04-01

    The role of plastic deformation on the corrosion behavior of a 25Cr-7Ni super-duplex stainless steel (SDSS) in a 3.5 wt.% sodium chloride solution at 90 °C was investigated. Different levels of plastic strain between 4 and 16% were applied to solution annealed tensile specimens and the effect on the pitting potential measured using potentiodynamic electrochemical techniques. A nonlinear relationship between the pitting potential and the plastic strain was recorded, with 8 and 16% causing a significant reduction in average E p, but 4 and 12% causing no significant change when compared with the solution-annealed specimens. The corrosion morphology revealed galvanic interaction between the anodic ferrite and the cathodic austenite causing preferential dissolution of the ferrite. Mixed potential theory and the changing surface areas of the two phases caused by the plastic deformation structures explain the reductions in pitting potential at certain critical plastic strain levels. End-users and manufacturers should evaluate the corrosion behavior of specific cold-worked duplex and SDSSs using their as-produced surface finishes assessing in-service corrosion performance.

  11. Experimental Investigation into Corrosion Effect on Mechanical Properties of High Strength Steel Bars under Dynamic Loadings

    Directory of Open Access Journals (Sweden)

    Hui Chen

    2018-01-01

    Full Text Available The tensile behaviors of corroded steel bars are important in the capacity evaluation of corroded reinforced concrete structures. The present paper studies the mechanical behavior of the corroded high strength reinforcing steel bars under static and dynamic loading. High strength reinforcing steel bars were corroded by using accelerated corrosion methods and the tensile tests were carried out under different strain rates. The results showed that the mechanical properties of corroded high strength steel bars were strain rate dependent, and the strain rate effect decreased with the increase of corrosion degree. The decreased nominal yield and ultimate strengths were mainly caused by the reduction of cross-sectional areas, and the decreased ultimate deformation and the shortened yield plateau resulted from the intensified stress concentration at the nonuniform reduction. Based on the test results, reduction factors were proposed to relate the tensile behaviors with the corrosion degree and strain rate for corroded bars. A modified Johnson-Cook strength model of corroded high strength steel bars under dynamic loading was proposed by taking into account the influence of corrosion degree. Comparison between the model and test results showed that proposed model properly describes the dynamic response of the corroded high strength rebars.

  12. Protective effect of KhOSP-10 inhibitor during corrosion, hydrogenadsorption and corrosion cracking of a steel in sulfuric acid

    Energy Technology Data Exchange (ETDEWEB)

    Mindyuk, A K; Svist, E I; Savitskaya, O P; Goyan, E B; Gopanenko, A N [AN Ukrainskoj SSR, Lvov. Fiziko-Mekhanicheskij Inst.

    1975-01-01

    The protective propeties of inhibitor KhOSP-10 in the time of corrosion and corrosive cracking of steel 40Kh are higher then those of inhibitors KPI-1, KI-1, I-I-V etc. Its ability to reduce steel hydrogenation is the same as in the case of KPI-1 inhibitor i.e. below that of KI-1. HCl additives enhance the efficiency of inhibitors KPI-1, KI-1, I-1-V etc. up to the protective ability of KhOSP-10. Kinetics of the electrode processes was estimated from polarization curves.

  13. Effect of Water Chemistry Variations on Corrosion of Zr-Alloys for BWR Applications

    International Nuclear Information System (INIS)

    Kim, Young-Jin; Yang- Lin, Pi; Lutz, Dan; Kucuk, Aylin; Cheng, Bo

    2012-09-01

    Two reference water chemistry conditions (60 ppb Zn and 60 μg/cm 2 Pt/Rh with either 500 ppb O 2 and 500 ppb H 2 O 2 , or 150 ppb H 2 ) were chosen for testing at 300 deg. C in refreshed autoclaves. For each reference water chemistry, the potential effects due to three chemical impurities of interest to BWRs (33 ppm Na, 10 ppm Li, and 10 ppm EHC fluid) were evaluated. Zircaloy-2 and GNF-Ziron (a Zr-based alloy with higher Fe additions than Zircaloy-2) cladding tubes were tested and the effects of tubing process variation and pre-filming were investigated. Tested channel materials included Zircaloy-2, Zircaloy-4, GNF-Ziron and NSF (a Zr-based alloy with Sn, Nb and Fe additions). The corrosion weight gain and hydrogen absorption were measured up to 12 months of exposure for a given water chemistry condition. Tests under 150 ppb H 2 based water chemistry, with or without chemical impurities, generally resulted in greater amounts of corrosion after 12 month exposure compared with 500 ppb O 2 and 500 ppb H 2 O 2 based water chemistries. Of the added chemical impurities, only 33 ppm Na addition produced slightly increased corrosion. Under various test conditions, the presence of a thin pre-film resulted in some initial corrosion benefits, but the benefits were no longer evident after 12 months exposure; however, slight hydrogen benefits remained. For GNF-Ziron cladding, hydrogen absorption was generally lower compared with similarly processed Zircaloy-2 under 150 ppb H 2 based water chemistry, when corrosion was generally higher. Of the channel material tested, NSF developed the lowest level of hydrogen absorption, particularly under 150 ppb H 2 based water chemistries. (authors)

  14. Effect of the Type of Surface Treatment and Cement on the Chloride Induced Corrosion of Galvanized Reinforcements

    Science.gov (United States)

    Tittarelli, Francesca; Mobili, Alessandra; Vicerè, Anna Maria; Roventi, Gabriella; Bellezze, Tiziano

    2017-10-01

    The effect of a new passivation treatment, obtained by immersion of the galvanized reinforcements in a trivalent chromium salts based solution, on the chlorides induced corrosion has been investigated. To investigate also the effect of cement alkalinity on corrosion behaviour of reinforcements, concretes manufactured with three different European cements were compared. The obtained results show that the alternative treatment based on hexavalent chromium-free baths forms effective protection layers on the galvanized rebar surfaces. The higher corrosion rates of zinc coating in concrete manufactured with Portland cement compared to those recorded for bars in concrete manufactured with pozzolanic cement depends strongly on the higher chloride content at the steel concrete interface.

  15. Effects of grain size on the corrosion resistance of pure magnesium by cooling rate-controlled solidification

    Science.gov (United States)

    Liu, Yichi; Liu, Debao; You, Chen; Chen, Minfang

    2015-09-01

    The aim of this study was to investigate the effect of grain size on the corrosion resistance of pure magnesium developed for biomedical applications. High-purity magnesium samples with different grain size were prepared by the cooling rate-controlled solidification. Electrochemical and immersion tests were employed to measure the corrosion resistance of pure magnesium with different grain size. The electrochemical polarization curves indicated that the corrosion susceptibility increased as the grain size decrease. However, the electrochemical impedance spectroscopy (EIS) and immersion tests indicated that the corrosion resistance of pure magnesium is improved as the grain size decreases. The improvement in the corrosion resistance is attributed to refine grain can produce more uniform and density film on the surface of sample.

  16. The Effect of Deep Cryogenic Treatment on the Corrosion Behavior of Mg-7Y-1.5Nd Magnesium Alloy

    Directory of Open Access Journals (Sweden)

    Quantong Jiang

    2017-10-01

    Full Text Available The effect of quenching on the corrosion resistance of Mg-7Y-1.5Nd alloy was investigated. The as-cast alloy was homogenized at 535 °C for 24 h, followed by quenching in air, water, and liquid nitrogen. Then, all of the samples were peak-aged at 225 °C for 14 h. The microstructures were studied by scanning electron microscopy, energy-dispersive spectrometry, and X-ray diffraction. Corrosion behavior was analyzed by using weight loss rate and gas collection. Electrochemical characterizations revealed that the T4-deep cryogenic sample displayed the strongest corrosion resistance among all of the samples. A new square phase was discovered in the microstructure of the T6-deep cryogenic sample; this phase was hugely responsible for the corrosion property. Cryogenic treatment significantly improved the corrosion resistance of Mg-7Y-1.5Nd alloy.

  17. Effect of pulsed gas tungsten arc welding on corrosion behavior of Ti-6Al-4V titanium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Balasubramanian, M. [Department of Mechanical Engineering, Maamallan Institute of Technology, Anna University, Sriperumpudur 602 105 (India)], E-mail: manianmb@rediffmail.com; Jayabalan, V. [Department of Manufacturing Engineering, Anna University, Guindy, Chennai 600 025 (India)], E-mail: jbalan@annauniv.edu; Balasubramanian, V. [Department of Manufacturing Engineering, Annamalai University, Annamalai Nagar 608 002 (India)], E-mail: visvabalu@yahoo.com

    2008-07-01

    Due to the excellent combination of properties such as elevated strength-to-weight ratio, high toughness and excellent resistance to corrosion, make titanium alloys attractive for many industrial applications. Advantages of pulsed current welding frequently reported in literature include refinement of fusion zone grain size, etc. Hence, in this investigation an attempt has been made to study the effect of pulsed current Gas Tungsten Arc (GTA) welding parameters on corrosion behavior of Ti-6Al-4V titanium alloy. Pulsed current gas tungsten arc welding was used to fabricate the joints. To optimize the number of experiments to be performed, central composite design was used. The investigation revealed increase in corrosion resistance with increase in peak current and pulse frequency up to an optimum value of the same and decrease in corrosion resistance beyond that optimum point. An increase in corrosion resistance with grain refinement was also detected.

  18. Effect of pulsed gas tungsten arc welding on corrosion behavior of Ti-6Al-4V titanium alloy

    International Nuclear Information System (INIS)

    Balasubramanian, M.; Jayabalan, V.; Balasubramanian, V.

    2008-01-01

    Due to the excellent combination of properties such as elevated strength-to-weight ratio, high toughness and excellent resistance to corrosion, make titanium alloys attractive for many industrial applications. Advantages of pulsed current welding frequently reported in literature include refinement of fusion zone grain size, etc. Hence, in this investigation an attempt has been made to study the effect of pulsed current Gas Tungsten Arc (GTA) welding parameters on corrosion behavior of Ti-6Al-4V titanium alloy. Pulsed current gas tungsten arc welding was used to fabricate the joints. To optimize the number of experiments to be performed, central composite design was used. The investigation revealed increase in corrosion resistance with increase in peak current and pulse frequency up to an optimum value of the same and decrease in corrosion resistance beyond that optimum point. An increase in corrosion resistance with grain refinement was also detected

  19. The effect lead impurities on the corrosion resistance of alloy 600 and alloy 690 in high temperature water

    International Nuclear Information System (INIS)

    Sakai, T.; Nakagomi, N.; Kikuchi, T.; Aoki, K.; Nakayasu, F.; Yamakawa, K.

    1998-01-01

    Degradation of nickel-based alloy steam generator (SG) tubing caused by lead-induced corrosion has been reported recently in some PWR plants. Several laboratory studies also have shown that lead causes intergranular or transgranular stress corrosion cracking (IGSCC or TGSCC) of the tubing materials. Information from previous studies suggests two possible explanations for the mechanism of lead-induced corrosion. One is selective dissolution of tube metal elements, resulting in formation of a lead-containing nickel-depleted oxide film as observed in mildly acidic environments. The other explanation is an increase in potential, as has been observed in lead-contaminated caustic environments, although not in all volatile treatment (AVT) water such as the ammonium-hydrazine water chemistry. These observation suggest that an electrochemical reaction between metal elements and dissolved lead might be the cause of lead-induced corrosion. The present work was undertaken to clarify the lead-induced corrosion mechanism of nickel-based alloys from an electrochemical viewpoint, focusing on mildly acidic and basic environments. These are the probable pH conditions in the crevice region between the tube and tube support plate of the SG where corrosion damage could occur. Measurements of corrosion potential and electrochemical polarization of nickel-based alloys were performed to investigate the effect of lead on electrochemical behavior of the alloys. Then, constant extension rate tests (CERT) were carried out to determine the corrosion susceptibility of the alloys in a lead-contaminated environment. (J.P.N.)

  20. An investigation on the effect of bleaching environment on pitting corrosion and trans-passive dissolution of 316 stainless steel

    International Nuclear Information System (INIS)

    Moayed, M.H.; Golestanipour, M.

    2004-01-01

    Pitting corrosion and trans-passive dissolution of 316 stainless steel in solution containing five percent of commercial bleaching liquid was investigated by employing potentiodynamic polarization method and recording corrosion potential during immersion. Today commercial bleaching liquids are widely used as cleaner additives, therefore, those house appliances made from stainless steels are in contact with aqueous solution containing bleaching liquid. This may cause sever localized corrosion and trans-passive dissolution. In order to investigate the possibility of trans-passive dissolution of stainless steel by bleaching liquid, potentiodynamic polarization and recording variation of corrosion potential of specimens were carried out in 0.2 M Na 2 SO 4 solution containing 5 %wt. commercial bleaching liquid. A 500 mV drop in trans-passive potential and also instantaneously ennobling corrosion potential revealed the possibility of trans-passive dissolution due to oxidizing effect of the species such as free chlorine and its derivatives in bleaching liquid. Evaluation of the occurrence of localized corrosion at the presence of Cl - and bleaching liquid was investigated by similar electrochemical experiments in 0.2 M Na 2 SO 4 + 0.4M NaCl containing 5%wt. bleaching solution. Initiation of stable pitting at potentials lower than trans-passive potential as well as sharp increasing of corrosion potential in this environment demonstrates the possibility of pitting corrosion. (authors)

  1. Effects of secondary phase and grain size on the corrosion of biodegradable Mg-Zn-Ca alloys.

    Science.gov (United States)

    Lu, Y; Bradshaw, A R; Chiu, Y L; Jones, I P

    2015-03-01

    The bio-corrosion behaviour of Mg-3Zn-0.3Ca (wt.%) alloy in simulated body fluid (SBF) at 37°C has been investigated using immersion testing and electrochemical measurements. Heat treatment has been used to alter the grain size and secondary phase volume fraction; the effects of these on the bio-corrosion behaviour of the alloy were then determined. The as-cast sample has the highest bio-corrosion rate due to micro-galvanic corrosion between the eutectic product (Mg+Ca2Mg6Zn3) and the surrounding magnesium matrix. The bio-corrosion resistance of the alloy can be improved by heat treatment. The volume fraction of secondary phases and grain size are both key factors controlling the bio-corrosion rate of the alloy. The bio-corrosion rate increases with volume fraction of secondary phase. When this is lower than 0.8%, the dependence of bio-corrosion rate becomes noticeable: large grains corrode more quickly. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Effect of Ethanolamines on Corrosion Inhibition of Ductile Cast Iron in Nitrite Containing Solutions

    International Nuclear Information System (INIS)

    Kim, K. T.; Kim, Y. S.; Chang, H. Y.; Lim, B. T.; Park, H. B.

    2016-01-01

    In this work, synergistic corrosion inhibition effect of nitrite and 3 kinds of ethanolamines on ductile cast iron using chemical and electrochemical methods was evaluated. This work attempts to clarify the synergistic effect of nitrite and ethanolamines. The effects of single addition of TEA, DEA, and MEA, and mixed addition of nitrite plus TEA, DEA or MEA on the corrosion inhibition of ductile cast iron in a tap water were evaluated. A huge amount of single addition of ethanolamine was needed. However, the synergistic effect by mixed addition was observed regardless of the combination of nitrite and triethanolamines, but their effects increased in a series of MEA + nitrite > DEA + nitrite > TEA + nitrite. This tendency of synergistic effect was attributed to the film properties and polar effect; TEA addition couldn't form the film showing high film resistance and semiconductive properties, but DEA or MEA could build the film having relatively high film resistance and n-type semiconductive properties. Moreover, it can be explained that this behaviour was closely related to electron attractive group within the ethanolamines, and thus corrosion inhibition power depends upon the number of the electron attractive group of MEA, DEA, and TEA.

  3. Effect of Ethanolamines on Corrosion Inhibition of Ductile Cast Iron in Nitrite Containing Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Kim, K. T.; Kim, Y. S. [Andong National University, Andong (Korea, Republic of); Chang, H. Y.; Lim, B. T.; Park, H. B. [KEPCO Engineering and Construction Company, Gimcheon (Korea, Republic of)

    2016-08-15

    In this work, synergistic corrosion inhibition effect of nitrite and 3 kinds of ethanolamines on ductile cast iron using chemical and electrochemical methods was evaluated. This work attempts to clarify the synergistic effect of nitrite and ethanolamines. The effects of single addition of TEA, DEA, and MEA, and mixed addition of nitrite plus TEA, DEA or MEA on the corrosion inhibition of ductile cast iron in a tap water were evaluated. A huge amount of single addition of ethanolamine was needed. However, the synergistic effect by mixed addition was observed regardless of the combination of nitrite and triethanolamines, but their effects increased in a series of MEA + nitrite > DEA + nitrite > TEA + nitrite. This tendency of synergistic effect was attributed to the film properties and polar effect; TEA addition couldn't form the film showing high film resistance and semiconductive properties, but DEA or MEA could build the film having relatively high film resistance and n-type semiconductive properties. Moreover, it can be explained that this behaviour was closely related to electron attractive group within the ethanolamines, and thus corrosion inhibition power depends upon the number of the electron attractive group of MEA, DEA, and TEA.

  4. 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.

  5. Localized Corrosion of Alloy 22 -Fabrication Effects-FY05 Summary Report

    International Nuclear Information System (INIS)

    Rebak, R B

    2005-01-01

    general and localized corrosion behavior both in the wrought and annealed condition and in the as-welded condition. The specimens for testing were mostly prepared from flat plates of material. It was important to determine if the process of fabricating a full diameter Alloy 22 container will affect the corrosion performance of this alloy. Specimens were prepared directly from a fabricated container and tested for corrosion resistance. Results show that both the anodic corrosion behavior and the localized corrosion resistance of specimens prepared from a welded fabricated container were the same as from flat welded plates. That is, rolling and welding plates using industrial practices do not hinder the corrosion resistant of Alloy 22. (3) Effect of Black Annealing Oxide Scale--The resistance of Alloy 22 to localized corrosion, mainly crevice corrosion, has been extensively investigated in the last few years. This was done mostly using freshly polished specimens. At this time it was important to address the effect an oxide film or scale that forms during the high temperature annealing process or solution heat treatment (SHT) and its subsequent water quenching. Electrochemical tests such as cyclic potentiodynamic polarization (CPP) have been carried out to determine the repassivation potential for localized corrosion and to assess the mode of attack on the specimens. Tests have been carried out in parallel using mill annealed (MA) specimens free from oxide on the surface. The comparative testing was carried out in six different electrolyte solutions at temperatures ranging from 60 to 100 C. Results show that the repassivation potential of the specimens containing the black anneal oxide film on the surface was practically the same as the repassivation potential for oxide-free specimens. (4) Heat-to-Heat Variability--Testing of Ni-Cr-Mo Plates with varying heat chemistry: The ASTM standard B 575 provides the range of the chemical composition of Nickel-Chromium-Molybdenum (Ni

  6. The Effect of Low-Quantity Cr Addition on the Corrosion Behaviour of Dual-Phase High Carbon Steel

    Directory of Open Access Journals (Sweden)

    Wilson Handoko

    2018-03-01

    Full Text Available Industrial application of high carbon low alloy steel with the dual-phase structure of martensite and austenite has increased drastically in recent years. Due to its excellent compression strength and its high abrasion resistance, this grade of steel has used as a high performance cutting tool and in press machinery applications. By increasing the usage of more corrosive media in industrial practice and increasing the demand for reducing the production cost, it is crucial to understand the effect of the small addition of Cr on the corrosion behaviour of this grade of steel. In this study, this effect was investigated using Secondary Electron Microscopy (SEM and in-situ Atomic Force Microscopy (AFM in the sodium chloride solution. Also, the corrosion rate was measured using the Tafel polarisation curve. It has been found that the small addition of Cr increased the stability of retained austenite, thus improving its corrosion resistance and reducing its corrosion rate. This effect has been acquired through in-situ high resolution topography images in which the samples were submerged in a corrosive solution. It has been demonstrated that the corrosion rate was reduced when the stability of austenite enhanced.

  7. The effect of magnetite on corrosion of stainless steel (SUS309S) in deaerated synthetic sea water

    International Nuclear Information System (INIS)

    Taniguchi, N.; Honda, A.

    1999-10-01

    The assessment of lifetime of carbon steel overpack needs to clear the effects of corrosion products on the corrosion rate of carbon steel. It is reported that the corrosion of carbon steel was accelerated under the presence of magnetite as simulated corrosion products. Therefore, it is important to clear the mechanism of the acceleration of corrosion under the presence of magnetite. If carbon steel overpack will not be able to avoid the acceleration of corrosion under repository condition, some countermeasures have to be taken. One of the countermeasures against the effect of magnetite is considered to be the addition of alloying elements to a steel. The immersion test of stainless steel (SUS309S) as the extreme case of alloying was conducted under the presence of magnetite on the metal surface in synthetic sea water. As the result of this test, the corrosion of stainless steel (SUS309S) was not accelerated by the presence of magnetite. Therefore, it is expected that the susceptibility to the effect of magnetite is able to be reduced by addition of alloying elements to a steel. (author)

  8. The Spread of Corrosion in Cast Iron and its Effect on the Life Cycle of Transportation Vehicles

    Directory of Open Access Journals (Sweden)

    Tomáš Binar

    2017-01-01

    Full Text Available This article deals with the spread of corrosion in material at different exposure times, and its effect on the measured brittle fracture and notch impact strength under different temperature conditions. To assess the degradational effect of corrosion on the material characteristics represented by the measured impact strength, we conducted a fractographic analysis of fracture surfaces, the aim of which was to evaluate the spread of corrosion in the material. In the first part of the experiment, two corrosion tests are simulated with a duration time of 432 and 648 hours, to compare the degradation effect of corrosion on the notch impact strength, depending on the duration of the corrosion tests. The following part shows the results of the impact bending test, where the experiment was conducted in an area of reduced and increased temperatures. The final part summarizes the results of the fractographic analysis of sample fracture surfaces from the impact bending tests. Based on the measured the length of the corrosion cracks, we analyzed the sample at the notch and from the material surface after the impact bending test.

  9. Effects of disinfectant and biofilm on the corrosion of cast iron pipes in a reclaimed water distribution system.

    Science.gov (United States)

    Wang, Haibo; Hu, Chun; Hu, Xuexiang; Yang, Min; Qu, Jiuhui

    2012-03-15

    The effects of disinfection and biofilm on the corrosion of cast iron pipe in a model reclaimed water distribution system were studied using annular reactors (ARs). The corrosion scales formed under different conditions were characterized by X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), and scanning electron microscopy (SEM), while the bacterial characteristics of biofilm on the surface were determined using several molecular methods. The corrosion scales from the ARs with chlorine included predominantly α-FeOOH and Fe2O3, while CaPO3(OH)·2H2O and α-FeOOH were the predominant phases after chloramines replaced chlorine. Studies of the consumption of chlorine and iron release indicated that the formation of dense oxide layers and biofilm inhibited iron corrosion, causing stable lower chlorine decay. It was verified that iron-oxidizing bacteria (IOB) such as Sediminibacterium sp., and iron-reducing bacteria (IRB) such as Shewanella sp., synergistically interacted with the corrosion product to prevent further corrosion. For the ARs without disinfection, α-FeOOH was the predominant phase at the primary stage, while CaCO3 and α-FeOOH were predominant with increasing time. The mixed corrosion-inducing bacteria, including the IRB Shewanella sp., the IOB Sediminibacterium sp., and the sulfur-oxidizing bacteria (SOB) Limnobacter thioxidans strain, promoted iron corrosion by synergistic interactions in the primary period, while anaerobic IRB became the predominant corrosion bacteria, preventing further corrosion via the formation of protective layers. Copyright © 2011 Elsevier Ltd. All rights reserved.

  10. Effect of nitrogen on the corrosion behavior of austenitic stainless steel in chloride solutions

    International Nuclear Information System (INIS)

    Ghanem, Wafaa A.

    2004-01-01

    The effect of partial replacement of nickel with nitrogen on the mechanism of localized corrosion resistance and re-passivation for nitrogen-bearing stainless steel was investigated using anodic potentiodynamic polarization technique. The solutions used for this study contained 0.0, 0.05 and 0.33 M Fe 3+ for solutions I, II and III respectively, in a total Cl - ion concentration 1 M. The pitting attack was found to be retarded by nitrogen addition and the samples were able to passivate as the nitrogen increase. Addition of nitrogen allows decreasing the percentage of Ni, but to a certain limit. Nitrogen is adsorbed on the interface of the metal oxide and results in repulsion of Cl - ions. Moreover, it reacts with H + ions in the solution leading to higher pH, which explains the retardation effect of nitrogen to corrosion. (author)

  11. The Effect of Multiple Shot Peening on the Corrosion Behavior of Duplex Stainless Steel

    Science.gov (United States)

    Feng, Qiang; She, Jia; Wu, Xueyan; Wang, Chengxi; Jiang, Chuanhai

    2018-03-01

    Various types of shot peening treatments were applied to duplex stainless steel. The effects of shot peening intensity and working procedures on the microstructure were investigated. The domain size and microstrain evolution in the surface layer were characterized utilizing the Rietveld method. As the shot peening intensity increased, the surface roughness increased in the surface layer; however, it decreased after multiple (dual and triple) shot peening. The mole fraction of strain-induced martensite as a function of the intensity of shot peening was evaluated by XRD measurements. Both potentiodynamic polarization curves and salt spray tests of shot-peened samples in NaCl solution were investigated. The results indicate that traditional shot peening has negative effects on corrosion resistance with increasing shot peening intensity; however, the corrosion rate can be reduced by means of multiple shot peening.

  12. On the Effects of Atmospheric Particles Contamination and Humidity on Tin Corrosion

    DEFF Research Database (Denmark)

    D’Angelo, L.; Verdingovas, V.; Ferrero, L.

    2017-01-01

    The effects of hygroscopic atmospheric particles are investigated in relation to the corrosion of tin. Surface insulation resistance test boards were directly contaminated both with ambient particles sampled in the field at Milan, Italy, and with pure saline particles generated in the laboratory....... An innovative particle deposition device was used to uniformly coat circular spots on to the test board surfaces. Deliquescence and crystallization of the water-soluble compounds were detected by observing the impedance response to varying relative humidity (RH) conditions with a gradual and continuous ramps....... The effects of the adsorption/desorption kinetics and of the temperature on the deliquescence and crystallization RH values were also investigated. Leakage current measurements at 5-V dc highlighted the ability of atmospheric particles to promote corrosion and electrochemical migration at RH levels far below...

  13. Redox conditions effect on flow accelerated corrosion: Influence of hydrazine and oxygen

    Energy Technology Data Exchange (ETDEWEB)

    Bouvier, O. de [EDF, R and D Div., Moret sur Loing (France); Bouchacourt, M. [EDF, Engineering and Service Div., Villeurbanne (France); Fruzzetti, K. [EPRI, Science and Technology Div., Palo Alto, CA (United States)

    2002-07-01

    Flow accelerated corrosion (FAC) of carbon steels has been studied world-wide for more than twenty years and is now fairly well understood. The influence of several parameters like water chemistry (i.e. pH and oxygen content), temperature, hydrodynamic or mass transfer conditions (i.e. flow velocity, geometry, steam quality..) and steel composition on the corrosion kinetics has been demonstrated both theoretically and experimentally. However, the effect of a reducing environment and variable redox conditions have not yet been fully explored. It's well known that a reducing environment is effective in increasing the resistance of steam generator tubing to intergranular attack / stress corrosion cracking (IGA/SCC) and pitting. In that way, secondary water chemistry specifications have been modified from low hydrazine to high hydrazine chemistry in the steam-water circuit. Nevertheless, increasing hydrazine levels up to 200 {mu}g/kg could have a detrimental effect by potentially enhancing the FAC process. Moreover, in order to have a complete understanding of the possible impact of the water chemistry environment it is also important to consider the impact of redox conditions during shutdowns (cold and/or hot shutdowns) and start up periods when aerated water injections are made to maintain a constant water level in the Steam Generators from the auxiliary feedwater circuit. Therefore, a common EDF and EPRI R and D effort has been recently carried out to study the effects of hydrazine and oxygen on FAC. The results are presented as follows. (authors)

  14. Predicting Effects of Corrosion Erosion of High Strength Steel Pipelines Elbow on CO2-Acetic Acid (HAc) Solution

    International Nuclear Information System (INIS)

    Asmara, Y. P.; Ismail, M. F.; Chui, L. Giok; Halimi, Jamiludin

    2016-01-01

    Simultaneously effect of erosion combined with corrosion becomes the most concern in oil and gas industries. It is due to the fast deterioration of metal as effects of solid particles mixed with corrosive environment. There are many corrosion software to investigate possible degradation mechanisms developed by researchers. They are using many combination factors of chemical reactions and physical process. However effects of CO 2 and acid on pipelines orientations are still remain uncovered in their simulation. This research will investigate combination effects of CO 2 and HAc on corrosion and erosion artificial environmental containing sands particles in 45°, 90° and 180° elbow pipelines. The research used theoretical calculations combined with experiments for verification. The main concerns are to investigate the maximum erosion corrosion rate and maximum shear stress at the surface. Methodology used to calculate corrosion rate are Linear Polarization Resistance (LPR) and weight loss. The results showed that at 45°, erosion rate is the more significant effects in contributing degradation of the metal. The effects of CO 2 and HAc gave significant effects when flow rate of the solution are high which reflect synergism effects of solid particles and those chemical compositions. (paper)

  15. 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.

  16. EFFECTIVENESS OF INHIBITORS OF METAL CORROSION IN AQUEOUS ENVIRONMENTS WITH VARYING SALINITY

    OpenAIRE

    Носачова, Юлія Вікторівна; Макаренко, Ірина Миколаївна; Шаблій, Тетяна Олександрівна

    2015-01-01

    EFFECTIVENESS OF INHIBITORS OF METAL CORROSION IN AQUEOUS ENVIRONMENTS WITH VARYING SALINITYThe main reason for the growing problem of water quality in Ukraine is the increase of anthropogenic impacts on water resources caused by intense chemical, biological and radiation contamination of existing and potential sources for industrial and communal water supply. Especially polluted rivers in Donbass and Krivbas area, that turned into collectors of saline wastewater. Especially hard environment...

  17. The effect of the PWR secondary circuit water chemistry on erosion corrosion

    International Nuclear Information System (INIS)

    Kaplan, J.

    1993-07-01

    The secondary circuit of WWER-440 and WWER-1000 reactors is described. The causes of erosion corrosion are outlined, and the effects of the physical properties and chemical composition of water are discussed with emphasis on specific conductivity and concentrations of oxygen, ammonia, iron, sodium, silicon and organics. Described are corrective actions to eliminate the deviations from the normal state during reactor power reduction or reactor shutdown. (J.B.)

  18. Effect of calcium on the microstructure and corrosion behavior of microarc oxidized Mg-xCa alloys.

    Science.gov (United States)

    Pan, Yaokun; Chen, Chuanzhong; Feng, Rui; Cui, Hongwei; Gong, Benkui; Zheng, Tingting; Ji, Yarou

    2018-01-16

    Magnesium alloys are potential biodegradable implants for biomedical applications, and calcium (Ca) is one kind of ideal element being examined for magnesium alloys and biodegradable ceramic coatings owing to its biocompatibility and mechanical suitability. In this study, microarc oxidation (MAO) coatings were prepared on Mg-xCa alloys to study the effect of Ca on the microstructure and corrosion resistance of Mg-xCa alloys and their surface MAO coatings. The electrochemical corrosion behavior was investigated using an electrochemical workstation, and the degradability and bioactivity were evaluated by soaking tests in simulated body fluid (SBF) solutions. The corrosion products were characterized by scanning electron microscopy, x-ray diffractometry, and Fourier transform infrared spectrometry. The effects of Ca on the alloy phase composition, microstructure, MAO coating formation mechanism, and corrosion behavior were investigated. Results showed that the Mg-0.82Ca alloy and MAO-coated Mg-0.82Ca exhibited the highest corrosion resistance. The number and distribution of Mg 2 Ca phases can be controlled by adjusting the Ca content in the Mg-xCa alloys. The proper amount of Ca in magnesium alloy was about 0.5-0.8 wt. %. The pore size, surface roughness, and corrosion behavior of microarc oxidized Mg-xCa samples can be controlled by the number and distribution of the Mg 2 Ca phase. The corrosion behaviors of microarc oxidized Mg-Ca in SBF solutions were discussed.

  19. Evaluating the effects of hydroxyapatite coating on the corrosion behavior of severely deformed 316Ti SS for surgical implants

    International Nuclear Information System (INIS)

    Mhaede, Mansour; Ahmed, Aymen; Wollmann, Manfred; Wagner, Lothar

    2015-01-01

    The present work investigates the effects of severe plastic deformation by cold rolling on the microstructure, the mechanical properties and the corrosion behavior of austenitic stainless steel (SS) 316Ti. Hydroxyapatite coating (HA) was applied on the deformed material to improve their corrosion resistance. The martensitic transformation due to cold rolling was recorded by X-ray diffraction spectra. The effects of cold rolling on the corrosion behavior were studied using potentiodynamic polarization. The electrochemical tests were carried out in Ringer's solution at 37 ± 1 °C. Cold rolling markedly enhanced the mechanical properties while the electrochemical tests referred to a lower corrosion resistance of the deformed material. The best combination of both high strength and good corrosion resistance was achieved after applying hydroxyapatite coating. - Highlights: • Cold rolling markedly increases the hardness of SS 316Ti from 125 to 460 HV10. • Higher deformation degrees lead to lower corrosion resistance. • Application of HA-coating leads to significant improvement of the corrosion resistance

  20. Effects of nitrogen in shielding gas on microstructure evolution and localized corrosion behavior of duplex stainless steel welding joint

    Science.gov (United States)

    Zhang, Zhiqiang; Jing, Hongyang; Xu, Lianyong; Han, Yongdian; Zhao, Lei; Zhou, Chao

    2017-05-01

    The effects of nitrogen addition in shielding gas on microstructure evolution and localized corrosion behavior of duplex stainless steel (DSS) welds were studied. N2-supplemented shielding gas facilitated the primary austenite formation, suppressed the Cr2N precipitation in weld root, and increased the microhardnesses of weld metal. Furthermore, N2-supplemented shielding gas increased pitting resistance equivalent number (PREN) of austenite, but which decreased slightly PREN of ferrite. The modified double loop electrochemical potentiokinetic reactivation in 2 M H2SO4 + 1 M HCl was an effective method to study the localized corrosion of the different zones in the DSS welds. The adding 2% N2 to pure Ar shielding gas improved the localized corrosion resistance in the DSS welds, which was due to compensation for nitrogen loss and promoting nitrogen further solution in the austenite phases, suppression of the Cr2N precipitation in the weld root, and increase of primary austenite content with higher PREN than the ferrite and secondary austenite. Secondary austenite are prone to selective corrosion because of lower PREN compared with ferrite and primary austenite. Cr2N precipitation in the pure Ar shielding weld root and heat affected zone caused the pitting corrosion within the ferrite and the intergranular corrosion at the ferrite boundary. In addition, sigma and M23C6 precipitation resulted in the intergranular corrosion at the ferrite boundary.

  1. Effects of Ultrasonic Nanocrystal Surface Modification on the Residual Stress, Microstructure, and Corrosion Resistance of 304 Stainless Steel Welds

    Science.gov (United States)

    Ye, Chang; Telang, Abhishek; Gill, Amrinder; Wen, Xingshuo; Mannava, Seetha R.; Qian, Dong; Vasudevan, Vijay K.

    2018-03-01

    In this study, ultrasonic nanocrystal surface modification (UNSM) of 304 stainless steel welds was carried out. UNSM effectively eliminates the tensile stress generated during welding and imparts beneficial compressive residual stresses. In addition, UNSM can effectively refine the grains and increase hardness in the near-surface region. Corrosion tests in boiling MgCl2 solution demonstrate that UNSM can significantly improve the corrosion resistance due to the compressive residual stresses and changes in the near-surface microstructure.

  2. Coatings and Corrosion Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — Purpose: The mission of the Coatings and Corrosion Laboratory is to develop and analyze the effectiveness of innovative coatings test procedures while evaluating the...

  3. Effect of boric acid on intergranular corrosion in tube support plate crevices

    International Nuclear Information System (INIS)

    Brunet, J.P.; Campan, J.L.

    1993-10-01

    Intergranular attack on steam generator tubing is one important phenomenon involved in availability of Pressurized Water Reactors. Boric acid appears to be a possible candidate for inhibiting the corrosion process. The program performed in Cadarache was supposed to give statistical informations on the boric acid effect. It was based on a large number of samples initially attacked during a program performed by BABCOCK ampersand WILCOX. These samples were sleeved onto Alloy 690 tubes, in order to prevent premature cracking. Unfortunately it was not possible to find chemical conditions able to produce significant additional corrosion; we postulated mainly due to a drastic reduction of the thermal flux resulting from the increase of the tube wall thickness under the tube support plates (TSP). The tests demonstrate that such sleeve could be a possible remedy of the corrosion when introduced under the TSP. The tests show indications of a possible beneficial effect of the boric acid, a large variability of the heats sensitivity to the IGA and a predominant effect of Na 2 CO 3 on IGA production

  4. 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.

  5. 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.

  6. EFFECT OF INTERMETALLIC PHASES ON CORROSION BEHAVIOR AND MECHANICAL PROPERTIES OF DUPLEX STAINLESS STEEL AND SUPER-DUPLEX STAINLESS STEEL

    Directory of Open Access Journals (Sweden)

    Prabhu Paulraj

    2015-08-01

    Full Text Available Duplex Stainless Steels (DSS and Super Duplex Stainless Steel (SDSS have excellent integration of mechanical and corrosion properties. However, the formation of intermetallic phases is a major problem in their usage. The mechanical and corrosion properties are deteriorated due to the presence of intermetallic phases. These phases are induced during welding, prolonged exposure to high temperatures, and improper heat treatments. The main emphasis of this review article is on intermetallic phases and their effects on corrosion and mechanical properties. First the effect of various alloying elements on DSS and SDSS has been discussed followed by formation of various intermetallic phases. The intermetallic phases affect impact toughness and corrosion resistance significantly. Their deleterious effect on weldments has also been reviewed.

  7. Temperature and humidity effects on the corrosion of aluminium-base reactor fuel cladding materials during dry storage

    International Nuclear Information System (INIS)

    Peacock, H.B.; Sindelar, R.L.; Lam, P.S.

    2004-01-01

    The effect of temperature and relative humidity on the high temperature (up to 200 deg. C) corrosion of aluminum cladding alloys was investigated for dry storage of spent nuclear fuels. A dependency on alloy type and temperature was determined for saturated water vapor conditions. Models were developed to allow prediction of cladding behaviour of 1100, 5052, and 6061 aluminum alloys for up to 50+ years at 100% relative humidity. Calculations show that for a closed system, corrosion stops after all moisture and oxygen is used up during corrosion reactions with aluminum alloys. (author)

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

    International Nuclear Information System (INIS)

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

    2010-01-01

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

  9. Effect of aging on the general corrosion and stress corrosion cracking of uranium--6 wt % niobium alloy

    International Nuclear Information System (INIS)

    Koger, J.W.; Ammons, A.M.; Ferguson, J.E.

    1975-11-01

    Mechanical properties of the uranium-6 wt percent niobium alloy change with aging time and temperature. In general, the ultimate tensile strength and hardness reach a peak, while elongation becomes a minimum at aging temperatures between 400 and 500 0 C. The first optical evidence of a second phase was in the 400 0 C-aged alloy, while complete transformation to a two-phase structure was seen in the 600 0 C-aged alloy. The maximum-strength conditions correlate with the minimum stress corrosion cracking (SCC) resistance. The maximum SCC resistance is found in the as-quenched and 150, 200, and 600 0 C-aged specimens. The as-quenched and 300 0 C-aged specimens had the greatest resistance to general corrosion in aqueous chloride solutions; the 600 0 C-aged specimen had the least resistance

  10. Effect of alternating voltage treatment on corrosion resistance of AZ91D magnesium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Liu, X. [Corrosion and Protection Laboratory, Key Laboratory of Superlight Materials and Surface Technology (Harbin Engineering University), Ministry of Education, Harbin (China); Zhang, T.; Shao, Y.; Meng, G.; Wang, F. [Corrosion and Protection Laboratory, Key Laboratory of Superlight Materials and Surface Technology (Harbin Engineering University), Ministry of Education, Harbin (China); State Key Laboratory for Corrosion and Protection, Institute of Metal Research, Chinese Academy of Sciences, Shenyang (China)

    2012-06-15

    AZ91D magnesium alloy was treated by the alternating voltage (AV) treatment technique. The optimal AV-treatment parameters of the alloy were determined by orthogonal experiments. Polarization curve, electrochemical impedance spectroscopy (EIS), and scanning electrochemical microscopy (SECM) were used to understand the effect of AV-treatment on the corrosion resistance of the alloy. AFM, contact angle, and XPS were employed to investigate further the influence of AV-treatment on the properties of the surface film formed on the alloy after AV-treatment. The results showed that a uniform and stable film was formed and the corrosion resistance of AZ91D magnesium alloy was significantly improved after AV-treatment. This was caused by the noticeable change of the chemical structure and semi-conducting properties of the surface film after AV-treatment. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Effect of Tryptophan on the corrosion behavior of low alloy steel in sulfamic acid

    Directory of Open Access Journals (Sweden)

    Hesham T.M. Abdel-Fatah

    2016-11-01

    Full Text Available Sulfamic acid is widely used in various industrial acid cleaning applications. In the present work, the inhibition effect of Tryptophan (Tryp on the corrosion of low alloy steel in sulfamic acid solutions at four different temperatures was studied. The investigations involved electrochemical methods (electrochemical impedance spectroscopy; EIS and the new technique electrochemical frequency modulation; EFM as well as gravimetric measurements. The inhibition efficiency and the apparent activation energy have been calculated in the presence and in the absence of Tryp. It is most probable that the inhibition property of Tryp was due to the electrostatic adsorption of the protonated form of Tryp on the steel surface. Adsorption of the inhibitor molecule, onto the steel surface followed the Temkin adsorption isotherm. The thermodynamic parameters of adsorption were determined and discussed. All of the obtained data from the three techniques were in close agreement, which confirmed that EFM technique can be used efficiently for monitoring the corrosion inhibition under the studied conditions.

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

    Science.gov (United States)

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

    2017-06-14

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

  13. Intramolecular synergistic effect of glutamic acid, cysteine and glycine against copper corrosion in hydrochloric acid solution

    International Nuclear Information System (INIS)

    Zhang Daquan; Xie Bin; Gao Lixin; Cai Qirui; Joo, Hyung Goun; Lee, Kang Yong

    2011-01-01

    The corrosion protection of copper by glutamic acid, cysteine, glycine and their derivative (glutathione) in 0.5 M hydrochloric acid solution has been studied by the electrochemical impedance spectroscopy and cyclic voltammetry. The inhibition efficiency of the organic inhibitors on copper corrosion increases in the order: glutathione > cysteine > cysteine + glutamic acid + glycine > glutamic acid > glycine. Maximum inhibition efficiency for cysteine reaches about 92.9% at 15 mM concentration level. The glutathione can give 96.4% inhibition efficiency at a concentration of 10 mM. The molecular structure parameters were obtained by PM3 (Parametric Method 3) semi-empirical calculation. The intramolecular synergistic effect of glutamic acid, cysteine and glycine moieties in glutathione is attributed to the lower energy of the lowest unoccupied molecular orbital (E LUMO ) level and to the excess hetero-atom adsorption centers and the bigger coverage on the copper surface.

  14. Effect of Iron-Containing Intermetallic Particles on the Corrosion Behaviour of Aluminium

    DEFF Research Database (Denmark)

    Ambat, Rajan

    2006-01-01

    The effect of heat treatment on the corrosion behaviour of binary Al-Fe alloys containing iron at levels between 0.04 and 0.42 wt.% was investigated by electrochemical measurements in both acidic and alkaline chloride solutions. Comparing solution heat-treated and quenched materials with samples...... with {100} facets, and are observed to contain numerous intermetallic particles. Fine facetted filaments also radiate out from the periphery of pits. The results demonstrate that the corrosion of "pure" 99.96% Al is thus dominated by the role of iron, which is the main impurity, and its electrochemical...... that had been subsequently annealed to promote precipitation of Al3Fe intermetallic particles, it was found that annealing increases both the cathodic and anodic reactivity. The increased cathodic reactivity is believed to be directly related to the increased available surface area of the iron...

  15. Activation of aluminum as an effective reducing agent by pitting corrosion for wet-chemical synthesis.

    Science.gov (United States)

    Li, Wei; Cochell, Thomas; Manthiram, Arumugam

    2013-01-01

    Metallic aluminum (Al) is of interest as a reducing agent because of its low standard reduction potential. However, its surface is invariably covered with a dense aluminum oxide film, which prevents its effective use as a reducing agent in wet-chemical synthesis. Pitting corrosion, known as an undesired reaction destroying Al and is enhanced by anions such as F⁻, Cl⁻, and Br⁻ in aqueous solutions, is applied here for the first time to activate Al as a reducing agent for wet-chemical synthesis of a diverse array of metals and alloys. Specifically, we demonstrate the synthesis of highly dispersed palladium nanoparticles on carbon black with stabilizers and the intermetallic Cu₂Sb/C, which are promising candidates, respectively, for fuel cell catalysts and lithium-ion battery anodes. Atomic hydrogen, an intermediate during the pitting corrosion of Al in protonic solvents (e.g., water and ethylene glycol), is validated as the actual reducing agent.

  16. Effects of heat input on pitting corrosion in super duplex stainless steel weld metals

    Science.gov (United States)

    Shin, Yong taek; Shin, Hak soo; Lee, Hae woo

    2012-12-01

    Due to the difference in reheating effects depending on the heat input of subsequent weld passes, the microstructure of the weld metal varies between acicular type austenite and a mixture of polygonal type and grain boundary mixed austenite. These microstructural changes may affect the corrosion properties of duplex stainless steel welds. This result indicates that the pitting resistance of the weld can be strongly influenced by the morphology of the secondary austenite phase. In particular, the ferrite phase adjacent to the acicular type austenite phase shows a lower Pitting Resistance Equivalent (PRE) value of 25.3, due to its lower chromium and molybdenum contents, whereas the secondary austenite phase maintains a higher PRE value of more than 38. Therefore, it can be inferred that the pitting corrosion is mainly due to the formation of ferrite phase with a much lower PRE value.

  17. 3DII implantation effect on corrosion properties of the AISI/SAE 1020 steel

    Energy Technology Data Exchange (ETDEWEB)

    Dulce M., H.J.; Rueda V., Alejandro [Universidad Francisco de Paula Santander, A.A. 1055, Cucuta (Colombia); Dougar-Jabon, Valeri [Universidad Industrial de Santander, A.A. 678, Bucaramanga (Colombia)

    2005-08-01

    The three dimensional ion implantation technology (3DII) is one of the methods of improving the tribological characteristics and resistance to hydrogen embrittlement processes in metals. In this report, some results concerning the resistance effect of nitrogen ion implantation to oxidation of the sample, made of AISI/SAE 1020 steel, are given. The nitrogen ions were implanted in the discharge chamber of the JUPITER reactor. Both the treated and untreated samples were tested through potential-static measurements, which permitted to determine the corrosion current, the slopes that characterise the braking level of anode and cathode reactions. The polarization resistance near the corrosion potential is calculated. The results of the study encourage to consider the nitrogen ion implantation in high voltage and low pressure discharges as one of the methods of anticorrosive protection which do not change the geometric configuration of the treated steel pieces. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  18. Effect of aging time on intergranular corrosion behavior of a newly developed LDX 2404 lean duplex stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Hui [School of Materials Engineering, Shanghai University of Engineering Science, Shanghai 201620 (China); Zhang, Ziying, E-mail: zzying@sues.edu.cn [School of Materials Engineering, Shanghai University of Engineering Science, Shanghai 201620 (China); Zhang, Huizhen [School of Management, University of Shanghai for Science and Technology, Shanghai 200093 (China); Hu, Jun [School of Materials Engineering, Shanghai University of Engineering Science, Shanghai 201620 (China); Li, Jin [Department of Materials Science, Fudan University, Shanghai 200433 (China)

    2016-07-05

    The effect of aging at 700 °C for various times on the intergranular corrosion behavior of LDX 2404 duplex stainless steel is investigated by morphological observation and electrochemical detection. Scanning electronic microscopy and transmission electronic microscopy analysis reveal that Cr{sub 2}N, M{sub 23}C{sub 6} and the sigma and chi phases nucleate simultaneously at the initial stages of aging. The granular particles of sigma phase grow larger but fewer with the increase of aging time. The electrochemical detection results show that intergranular corrosion become more severe and the corrosion type evolves from intergranular corrosion into general corrosion as the holding time extends to 48 h. - Highlights: • The IGC behavior of aged LDX 2404 is investigated. • Cr{sub 2}N, M{sub 23}C{sub 6} and the σ and χ phases nucleate simultaneously at the initial stages of aging. • IGC resistance decreases with the increase of aging time. • The corrosion type evolves from IGC into general corrosion for longer aging times.

  19. Effects of metallurgical factors on stress corrosion cracking of Ni-base alloys in high temperature water

    International Nuclear Information System (INIS)

    Yonezawa, T.; Sasaguri, N.; Onimura, K.

    1988-01-01

    Nickel-base Alloy 600 is the principal material used for the steam generator tubes of PWRs. Generally, this alloy has been proven to be satisfactory for this application, however when it is subjected to extremely high stress level in PWR primary water, it may suffer from stress corrosion cracking. The authors have systematically studied the effects of test temperature and such metallurgical factors as cold working, chemical composition and heat treatment on the stress corrosion cracking of Alloy 600 in high temperature water, and also on that of Alloy 690 which is a promising material for the tubes and may provide improved crrosion resistance for steam generators. The test materials, the stress corrosion cracking test and the test results are reported. When the test temperature was raise, the stress corrosion cracking of the nickel-base alloys was accelerated. The time of stress corrosion cracking occurrence decreased with increasing applied stress, and it occurred at the stress level higher than the 0.2 % offset proof stress of Alloy 600. In Alloy 690, stress corrosion cracking was not observed at such stress level. Cold worked Alloy 600 showed higher resistance to stress corrosion cracking than the annealed alloy. (Kako, I.)

  20. The Effect of pH on Slurry Erosion-Corrosion of Tungsten Carbide Overlays Alloyed with Ru

    Science.gov (United States)

    Nelwalani, Ndivhuwo B.; van der Merwe, Josias W.

    2018-02-01

    The aim of the study was to determine the effect of Ru additions to WC-Fe overlays when exposed to low pH slurry erosion conditions. These overlays were applied through Plasma Transferred Arc, and the original bulk Ru powder concentrations varied from 0.5 to 5 wt.%. A slurry jet impingement erosion-corrosion test rig was used to evaluate wear, and electrochemical measurements were performed to characterize the corrosion properties. The slurry mixtures contained silica sand and synthetic mine water. The pH was varied between 3 and 6.5 for the slurry erosion tests and lowered further for the corrosion characterization. Samples were examined optically and with a scanning electron microscope using energy-dispersive x-ray spectroscopy. X-ray diffraction analysis was used to determine the phases present. For the slurry erosion-corrosion results at the pH of 6.5, addition of Ru did not show a decrease in erosion-corrosion rates. However, when the pH was decreased to 3, by the addition of HCl, Ru improved the resistance. From the electrochemistry, it was also clear that Ru additions improved the corrosion resistance, but more than 1 wt.% Ru was required. At very low pH levels, the presence of Ru was not able to prevent corrosion.

  1. Effect of cerium conversion of A3xx.x/SiCp composites surfaces on salt fog corrosion behaviour

    Energy Technology Data Exchange (ETDEWEB)

    Pardo, A.; Merino, M.C.; Arrabal, R.; Viejo, F.; Carboneras, M.; Coy, A.E. [Departamento de Ciencia de Materiales, Facultad de Quimica, Universidad Complutense, 28040, Madrid (Spain); Merino, S. [Departamento de Tecnologia Industrial, Universidad Alfonso X El Sabio, 28691, Villanueva de la Canada, Madrid (Spain)

    2004-07-01

    A study of the effect of cerium conversion treatment on surface of four composites (A360/SiC/10p, A360/SiC/20p, A380/SiC/10p, A380/SiC/20p) on their salt fog corrosion behaviour was performed. The conversion treatment was carried out using thermal activated full immersion in Ce(III) aqueous solutions. The matrix of A360/SiC/xxp composites is virtually free of Cu while the A380/SiC/xxp matrix contains 1.39-1.44 wt.%Ni and 3.13-3.45 wt.%Cu. Conversion performance was evaluated in neutral salt fog environment according to ASTM B117. The kinetics of the corrosion process were studied on the basis of gravimetric tests. The influence of SiCp proportion and matrix composition was evaluated and the nature of corrosion products was analysed by SEM and low angle XRD before and after accelerated testing to determine the influence of microstructural changes on corrosion behaviour during exposure to the corrosive environment. The Ce(III) precipitates on the cathodic sites, mainly on the intermetallic compounds, decreased both the cathodic current density and the corrosion rate of the composites tested. The presence of Cu in the matrix composition increased the corrosion rate, due to the galvanic couple Al/Cu. (authors)

  2. Effect of postreatment on the corrosion behaviour of tartaric-sulphuric anodic films

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Rubio, M. [Departamento de Quimica-Fisica Aplicada, Universidad Autonoma de Madrid, 28049 Madrid (Spain); Department of Surface Technologies, Engineering of Materials and Processes, Airbus Spain, Av. John Lennon s/n 28906 Getafe (Spain); Lara, M.P. de [Departamento de Quimica-Fisica Aplicada, Universidad Autonoma de Madrid, 28049 Madrid (Spain); Ocon, P. [Departamento de Quimica-Fisica Aplicada, Universidad Autonoma de Madrid, 28049 Madrid (Spain)], E-mail: pilar.ocon@uam.es; Diekhoff, S. [Fraunhofer-IFAM, Lesumer Heerstrasse 36, 28717 Bremen (Germany); Beneke, M. [Department of Surface Technologies, Engineering of Materials and Processes, Airbus Deutschland, GmbH Hunefeldstr. 1-5, 28199 Bremen (Germany); Lavia, A.; Garcia, I. [Department of Surface Technologies, Engineering of Materials and Processes, Airbus Spain, Av. John Lennon s/n 28906 Getafe (Spain)

    2009-08-30

    Unclad and clad AA2024 T3 specimens were anodised in a chromium-free tartaric-sulphuric acid bath (TSA) and subsequently postreated by different processes including impregnation in a cold, concentrated chromate solution, Cr-free hot-water sealing, and dichromate hot-water sealing. The purpose of this work is to evaluate the effectiveness of the classical postreatments used in the aircraft industry on the TSA-anodic films and their corrosion resistance behaviour. TSA-anodic films were characterised by scanning electron microscopy (SEM) and their thicknesses were measured by SEM and the eddy current method. Electrochemical impedance spectroscopy (EIS) was used to characterise the barrier and porous layers, and jointly with potentiodynamic polarisation allowed the evaluation of corrosion resistance parameters with immersion time in NaCl solution for anodised and postreated specimens. In all cases the postreatments increased the resistance of the barrier layer against degradation. However, the NaCl electrolyte easily penetrated TSA-anodised porous layers when they were not postreated, while penetration was slightly more difficult in cold-postreated specimens. The effective pore plugging was observed in the sealed TSA specimens resulting in an improved corrosion resistance. On the other hand, unsealed clad AA2024 specimens showed a self-sealing process of the TSA-anodic layer, which was slower for the cold chromate solution-postreated specimens.

  3. Effect of postreatment on the corrosion behaviour of tartaric-sulphuric anodic films

    International Nuclear Information System (INIS)

    Garcia-Rubio, M.; Lara, M.P. de; Ocon, P.; Diekhoff, S.; Beneke, M.; Lavia, A.; Garcia, I.

    2009-01-01

    Unclad and clad AA2024 T3 specimens were anodised in a chromium-free tartaric-sulphuric acid bath (TSA) and subsequently postreated by different processes including impregnation in a cold, concentrated chromate solution, Cr-free hot-water sealing, and dichromate hot-water sealing. The purpose of this work is to evaluate the effectiveness of the classical postreatments used in the aircraft industry on the TSA-anodic films and their corrosion resistance behaviour. TSA-anodic films were characterised by scanning electron microscopy (SEM) and their thicknesses were measured by SEM and the eddy current method. Electrochemical impedance spectroscopy (EIS) was used to characterise the barrier and porous layers, and jointly with potentiodynamic polarisation allowed the evaluation of corrosion resistance parameters with immersion time in NaCl solution for anodised and postreated specimens. In all cases the postreatments increased the resistance of the barrier layer against degradation. However, the NaCl electrolyte easily penetrated TSA-anodised porous layers when they were not postreated, while penetration was slightly more difficult in cold-postreated specimens. The effective pore plugging was observed in the sealed TSA specimens resulting in an improved corrosion resistance. On the other hand, unsealed clad AA2024 specimens showed a self-sealing process of the TSA-anodic layer, which was slower for the cold chromate solution-postreated specimens.

  4. The effect of second-phase particles on the corrosion and struture of Zircaloy-4

    International Nuclear Information System (INIS)

    Cortie, M.B.

    1982-10-01

    The effect of heat treatment and second-phase particles on the corrosion resistance and microstructure of Zircaloy-4 has been examined. In particular the effect of precipitates on the rate and mechanism of high-temperature, high-pressure water or steam corrosion is discussed. Measurements of corrosion rate are presented for specimens which have received various heat treatments. The heat treatments studied included a fast cool from the beta field, prolonged annealing at temperatures ranging from 500 degrees Celsius to 1 100 degrees Celsius as well as combinations of the above. The fabrication of a small quantity of Zircaloy-4 strip was undertaken and the methods used and observations made are recorded. The wide range of microstructures produced in Zircaloy-4 by the heat treatments and fabrication procedures utilized are described and discussed with optical or electron microscope photographs showing the important features. Qualitative and semi-quantitative chemical analyses of the second-phase particles were carried out by both the scanning electron microscope and Auger spectroscopy. Evidence for the existence of a tin-rich precipitate in Zircaloy-4 is presented and discussed

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

    International Nuclear Information System (INIS)

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

    1993-01-01

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

  6. The effectiveness of sucralfate against stricture formation in experimental corrosive esophageal burns.

    Science.gov (United States)

    Temir, Z Günyüz; Karkiner, Aytaç; Karaca, Irfan; Ortaç, Ragip; Ozdamar, Aykut

    2005-01-01

    In this study, the effectiveness of sucralfate against stricture formation in experimental corrosive esophageal burn is reported. Sixty-four Swiss albino adult male rats were divided into three groups, group A (control; n, 7), group B (esophageal burn induced but not treated; n, 25), and group C (esophageal burn induced and treated with sucralfate, n, 32). Groups B and C were further subdivided into subgroups for evaluation on days 2, 7, and 28. A standard esophageal burn was performed by the method of Gehanno, using 50% NaOH. Oral sucralfate treatment was given to group C at a dosage of 50 mg/100 g twice daily. The rats were then killed after 2, 7, or 28 days. Levels of tissue hydroxyproline were measured in excised abdominal esophageal segments, and a histopathological evaluation was performed with hematoxylin-eosin and Masson's trichrome staining. The tissue hydroxyproline levels were significantly lower in group C than in group B (P = 0.017). There was a significant difference in the stenosis index between groups B and C (P = 0.016). When compared with group B, the collagen deposition in the submucosa and tunica muscularis was significantly lower in group C (P = 0.02). Sucralfate has an inhibitory effect on stricture formation in experimental corrosive burns and can be used in the treatment of corrosive esophageal burns to enhance mucosal healing and suppress stricture formation.

  7. Effect of surface modification on the corrosion resistivity in supercritical water

    International Nuclear Information System (INIS)

    Penttila, S.; Horvath, A.; Toivonen, A.; Zolnai, Z.

    2011-01-01

    This paper summarizes the results of high temperature corrosion studies of the candidate austenitic alloys at relevant operating conditions for SCWR. The high temperature and pressure above the thermodynamic critical point of water result in higher oxidation rate which might be critical for thin-wall components like fuel cladding. The goal of this work was to study the effect of surface preparation on the oxidation rate on Ti-stabilized austenitic alloy 1.4970. Surfaces were prepared with ion implantation using He"+- and N"+-ions. Samples were immersed in supercritical water at 650"oC/25 MPa, for up to 2000 hours. Added to this, conventional surface treatments were conducted for austenitic alloy 316L tube samples in order to study the effect of cold work in sample surface on corrosion resistance. The corrosion rate was evaluated by measuring the weight change of the samples. The compositions of the oxide layers were analyzed using scanning electron microscope (SEM) in conjunction with Energy Dispersive Spectroscopy (EDS). (author)

  8. Effect of composition on the corrosion behavior of 316 stainless steel in flowing sodium

    International Nuclear Information System (INIS)

    Bates, J.F.; Brehm, W.F.

    1976-03-01

    Type 316 stainless steel specimens irradiated and non-irradiated, with minor variations in C, N, Cr, Ni, Si, and Mn content, were exposed to flowing sodium in the Source Term Control Loop-1 facility. Test conditions of 604 0 C, a sodium velocity of 6.7 m/s, and an oxygen content of 0.5 and 2.5 ppM were used to ascertain the effect of these compositional variations on the corrosion rate and on the 54 Mn release rate. Variations in C, N, and Mn had no significant effect on the corrosion rate. The corrosion rate increased somewhat as the Ni and Si content of the steel was increased, and decreased with an increase in Cr content. Microprobe examination showed preferential leaching of Mn, Si, Cr, and Ni to depths of up to 10 μm (0.4 mil) after exposure times ranging from 5000 to 8000 hours. Variations in natural ( 55 Mn) content did not affect release rates of 54 Mn generated by 54 Fe(n,p) 54 Mn. 10 fig, 4 tables

  9. Effect of surface nanocrystallization on the microstructural and corrosion characteristics of AZ91D magnesium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Laleh, M., E-mail: laleh.m.1992@gmail.com [Department of Materials Engineering, Faculty of Engineering, Tarbiat Modares University, P.O. Box 14115-143, Tehran (Iran, Islamic Republic of); Kargar, Farzad, E-mail: farzad.kargar@gmail.com [Department of Materials Engineering, Faculty of Engineering, Tarbiat Modares University, P.O. Box 14115-143, Tehran (Iran, Islamic Republic of)

    2011-09-15

    Highlights: > Nanostructured surface layers were produced on AZ91D magnesium alloy by using SMAT. > Thickness of the deformed layer increased with increasing of the balls size. > Top surface microhardness for all of the SMATed samples increased significantly. > SMAT increased the surface roughness; increase in balls diameter increased the roughness. > SMAT using 2 mm balls increased the corrosion resistance significantly. - Abstract: Surface distinct deformed layers with thicknesses up to 150 {mu}m, with grain size in the top most surface is in the nanometer scale, were produced on AZ91D magnesium alloy using surface mechanical attrition treatment (SMAT). Effects of different ball size on the properties of the SMATed samples were investigated. The microstructural, grain size, hardness and roughness features of the treated surfaces were characterized using optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), micro-indenter and digital roughness meter, respectively. Corrosion behavior of the samples was evaluated using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. It is found that the ball diameter does not have a significant effect on the top surface grain size, but the thickness of the deformed layer increases with increase of ball size, from 50 {mu}m for 2 mm balls to 150 {mu}m for 5 mm balls. For all of the SMATed samples, the top surface microhardness value increased significantly and did not show any obvious change for samples treated with different balls. Corrosion studies show that the corrosion resistance of the sample treated with 2 mm balls is higher than that of those treated with 3 mm and 5 mm balls. This can be mainly attributed to the surface roughness and defects density of the samples, which are higher for the SMATed samples with 3 mm and 5 mm balls compared with that of sample SMATed with 2 mm balls.

  10. Effect of surface nanocrystallization on the microstructural and corrosion characteristics of AZ91D magnesium alloy

    International Nuclear Information System (INIS)

    Laleh, M.; Kargar, Farzad

    2011-01-01

    Highlights: → Nanostructured surface layers were produced on AZ91D magnesium alloy by using SMAT. → Thickness of the deformed layer increased with increasing of the balls size. → Top surface microhardness for all of the SMATed samples increased significantly. → SMAT increased the surface roughness; increase in balls diameter increased the roughness. → SMAT using 2 mm balls increased the corrosion resistance significantly. - Abstract: Surface distinct deformed layers with thicknesses up to 150 μm, with grain size in the top most surface is in the nanometer scale, were produced on AZ91D magnesium alloy using surface mechanical attrition treatment (SMAT). Effects of different ball size on the properties of the SMATed samples were investigated. The microstructural, grain size, hardness and roughness features of the treated surfaces were characterized using optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), micro-indenter and digital roughness meter, respectively. Corrosion behavior of the samples was evaluated using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. It is found that the ball diameter does not have a significant effect on the top surface grain size, but the thickness of the deformed layer increases with increase of ball size, from 50 μm for 2 mm balls to 150 μm for 5 mm balls. For all of the SMATed samples, the top surface microhardness value increased significantly and did not show any obvious change for samples treated with different balls. Corrosion studies show that the corrosion resistance of the sample treated with 2 mm balls is higher than that of those treated with 3 mm and 5 mm balls. This can be mainly attributed to the surface roughness and defects density of the samples, which are higher for the SMATed samples with 3 mm and 5 mm balls compared with that of sample SMATed with 2 mm balls.

  11. Inhibiting effects of imidazole on copper corrosion in 1 M HNO3 solution

    International Nuclear Information System (INIS)

    Lee, Woo-Jin

    2003-01-01

    The present work deals with the inhibiting effects of imidazole on the pure copper (Cu) corrosion in 1 M HNO 3 solution analysing potentiodynamic polarisation curves, potentiostatic anodic current transient, AC impedance spectra and X-ray photoelectron spectra (XPS). By adding imidazole to HNO 3 solution, the polarisation curves showed decrease in the corrosion current and the cathodic current, suggesting that imidazole acts as an effective cathodic inhibitor to Cu corrosion. From the measured anodic current transients, it is inferred that the protective Cu-imidazole complex film is simultaneously formed with the Cu oxide in the presence of imidazole during the early stage of the anodic polarisation. Analysis of the AC impedance spectra revealed that the values of the charge transfer resistance R ct obtained in imidazole-containing HNO 3 solution were greater than that value in imidazole-free one and at the same time steadily increased with immersion time to the constant value. Contrarily, the capacitance value was abruptly lowered from the double layer capacitance C dl to the complex film capacitance C cf in the progress of immersion time. Furthermore, the Warburg coefficient σ value for the ion diffusion through the complex film was observed to increase with immersion time. This means that the Cu(N-OH) complex film becomes thicker during immersion in the HNO 3 solution with imidazole through the inward growth of the N-rich outer layer to the O-rich inner layer, as well validated by XPS. Based upon the experimental results, it is suggested that the Cu corrosion in 1 M HNO 3 solution is efficiently inhibited with the addition of imidazole by retarding both the charge transfer on cathodic sites of the Cu surface in the early stage of immersion time and the subsequent ion diffusion through the steadily growing complex film

  12. Effect of heat treatment and composition on stress corrosion cracking of steam generation tubing materials

    International Nuclear Information System (INIS)

    Kim, H. P.; Hwang, S. S.; Kuk, I. H.; Kim, J. S.; Oh, C. Y.

    1998-01-01

    Effects of heat treatment and alloy composition on stress corrosion cracking (SCC) of steam generator tubing materials have been studied in 40% NaOH at 315.deg.C at potential of +200mV above corrosion potential using C-ring specimen and reverse U bend specimen. The tubing materials used were commercial Alloy 600, Alloy 690 and laboratory alloys, Ni-χCr-10Fe. Commercial Alloy 600, Alloy 690 were mill annealed or thermally treated.Laboratory alloy Ni-χCr-10Fe, and some of Alloy 600 and Alloy 690 were solution annealed. Polarization curves were measured to find out any relationship between SCC susceptibility and electrochemical behaviour. The variation in thermal treatment of Alloy 600 and Alloy 690 had no effect on polarization behaviour probably due to small area fraction of carbide and Cr depletion zone near grain boundary. In anodic polarization curves, the first and second anodic peaks at about 170mV and about at 260mV, respectively, above corrosion potential were independent of Cr content, whereas the third peak at 750mV above corrosion potential and passive current density in-creased with Cr content. SCC susceptibility decreased with Cr content and thermal treatment producing semicontinuous grain boundary decoration. Examination of cross sectional area of C-ring specimen showed deep SCC cracks for the alloys with less than 17%Cr and many shallow attacks for alloy 690. The role of Cr content in steam generator tubing materials and grain boundary carbide on SCC were discussed

  13. Electrochemical corrosion of grinding media and effect of anions present in industrial waters; Corrosion electroquimica de medios de molienda y efecto de aniones presentes en aguas industriales

    Energy Technology Data Exchange (ETDEWEB)

    Magne, L.; Navarro, P.; Vargas, C.; Carrasco, S.

    2001-07-01

    The steel used in the minerals processing as grinding media (balls or bars), is an important input in terms of cost of the process. Considering the importance of the steel consumption in these processes, this work is guided to evaluate to laboratory scale the effect of the anions present in the industrial waters on the electrochemical corrosion of grinding media. Tests in electrochemical cell, were accomplished measuring potential and corrosion current to four electrodes that were manufactured using sufficiently pure sample of chalcopyrite, bornite, enargite and steel ball. The ions used in the tests were chlorides, sulfates, nitrates and carbonates in concentrations from 1 to 180 ppm in individual form or in mixtures, according to the levels measurement of these in industrial waters. (Author) 10 refs.

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

    Science.gov (United States)

    Shen, Zhanhui; Ren, Hongqiang; Xu, Ke; Geng, Jinju; Ding, Lili

    2013-01-01

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

  15. Effect of LiOH, NaOH and KOH on corrosion and oxide microstructure of Zr-based alloys

    International Nuclear Information System (INIS)

    Jeong, Y.H.; Kim, H.G.; Jung, Y.H.; Ruhmann, H.

    1999-01-01

    Long-term corrosion test, SIMS analysis, and TEM microstructural study were carried out to investigate the corrosion characteristics and mechanism of Zr alloys in alkali hydroxides. The corrosion tests were performed in solutions of LiOH, NaOH, KOH, RbOH, and CsOH at 350 deg. C for 500 days. SIMS analysis was performed for the specimens prepared to have an equal oxide thickness. TEM studies on the specimens with an equal oxide thickness in various solutions in both pre- and post-transition regimes were also conducted. The corrosion rate in alkali hydroxide solutions was observed to decrease as the ionic radius of alkali cation was increased. The penetration depth of cation into the oxide decreases with increasing the ionic radius of cation. Even though the oxide thickness was equal, the different oxide morphologies were observed in specimens. Namely, in LiOH solution the oxide morphology was transformed early from columnar to equiaxed structure. However, in KOH solution the columnar structure was maintained up to post-transition regime. Based on the corrosion test, SIMS analysis, and microstructural study, the cation is considered to control the corrosion in a alkali hydroxide solution and its effect is dependent on the concentration of alkali and the oxide thickness. The slight acceleration of the corrosion rate at a low concentration is thought to be caused by cation incorporation into oxide while the significant acceleration at a high concentration is due to the transformation of oxide microstructure that would be induced by cation incorporation. KOH was shown not to affect significantly the corrosion and the hydrogen pickup of Zircaloy. Therefore, it has a potential for PWR application only from the point of view of Zircaloy corrosion. (author)

  16. Analysis of the effects of corrosion probe on riser 241-AN-102-WST-16 during seismic event

    International Nuclear Information System (INIS)

    ZIADA, H.H.

    1998-01-01

    This analysis supports the installation activity of the corrosion probe in Tank 241-AN-102. The probe is scheduled to be installed in Riser 241-AN-102-WST-16 (formerly known as Riser 15B). The purpose of this analysis is to evaluate the potential effect of the corrosion probe on the riser during a credible seismic event. The previous analysis (HNF 1997a) considered only pump jet impingement loading

  17. Effects of solution treatment on mechanical properties and corrosion resistance of 4A duplex stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Panpan; Wang, Aiqin; Wang, Wenyan [Henan Univ. of Science and Technology, Luoyang (China). School of Material Science and Engineering; Xie, Jingpei [Henan Univ. of Science and Technology, Luoyang (China). Collaborative Innovation Center of Nonferrous Metals

    2018-02-15

    In this study, 4A duplex stainless steels were prepared via remelting in an intermediate frequency furnace and subsequently solution treated at different temperatures. The effects of solution treatment on the mechanical properties and corrosion resistance of 4A duplex stainless steel were investigated. Microstructures were characterized via optical microscopy and scanning electron microscopy. The mechanical properties were evaluated via hardness test, tensile test, and impact test experiments. The point corrosion resistance was studied via chemical immersion and potentiodynamic anodic polarization. The results showed that with increasing solution temperature in the range of 1223 - 1423 K, the tensile strength and hardness first decreased and then increased, and minimum values were obtained at 1323 K. The σ phase precipitated at the boundaries of the α/γ phases in samples solution treated at 1223 K, decreasing both impact energy and pitting potential of the experimental steels. When experimental steels were solution treated at 1373 K for 2 h, a suitable volume fraction of α/γ was uniformly distributed throughout the microstructure, and the steels exhibited optimal mechanical properties and pitting corrosion resistance.

  18. Effects of surface modification with hydroxyl terminated polydimethylsiloxane on the corrosion protection of polyurethane coating

    International Nuclear Information System (INIS)

    Jeon, Jae Hong; Shon, Min Young

    2014-01-01

    Polyurethane coating was designed to give a hydrophobic property on its surface by modifying it with hydroxyl terminated polydimethylsiloxane and then effects of surface hydrophobic tendency, water transport behavior and hence corrosion protectiveness of the modified polyurethane coating were examined using FT-IR/ATR spectroscopy, contact angle measurement and electrochemical impedance test. As results, the surface of polyurethane coating was changed from hydrophilic to hydrophobic property due primarily to a phase separation tendency between polyurethane and modifier by the modification. The phase separation tendency is more appreciable when modified by polydimethylsiloxane with higher content. Water transport behavior of the modified polyurethane coating decreased more in that with higher hydrophobic surface property. The decrease in the impedance modulus ⅠZⅠ at low frequency region in immersion test for polyurethane coatings was associated with the water transport behavior and surface hydrophobic properties of modified polyurethane coatings. The corrosion protectiveness of the modified polyurethane coated carbon steel generally increased with an increase in the modifier content, confirming that corrosion protectiveness of the modified polyurethane coating is well agreed with its water transport behavior

  19. The effect of cysteine on the corrosion of 304L stainless steel in sulphuric acid

    International Nuclear Information System (INIS)

    Silva, A.B.; Agostinho, S.M.L.; Barcia, O.E.; Cordeiro, G.G.O.; D'Elia, E.

    2006-01-01

    The effect of cysteine on the corrosion of 304L stainless steel in 1 mol l -1 H 2 SO 4 was studied using open-circuit potential measurements, anodic polarization curves, electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). All the electrochemical measurements obtained in the presence of low cysteine concentration (10 -6 -10 -5 mol l -1 ) presented the same behaviour as those obtained in the absence of cysteine, a passivated steel surface. However, for higher cysteine concentrations (10 -4 -10 -2 mol l -1 ), a different behaviour was observed: the corrosion potential stabilized at a more negative value; an active region was observed in the anodic polarization curves and the electrochemical impedance diagrams showed an inductive loop at lower frequencies and a much lower polarization resistance. These results show that the presence of cysteine at high concentration turns the surface of 304L stainless steel electrochemically active, probably dissolving the passivation layer and promoting the stainless steel anodic dissolution. SEM experiments performed after immersion experiments at corrosion potential were in good agreement with the electrochemical results

  20. Effects of water chemistry on flow accelerated corrosion and liquid droplet impingement

    International Nuclear Information System (INIS)

    Uchida, Shunsuke; Naitoh, Masanori; Okada, Hidetoshi; Uehara, Yasushi; Koshizuka, Seiichi; Lister, Derek H.

    2009-01-01

    Overlapping effects of flow dynamics and corrosion are important issues to determine reliability and lifetime of major structures and components in light water reactor plants. Flow accelerated corrosion (FAC) and liquid droplet impingement (LDI) are typical phenomena due to both interactions. In order to evaluation local wall thinning due to FAC and LDI, 6 step evaluation procedures have been proposed. (1) Flow pattern along the flow path was obtained with 1D computational flow dynamics (CFD) codes, (2) Corrosive conditions, e.g., oxygen concentration along the flow path were calculated with a hydrazine oxygen reaction code for FAC evaluation, while flow pattern of liquid droplets in high velocity steam and possibility of their collision to pipe inner surface were evaluated for LDI evaluation. (3) Mass transfer coefficient at the structure surface was calculated with 3D CFD codes for FAC evaluation, while frequency of oxide film rupture due to droplet collision was calculated for LDI evaluation. (4) High risk zones for FAC/LDI occurrence were evaluated by coupling major parameters, and then, (5) Wall thinning rates were calculated with the coupled model of static electrochemical analysis and dynamic double oxide layer analysis at the identified high FAC/LDI risk zone. (author)

  1. Effect of steam corrosion on core post strength loss: I. Low, chronic steam ingress rates

    International Nuclear Information System (INIS)

    Wichner, R.P.

    1976-10-01

    The purpose of the study was to assess the effect of chronic, low levels of steam ingress into the primary system of the HTGR on the corrosion, and consequent strength loss of the core support posts. The assessment proceeded through the following three steps: (1) The impurity composition in the primary system was estimated as a function of a range of steady ingress rates of from 0.001 to 1.0 g/sec, both by means of an analysis of the Dragon steam ingress experiment and a computer code, TIMOX, which treats the primary system as a well-mixed pot. (2) The core post burnoffs which result from 40-year exposures to these determined impurity atmospheres were then estimated using a corrosion rate expression derived from published ATJ-graphite corrosion rate data. Burnoffs were determined for both the core posts at the nominal and the maximum sustained temperature, estimated to be 90 0 C above nominal. (3) The final step involved assessment of the degree of strength loss resulting from the estimated burnoffs. An empirical equation was developed for this purpose which compares reasonably well with strength loss data for a number of different graphites and specimen geometries

  2. Effects of sulfate on heavy metal release from iron corrosion scales in drinking water distribution system.

    Science.gov (United States)

    Sun, Huifang; Shi, Baoyou; Yang, Fan; Wang, Dongsheng

    2017-05-01

    Trace heavy metals accumulated in iron corrosion scales within a drinking water distribution system (DWDS) could potentially be released to bulk water and consequently deteriorate the tap water quality. The objective of this study was to identify and evaluate the release of trace heavy metals in DWDS under changing source water conditions. Experimental pipe loops with different iron corrosion scales were set up to simulate the actual DWDS. The effects of sulfate levels on heavy metal release were systemically investigated. Heavy metal releases of Mn, Ni, Cu, Pb, Cr and As could be rapidly triggered by sulfate addition but the releases slowly decreased over time. Heavy metal release was more severe in pipes transporting groundwater (GW) than in pipes transporting surface water (SW). There were strong positive correlations (R 2  > 0.8) between the releases of Fe and Mn, Fe and Ni, Fe and Cu, and Fe and Pb. When switching to higher sulfate water, iron corrosion scales in all pipe loops tended to be more stable (especially in pipes transporting GW), with a larger proportion of stable constituents (mainly Fe 3 O 4 ) and fewer unstable compounds (β-FeOOH, γ-FeOOH, FeCO 3 and amorphous iron oxides). The main functional iron reducing bacteria (IRB) communities were favorable for the formation of Fe 3 O 4 . The transformation of corrosion scales and the growth of sulfate reducing bacteria (SRB) accounted for the gradually reduced heavy metal release with time. The higher metal release in pipes transporting GW could be due to increased Fe 6 (OH) 12 CO 3 content under higher sulfate concentrations. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Corrosion Effects on the Fatigue Crack Propagation of Giga-Grade Steel and its Heat Affected Zone in pH Buffer Solutions for Automotive Application

    Science.gov (United States)

    Lee, H. S.

    2018-03-01

    Corrosion fatigue crack propagation test was conducted of giga-grade steel and its heat affected zone in pH buffer solutions, and the results were compared with model predictions. Pure corrosion effect on fatigue crack propagation, particularly, in corrosive environment was evaluated by means of the modified Forman equation. As shown in results, the average corrosion rate determined from the ratio of pure corrosion induced crack length to entire crack length under a cycle load were 0.11 and 0.37 for base metal and heat affected zone, respectively, with load ratio of 0.5, frequency of 0.5 and pH 10.0 environment. These results demonstrate new interpretation methodology for corrosion fatigue crack propagation enabling the pure corrosion effects on the behavior to be determined.

  4. Effects of the Solid Solution Heat Treatment on the Corrosion Resistance Property of SSC13 Cast Alloy

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kuk-Jin [Hi-Sten Co., Ltd., Gimhae (Korea, Republic of); Lim, Su Gun [Gyeongsang National University, Jinju (Korea, Republic of); Pak, S. J. [Gachon BioNano Research Institute, Gachon University, Sungnam (Korea, Republic of)

    2015-04-15

    Recently, Stainless steels have been increasingly selected as the fitting or the valve materials of water pipes as the human health issue is getting higher and higher. Therefore, the connectors attached at pipes to deliver water are exposed to more severe environments than the pipes because crevice or galvanic corrosion is apt to occur at the fittings or the valves. Effects of the solid solution annealing, cooling rate after this heat treatment, and passivation on the corrosion properties of the shell mold casted SSC13 (STS304 alloy equivalent) were studied. The heating and quenching treatment more or less reduced hardness but effectively improved corrosion resistance. It was explained by the reduction of delta ferrite contents. Independent of heat treatment, the chemical passivation treatment also lowered corrosion rate but the improvement of corrosion resistance depended on temperature and time for passivation treatment indicating that the optimum conditions for passivation treatment were the bath temperature of 34 .deg. C and operating time of 10 minutes. Therefore it is suggested that the corrosion resistance of SSC13 can be effectively improved with the heat treatment, where SSC13 is heated for 10 minutes at 1120 °C and quenched and passivation treatment, where SSC13 is passivated for at least 10 seconds at 34 °C nitric acid solution.

  5. Effect of water flow rate and water chemistry on corrosion environment in reactor pressure vessel bottom of BWRs

    Energy Technology Data Exchange (ETDEWEB)

    Ichikawa, Nagayoshi; Hemmi, Yukio; Takagi, Junichi; Urata, Hidehiro [Toshiba Corp., Kawasaki, Kanagawa (Japan)

    1999-07-01

    To evaluate the corrosion environment at the bottom of the reactor pressure vessel in a BWR and the effect of hydrogen water chemistry on the corrosion of materials in the region, measurements of the corrosion potential of Type-304 stainless steel and nickel base alloy were made in a laboratory test loop. The effect of water chemistry on the corrosion potential of nickel base alloy is found to be similar to the effect on Type-304 stainless steel. Flow analysis and precise evaluations of the corrosion potential of materials in the bottom region were implemented. Corrosion potentials throughout the region were evaluated from the flow analysis results. At the jet pump outlet and shroud support leg, a rather large amount of hydrogen had to be added to reduce the potential. Conversely, a small amount of hydrogen was enough in the case of the stub tube of the control rod drive guide tubing and the ICM housings located in the center of the bottom region. (author)

  6. Effects of Welding Parameters on Strength and Corrosion Behavior of Dissimilar Galvanized Q&P and TRIP Spot Welds

    Directory of Open Access Journals (Sweden)

    Pasquale Russo Spena

    2017-12-01

    Full Text Available This study investigates the effects of the main welding parameters on mechanical strength and corrosion behavior of galvanized quenching and partitioning and transformation induced plasticity spot welds, which are proposed to assemble advanced structural car elements for the automotive industry. Steel sheets have been welded with different current, clamping force, and welding time settings. The quality of the spot welds has been assessed through lap-shear and salt spray corrosion tests, also evaluating the effects of metal expulsion on strength and corrosion resistance of the joints. An energy dispersive spectrometry elemental mapping has been used to assess the damage of the galvanized zinc coating and the nature of the corrosive products. Welding current and time have the strongest influence on the shear strength of the spot welds, whereas clamping force is of minor importance. However, clamping force has the primary effect on avoiding expulsion of molten metal from the nugget during the joining process. Furthermore, clamping force has a beneficial influence on the corrosion resistance because it mainly hinders the permeation of the corrosive environment towards the spot welds. Although the welded samples can exhibit high shear strength also when a metal expulsion occurs, this phenomenon should be avoided because it enhances the damage and vaporization of the protective zinc coating.

  7. Effect of water flow rate and water chemistry on corrosion environment in reactor pressure vessel bottom of BWRs

    International Nuclear Information System (INIS)

    Ichikawa, Nagayoshi; Hemmi, Yukio; Takagi, Junichi; Urata, Hidehiro

    1999-01-01

    To evaluate the corrosion environment at the bottom of the reactor pressure vessel in a BWR and the effect of hydrogen water chemistry on the corrosion of materials in the region, measurements of the corrosion potential of Type-304 stainless steel and nickel base alloy were made in a laboratory test loop. The effect of water chemistry on the corrosion potential of nickel base alloy is found to be similar to the effect on Type-304 stainless steel. Flow analysis and precise evaluations of the corrosion potential of materials in the bottom region were implemented. Corrosion potentials throughout the region were evaluated from the flow analysis results. At the jet pump outlet and shroud support leg, a rather large amount of hydrogen had to be added to reduce the potential. Conversely, a small amount of hydrogen was enough in the case of the stub tube of the control rod drive guide tubing and the ICM housings located in the center of the bottom region. (author)

  8. Chemical and structural effects of phosphorus on the corrosion behavior of ion beam mixed Fe-Cr-P alloys

    International Nuclear Information System (INIS)

    Demaree, J.D.; Was, G.S.; Sorensen, N.R.

    1992-01-01

    An experimental program was conducted to determine the mechanisms by which phosphorus affects the corrosion and passivation behavior of Fe-Cr-P alloys. To identify separately the effects of structure and chemistry on the corrosion behavior, thin films of Fe-10Cr-xP (0≤x≤35 at.%) were prepared by ion beam mixing. Films with a phosphorus content greater than approximately 20at.% were found to be entirely amorphous. Devitrification of the amorphous phase was accomplished by heating the samples to 450degC in an inert environment. Standard polarization tests of the sulfuric acid (with and without Cl - ) indicated that the films containing phosphorus were more corrosion resistant than Fe-10Cr, at both active and passive potentials. There was a monotonic relationship between the amount of phosphorus in the alloy and the corrosion resistance, with the open-circuit corrosion rate of Fe-10Cr-35P nearly four orders of magnitude lower than that of Fe-10Cr. Devitrification of the alloys had no significant effect on the corrosion rate, indicating that the primary effect of phosphorus is chemical in nature, and not structural. The passive oxides were depth-profiled using X-ray photoelectron spectroscopy, which indicated that phosphorus was a primary constituent, as phosphate. The presence of phosphate in the passive oxides reduced the overall corrosion rate directly, by suppressing anodic dissolution. The presence of phosphorus did enhance chromium enrichment in the oxide, but that was not thought to be the primary mechanism by which phosphorus increased the corrosion resistance. (orig.)

  9. Corrosion Effects on the I-V Characteristics of Electrically ...

    African Journals Online (AJOL)

    Experimental analysis on the effects of atmospheric Pollution and environmental degradation on the electrical properties of un-protected high tension cables, using copper and Aluminum wires of various diameters as case study, has been advanced. The analysis of the various data obtained in the course of the experiment, ...

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

    Science.gov (United States)

    Ramachandran, Rahul

    Concrete and metallic materials are widely used in construction and water industry. The interaction of both these materials with water and ice (or snow) produces undesirable results and is therefore of interest. Water that gets absorbed into the pores of dry concrete expands on freezing and can lead to crack formation. Also, the ice accretion on concrete surfaces such as roadways can have disastrous consequence. Metallic components used in the water industry undergo corrosion due to contact with aqueous corrosive solutions. Therefore, it is desirable to make concrete water/ice-repellent, and to make metallic surfaces corrosion-resistant. Recent advances in micro/nanotechnology have made it possible to design functional micro/nanostructured surfaces with micro/nanotopography providing low adhesion. Some examples of such surfaces are superhydrophobic surfaces, which are extremely water repellent, and icephobic surfaces, which have low ice adhesion, repel incoming water droplets before freezing, or delay ice nucleation. This dissertation investigates the effects of surface micro/nanotopography and small amplitude fast vibrations on the wetting and adhesion of concrete with the goal of producing hydrophobic and icephobic concrete, and on the wetting of metallic surfaces to prevent corrosion. The relationship between surface micro/nanotopography and small fast vibrations is established using the method of separation of motions. Both these small scale effects can be substituted by an effective force or energy. The structure-property relationships in materials and surfaces are established. Both vibrations as well as surface micro/nanopatterns can affect wetting properties such as contact angle and surface free energy. Hydrophobic engineered cementitious composite samples are produced by controlling their surface topography and surface free energy. The surface topography is controlled by varying the concrete mixture composition. The surface free energy of concrete is

  11. The effect of quench rate on the microstructure, mechanical properties, and corrosion behavior of U-6 Wt Pct Nb

    International Nuclear Information System (INIS)

    Eckelmeyer, K.H.; Romiy, A.D.; Weirick, L.J.

    1984-01-01

    The effect of cooling rate on microstructure, mechanical behavior, corrosion resistance, and subsequent age hardenability is discussed. Cooling rates in excess of 20 Ks -1 cause the parent γ-phase to transform martensitically to a niobium supersaturated variant of the α-phase. This phase exhibits low hardness and strength, high ductility, good corrosion resistance, and age hardenability. As cooling rate decreases from 10 Ks -1 to 0.2 Ks -1 , microstructural changes (consistent with spinodal decomposition) occur to an increasing extent. These changes produce increases in hardness and strength and decreases in ductility, corrosion resistance, and age hardenability. At cooling rates less than 0.2 Ks -1 the parent phase undergoes cellular decomposition to a coarse two-phase lamellar microstructure which exhibits intermediate strength and ductility, reduced corrosion resistance, and no age hardenability. An analysis of the cooling rates indicates that fully martensitic microstructures can be obtained in plates as thick as 50 mm

  12. Effects of laser shock processing on electrochemical corrosion resistance of ANSI 304 stainless steel weldments after cavitation erosion

    International Nuclear Information System (INIS)

    Zhang, L.; Zhang, Y.K.; Lu, J.Z.; Dai, F.Z.; Feng, A.X.; Luo, K.Y.; Zhong, J.S.; Wang, Q.W.; Luo, M.; Qi, H.

    2013-01-01

    Highlights: ► Weldments were done with laser shock processing impacts after cavitation erosion. ► Laser shock processing enhanced the erosion and corrosion resistance of weldments. ► Tensile residual stress and surface roughness decreased by laser shock processing. ► Microstructure was observed to explain the improvement by laser shock processing. ► Obvious passivation areas occurred with laser shock processing impacts. - Abstract: Effects of laser shock processing (LSP) on electrochemical corrosion resistance of weldments after cavitation erosion were investigated by X-ray diffraction (XRD) technology, scanning electron microscope (SEM), roughness tester and optical microscope (OM). Some main factors to influence erosion and corrosion of weldments, residual stresses, surface roughness, grain refinements and slip, were discussed in detail. Results show that LSP impacts can induce compressive residual stresses, decrease surface roughness, refine grains and generate the slip. Thus, the erosion and corrosion resistance with LSP impacts is improved.

  13. Effect of Sn addition on the corrosion behavior of Ti-7Cu-Sn cast alloys for biomedical applications.

    Science.gov (United States)

    Tsao, L C

    2015-01-01

    The aim of this study was to investigate the effects of Sn content on the microstructure and corrosion resistance of Ti7CuXSn (x=0-5 wt.%) samples. The corrosion tests were carried out in 0.9 wt.% NaCl solution at 25 °C. The electrochemical corrosion behavior of the Ti7CuXSn alloy samples was evaluated using potentiodynamic polarization curves, electrochemical impedance spectroscopy (EIS), and equivalent circuit analysis. The resulting impedance parameters and polarization curves showed that adding Sn improved the electrochemical corrosion behavior of the Ti7CuXSn alloy. The Ti7CuXSn alloy samples were composed of a dual-layer oxide consisting of an inner barrier layer and an outer porous layer. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Effect of magnesium hydride on the corrosion behavior of an AZ91 magnesium alloy in sodium chloride solution

    International Nuclear Information System (INIS)

    Chen Jian; Dong Junhua; Wang Jianqiu; Han Enhou; Ke Wei

    2008-01-01

    The effect of magnesium hydride on the corrosion behavior of an as-cast AZ91 alloy in 3.5 wt.% NaCl solution was investigated using gas collection method and potentiostatic test. The Pourbaix diagram of Mg-H 2 O system was built using thermodynamic calculation. It was possible that magnesium hydride could form in the whole pH range in theory. The experimental results showed that at cathodic region, magnesium hydride formed on surface, which was the controlling process for the corrosion behavior of AZ91 alloy; at anodic region and free corrosion potential, magnesium hydride model and partially protective film model, monovalent magnesium ion model and particle undermining model were responsible for the corrosion process of AZ91 alloy

  15. Effects of electrodeposition potential on the corrosion properties of bis-1,2-[triethoxysilyl] ethane films on aluminum alloy

    International Nuclear Information System (INIS)

    Hu Jiming; Liu Liang; Zhang Jianqing; Cao Chunan

    2006-01-01

    Bis-1,2-[triethoxysilyl] ethane (BTSE) films were prepared on 2024-T3 alloys by using potentiostatic method for corrosion protection. This work mainly investigated the effects of electrodeposition potential on the corrosion properties of silane films. Films prepared at cathodic potentials display an improvement in corrosion inhibition properties, while those prepared at anodic potentials present the deterioration of protectiveness. In the case of cathodic deposition, when the potential shifts negatively from the open-circuit potential (OCP), corrosion protection of the obtained films initially increases and then decreases, with the optimal deposition potential at -0.8 V/SCE. As indicated in scanning electron microscopy (SEM) images, films deposited at the optimum potential present the most uniform and compact morphologies. In addition, steady-state polarization and current-time curves have been also recorded on Al alloys in BTSE solutions during the deposition, respectively

  16. Effects of Ca on microstructure, mechanical and corrosion properties and biocompatibility of Mg-Zn-Ca alloys.

    Science.gov (United States)

    Yin, Ping; Li, Nian Feng; Lei, Ting; Liu, Lin; Ouyang, Chun

    2013-06-01

    Zn and Ca were selected as alloying elements to develop an Mg-Zn-Ca alloy system for biomedical application due to their good biocompatibility. The effects of Ca on the microstructure, mechanical and corrosion properties as well as the biocompatibility of the as-cast Mg-Zn-Ca alloys were studied. Results indicate that the microstructure of Mg-Zn-Ca alloys typically consists of primary α-Mg matrix and Ca₂Mg₆Zn₃/Mg₂Ca intermetallic phase mainly distributed along grain boundary. The yield strength of Mg-Zn-Ca alloy increased slightly with the increase of Ca content, whilst its tensile strength increased at first and then decreased. Corrosion tests in the simulated body fluid revealed that the addition of Ca is detrimental to corrosion resistance due to the micro-galvanic corrosion acceleration. In vitro hemolysis and cytotoxicity assessment disclose that Mg-5Zn-1.0Ca alloy has suitable biocompatibility.

  17. The effect of Sn on autoclave corrosion performance and corrosion mechanisms in Zr–Sn–Nb alloys

    International Nuclear Information System (INIS)

    Wei, J.; Frankel, P.; Polatidis, E.; Blat, M.; Ambard, A.; Comstock, R.J.; Hallstadius, L.; Hudson, D.; Smith, G.D.W.; Grovenor, C.R.M.; Klaus, M.; Cottis, R.A.; Lyon, S.; Preuss, M.

    2013-01-01

    The desire to improve the corrosion resistance of Zr cladding material for high burn-up has resulted in a general trend among fuel manufacturers to develop alloys with reduced levels of Sn. While commonly accepted, the reason for the improved corrosion performance observed for low-tin zirconium alloys in high-temperature aqueous environments remains unclear. High-energy synchrotron X-ray diffraction was used to characterize the oxides formed by autoclave exposure on Zr–Sn–Nb alloys with tin concentration ranging from 0.01 to 0.92 wt.%. The alloys studied included the commercial alloy ZIRLO® (ZIRLO® is a registered trademark of Westinghouse Electric Company LLC in the USA and may be registered in other countries throughout the world. All rights reserved. Unauthorized use is strictly prohibited.) and two variants of ZIRLO with significantly lower tin levels, referred to here as A-0.6Sn and A-0.0Sn. The nature of the oxide grown on tube samples from each alloy was investigated via cross-sectional scanning electron microscopy. Atom probe analysis of ZIRLO demonstrated that the tin present in the alloy passes into the oxide as it forms, with no significant difference in the Sn/Zr ratio between the two. Synchrotron X-ray diffraction measurements on the oxides formed on each alloy revealed that the monoclinic and tetragonal oxide phases display highly compressive in-plane residual stresses with the magnitudes dependent on the phase and alloy. The amount of tetragonal phase present and, more importantly, the level of tetragonal-to-monoclinic phase transformation both decrease with decreasing tin levels, suggesting that tin is a tetragonal oxide phase stabilizing element. It is proposed that in Zr–Nb–Sn alloys with low Sn, the tetragonal phase is mainly stabilized by very small grain size and therefore remains stable throughout the corrosion process. In contrast, alloys with higher tin levels can in addition grow larger, stress stabilized, tetragonal grains that

  18. Biocide and corrosion inhibition use in the oil and gas industry: Effectiveness and potential environmental impacts

    International Nuclear Information System (INIS)

    Brandon, D.M.; Fillo, J.P.; Morris, A.E.; Evans, J.M.

    1995-01-01

    Treatment chemicals are used in all facets of the natural gas industry (NGI) from well development through transmission and storage of natural gas. The multitude of chemicals used, combined with the dozens of chemical manufacturers and/or suppliers has lead to the availability of hundreds of possible chemical products. Because of the widespread use of chemical products and their numerous sources, the NGI needs access to consistent data regarding their effectiveness and potential environmental impacts. The objective of this work was to evaluate the effectiveness and potential environmental impacts of, chemical products used in the NGI. This assessment was initially focused on biocides and corrosion inhibitors and their use in the gas production, storage and transmission facilities, The overall approach was obtain the necessary data on chemical use and effectiveness directly from the oil and gas industry, supplemented with data/information obtained from the published literature. Five case histories of chemical use were documented and evaluated to assess the effectiveness of these chemicals. Potential environmental impacts were addressed by performing a screening environmental assessment on the use of glutaraldehyde, a widely used biocide. Prototype discharge scenarios were formulated and modeled to evaluate potential impacts to groundwater and surface water. The paper describes the basis for the study, provides an overview of chemical use with a focus on biocides and corrosion inhibitors, describes and assesses the specific uses of chemicals, and presents the results of the environmental assessment. It was found that various chemicals can be effective in treating microbiologically influenced corrosion and souring, but that the effectiveness of specific chemicals is dependent on the operational scenario and the site-specific conditions

  19. Effect of water chemistry improvement on flow accelerated corrosion in light-water nuclear reactor

    International Nuclear Information System (INIS)

    Sugino, Wataru; Ohira, Taku; Nagata, Nobuaki; Abe, Ayumi; Takiguchi, Hideki

    2009-01-01

    Flow Accelerated Corrosion (FAC) of Carbon Steel (CS) piping has been one of main issues in Light-Water Nuclear Reactor (LWRs). Wall thinning of CS piping due to FAC increases potential risk of pipe rupture and cost for inspection and replacement of damaged pipes. In particular, corrosion products generated by FAC of CS piping brought steam generator (SG) tube corrosion and degradation of thermal performance, when it intruded and accumulated in secondary side of PWR. To preserve SG integrity by suppressing the corrosion of CS, High-AVT chemistry (Feedwater pH9.8±0.2) has been adopted to Tsuruga-2 (1160 MWe PWR, commercial operation in 1987) in July 2005 instead of conventional Low-AVT chemistry (Feedwater pH 9.3). By the High-AVT adoption, the accumulation rate of iron in SG was reduced to one-quarter of that under conventional Low-AVT. As a result, a tendency to degradation of the SG thermal efficiency was improved. On the other hand, it was clarified that High-AVT is ineffective against Flow Accelerated Corrosion (FAC) at the region where the flow turbulence is much larger. By contrast, wall thinning of CS feed water pipes due to FAC has been successfully controlled by oxygen treatment (OT) for long time in BWRs. Because Magnetite film formed on CS surface under AVT chemistry has higher solubility and porosity in comparison with Hematite film, which is formed under OT. In this paper, behavior of the FAC under various pH and dissolved oxygen concentration are discussed based on the actual wall thinning rate of BWR and PWR plant and experimental results by FAC test-loop. And, it is clarified that the FAC is suppressed even under extremely low DO concentration such as 2ppb under AVT condition in PWR. Based on this result, we propose the oxygenated water chemistry (OWC) for PWR secondary system which can mitigate the FAC of CS piping without any adverse effect for the SG integrity. Furthermore, the applicability and effectiveness of this concept developed for FAC

  20. Effect of Mucin and Bicarbonate Ion on Corrosion Behavior of AZ31 Magnesium Alloy for Airway Stents

    Directory of Open Access Journals (Sweden)

    Yongseok Jang

    2014-08-01

    Full Text Available The biodegradable ability of magnesium alloys is an attractive feature for tracheal stents since they can be absorbed by the body through gradual degradation after healing of the airway structure, which can reduce the risk of inflammation caused by long-term implantation and prevent the repetitive surgery for removal of existing stent. In this study, the effects of bicarbonate ion (HCO3− and mucin in Gamble’s solution on the corrosion behavior of AZ31 magnesium alloy were investigated, using immersion and electrochemical tests to systematically identify the biodegradation kinetics of magnesium alloy under in vitro environment, mimicking the epithelial mucus surfaces in a trachea for development of biodegradable airway stents. Analysis of corrosion products after immersion test was performed using scanning electron microscopy (SEM, energy dispersive X-ray spectroscopy (EDX and X-ray diffraction (XRD. Electrochemical impedance spectroscopy (EIS was used to identify the effects of bicarbonate ions and mucin on the corrosion behavior of AZ31 magnesium alloys with the temporal change of corrosion resistance. The results show that the increase of the bicarbonate ions in Gamble’s solution accelerates the dissolution of AZ31 magnesium alloy, while the addition of mucin retards the corrosion. The experimental data in this work is intended to be used as foundational knowledge to predict the corrosion behavior of AZ31 magnesium alloy in the airway environment while providing degradation information for future in vivo studies.

  1. Effect of Mucin and Bicarbonate Ion on Corrosion Behavior of AZ31 Magnesium Alloy for Airway Stents.

    Science.gov (United States)

    Jang, Yongseok; Owuor, Daniel; Waterman, Jenora T; White, Leon; Collins, Boyce; Sankar, Jagannathan; Gilbert, Thomas W; Yun, Yeoheung

    2014-08-15

    The biodegradable ability of magnesium alloys is an attractive feature for tracheal stents since they can be absorbed by the body through gradual degradation after healing of the airway structure, which can reduce the risk of inflammation caused by long-term implantation and prevent the repetitive surgery for removal of existing stent. In this study, the effects of bicarbonate ion (HCO₃ - ) and mucin in Gamble's solution on the corrosion behavior of AZ31 magnesium alloy were investigated, using immersion and electrochemical tests to systematically identify the biodegradation kinetics of magnesium alloy under in vitro environment, mimicking the epithelial mucus surfaces in a trachea for development of biodegradable airway stents. Analysis of corrosion products after immersion test was performed using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD). Electrochemical impedance spectroscopy (EIS) was used to identify the effects of bicarbonate ions and mucin on the corrosion behavior of AZ31 magnesium alloys with the temporal change of corrosion resistance. The results show that the increase of the bicarbonate ions in Gamble's solution accelerates the dissolution of AZ31 magnesium alloy, while the addition of mucin retards the corrosion. The experimental data in this work is intended to be used as foundational knowledge to predict the corrosion behavior of AZ31 magnesium alloy in the airway environment while providing degradation information for future in vivo studies.

  2. Effect of Al and Ce oxide layers electrodeposited on OC4004 stainless steel on its corrosion characteristics in acid media

    International Nuclear Information System (INIS)

    Stoyanova, E.; Nikolova, D.; Stoychev, D.; Stefanov, P.; Marinova, T.

    2006-01-01

    The changes in the corrosion characteristics of stainless steel OC4004 in 0.1 M HNO 3 after electrodeposition of thin Al and Ce oxide films on it has been investigated. The Ce 2 O 3 -CeO 2 layers have been found to possess a pronounced stabilizing effect on the steel passive state and on its corrosion resistance, respectively, whereas the Al 2 O 3 layers do not improve considerably the corrosion behaviour of the SS/Al 2 O 3 system. A twice-lower corrosion current was observed with a ternary SS/Al 2 O 3 /Ce 2 O 3 -CeO 2 system in the passive region, while the zones of potentials, where the steel is in a stable passive state, are not changed. The obtained results permit the assumption that the cerium oxides layer acts as an effective cathode playing a determining role with respect to the improvement of the corrosion behavior of the steel. It has been concluded that when the SS/Al 2 O 3 /Ce 2 O 3 -CeO 2 system is used in media containing nitric acid, the corrosion will proceed at potentials where the passive state of steel would not be disturbed

  3. Adhesion of Bacillus subtilis and Pseudoalteromonas lipolytica to steel in a seawater environment and their effects on corrosion.

    Science.gov (United States)

    Guo, Zhangwei; Liu, Tao; Cheng, Y Frank; Guo, Na; Yin, Yansheng

    2017-09-01

    In a marine environment, Bacillus subtilis and Pseudoalteromonas lipolytica are commonly found in the biofilms adherent to low-alloy engineering steel, and they have distinct effects on corrosion. In the present work, this phenomenon was investigated through the study of various materials characterization methods, electrochemical techniques, and contact angle measurements. It was found that the surface film formed on the steel in the presence of B. subtilis was compact, uniform, free of cracks, and hydrophobic. However, the film formed in the presence of P. lipolytica was loose, rough, heterogeneous, and hydrophilic. The main components of the films formed in the presence of B. subtilis and P. lipolytica were polysaccharides/TasA amyloid fibers and proteins/carboxylic acid, respectively. The composition, structure, and properties of the surface films formed on the steel were associated with different effects on corrosion. The presence of B. subtilis enhances the steel's resistance to corrosion, whereas corrosion was increased by the presence of P. lipolytica. In short, the compact and hydrophobic biofilm of B. subtilis appears to inhibit the corrosion of steel, while the loose, hydrophilic film of P. lipolytica tends to induce pitting corrosion. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Effect of corrosion and sandblasting on the high cycle fatigue behavior of reinforcing B500C steel bars

    Directory of Open Access Journals (Sweden)

    Marina C. Vasco

    2017-10-01

    Full Text Available In a series of applications, steel reinforced concrete structures are subjected to fatigue loads during their service life, what in most cases happens in corrosive environments. Surface treatments have been proved to represent proper processes in order to improve both fatigue and corrosion resistances. In this work, the effect of corrosion and sandblasting on the high cycle fatigue behavior reinforcing steel bars is investigated. The investigated material is the reinforcing steel bar of technical class B500C, of nominal diameter of 12 mm. Steel bars specimens were first exposed to corrosion in alternate salt spray environment for 30 and 60 days and subjected to both tensile and fatigue tests. Then, a series of specimens were subjected to common sandblasting, corroded and mechanically tested. Metallographic investigation and corrosion damage evaluation regarding mass loss and martensitic area reduction were performed. Tensile tests were conducted after each corrosion exposure period prior to the fatigue tests. Fatigue tests were performed at a stress ratio, R, of 0.1 and loading frequency of 20 Hz. All fatigue tests series as well as tensile test were also performed for as received steel bars to obtain the reference behavior. The results have shown that sandblasting hardly affects the tensile behavior of the uncorroded material. The effect of sandblasting on the tensile behavior of pre-corroded specimens seems to be also limited. On the other hand, fatigue results indicate an improved fatigue behavior for the sandblasted material after 60 days of corrosion exposure. Martensitic area reductions, mass loss and depth of the pits were significantly smaller for the case of sandblasted materials, which confirms an increased corrosion resistance

  5. Monitoring Microbially Influenced Corrosion

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel

    and diffusional effects and unreliable corrosion rates, when biofilm and ferrous sulphide corrosion products cover the steel surface. Corrosion rates can be overestimated by a factor of 10 to 100 by electrochemical techniques. Weight loss coupons and ER are recommended as necessary basic monitoring techniques......Abstract Microbially influenced corrosion (MIC) of carbon steel may occur in media with microbiological activity of especially sulphate-reducing bacteria (SRB). The applicability and reliability of a number of corrosion monitoring techniques for monitoring MIC has been evaluated in experiments....... EIS might be used for detection of MIC as the appearance of very large capacitances can be attributed to the combined ferrous sulphide and biofilm formation. Capacitance correlates directly with sulphide concentration in sterile sulphide media. Keywords: Corrosion monitoring, carbon steel, MIC, SRB...

  6. Effect of cold-rolling on pitting corrosion of 304 austenitic stainless steel

    International Nuclear Information System (INIS)

    Peguet, L.; Malki, B.; Baroux, B.

    2004-01-01

    Full text of publication follows: This paper deals with a not very often investigated topic on relation between cold-working and stainless steels localized corrosion resistance. It is devoted to the study of the cold-rolling effects on the pitting corrosion behavior of a 304 stainless steel grade in chloride containing aqueous electrolytes. It focus particularly on the analysis of metastable pitting transients observed at Open Circuit Potential using an experimental protocol including two identical working electrodes connected through a zero-impedance. As received the used specimens were heat-treated at 1100 C for 30 s and cold-rolled at 10%, 20%, 30% up to a final reduction pass of 70% inducing a large amount of α'-martensite. Then, current-potential fluctuations measurements were performed at OCP in NaCl 0.1 M + FeCl 3 2.10 -4 M containing aqueous solution during 24 h from the immersion time. As expected, a detrimental effect on corrosion behavior induced by cold rolling has been confirmed. Surprisingly, this is a nonlinear effect as a function of cold-rolling rate which controverts the hypothesis that strain induced martensite is the principal factor to explain this kind of sensibilizing. In particular, the results show a maximum of the metastable pits initiation frequency at 20% of cold-rolling rate. Moreover, the passive film/electrochemical double layer resistance and capacity deduced from the transients study show an analog nonlinear behavior. So, the transfer resistance show a minimum around 10-20% of cold-rolling rate where one can assume an increase of the electrons transfer kinetics through the interface. Conversely, the interfacial capacity is the highest at 20% of cold-rolling rate. Finally, It is expected a combined effect of the cold-rolled induced martensite and the dislocations arrangement via the mechano-chemical theory discussed by Gutman. (authors)

  7. Effects of laser remelting on microstructures and immersion corrosion performance of arc sprayed Al coating in 3.5% NaCl solution

    Science.gov (United States)

    Sun, Ze; Zhang, Donghui; Yan, Baoxu; Kong, Dejun

    2018-02-01

    An arc sprayed aluminum (Al) coating on S355 steel was processed using a laser remelting (LR). The microstructures, chemical element composition, and phases of the obtained Al coating were analyzed using a field mission scanning electronic microscope (FESEM), energy dispersive spectrometer (EDS), and X-ray diffractometer (XRD), respectively, and the residual stresses were measured using an X-ray diffraction stress tester. The immersion corrosion tests and potentiodynamic polarization of Al coating in 3.5% NaCl solution were performed to investigate the effects of LR on its immersion corrosion behaviors, and the corrosion mechanism of Al coating was also discussed. The results show that the arc sprayed Al coating is composed of Al phase, while that by LR is composed of Al-Fe and AlO4FeO6 phases, and the porosities and cracks in the arc sprayed Al coating are eliminated by LR, The residual stress of arc sprayed Al coating is -5.6 ± 18 MPa, while that after LR is 137.9 ± 12 MPa, which deduces the immersion corrosion resistance of Al coating. The corrosion mechanism of arc sprayed Al coating is pitting corrosion and crevice corrosion, while that by LR is uniform corrosion and pitting corrosion. The corrosion potential of arc sprayed Al coating by LR shifts positively, which improves its immersion corrosion resistance.

  8. [The effect of epigallocatechin gallate (EGCG) on the surface properties of nickel-chromium dental casting alloys after electrochemical corrosion].

    Science.gov (United States)

    Qiao, Guang-yan; Zhang, Li-xia; Wang, Jue; Shen, Qing-ping; Su, Jian-sheng

    2014-08-01

    To investigate the effect of epigallocatechin gallate (EGCG) on the surface properties of nickel-chromium dental alloys after electrochemical corrosion. The surface morphology and surface structure of nickel-chromium dental alloys were examined by stereomicroscope and scanning electron microscopy before and after electrochemical tests in 0 g/L and 1.0 g/L EGCG artificial saliva. The surface element component and chemical states of nickel-chromium dental alloys were analyzed by X-ray photoelectron spectrograph after electrochemical tests in 0 g/L and 1.0 g/L EGCG artificial saliva. More serious corrosion happened on the surface of nickel-chromium alloy in 1.0 g/L EGCG artificial saliva than in 0 g/L EGCG. The diameters of corrosion pits were smaller, and the dendrite structure of the alloy surface was not affected in 0 g/L EGCG. While the diameters of corrosion pits were larger, the dendritic interval of the alloy surface began to merge, and the dendrite structure was fuzzy in 1.0 g/L EGCG. In addition, the O, Ni, Cr, Be, C and Mo elements were detected on the surface of nickel-chromium alloys after sputtered for 120 s in 0 g/L EGCG and 1.0 g/L EGCG artificial saliva after electrochemical corrosion, and the surface oxides were mainly NiO and Cr(2)O(3). Compared with 0 g/L EGCG artificial saliva, the content of O, NiO and Cr(2)O(3) were lower in 1.0 g/L EGCG. The results of surface morphology and the corrosion products both show that the corrosion resistance of nickel-chromium alloys become worse and the oxide content of corrosion products on the surface reduce in 1.0 g/L EGCG artificial saliva.

  9. Detrimental effect of Air pollution, Corrosion on Building Materials and Historical Structures

    OpenAIRE

    N. Venkat Rao; M. Rajasekhar; Dr. G. Chinna Rao

    2016-01-01

    The economy of any country would be drastically changed if there were no corrosion. The annual cost of corrosion world wise is over 3 % of the worlds GDP. As pet the sources available, India losses $ 45 billion every year on account of corrosion of infrastructure, Industrial machinery and other historical heritage. Keeping this critical and alarming situation in view, this paper focuses on how all these forms of corrosion affect building materials and historical structures. It als...

  10. The Effect of Applied Tensile Stress on Localized Corrosion in Sensitized AA5083

    Science.gov (United States)

    2015-09-01

    corrosion, but if exposed to elevated temperature for prolonged periods of time the alloy becomes sensitized. Since the β phase is more anodic than the...degree of localized corrosion for sensitized AA5083 under an applied tensile stress. AA5083 is an aluminum -magnesium alloy that experiences severe...direction. 14. SUBJECT TERMS Aluminum alloy , AA5083, IGSCC, intergranular stress corrosion cracking, localized corrosion, sensitized aluminum 15

  11. Effects of Fe and Cr on corrosion behavior of ZrFeCr alloys in 500 oC steam

    International Nuclear Information System (INIS)

    Wang Jun; Fan Hongyuan; Xiong Ji; Liu Hong; Miao Zhi; Ying Shihao; Yang Gang

    2011-01-01

    Research highlights: Amount and size of SPP will effect the corrosion resistance of Zr alloy at 500 o C/10.3 MPa. - Abstract: A study of the corrosion behaviors of ZrFeCr alloy and the influence of microstructure on corrosion resistance are described by X-ray diffraction and scanning electron microscope in this paper. The results show that several ZrFeCr alloys exhibit protective behavior throughout the test and oxide growth is stable and protective. The best alloy has the composition Zr1.0Fe0.6Cr. Fitting of the weight gain curves for the protective oxide alloys in the region of protective behavior, it showed nearly cubic behavior for the most protective alloys. The Zr1.0Fe0.6Cr has the more laves Zr(Fe,Cr) 2 precipitate in matrix and it has the better corrosion resistance. The Zr0.2Fe0.1Cr has little precipitate, the biggest hydrogen absorption and the worst corrosion resistance. The number of precipitates and the amount of hydrogen absorption in Zr alloy plays an important role on corrosion resistance behaviors in 500 o C/10.3 MPa steam.

  12. Corrosion rate of API 5L Gr. X60 multipurpose steel pipeline under combined effect of water and crude oil

    Science.gov (United States)

    Miao, Jian; Wang, Qiang

    2016-09-01

    Multipurpose pipeline is often seriously corroded during its service life, and the phenomenon is more prominent once the transportation medium is changed. Electrochemical polarization curves and impedance spectroscopy of the API 5L Gr. X60 steel pipeline's corrosion process in sedimentary water with different ion types and their concentrations have been studied in this work. The results showed that the corrosion rates were found to be 0.00418 and 0.00232 mm/a for pure water and crude oil, respectively. However, for the mixtures of water and crude oil (with water content increased from 0.2 vol% to 10 vol%), the corrosion rate increased consistently and reached a maximum value of 0.15557 mm/a for 10 vol% water in crude oil. The effect of the concentration of various ions, namely, chloride, bicarbonate and sulfate in (oil/water) mixtures on the corrosion rate was characterized by weight-loss method. The results showed that with increasing the ions' concentrations, the corresponding exchange current density increased significantly. The results were further supported by the observations of corrosion morphology using scanning electron microscopy and are helpful in devising guidelines which would help in reducing corrosion in multipurpose transport pipelines involving a change of transported medium during their service life.

  13. Effect of inclusions modified by rare earth elements (Ce, La) on localized marine corrosion in Q460NH weathering steel

    International Nuclear Information System (INIS)

    Liu, Chao; Revilla, Reynier I.; Liu, Zhiyong; Zhang, Dawei; Li, Xiaogang; Terryn, Herman

    2017-01-01

    Highlights: •The initial stages of the pitting corrosion of Q460NH steel in a marine environment was studied. •Two different types of inclusions formed in the Q460NH steel after adding rare earth. •Both types of inclusions showed a lower Volta potential than the matrix. •Pitting corrosion was induced by the dissolution of inclusions rather than the matrix. •Inclusions containing (RE)AlO 3 dissolved completely as a result of the acidic solution formed in the pits. -- Abstract: In this work the initial stages of the pitting corrosion in Q460NH weathering steel in a marine environment was studied. To elucidate the effects of inclusions modified by rare earth (RE) elements on pitting corrosion, field emission-scanning electron microscopy-energy dispersive spectrometry (FE-SEM-EDS) analyses, scanning Kelvin probe force microscopy (SKPFM) tests, and a series of immersion tests were conducted. Two main types of inclusions were formed in the steel, and different pit morphologies were observed. The pitting corrosion was initiated by the dissolution of (RE) 2 O 2 S-(RE)xSy in both types of inclusions due to the lower potential of this phase compared to the matrix, which indicated that the inclusions in the Q460NH weathering steel had a lower pitting corrosion resistance than the matrix.

  14. Effect of nano-TiO{sub 2} particles size on the corrosion resistance of alkyd coating

    Energy Technology Data Exchange (ETDEWEB)

    Deyab, M.A., E-mail: hamadadeiab@yahoo.com; Keera, S.T.

    2014-08-01

    The coating system containing various sizes (∼10, 50, 100, 150 nm) of nano-TiO{sub 2} were prepared and investigated for corrosion protection of carbon steel in 1.0 M H{sub 2}SO{sub 4} using polarization, EIS and transmission electron microscopy (TEM) techniques. It was found that nano-TiO{sub 2} particles improved the corrosion resistance of alkyd coatings. The corrosion resistance occurs via physical adhesion on the metal surface. O{sub 2} and H{sub 2}O permeability of coating decreased with decrease in the nano-TiO{sub 2} size. The inhibition efficiency was found to increase with decreasing the size of nano-TiO{sub 2} and with decreasing the temperature. - Highlights: • Nano-TiO{sub 2} coating were prepared and used for corrosion protection of C-steel. • Nano-TiO{sub 2} particles in coating are effective to improve the corrosion resistance. • Nano-TiO{sub 2} coating inhibit both anodic and cathodic reactions. • Corrosion inhibition efficiency increases with decrease in the size of nano-TiO{sub 2}. • O{sub 2} and H{sub 2}O permeability of coating decreased with decrease in the nano-TiO{sub 2} size.

  15. The effect of β-FeOOH on the corrosion behavior of low carbon steel exposed in tropic marine environment

    International Nuclear Information System (INIS)

    Ma Yuantai; Li Ying; Wang Fuhui

    2008-01-01

    The atmospheric corrosion performance of carbon steel exposed in Wanning area, which located in the south part of China with tropic marine environment characters, was studied at different exposure periods (up to 2 years). To investigate the effect of β-FeOOH on the corrosion behavior of carbon steel in high chloride ion environment, rust layer was analyzed by using infrared spectroscopy, scanning electron microscope, X-ray diffraction, and the rusted steel was measured by electrochemical impedance spectroscopy method. The weight loss test indicated that the corrosion rate of carbon steel sharply increased during 6 months' exposure and gradually reduced after longer exposure. The results of rust analysis revealed that the underlying corrosion performance of the carbon steel was dependent on the inherent properties of the rust layers formed under different conditions such as composition and structure. Among all the iron oxide, β-FeOOH exerted significant influence. The presence of a monolayer of the rust as well as β-FeOOH accelerated the corrosion process during the initial exposure stage. EIS data implied that β-FeOOH in the inner layer was gradually consumed and transformed to γ-Fe 2 O 3 in the wet-dry cycle, which was beneficial to protect the substrate and reduced the corrosion rate

  16. Modeling the Effect of Nail Corrosion on the Lateral Strength of Joints

    Science.gov (United States)

    Samuel L. Zelinka; Douglas R. Rammer

    2012-01-01

    This article describes a theoretical method of linking fastener corrosion in wood connections to potential reduction in lateral shear strength. It builds upon published quantitative data of corrosion rates of metals in contact with treated wood for several different wood preservatives. These corrosion rates are then combined with yield theory equations to calculate a...

  17. Effect of Cl on the corrosive wear of AISI 321 stainless steel in ...

    Indian Academy of Sciences (India)

    Unknown

    2002-07-25

    Jul 25, 2002 ... The passivation current oscillates tremendously due to the coexistence of passive and active ions in the solution with 0⋅2 mol/l Cl–. 3.2 Corrosive wear behaviour of 321 stainless steel in Cl– + H2SO4 solution at free corrosion and passive potentials. The relationship between corrosive wear rate and Cl–.

  18. Corrosion allowances for sodium heated steam generators: evaluation of effects and extrapolation to component life time

    Energy Technology Data Exchange (ETDEWEB)

    Grosser, E E; Menken, G

    1975-07-01

    Steam generator tubes are subjected to two categories of corrosion; metal/sodium reactions and metal/water-steam interactions. Referring to these environmental conditions the relevant parameters are discussed. The influences of these parameters on the sodium corrosion and water/steam-reactions are evaluated. Extrapolations of corrosion values to steam generator design conditions are performed and discussed in detail. (author)

  19. Corrosion allowances for sodium heated steam generators: evaluation of effects and extrapolation to component life time

    International Nuclear Information System (INIS)

    Grosser, E.E.; Menken, G.

    1975-01-01

    Steam generator tubes are subjected to two categories of corrosion; metal/sodium reactions and metal/water-steam interactions. Referring to these environmental conditions the relevant parameters are discussed. The influences of these parameters on the sodium corrosion and water/steam-reactions are evaluated. Extrapolations of corrosion values to steam generator design conditions are performed and discussed in detail. (author)

  20. Effect of hydrazine on general corrosion of carbon and low-alloyed steels in pressurized water reactor secondary side water

    Energy Technology Data Exchange (ETDEWEB)

    Järvimäki, Sari [Fortum Ltd, Loviisa Power Plant, Loviisa (Finland); Saario, Timo; Sipilä, Konsta [VTT Technical Research Centre of Finland Ltd., Nuclear Safety, P.O. Box 1000, FIN-02044 VTT (Finland); Bojinov, Martin, E-mail: martin@uctm.edu [Department of Physical Chemistry, University of Chemical Technology and Metallurgy, Kl. Ohridski Blvd, 8, 1756 Sofia (Bulgaria)

    2015-12-15

    Highlights: • The effect of hydrazine on the corrosion of steel in secondary side water investigated by in situ and ex situ techniques. • Oxide grown on steel in 100 ppb hydrazine shows weaker protective properties – higher corrosion rates. • Possible explanation of the accelerating effect of higher concentrations of hydrazine on flow assisted corrosion offered. - Abstract: The effect of hydrazine on corrosion rate of low-alloyed steel (LAS) and carbon steel (CS) was studied by in situ and ex situ techniques under pressurized water reactor secondary side water chemistry conditions at T = 228 °C and pH{sub RT} = 9.2 (adjusted by NH{sub 3}). It is found that hydrazine injection to a maximum level of 5.06 μmol l{sup −1} onto surfaces previously oxidized in ammonia does not affect the corrosion rate of LAS or CS. This is confirmed also by plant measurements at Loviisa NPP. On the other hand, hydrazine at the level of 3.1 μmol l{sup −1} decreases markedly the amount and the size of deposited oxide crystals on LAS and CS surface. In addition, the oxide grown in the presence of 3.1 μmol l{sup −1} hydrazine is somewhat less protective and sustains a higher corrosion rate compared to an oxide film grown without hydrazine. These observations could explain the accelerating effect of higher concentrations of hydrazine found in corrosion studies of LAS and CS.

  1. Effect of flow conditions on flow accelerated corrosion in pipe bends

    International Nuclear Information System (INIS)

    Mazhar, H.; Ching, C.Y.

    2015-01-01

    Flow Accelerated Corrosion (FAC) in piping systems is a safety and reliability problem in the nuclear industry. In this study, the pipe wall thinning rates and development of surface roughness in pipe bends are compared for single phase and two phase annular flow conditions. The FAC rates were measured using the dissolution of test sections cast from gypsum in water with a Schmidt number of 1280. The change in location and levels of maximum FAC under single phase and two phase flow conditions are examined. The comparison of the relative roughness indicates a higher effect for the surface roughness in single phase flow than in two phase flow. (author)

  2. Effect of Water Vapor on High-Temperature Corrosion under Conditions Mimicking Biomass Firing

    DEFF Research Database (Denmark)

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

    2015-01-01

    The variable flue gas composition in biomass-fired plants, among other parameters, contributes to the complexityof high-temperature corrosion of materials. Systematic parameter studies are thus necessary to understand the underlyingcorrosion mechanisms. This paper investigates the effect of water...... (H2O) vapor content in the flue gas on the high-temperaturecorrosion of austenitic stainless steel (TP 347H FG) under laboratory conditions, to improve the understanding of corrosionmechanisms. Deposit-coated and deposit-free samples were isothermally exposed for 72 h in a synthetic flue gas...... previouslyreported findings suggest that an increase in the water vapor content will cause competitive adsorption on active sites....

  3. The effect of crack branching on the residual lifetime of machine components containing stress corrosion cracks

    International Nuclear Information System (INIS)

    Magdowski, R.M.; Uggowitzer, P.J.; Speidel, M.O.

    1985-01-01

    A comparison is presented of theoretical, numerical and experimental investigations concerning the effect of crack branching on the reduction of stress intensity at the tip of single cracks. The results indicate that the division of a single crack into n branches reduces the stress intensity at the branch tips by a factor of about 1/√n. This permits branched cracks to grow to larger depths before becoming critical. The implication is that longer residual lifetimes and longer operating times between inspections can be calculated for machine components with growing branched stress corrosion cracks. (author)

  4. Effect of cold working and annealing on stress corrosion cracking of AISI 304 stainless steel

    International Nuclear Information System (INIS)

    Yeon, Y.M.; Kwun, S.I.

    1983-01-01

    A study was made of the effects of cold working and annealing on the stress corrosion cracking of AISI 304 stainless steel in boiling 42% MgCl 2 solution. When the 60% or 76% of yield stress was applied, the resistance to SCC showed maximum at 30% of cold work. However, when the same load was applied to the annealed specimens after cold working, the resistance to SCC decreased abruptly at 675degC annealing. The fracture mode changed mode change mixed → intergranular → transgranular as the amount of cold work increased. (Author)

  5. 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.

  6. Effect of layerwise structural inhomogeneity on stress- corrosion cracking of steel tubes

    Science.gov (United States)

    Perlovich, Yu A.; Krymskaya, O. A.; Isaenkova, M. G.; Morozov, N. S.; Fesenko, V. A.; Ryakhovskikh, I. V.; Esiev, T. S.

    2016-04-01

    Based on X-ray texture and structure analysis data of the material of main gas pipelines it was shown that the layerwise inhomogeneity of tubes is formed during their manufacturing. The degree of this inhomogeneity affects on the tendency of tubes to stress- corrosion cracking under exploitation. Samples of tubes were cut out from gas pipelines located under various operating conditions. Herewith the study was conducted both for sections with detected stress-corrosion defects and without them. Distributions along tube wall thickness for lattice parameters and half-width of X-ray lines were constructed. Crystallographic texture analysis of external and internal tube layers was also carried out. Obtained data testifies about considerable layerwise inhomogeneity of all samples. Despite the different nature of the texture inhomogeneity of gas pipeline tubes, the more inhomogeneous distribution of texture or structure features causes the increasing of resistance to stress- corrosion. The observed effect can be explained by saturation with interstitial impurities of the surface layer of the hot-rolled sheet and obtained therefrom tube. This results in rising of lattice parameters in the external layer of tube as compared to those in underlying metal. Thus, internal layers have a compressive effect on external layers in the rolling plane that prevents cracks opening at the tube surface. Moreover, the high mutual misorientation of grains within external and internal layers of tube results in the necessity to change the moving crack plane, so that the crack growth can be inhibited when reaching the layer with a modified texture.

  7. Effect of pulse current parameters on the mechanical and corrosion properties of anodized nanoporous aluminum coatings

    International Nuclear Information System (INIS)

    Mohammadi, Iman; Ahmadi, Shahab; Afshar, Abdollah

    2016-01-01

    In this study, the effects of pulse current parameters on corrosion resistance and mechanical properties of anodized coatings were evaluated. Hardness measurements, polarization and electrochemical impedance spectroscopy tests were employed to investigate the mechanical properties and corrosion behavior of these coatings. Also, field emission scanning electron microscopy (FE-SEM) was used to analyze the surface morphology and microstructure of the coatings. It was found that the properties of anodized coatings were dependent on various parameters, among which, time, temperature and pulse current parameters (current density limit, frequency and duty cycle) were optimized. Analysis of Variance (ANOVA) was conducted in order to optimize the results of designed experiments for predicting the hardness of anodic Al_2O_3 coatings. Experimental results showed that the temperature and the interaction of quadratic behavior of minimum current density with frequency and duty cycle were the most important factors influencing the hardness of these coatings. It was indicated that the highest hardness value of 642 HV was attained at the maximum and minimum current densities of 4.4, 1.27 A/dm"2, respectively, a frequency of 82 Hz, procedure time of 27.2 min, duty cycle of 80.2% and the bath temperature of 13.5 °C. In addition, the FE-SEM micrographs showed that the highest density is obtained through the mentioned optimum conditions. Moreover, the electrochemical tests revealed that the highest polarization resistance obtained at optimum conditions was more than 20 times greater than the other samples. - Highlights: • Electrolyte temperature undesirably influences the hardness of anodized coatings. • Maximum hardness of coatings was evaluated by optimization of effective parameters. • The diameter of alumina nanotube considerably affects hardness of anodized coating. • R_P of the sample formed at optimum condition was at least 20 times more than others. • Porosity is the

  8. Effect of pulse current parameters on the mechanical and corrosion properties of anodized nanoporous aluminum coatings

    Energy Technology Data Exchange (ETDEWEB)

    Mohammadi, Iman, E-mail: imanmohammadi68@gmail.com; Ahmadi, Shahab; Afshar, Abdollah

    2016-11-01

    In this study, the effects of pulse current parameters on corrosion resistance and mechanical properties of anodized coatings were evaluated. Hardness measurements, polarization and electrochemical impedance spectroscopy tests were employed to investigate the mechanical properties and corrosion behavior of these coatings. Also, field emission scanning electron microscopy (FE-SEM) was used to analyze the surface morphology and microstructure of the coatings. It was found that the properties of anodized coatings were dependent on various parameters, among which, time, temperature and pulse current parameters (current density limit, frequency and duty cycle) were optimized. Analysis of Variance (ANOVA) was conducted in order to optimize the results of designed experiments for predicting the hardness of anodic Al{sub 2}O{sub 3} coatings. Experimental results showed that the temperature and the interaction of quadratic behavior of minimum current density with frequency and duty cycle were the most important factors influencing the hardness of these coatings. It was indicated that the highest hardness value of 642 HV was attained at the maximum and minimum current densities of 4.4, 1.27 A/dm{sup 2}, respectively, a frequency of 82 Hz, procedure time of 27.2 min, duty cycle of 80.2% and the bath temperature of 13.5 °C. In addition, the FE-SEM micrographs showed that the highest density is obtained through the mentioned optimum conditions. Moreover, the electrochemical tests revealed that the highest polarization resistance obtained at optimum conditions was more than 20 times greater than the other samples. - Highlights: • Electrolyte temperature undesirably influences the hardness of anodized coatings. • Maximum hardness of coatings was evaluated by optimization of effective parameters. • The diameter of alumina nanotube considerably affects hardness of anodized coating. • R{sub P} of the sample formed at optimum condition was at least 20 times more than others

  9. Effect of mechanical pre-loadings on corrosion resistance of chromium-electroplated steel rods in marine environment

    Science.gov (United States)

    Shubina Helbert, Varvara; Dhondt, Matthieu; Homette, Remi; Arbab Chirani, Shabnam; Calloch, Sylvain

    2018-03-01

    Providing high hardness, low friction coefficient, as well as, relatively good corrosion resistance, chromium-plated coatings (∼20 μm) are widely used for steel cylinder rods in marine environment. However, the standardized corrosion test method (ISO 9227, NSS) used to evaluate efficiency of this type of coatings does not take into account in-service mechanical loadings on cylinder rods. Nevertheless, the uniform initial network of microcracks in chromium coating is changing under mechanical loadings. Propagation of these microcracks explains premature corrosion of the steel substrate. The aim of the study was to evaluate relationship between mechanical loadings, propagation of microcracks network and corrosion resistance of chromium coatings. After monotonic pre-loading tests, it was demonstrated by microscopic observations that the microcracks propagation started at stress levels higher than the substrate yield stress (520 MPa). The microcracks become effective, i.e. they have instantly undergone through the whole coating thickness to reach the steel substrate. The density of effective microcracks increases with the total macroscopic level, i.e. the intercrack distance goes from 60 ± 5 μm at 1% of total strain to approximately 27 ± 2 μm at 10%. Electrochemical measurements have shown that the higher the plastic strain level applied during mechanical loading, the more the corrosion potential of the sample decreased until reaching the steel substrate value of approximately ‑0.65 V/SCE after 2 h of immersion. The polarization curves have also highligthed an increase in the corrosion current density with the strain level. Therefore, electrochemical measurements could be used to realize quick and comprehensive assesment of the effect of monotonic pre-loadings on corrosion properties of the chromium coating.

  10. 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

  11. On the corrosion and soiling effects on materials by air pollution in Athens, Greece

    Directory of Open Access Journals (Sweden)

    C. Tzanis

    2011-12-01

    Full Text Available In the frame of the European project, entitled MULTI-ASSESS, specimens of structural metals, glass, stone and concrete materials were exposed to air pollution at a station, which was installed for this purpose on a building, located in the centre of Athens. The main purpose of this project was to determine the corrosion and soiling effects of air pollution on materials. A set of the specimens was exposed in a position that was sheltered from rain and partly from wind, and another set was exposed in unsheltered positions on the roof of the above said building. In addition, other specimens were exposed at different heights on the same building, in order to investigate for the first time the corrosion and soiling effects on various materials as a function of height. For the determination of these effects, chemical analysis of the specimens was performed and basic parameters as the weight change, the layer thickness and the optical properties were calculated. Finally, the results obtained are discussed and their plausible interpretation is attempted.

  12. Reinforced concrete bridges: effects due to corrosion and concrete young modulus variation

    Directory of Open Access Journals (Sweden)

    P. T. C. Mendes

    Full Text Available Most of the Brazilian bridges of federal road network are made of reinforced concrete and are more than 30 years old, with little information about the mechanical properties of their constitutive materials. Along the service life of these bridges much modification occurred on vehicles load and geometry and in design standard. Many of them show signs of concrete and steel deterioration and their stability conditions are unknown. With the aim of contributing to the structural evaluation of reinforced concrete bridges it was decided to analyze the stresses in reinforced concrete bridge sections to verify the effects due to reinforcement corrosion and variation of the concrete Young modulus on the stress distribution regarding several load patterns and cracking effects in a representative bridge of the Brazilian road network with different longitudinal reinforcement taxes and two concrete Young modulus, Ec and 0.5Ec, and with different percentage of reinforcement corrosion. The analysis considered two finite element models: frame and shell elements as well as solid elements. The results indicate that these variation effects are more significant in reinforcement bars than in concrete.

  13. Contradictory effect of chromate inhibitor on corrosive wear of aluminium alloy

    International Nuclear Information System (INIS)

    Pokhmurskii, V.I.; Zin, I.M.; Vynar, V.A.; Bily, L.M.

    2011-01-01

    Research highlights: → Corrosive wear of aluminium alloy in inhibited artificial acid rain was studied. → Tribometer with linear reciprocating ball-on-flat geometry was used.→ Corrosion potential, polarization current and friction coefficient were measured. → Chromate decreases corrosion of aluminium alloy under wear conditions. → Chromate in general accelerates corrosive wear of the alloy in acid rain. - Abstract: The corrosive wear of D16T aluminium alloy in artificial acid rain was studied. A special tribometer with the linear reciprocating ball-on-flat geometry was used. The setup allows to measure simultaneously an open circuit potential, to carry out potentiostatic and potentiodynamic polarization studies of the alloy corrosion and to record the friction coefficient. It was established that the addition of strontium chromate inhibitor to the working environment decreases an electrochemical corrosion of the aluminium alloy under wear conditions, but in general accelerates its destruction due to insufficient wear resistance of a formed surface film.

  14. Effects of external stresses on hot corrosion behavior of stainless steel TP347HFG

    International Nuclear Information System (INIS)

    Fu, Jiapeng; Zhou, Qulan; Li, Na; Liu, Zhuhan; Liu, Taisheng

    2016-01-01

    Highlights: • Hot corrosion tests of TP347HFG under different stresses were conducted. • The corrosion resistance was strengthened by the exertion of tensile stresses. • External stresses promoted faster formation of the protective Cr_2O_3 layer. • Specimens under critical stress 40 MPa condition present the best resistance. - Abstract: Hot corrosion experiments of alloy TP347HFG under different stresses were conducted. Corroded specimens were examined by means of corrosion products, morphology and compositional changes in corrosion scales. The corrosion behavior was strongly associated with the formation of oxides layers. The corrosion resistance was strengthened by the external stress. It seemed that the exertion of stresses caused many micro cracks and defects, which acted as faster and easier diffusion paths for Cr atoms to diffuse to the surface, and thus, promote faster formation of the protective Cr_2O_3 oxide layer. Critical stress 40 MPa was found, specimens under which present the best resistance.

  15. Uniform and pitting corrosion events induced by SCN- anions on Al alloys surfaces and the effect of UV light

    International Nuclear Information System (INIS)

    Amin, Mohammed A.

    2011-01-01

    The influence of the alloying elements on the uniform and pitting corrosion processes of Al-6061, Al-4.5%Cu, Al-7.5%Cu, Al-6%Si and Al-12%Si alloys was studied in 0.50 M KSCN solution at 25 o C. Open-circuit potential, Tafel polarization, linear polarization resistance (LPR) and ICP-AES measurements were used to study the uniform corrosion process on the surfaces of the tested alloys. Cyclic polarization, potentiostatic current-time transients and impedance techniques were employed for pitting corrosion studies. Obtained results were compared with pure Al. Passivation kinetics of the tested Al samples were also studied as a function of applied potential, [SCN - ] and sample composition by means of potentiostatic current transients. The induction time, after which the growth of stable pits occurs, decreased with increasing applied potential and [SCN - ]. Regarding to uniform corrosion, alloyed Cu was found to enhance the corrosion rate, while alloyed Si suppressed it. Alloying elements of the tested samples diminished pitting attack to an extent depending on the percentage of the alloying element in the sample. Among the investigated materials, Al-Si alloys exhibited the highest corrosion resistance towards uniform and pitting corrosion processes in KSCN solutions. The passive and dissolution behaviour of Al was also studied under the conditions of continuous illumination (300-450 nm) based on cyclic polarization and potentiostatic techniques. The incident photons had a little influence on pit initiation and a marked effect on pit growth. These explained in terms of a photo-induced modification of the passive film formed on the anode surface, which render it more resistant to pitting. The effects of UV photons energy and period of illumination on the morphology of the pitted surfaces were also studied.

  16. Oesophageal strictures caused by the ingestion of corrosive agents: effectiveness of balloon dilatation in children

    Energy Technology Data Exchange (ETDEWEB)

    Doo, E.-Y. [Department of Radiology, Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center (Korea, Republic of); Shin, J.H. [Department of Radiology, Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center (Korea, Republic of)], E-mail: jhshin@amc.seoul.kr; Kim, J.H.; Song, H.-Y. [Department of Radiology, Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center (Korea, Republic of)

    2009-03-15

    Aim: To evaluate the safety and clinical effectiveness of balloon dilatation in children for oesophageal strictures caused by the ingestion of corrosive agents. Materials and methods: The study comprised 11 children (median age 6 years; range 1-14 years) with oesophageal strictures caused by corrosive agents, who underwent a total of 36 balloon dilatation sessions. The technical and clinical success, recurrence of dysphagia, complications, and primary and secondary patency rates were retrospectively evaluated. Results: Technical success was achieved in 91% of patients and in 97% of balloon dilatation sessions. Clinical success (defined as improved food intake and reduced dysphagia within 1 month of the first balloon dilatation session) was achieved in 64% of patients (7/11). During the mean 35-month follow-up period (range 1-89 months), 10 (91%) patients experienced recurrence. Oesophageal rupture (types 1 or 2) occurred in 45% of patients and in 31% of balloon dilatation sessions. Primary patency rates at 6 months and 1, 2, 3, 4, and 5 years were 36, 27, 14, 14, 14, and 14%, respectively. Secondary patency rates at 6 months and 1, 2, 3, 4, and 5 years were 82, 82, 82, 56, 42, and 42%, respectively. The secondary patency rate was higher than the primary patency rate (p < 0.05). Conclusion: The present study examined oesophageal balloon dilatation for paediatric oesophageal strictures caused by the ingestion of corrosive agents. Although the technical success rate was high and there were no deaths, the clinical success rate was low owing to a high recurrence rate. However, repeated balloon dilatations resulted in an acceptable secondary patency rate.

  17. Investigation of duty cycle effect on corrosion properties of electrodeposited calcium phosphate coatings

    Energy Technology Data Exchange (ETDEWEB)

    Azem, Funda Ak, E-mail: funda.ak@deu.edu.tr [Dokuz Eylul University, Faculty of Engineering, Department of Metallurgical and Materials Engineering, Buca, 35390 Izmir (Turkey); Delice, Tulay Koc, E-mail: tulaykocdelice@gmail.com [Dokuz Eylul University, The Graduate School of Natural and Applied Sciences, Buca, 35390 Izmir (Turkey); Ungan, Guler, E-mail: gulerungan@hotmail.com [Es Group, Izmir (Turkey); Cakir, Ahmet, E-mail: ahmet.cakir@deu.edu.tr [Dokuz Eylul University, Faculty of Engineering, Department of Metallurgical and Materials Engineering, Buca, 35390 Izmir (Turkey)

    2016-11-01

    The bioceramic calcium phosphate (CaP) is frequently used for improving bone fixation in titanium medical implants and thus increasing lifetime of the implant. It is known that the application of CaP coatings on metallic implant devices offers the possibility of combining the strength of the metals and the bioactivity of the ceramic materials. Many different techniques are available for producing CaP coatings. Electrochemical deposition method is widely used because of its ease of operation parameters, low temperature requirement, reproducibility and suitability for coating complex structures. This technique allows obtaining CaP coatings which promote bone in growth during the first healing period leading to permanent fixation. Electrochemical pulse technique is an alternative to calcium phosphate deposition techniques usually employed to cover orthopedic or dental titanium implant surfaces. Additionally, pulse electrodeposition technique can produce more uniform and denser CaP coatings on metallic implants. In this study, CaP based coatings were produced by electrochemical pulse technique on Ti6Al4V substrates. The resulting CaP deposits were investigated by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Corrosion properties of the CaP coatings were also investigated. The results showed that various duty cycle ranges have remarkably effect on morphology, crystallinity and corrosion properties of the produced CaP coatings. - Highlights: • Electrodeposited CaP based coating were produced by pulse deposition technique. • The pulsed electrodeposited coatings produced under 30% and 50% duty cycles were exhibited better corrosion resistance. • Produced coatings consist of irregular flake-like structure and compact network with fine needles.

  18. Effects of Mg on corrosion resistance of Al galvanically coupled to Fe

    International Nuclear Information System (INIS)

    Hyun, Youngmin; Kim, Heesan

    2013-01-01

    Effects of magnesium and pH on corrosion of aluminum galvanically coupled to iron have studied by using potentio- dynamic and static tests for polarization curves, Mott-Schottky test for analysis of semiconductor property, and GD-AES and XPS for film analysis. Pitting potential was sensitive to magnesium as an alloying element but not to pH, while passive current was sensitive to pH but not to magnesium. It was explained with, instead of point defect model (PDM), surface charge model describing that the ingression of chloride depends on the state of surface charge and passive film at film/solution interface is affected by pH. In addition, galvanic current of aluminum electrically coupled to iron was not affected by magnesium in pH 8.4, 0.2M citrate solution but was increased by magnesium at the solution of pH 9.1. The galvanic current at pH 9.1 increased with time at the initial stage and after the exposure of about 200 minute, decreased and stabilized. The behavior of the galvanic current was related with the concentration of magnesium at the surface. It agreed with the depletion of magnesium at the oxide surface by using glow discharge atomic emission spectroscopy (GD-AES). In addition, pitting potential of pure aluminum was reduced in neutral pH solution where chloride ion maybe are competitively adsorbed on pure aluminum. It was confirmed by the exponential decrease of pitting potential with log of [Cl - ] around 0.025 M of [Cl - ] and linear decrease of the pitting potential. From the above results, unlike magnesium, alloying elements with higher electron negativity, lowering isoelectric point (ISE), are recommended to be added to improve pitting corrosion resistance of aluminum and its alloys in neutral solutions as well as their galvanic corrosion resistance in weakly basic solutions

  19. Effects of Mg on corrosion resistance of Al galvanically coupled to Fe

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-01-15

    Effects of magnesium and pH on corrosion of aluminum galvanically coupled to iron have studied by using potentio- dynamic and static tests for polarization curves, Mott-Schottky test for analysis of semiconductor property, and GD-AES and XPS for film analysis. Pitting potential was sensitive to magnesium as an alloying element but not to pH, while passive current was sensitive to pH but not to magnesium. It was explained with, instead of point defect model (PDM), surface charge model describing that the ingression of chloride depends on the state of surface charge and passive film at film/solution interface is affected by pH. In addition, galvanic current of aluminum electrically coupled to iron was not affected by magnesium in pH 8.4, 0.2M citrate solution but was increased by magnesium at the solution of pH 9.1. The galvanic current at pH 9.1 increased with time at the initial stage and after the exposure of about 200 minute, decreased and stabilized. The behavior of the galvanic current was related with the concentration of magnesium at the surface. It agreed with the depletion of magnesium at the oxide surface by using glow discharge atomic emission spectroscopy (GD-AES). In addition, pitting potential of pure aluminum was reduced in neutral pH solution where chloride ion maybe are competitively adsorbed on pure aluminum. It was confirmed by the exponential decrease of pitting potential with log of [Cl{sup -}] around 0.025 M of [Cl{sup -}] and linear decrease of the pitting potential. From the above results, unlike magnesium, alloying elements with higher electron negativity, lowering isoelectric point (ISE), are recommended to be added to improve pitting corrosion resistance of aluminum and its alloys in neutral solutions as well as their galvanic corrosion resistance in weakly basic solutions.

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

    Directory of Open Access Journals (Sweden)

    Леонід Кімович Лещинськiй

    2017-06-01

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

  1. Stochastic theory of fatigue corrosion

    Science.gov (United States)

    Hu, Haiyun

    1999-10-01

    A stochastic theory of corrosion has been constructed. The stochastic equations are described giving the transportation corrosion rate and fluctuation corrosion coefficient. In addition the pit diameter distribution function, the average pit diameter and the most probable pit diameter including other related empirical formula have been derived. In order to clarify the effect of stress range on the initiation and growth behaviour of pitting corrosion, round smooth specimen were tested under cyclic loading in 3.5% NaCl solution.

  2. Evaluation of the inhibitive effect of some plant extracts on the acid corrosion of mild steel

    International Nuclear Information System (INIS)

    Oguzie, Emeka E.

    2008-01-01

    Corrosion inhibition of mild steel in 2 M HCl and 1 M H 2 SO 4 by extracts of selected plants was investigated using a gasometric technique at temperatures of 30 and 60 deg. C. The studied plants materials include leaf extracts Occimum viridis (OV), Telferia occidentalis (TO), Azadirachta indica (AI) and Hibiscus sabdariffa (HS) as well as extracts from the seeds of Garcinia kola (GK). The results indicate that all the extracts inhibited the corrosion process in both acid media by virtue of adsorption and inhibition efficiency improved with concentration. Synergistic effects increased the inhibition efficiency in the presence of halide additives. Inhibition mechanisms were deduced from the temperature dependence of the inhibition efficiency as well as from assessment of kinetic and activation parameters that govern the processes. Comparative analysis of the inhibitor adsorption behaviour in 2 M HCl and 1 M H 2 SO 4 as well as the effects of temperature and halide additives suggest that both protonated and molecular species could be responsible for the inhibiting action of the extracts

  3. Evaluation of the inhibitive effect of some plant extracts on the acid corrosion of mild steel

    Energy Technology Data Exchange (ETDEWEB)

    Oguzie, Emeka E. [Electrochemistry and Materials Science Research Laboratory, Department of Chemistry, Federal University of Technology, PMB 1526, Owerri (Nigeria)], E-mail: oguziemeka@yahoo.com

    2008-11-15

    Corrosion inhibition of mild steel in 2 M HCl and 1 M H{sub 2}SO{sub 4} by extracts of selected plants was investigated using a gasometric technique at temperatures of 30 and 60 deg. C. The studied plants materials include leaf extracts Occimum viridis (OV), Telferia occidentalis (TO), Azadirachta indica (AI) and Hibiscus sabdariffa (HS) as well as extracts from the seeds of Garcinia kola (GK). The results indicate that all the extracts inhibited the corrosion process in both acid media by virtue of adsorption and inhibition efficiency improved with concentration. Synergistic effects increased the inhibition efficiency in the presence of halide additives. Inhibition mechanisms were deduced from the temperature dependence of the inhibition efficiency as well as from assessment of kinetic and activation parameters that govern the processes. Comparative analysis of the inhibitor adsorption behaviour in 2 M HCl and 1 M H{sub 2}SO{sub 4} as well as the effects of temperature and halide additives suggest that both protonated and molecular species could be responsible for the inhibiting action of the extracts.

  4. Tri-fuel (diesel-biodiesel-ethanol) emulsion characterization, stability and the corrosion effect

    Science.gov (United States)

    Low, M. H.; Mukhtar, N. A. M.; Yohaness Hagos, Ftwi; Noor, M. M.

    2017-10-01

    This paper presents the result of experimenting emulsified tri-fuel in term of stability, physico-chemical properties and corrosion effect on three common metals. The results were interpreted in terms of the impact of five minutes emulsification approach. Tri-fuel emulsions were varied in proportion ratio consist of biodiesel; 0%, 5%, 10%, and ethanol; 5%, 10%, 15%. Fuel characterization includes density, calorific value, flash point, and kinematic viscosity. Flash point of tri-fuel emulsion came with range catalog. Calorific value of tri-fuel emulsion appeared in declining pattern as more ethanol and biodiesel were added. Biodiesel promoted flow resistance while ethanol with opposite effect. 15% ethanol content in tri-fuel emulsion separated faster than 10% ethanol content but ethanol content with 5% yield no phase separation at all. Close cap under static immersion with various ratio of tri-fuel emulsions for over a month, corrosiveness attack was detected via weight loss technique on aluminum, stainless steel and mild steel.

  5. Improvement of corrosion resistance of Ni−Mo alloy coatings: Effect of heat treatment

    Energy Technology Data Exchange (ETDEWEB)

    Mousavi, R., E-mail: mousavi@scu.ac.ir [Department of Materials Science and Engineering, Shiraz University, Shiraz (Iran, Islamic Republic of); Bahrololoom, M.E. [Department of Materials Science and Engineering, Shiraz University, Shiraz (Iran, Islamic Republic of); Deflorian, F.; Ecco, L. [Department of Industrial Engineering, University of Trento, via Sommarive 9, Trento (Italy)

    2016-02-28

    Graphical abstract: - Highlights: • Conjunction between SEM, EIS, and Tafel measurements to obtain a coat with dense morphology and without crack. • An inverse Hall-Petch effect is observed after annealing the coatings, i.e. the coatings get harder as the grain size is increased by increasing annealing temperature up to 600 {sup o}C. • Heat treatment can improve the mechanical and corrosion properties of coatings. - Abstract: In this paper, Ni−Mo alloy coatings were deposited from bath containing sodium citrate, nickel sulphate, and sodium molybdate. Essentially, this work is divided into two mains parts: (i) the optimization on the coatings deposition parameters and (ii) the effect of the heat treatment. Polarization curves and electrochemical impedance spectroscopy were acquired using potentiostat/galvanostat and a frequency response analyzer, respectively. Morphology and chemical composition of the coatings were investigated by scanning electron microscopy and energy dispersive spectroscopy, respectively. Polarization curves at different condition revealed that electroplating at temperature 40 {sup o}C, pH 9 provides a dense coating with high efficiency. Following the optimization of the deposition parameters, the coatings were annealed at 200, 400, and 600 {sup o}C for 25 min. The results showed that the coatings obtained at temperature 40 {sup o}C, pH 9, and annealing at 600 {sup o}C has the highest corrosion resistance and microhardness.

  6. Intraoral corrosion of self-ligating metallic brackets and archwires and the effect on friction

    Science.gov (United States)

    Tima, Lori Lynn

    The purpose of this study was to investigate how the frictional coefficient was affected due to intraoral use. A secondary aim of this study was to determine whether or not there was a relationship between corrosion of orthodontic alloys and friction via scanning electron microscopic qualitative analysis. Orthodontic brackets and 0.019 x 0.025 inch stainless steel archwires were collected and divided into three groups of n=10: used bracket and used wires (UBUW), used brackets and new wires (UBNW), and new brackets and new wires (NBNW). New materials were as-received from the manufacturer, and used materials were clinically used bracket and wires collected from patients following orthodontic treatment. Archwires were pulled through bracket slots at a rate of 0.5mm/min while friction forces were measured. Following a cleaning process, the surface topography of the bracket slots was examined under a scanning electron microscope (SEM). Based on a 1-factor MANOVA, there was no significant group effect (all p>0.05) on frictional forces. Partial eta squared values indicated that intraoral exposure had only a small effect on frictional forces (≤ 3%). Qualitative analysis of SEM images did not show an association between surface characteristics of the bracket slots and magnitude of frictional force. Results suggest that surface corrosion from intraoral use does not significantly affect friction at the bracket wire interface.

  7. Inhibition effect of fatty amides with secondary compound on carbon steel corrosion in hydrodynamic condition

    Science.gov (United States)

    Ibrahim, I. M.; Jai, J.; Daud, M.; Hashim, Md A.

    2018-03-01

    The inhibition effect demonstrates an increase in the inhibition performance in presence of a secondary compound in the inhibited solution. This study introduces fatty amides as corrosion inhibitor and oxygen scavenger, namely, sodium sulphite as a secondary compound. The main objective is to determine the synergistic inhibition effect of a system by using fatty amides together with sodium sulphite in hydrodynamic condition. The synergistic inhibition of fatty amides and sodium sulphite on corrosion of carbon steel in 3.5 wt% sodium chloride solution had been studied using linear polarization resistance method and scanning electron microscope (SEM) with energy dispersive X-ray spectroscopy (EDX). Electrochemical measurement was carried out using rotating cylinder electrode at different flow regimes (static, laminar, transition and turbulent). Linear polarization resistance experiments showed the changes in polarization resistance when the rotation speed increased. It found that, by addition of fatty amides together with sodium sulphite in test solution, the inhibition efficiency increased when rotation speed increased. The results collected from LPR experiment correlated with results from SEM-EDX. The results showed inhibition efficiency of system was enhanced when fatty amides and oxygen scavengers were present together.

  8. [The effect of bacteria reaction time on corrosion properties of Ni-Cr alloys pretreated with different proteins].

    Science.gov (United States)

    Qi, Han-quan; Zhang, Song-mei; Qian, Chao; Yuan-Li, Zheng

    2015-12-01

    To evaluate the corrosion properties of absorbed protein on the surface of NiCr alloys, and provide experimental base for corrosion resistance of dental casting alloys. NiCr alloy specimens were divided into 3 groups: one group was exposed to the artificial saliva(control group), and the other 2 groups were exposed to the artificial saliva with 1% bovine serum albumin(BSA), or 0.22% lysozyme(LSZ). Group of BSA and group of LSZ were the experimental group. Specimens in 3 groups were cultured in solution of Streptococcus mutans for 12 h, 24 h, 36 h and 48h, and investigated with electrochemical impedance spectroscopy measurement(EIS) and potentiodynamic polarization measurement(POT) to determine the corrosion resistance of the alloys. The data was analyzed with SPSS 17.0 software package. The results indicated that the corrosion resistance of both BSA group and LSZ group were higher than that of the control group (Pcorrosion resistance of BSA group and LSZ group had no significant difference (P>0.05), but was still higher than that of the control group. After 36 h culture time, the control group and the BSA group had no statistical difference in corrosion resistance (P>0.05), while the LSZ group had the poorest corrosion resistance. When the culture time extended to 48 h, the control group had a better corrosion resistance compared with the BAS group and the LSZ group(Pcorrosion properties than LSZ group. The potentiodynamic polarization curve and electrochemical impedance spectroscopy had similar results. The adhesion of BSA and LSZ on the surface of the NiCr alloys in the early time could effectively inhibit the corrosive effect of Streptococcus mutans. The LSZ had better effect than BSA. With the continuing role of bacteria and the consumption of the absorb protein, the corrosion resistance of NiCr alloys toward Streptococcus mutans becomes lower than the alloys without absorb protein, which demonstrated that the adhesion of protein would change the surface

  9. The Effect of Corrosion on the Seismic Behavior of Buried Pipelines and a Remedy for Their Seismic Retrofit

    International Nuclear Information System (INIS)

    Hosseini, Mahmood; Salek, Shamila; Moradi, Masoud

    2008-01-01

    The effect of corrosion phenomenon has been investigated by performing some sets of 3-Dimensional Nonlinear Time History Analysis (3-D NLTHA) in which soil structure interaction as well as wave propagation effects have been taken into consideration. The 3-D NLTHA has been performed by using a finite element computer program, and both states of overall and local corrosions have been considered for the study. The corrosion has been modeled in the computer program by introducing decreased values of either pipe wall thickness or modulus of elasticity and Poisson ratio. Three sets of 3-component accelerograms have been used in analyses, and some appropriate numbers of zeros have been added at the beginning of records to take into account the wave propagation in soil and its multi-support excitation effect. The soil has been modeled by nonlinear springs in longitudinal, lateral, and vertical directions. A relatively long segment of the pipeline has been considered for the study and the effect of end conditions has been investigated by assuming different kinds end supports for the segment. After studying the corroded pipeline, a remedy has been considered for the seismic retrofit of corroded pipe by using a kind of Fiber Reinforced Polymers (FRP) cover. The analyses have been repeated for the retrofitted pipeline to realize the adequacy of FRP cover. Numerical results show that if the length of the pipeline segment is large enough, comparing to the wave length of shear wave in the soil, the end conditions do not have any major effect on the maximum stress and strain values in the pipe. Results also show that corrosion can lead to the increase in plastic strain values in the pipe up to 4 times in the case of overall corrosion and up to 20 times in the case of local corrosion. The satisfactory effect of using FRP cover is also shown by the analyses results, which confirm the decrease of strain values to 1/3

  10. The Effect of Corrosion on the Seismic Behavior of Buried Pipelines and a Remedy for Their Seismic Retrofit

    Science.gov (United States)

    Hosseini, Mahmood; Salek, Shamila; Moradi, Masoud

    2008-07-01

    The effect of corrosion phenomenon has been investigated by performing some sets of 3-Dimensional Nonlinear Time History Analysis (3-D NLTHA) in which soil structure interaction as well as wave propagation effects have been taken into consideration. The 3-D NLTHA has been performed by using a finite element computer program, and both states of overall and local corrosions have been considered for the study. The corrosion has been modeled in the computer program by introducing decreased values of either pipe wall thickness or modulus of elasticity and Poisson ratio. Three sets of 3-component accelerograms have been used in analyses, and some appropriate numbers of zeros have been added at the beginning of records to take into account the wave propagation in soil and its multi-support excitation effect. The soil has been modeled by nonlinear springs in longitudinal, lateral, and vertical directions. A relatively long segment of the pipeline has been considered for the study and the effect of end conditions has been investigated by assuming different kinds end supports for the segment. After studying the corroded pipeline, a remedy has been considered for the seismic retrofit of corroded pipe by using a kind of Fiber Reinforced Polymers (FRP) cover. The analyses have been repeated for the retrofitted pipeline to realize the adequacy of FRP cover. Numerical results show that if the length of the pipeline segment is large enough, comparing to the wave length of shear wave in the soil, the end conditions do not have any major effect on the maximum stress and strain values in the pipe. Results also show that corrosion can lead to the increase in plastic strain values in the pipe up to 4 times in the case of overall corrosion and up to 20 times in the case of local corrosion. The satisfactory effect of using FRP cover is also shown by the analyses results, which confirm the decrease of strain values to 1/3.

  11. The effect of discontinuities on the corrosion behaviour of copper canisters

    International Nuclear Information System (INIS)

    King, F.

    2004-03-01

    Discontinuities may remain in the weld region of copper canisters following the final closure welding and inspection procedures. Although the shell of the copper canister is expected to exhibit excellent corrosion properties in the repository environment, the question remains what impact these discontinuities might have on the long-term performance and service life of the canister. A review of the relevant corrosion literature has been carried out and an expert opinion of the impact of these discontinuities on the canister lifetime has been developed. Since the amount of oxidant in the repository is limited and the maximum wall penetration is expected to be 2 O/Cu(OH) 2 film at a critical electrochemical potential determines where and when pits initiate, not the presence of pit-shaped surface discontinuities. The factors controlling pit growth and death are well understood. There is evidence for a maximum pit radius for copper in chloride solutions, above which the small anodic: cathodic surface area ratio required for the formation of deep pits cannot be sustained. This maximum pit radius is of the order of 0.1-0.5 mm. Surface discontinuities larger than this size are unlikely to propagate as pits, and pits generated from smaller discontinuities will die once they reach this maximum size. Death of propagating pits will be compounded by the decrease in oxygen flux to the canister as the repository environment becomes anoxic. Surface discontinuities could impact the SCC behaviour either through their effect on the local environment or via stress concentration or intensification. There is no evidence that surface discontinuities will affect the initiation of SCC by ennoblement of the corrosion potential or the formation of locally aggressive conditions. Stress concentration at pits could lead to crack initiation under some circumstances, but the stress intensity factor for the resultant cracks, or for pre-existing crack-like discontinuities, will be smaller than the

  12. effect of pre effect of pre-ageing thermal conditions on the corrosion

    African Journals Online (AJOL)

    eobe

    solution heat treatment and ageing) and Double thermal ageing treatmen ... Corrosion of aluminium alloys lead to impairment of ... of passive protection by coating or by means of active ... The Al-Si-Mg alloy with the chemical composition as .... Heat. Transfer and Solidification Behavior of Modified A356 alloy. Journal of ...

  13. Effect of Rare Earth on Corrosion Products and Impedance Behavior of AZ91 Magnesium Alloy Under Dry-wet Cycles

    Directory of Open Access Journals (Sweden)

    ZHAO Xi

    2017-04-01

    Full Text Available The effect of mischmetal of lanthanum and cerium on the composition and structure of the corrosion products on the surface of AZ91 Mg alloy in deicing salt solution under dry-wet cycles was investigated by scanning electron microscopy (SEM, X-ray diffraction (XRD and energy dispersive spectrometer (EDS. The results show that the corrosion products of AZ91 Mg alloy without mischmetal addition (La,Ce are mainly composed of Mg(OH2, MgO, CaCO3 and Mg6Al2CO3(OH16·4H2O; and (La,CeAlO3 can be found in the products of AZ91 with mischmetal addition, meanwhile dense layer occurs in the corrosion products. Electrochemical impedance spectroscopy (EIS measurements show that the charge transfer resistance of AZ91 alloy with mischmetal addition tested in the same dry-wet cycles is much higher than that of AZ91 alloy, the addition of mischmetal helps to reduce the dispersing effect of impedance spectroscopy, indicating that the corrosion resistance of AZ91 Mg alloy and the stability of corrosion product films can be improved by mischmetal of La and Ce.

  14. Effects of sintering temperature on the corrosion behavior of AZ31 alloy with Ca–P sol–gel coating

    Energy Technology Data Exchange (ETDEWEB)

    Niu, Bo [School of Materials Science and Engineering, Liaoning University of Technology, Jinzhou, Liaoning Province, 121001 (China); Shi, Ping, E-mail: p_shi@sohu.com [School of Materials Science and Engineering, Liaoning University of Technology, Jinzhou, Liaoning Province, 121001 (China); Wei, Donghua [School of Materials Science and Engineering, Liaoning University of Technology, Jinzhou, Liaoning Province, 121001 (China); E, Shanshan [School of Mathematics and Physics, Bohai University, Jinzhou, Liaoning Province, 121013 (China); Li, Qiang; Chen, Yang [School of Materials Science and Engineering, Liaoning University of Technology, Jinzhou, Liaoning Province, 121001 (China)

    2016-04-25

    To slow down the initial biodegradation rate of magnesium alloy, calcium phosphate (Ca–P) coatings were prepared on AZ31 magnesium alloy by a sol–gel technique. To study the effects of sintering temperature on microstructure, bonding strength and corrosion behavior of the coatings, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and an adhesive strength test were used to characterize the coatings. The corrosion resistance of the coatings was investigated by immersion test and electrochemical corrosion techniques in simulated body fluid (SBF) solution. It shows that the sol–gel coatings consist of Ca{sub 2}P{sub 2}O{sub 7}, mixture of Ca{sub 2}P{sub 2}O{sub 7}, Ca{sub 3}(PO{sub 4}){sub 2} and hydroxyapatite, and hydroxyapatite, by sintering respectively at 300 °C, 400 °C and 500 °C. There are major cracks on the coatings. The crack area portion on the coating and the bonding strength at the interface between the calcium phosphate coating and the bare AZ31 increases, and the corrosion resistance of the coated AZ31 in SBF decreases with increasing sintering temperatures from 300 °C to 500 °C. Based on our investigations, the corrosion resistance of the coated AZ31 in SBF depends mainly on the crack area portion on the coatings, rather than on the coating phase stability. - Highlights: • Ca–P coating was prepared on AZ31 alloy by a sol–gel technique. • Crack area portion in the coating increases with temperatures. • Bonding strength between Ca–P coating and substrate increases with temperatures. • Corrosion resistance of the coated AZ31 in SBF decreases with temperatures. • Corrosion resistance of the coated AZ31 depends mainly on the crack area portion.

  15. Effect of Homogenization on Microstructure Characteristics, Corrosion and Biocompatibility of Mg-Zn-Mn-xCa Alloys

    Science.gov (United States)

    Li, Jingyuan; Lai, Huiying; Xu, Yuzhao

    2018-01-01

    The corrosion behaviors of Mg-2Zn-0.2Mn-xCa (denoted as MZM-xCa alloys) in homogenization state have been investigated by immersion test and electrochemical techniques in a simulated physiological condition. The microstructure features were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM) and electron probe microanalysis (EPMA), and the corrosion mechanism was illustrated using atomic force microscope (AFM), X-ray photoelectron spectroscopy (XPS) and confocal laser scanning microscopy (CLSM). The electrochemical and immersion test verify the MZM-0.38% Ca owns the best corrosion performance with the corrosion rate of 6.27 mm/year. Furthermore, the film layer of MZM-0.38% Ca is more compact and denser than that of others. This improvement could be associated with the combined effects of the suitable content of Zn/Ca dissolving into the α-Mg matrix and the modification of Ca-containing compounds by heat-treatment. However, the morphologies were transformed from uniform corrosion to localized pitting corrosion with Ca further addition. It could be explained that the excessive Ca addition can strengthen the nucleation driving force for the second phase formation, and the large volumes fraction of micro-galvanic present interface sites accelerate the nucleation driving force for corrosion propagation. In addition, in vitro biocompatibility tests also show the MZM-0.38% Ca was safe to bone mesenchymal stem cells (BMSCs) and was promising to be utilized as implant materials. PMID:29389894

  16. Effect of Homogenization on Microstructure Characteristics, Corrosion and Biocompatibility of Mg-Zn-Mn-xCa Alloys

    Directory of Open Access Journals (Sweden)

    Yuan Zhang

    2018-02-01

    Full Text Available The corrosion behaviors of Mg-2Zn-0.2Mn-xCa (denoted as MZM-xCa alloys in homogenization state have been investigated by immersion test and electrochemical techniques in a simulated physiological condition. The microstructure features were characterized using scanning electron microscopy (SEM, X-ray diffraction (XRD, transmission electron microscopy (TEM and electron probe microanalysis (EPMA, and the corrosion mechanism was illustrated using atomic force microscope (AFM, X-ray photoelectron spectroscopy (XPS and confocal laser scanning microscopy (CLSM. The electrochemical and immersion test verify the MZM-0.38% Ca owns the best corrosion performance with the corrosion rate of 6.27 mm/year. Furthermore, the film layer of MZM-0.38% Ca is more compact and denser than that of others. This improvement could be associated with the combined effects of the suitable content of Zn/Ca dissolving into the α-Mg matrix and the modification of Ca-containing compounds by heat-treatment. However, the morphologies were transformed from uniform corrosion to localized pitting corrosion with Ca further addition. It could be explained that the excessive Ca addition can strengthen the nucleation driving force for the second phase formation, and the large volumes fraction of micro-galvanic present interface sites accelerate the nucleation driving force for corrosion propagation. In addition, in vitro biocompatibility tests also show the MZM-0.38% Ca was safe to bone mesenchymal stem cells (BMSCs and was promising to be utilized as implant materials.

  17. Achievments of corrosion science and corrosion protection technology

    International Nuclear Information System (INIS)

    Fontana, M.; Stehjl, R.

    1985-01-01

    Problems of corrosion-mechanical strength of metals, effect of corrosive media on creep characteristics are presented. New concepts of the mechanism of corrosion cracking and its relation to hydrogen embrittlement are described. Kinetics and mechanism of hydrogen embrittlement effect on the process of corrosion cracking of different steels and alloys are considered. The dependence of such types of failure on various structural factors is shown. Data on corrosion cracking of high-strength aluminium and titanium alloys, mechanism of the processes and protective methods are given

  18. Formation of the self-assembled structures by the ultrasonic cavitation erosion-corrosion effect on carbon steel

    Directory of Open Access Journals (Sweden)

    Dayun Yan

    2015-11-01

    Full Text Available The cavitation erosion-corrosion effect on the metal surface always forms irregular oxide structures. In this study, we reported the formation of regular self-assembled structures of amorphous nanoparticles around the cavitation erosion pits on carbon steel upon the ultrasonic cavitation in methylene blue solution. Each self-assembled structure was composed of linearly aligned nanoparticles of about 100 nm. The formation of self-assembled structures might be due to the combined effect of corrosion, specific sonochemical reaction in methylene blue solution, and the magnetic domain structures on the carbon steel.

  19. Effects of Heat Input on Microstructure, Corrosion and Mechanical Characteristics of Welded Austenitic and Duplex Stainless Steels: A Review

    Directory of Open Access Journals (Sweden)

    Ghusoon Ridha Mohammed

    2017-01-01

    Full Text Available The effects of input heat of different welding processes on the microstructure, corrosion, and mechanical characteristics of welded duplex stainless steel (DSS are reviewed. Austenitic stainless steel (ASS is welded using low-heat inputs. However, owing to differences in the physical metallurgy between ASS and DSS, low-heat inputs should be avoided for DSS. This review highlights the differences in solidification mode and transformation characteristics between ASS and DSS with regard to the heat input in welding processes. Specifically, many studies about the effects of heat energy input in welding process on the pitting corrosion, intergranular stress, stresscorrosion cracking, and mechanical properties of weldments of DSS are reviewed.

  20. Effectiveness of Ti-micro alloying in relation to cooling rate on corrosion of AZ91 Mg alloy

    International Nuclear Information System (INIS)

    Candan, S.; Celik, M.; Candan, E.

    2016-01-01

    In this study, micro Ti-alloyed AZ91 Mg alloys (AZ91 + 0.5wt.%Ti) have been investigated in order to clarify effectiveness of micro alloying and/or cooling rate on their corrosion properties. Molten alloys were solidified under various cooling rates by using four stage step mold. The microstructural investigations were carried out by using scanning electron microscopy (SEM). Corrosion behaviors of the alloys were evaluated by means of immersion and electrochemical polarization tests in 3.5% NaCl solution. Results showed that the Mg 17 Al 12 (β) intermetallic phase in the microstructure of AZ91 Mg alloy formed as a net-like structure. The Ti addition has reduced the distribution and continuity of β intermetallic phase and its morphology has emerged as fully divorced eutectic. Compared to AZ91 alloy, the effect of the cooling rate in Ti-added alloy on the grain size was less pronounced. When AZ91 and its Ti-added alloys were compared under the same cooling conditions, the Ti addition showed notably high corrosion resistance. Electrochemical test results showed that while I corr values of AZ91 decrease with the increase in the cooling rate, the effect of the cooling rate on I corr values was much lower in the Ti-added alloy. The corrosion resistance of AZ91 Mg alloy was sensitive towards the cooling rates while Ti-added alloy was not affected much from the cooling conditions. - Highlights: • Effect the cooling rate on grain size was less pronounced in the Ti-added alloy. • The morphology of the β phase transformed into fully divorced eutectics. • Ti addition exhibited significantly higher corrosion resistance. • Ti micro alloying is more effective than faster cooling of the alloy on corrosion.

  1. Mechanism research on coupling effect between dew point corrosion and ash deposition

    International Nuclear Information System (INIS)

    Wang, Yun-Gang; Zhao, Qin-Xin; Zhang, Zhi-Xiang; Zhang, Zhi-Chao; Tao, Wen-Quan

    2013-01-01

    In order to study the coupling mechanism between ash deposition and dew point corrosion, five kinds of tube materials frequently used as anti-dew point corrosion materials were selected as research objects. Dew point corrosion and ash deposition experiments were performed with a new type experimental device in a Chinese thermal power plant. The microstructures of the materials and the composition of ash deposition were analyzed by X-ray diffraction (XRD) and Energy Dispersive Spectrometer (EDS). The results showed that the ash deposition layer could be divided into non-condensation zone, the main condensation zone and the secondary condensation zone. The acid vapor condensed in the main condensation zone rather than directly on the tube wall surface. The dew point corrosion mainly is oxygen corrosion under the condition of the viscosity ash deposition, and the corrosion products are composed of the ash and acid reaction products in the outer layer, iron sulfate in the middle layer, and iron oxide in the inner layer. The innermost layer is the main corrosion layer. With the increase of the tube wall temperature, the ash deposition changes from the viscosity ash deposition to the dry loose ash deposition, the ash deposition rate decreases dramatically and dew point corrosion is alleviated efficiently. The sulfuric dew point corrosion resistance of the five test materials is as follows: 316L > ND > Corten>20G > 20 steel. -- Highlights: ► Dew point corrosion and ash deposition tests of five materials were performed. ► Acid vapor condensed in the ash deposit rather than directly on the tube surface. ► Dew point corrosion resistance is as follow: 316L > ND > Corten>20G > 20 steel. ► Dew point corrosion mainly is oxygen corrosion under viscosity ash deposition

  2. Effect of radioactive chromate on the corrosion and polarisation of mild steel in sodium chloride solution

    International Nuclear Information System (INIS)

    Subramanyan, N.; Ramakrishnaiah, K.; Iyer, S.V.; Kapali, V.

    1980-01-01

    Corrosion tests of mild steel in 0.01% sodium chloride containing radioactive chromate and non-radioactive chromate have been carried out. It has been observed that the labelled sodium chromate has a deleterious effect on the inhibitive action of non-radioactive chromate. The effect of radioactive chromate on the potentiostatic polarization of m.s. in sodium chloride solution containing non-radioactive sodium chromate has also been studied. It is observed that both the cathodic and the anodic polarisation of the metal is diminished in the presence of radioactive chromate. The behaviour of the system in the presence of radioactive chromate is attributed both to the action of depolarisers produced by radiolysis of water and to the effect of gamma radiation on the metal. (author)

  3. Effect of phase composition on the corrosion properties of alloys of the magnesium-yttrium system in neutral solutions

    International Nuclear Information System (INIS)

    Krasnoyarskii, V.V.; Petrova, L.M.; Dobatkina, T.V.; Korol'kova, I.G.

    1992-01-01

    A study is made of the effect of phase composition on the corrosive dissolution of binary alloys of the system magnesium-8.2% yttrium. It is shown that the appearance of the intermetallide Mg 24 Y 5 - being the effective cathode - intensifies self-dissolution of the alloy under conditions of anodic galvanostatic polarization

  4. Effective new chemicals to prevent corrosion due to chlorine in power plant superheaters

    Energy Technology Data Exchange (ETDEWEB)

    Martti Aho; Pasi Vainikka; Raili Taipale; Patrik Yrjas [VTT, Jyvaeskylae (Finland)

    2008-05-15

    Firing or co-firing of biomass in efficient power plants can lead to high-temperature corrosion of superheaters due to condensation of alkali chlorides into superheater deposits. Corrosion can be prevented if a significant portion of the alkali chlorides present in the flue gases is destroyed before reaching the superheaters. The alkali capturing power of aluminium and ferric sulphates was determined in a pilot-scale fluidised bed (FB) reactor. The reagents were added in solution, through a spraying nozzle, to the upper part of the freeboard. Both reagents, at economical dosages, fast and effectively destroyed the alkali chlorides by producing sufficient SO{sub 3} for the sulphation. Both the mass flow rate and type of sulphate affected the sulphation ability. Thus, the cation, too, plays a role in the reaction. The required chemical dosage is not directly proportional to the S{sub reagent}/Cl{sub 2fuel} ratio because alkali chlorides must compete with calcium and magnesium oxides and probably also with alkali oxides for the available SO{sub 3}. 17 refs., 16 figs., 1 tab.

  5. Effect of air humidity on microstructure and phase composition of lithium deuteride corrosion products

    International Nuclear Information System (INIS)

    Liu, Xiaobo; Liu, Jiping

    2017-01-01

    Highlights: • Lithium deuteride samples are corroded by air with different relative humidity. • Show the structure and composition of fracture surface of corrosion particle. • The lithium carbonate formation is related to air humidity. • The lithium carbonate only exists in the surface of lithium hydroxide layer. • There is a concentration gradient of H 2 O across the lithium hydroxide layer. - Abstract: Lithium deuteride (LiD) was exposed to air for 600 min to determine the effect of air humidity on its microstructure and phase composition. XRD and XPS results revealed that LiOH and Li 2 CO 3 formed at relative humidity values of >30%, whereas only LiOH formed at values <20%. SEM and EDS images showed a clear LiOH layer; Li 2 CO 3 was confined to the surface of this layer. The schematic illustration revealed that the concentration gradient of H 2 O across the LiOH layer resulted in little Li 2 CO 3 formed in the layer. This work will contribute to increase understanding of LiD corrosion in air.

  6. Effect of the electrochemical passivation on the corrosion behaviour of austenitic stainless steel

    International Nuclear Information System (INIS)

    Barbucci, A.; Delucchi, M.; Panizza, M.; Farne, G.; Cerisola, G.

    2004-01-01

    Cold rolled SS is also fruitfully used in deep drawing however the presence of scales or oxides on the surface reduces the life of the tools and emphasises creep phenomena of the material. Then a cleaning of the SS surface from these impurities is necessary. Oxides can be formed during the hot rolling preceding the cold one, or during the annealing performed between the several steps of thickness reduction. The annealing helps to decrease the work hardening occurring during the process. Normally this heat treatment is performed in reducing atmosphere of pure hydrogen (bright annealing), but even in this conditions oxides are formed on the SS surface. To avoid this uncontrolled oxide growth one method recently applied is an electrochemical cleaning performed in an electrolytic solution containing chrome, generally called electrochemical passivation. The electrochemical passivation allows the dissolution of the contaminating hard particles on the strips. Few scientific contributions are available in literature, which explain in detail the process mechanism. The aim of this work is to investigate if the electrochemical passivated surface acts in a different way with regard to corrosion phenomena with respect to conventional SS. Electrochemical measurements like polarisation, chrono-amperometries and surface analysis were used to investigate the corrosion behaviour of electrochemically passivated AISI 304L and AISI 305. The effect of some process parameters were considered, too. (authors)

  7. Effect of the electrochemical passivation on the corrosion behaviour of austenitic stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Barbucci, A.; Delucchi, M.; Panizza, M.; Farne, G.; Cerisola, G. [DICheP, University of Genova, P.le Kennedy 1, 16129 Genova (Italy)

    2004-07-01

    Cold rolled SS is also fruitfully used in deep drawing however the presence of scales or oxides on the surface reduces the life of the tools and emphasises creep phenomena of the material. Then a cleaning of the SS surface from these impurities is necessary. Oxides can be formed during the hot rolling preceding the cold one, or during the annealing performed between the several steps of thickness reduction. The annealing helps to decrease the work hardening occurring during the process. Normally this heat treatment is performed in reducing atmosphere of pure hydrogen (bright annealing), but even in this conditions oxides are formed on the SS surface. To avoid this uncontrolled oxide growth one method recently applied is an electrochemical cleaning performed in an electrolytic solution containing chrome, generally called electrochemical passivation. The electrochemical passivation allows the dissolution of the contaminating hard particles on the strips. Few scientific contributions are available in literature, which explain in detail the process mechanism. The aim of this work is to investigate if the electrochemical passivated surface acts in a different way with regard to corrosion phenomena with respect to conventional SS. Electrochemical measurements like polarisation, chrono-amperometries and surface analysis were used to investigate the corrosion behaviour of electrochemically passivated AISI 304L and AISI 305. The effect of some process parameters were considered, too. (authors)

  8. Effect of friction stir processing on erosion–corrosion behavior of nickel–aluminum bronze

    International Nuclear Information System (INIS)

    Lotfollahi, M.; Shamanian, M.; Saatchi, A.

    2014-01-01

    Highlights: • The average hardness value of the FSP samples was higher than cast sample. • Erosion–corrosion rate of the FSP samples was higher than cast sample. • The gravimetric analysis showed a negative synergy. - Abstract: In the present investigation, effects of Friction Stir Processing (FSP) on Erosion–Corrosion (E–C) behavior of Nickel–Aluminum Bronze (NAB) were studied by weight-loss measurements and surface characterization using an impingement jet test system. After FSP, the initial coarse microstructure of the cast NAB was transformed to a fine structure, and the porosity defects were eliminated. In addition, different FSP structures were produced by each rotation rate. Microhardness measurements showed a marked increase in FSP samples depending upon the FSP parameters. E–C tests were carried out by erodent at kinetic energies about 0.45 μJ and in 30°, 60° and 90° impact angles to simulate actual service conditions. The maximum weight-loss was observed in FSP samples and Scanning Electron Microscopy (SEM) results showed signs of brittle fracture mechanism in FSP samples. By gravimetric analysis, the degree of synergy was evaluated at 0.45 μJ kinetic energy at normal impact angle and negative synergy result implies the presence of a protective film on all sample surfaces

  9. Enzymatic effect of a bio-film on corrosion of stainless steels immersed in natural seawater

    International Nuclear Information System (INIS)

    L'Hostis, V.

    2002-09-01

    Immersion of stainless steels in natural seawater leads to an ennoblement of their free corrosion potential (Ecor) with time. This evolution is linked to colonization of surface by bacteria, forming a bio-film. Literature synthesis has showed common points between proposed mechanisms, like a modification of cathodic reactions, and importance of hydrogen peroxide, but also differences, as acidity inside bio-films, or chemical composition of the passive layer, or enzymes present inside bio-films. The aim of the study was to precise these hypothesis, and finally mechanisms which leads to increase of Ecor. Experiments with addition of enzymes (glucose oxidase) have been performed and have lead to reproduce the electrochemical behaviour of stainless steels in natural seawater, including the cathodic behaviour. Study of composition of passive film and its semi-conducting properties, analysed respectively by XPS and Mott-Schottky plots, has lead to precise roles of hydrogen peroxide and oxidases. Moreover, study of donor densities of passive film has pointed out the effect of gluconic acid for evolution of cathodic reaction. This enzymatic mechanism has been applied and verified on crevice corrosion, and has been extended to other metallic materials, and other enzymes. (author)

  10. Effect of corrosive marine atmosphere on construction materials in Tanzania: Exposure sites and preliminary results

    International Nuclear Information System (INIS)

    Mmari, A.G.; Uiso, C.B.S.; Makundi, I.N.; Potgieter-Vermaak, S.S.; Potgieter, J.H.; Van Grieken, R.

    2007-01-01

    Air pollution studies in Africa are limited and the influence of ambient air quality on buildings and constructions have not been investigated in the larger part of Sub-Saharan Africa. The increasing burden of emission from industry, traffic and coal power plants on ambient air pollution in Sub-Saharan Africa necessitated reviewing previous and current studies. In South Africa a 20-year exposure program, focusing on the effect of ambient exposure on various metals and alloys, showed that the amount of rainfall, relative humidity, atmospheric pollution, wind speed, solar radiation and structural design are some of the factors controlling atmospheric corrosion. Tanzania, being among the Sub-Saharan African countries and partly bordered by Indian ocean, the main source of marine atmosphere, experiences corrosive degradation on metal roofing and cementitious materials. This paper describes the exposure site set-up and will report on some preliminary results of air quality and its relation with the meteorological conditions, as well as surface changes observed, for the year one of exposure. These will thereafter be compared to the completed European and Asian studies, as reported by CLRTAP and RAPIDC respectively. (author)

  11. Effect of Aging Treatment on Impact Toughness and Corrosion Resistance of Super Duplex Stainless Steel

    Science.gov (United States)

    Kim, Jae-Hwan; Oh, Eun-Ji; Lee, Byung-Chan; Kang, Chang-Yong

    2016-01-01

    The effect of aging time on impact toughness and corrosion resistance of 25%Cr-7%Ni-2%Mo-4%W-0.2%N super duplex stainless steel from the viewpoint of intermetallic secondary phase variation was investigated with scanning electron microscopic observation with energy-dispersive x-ray spectroscopic analysis and transmission electron microscopy. The results clarified that R-phase is precipitated not only at the interface of ferrite and austenite but inside the ferrite at an initial stage of aging and then transformed into σ-phase from an aging time of 1 h, while the ferrite phase decomposed into γ2 and σ-phase with increase of aging time. This variation of the phases led to decrease of its impact toughness, and specifically, the R-phase was proved to be predominant in the degradation of the impact toughness at the initial stage of the aging. Additionally, these secondary phases led to deterioration of corrosion resistance because of Cr depletion.

  12. Effect of Annealing on the Pitting Corrosion Resistance of Anodized Aluminum-Magnesium Alloy Processed by Equal Channel Angular Pressing

    Energy Technology Data Exchange (ETDEWEB)

    Son, In Joon; Nakano, Hiroaki; Oue, Satoshi; Fukushima, Hisaaki; Horita, Zenji [Kyushu University, Fukuoka (Japan); Kobayashi, Shigeo [Kyushu Sangyo University, Fukuoka (Japan)

    2007-12-15

    The effect of annealing on the pitting corrosion resistance of anodized Al-Mg alloy (AA5052) processed by equal-channel angular pressing (ECAP) was investigated by electrochemical techniques in a solution containing 0.2 mol/L of AlCl{sub 3} and also by surface analysis. The Al-Mg alloy was annealed at a fixed temperature between 473 and 573 K for 120 min in air after ECAP. Anodizing was conducted for 40 min at 100-400 A/m{sup 2} at 293 K in a solution containing 1.53 mol/L of H{sub 2}SO{sub 4} and 0.0185 mol/L of Al{sub 2}(SO{sub 4}){sub 3}. The internal stress generated in anodic oxide films during anodization was measured with a strain gauge to clarify the effect of ECAP on the pitting corrosion resistance of anodized Al-Mg alloy. The time required to initiate the pitting corrosion of anodized Al-Mg alloy was shorter in samples subjected to ECAP, indicating that ECAP decreased the pitting corrosion resistance. however, the pitting corrosion resistance was greatly improved by annealing after ECAP. The time required to initiate pitting corrosion increased with increasing annealing temperature. The strain gauge attached to Al-Mg alloy revealed that the internal stress present in the anodic oxide films was compressive stress, and that the stress was larger with ECAP than without. The compressive internal stress gradually decreased with increasing annealing temperature. Scanning electron microscopy showed that cracks occurred in the anodic oxide film on Al-Mg alloy during initial corrosion and that the cracks were larger with ECAP than without. The ECAP process of severe plastic deformation produces large internal stresses in the Al-Mg alloy: the stresses remain in the anodic oxide films, increasing the likelihood of cracks. it is assumed that the pitting corrosion is promoted by these cracks as a result of the higher internal stress resulting from ECAP. The improvement in the pitting corrosion resistance of anodized AlMg alloy as a result of annealing appears to be

  13. Effect of Annealing on the Pitting Corrosion Resistance of Anodized Aluminum-Magnesium Alloy Processed by Equal Channel Angular Pressing

    International Nuclear Information System (INIS)

    Son, In Joon; Nakano, Hiroaki; Oue, Satoshi; Fukushima, Hisaaki; Horita, Zenji; Kobayashi, Shigeo

    2007-01-01

    The effect of annealing on the pitting corrosion resistance of anodized Al-Mg alloy (AA5052) processed by equal-channel angular pressing (ECAP) was investigated by electrochemical techniques in a solution containing 0.2 mol/L of AlCl 3 and also by surface analysis. The Al-Mg alloy was annealed at a fixed temperature between 473 and 573 K for 120 min in air after ECAP. Anodizing was conducted for 40 min at 100-400 A/m 2 at 293 K in a solution containing 1.53 mol/L of H 2 SO 4 and 0.0185 mol/L of Al 2 (SO 4 ) 3 . The internal stress generated in anodic oxide films during anodization was measured with a strain gauge to clarify the effect of ECAP on the pitting corrosion resistance of anodized Al-Mg alloy. The time required to initiate the pitting corrosion of anodized Al-Mg alloy was shorter in samples subjected to ECAP, indicating that ECAP decreased the pitting corrosion resistance. however, the pitting corrosion resistance was greatly improved by annealing after ECAP. The time required to initiate pitting corrosion increased with increasing annealing temperature. The strain gauge attached to Al-Mg alloy revealed that the internal stress present in the anodic oxide films was compressive stress, and that the stress was larger with ECAP than without. The compressive internal stress gradually decreased with increasing annealing temperature. Scanning electron microscopy showed that cracks occurred in the anodic oxide film on Al-Mg alloy during initial corrosion and that the cracks were larger with ECAP than without. The ECAP process of severe plastic deformation produces large internal stresses in the Al-Mg alloy: the stresses remain in the anodic oxide films, increasing the likelihood of cracks. it is assumed that the pitting corrosion is promoted by these cracks as a result of the higher internal stress resulting from ECAP. The improvement in the pitting corrosion resistance of anodized AlMg alloy as a result of annealing appears to be attributable to a decrease in

  14. Effect of H{sub 2}O{sub 2} on the corrosion behavior of 304L stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Song, Taek Hoh; Kim, In Sub [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of); Noh, Sung Kee [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1995-08-01

    In connection with the safe storage of high level nuclear waste, effect of H{sub 2}O{sub 2} on the corrosion behavior of 304L stainless steel was examined. Open circuit potentials and polarization curves were measured with and without H{sub 2}O{sub 2}. The experimental results show that H{sub 2}O{sub 2} increased corrosion potential and decreased pitting potential. The passive range, therefore, decreased as H{sub 2}O{sub 2} concentration increased, indicating that pitting resistance was decreased by the existence of H{sub 2}O{sub 2} in the electrolyte. These effects of H{sub 2}O{sub 2} on corrosion of 304L stainless steel are considered to be similar to those of {gamma}-irradiation. To compare the effects of H{sub 2}O{sub 2} with those of O{sub 2}, cathodic and anodic polarization curves were made in three types of electrolyte such as aerated, deaerated, and stirred electrolyte. The experimental results show that the effects of H{sub 2}O{sub 2} on the corrosion behavior were very similar to those of O{sub 2} such as increase of corrosion potential, decrease of pitting resistance, and increase of repassivation potential. In acid and alkaline media, the corrosion potential shifts by H{sub 2}O{sub 2} were restricted by the large current density of proton reduction and by the le Chatelier`s principle respectively. 13 figs., 1 tabs., 17 refs. (Author).

  15. Effect of corrosion product layer on SCC susceptibility of copper containing type 304 stainless steel in 1 M H2SO4

    International Nuclear Information System (INIS)

    Asawa, M.; Devasenapathi, A.; Fujisawa, M.

    2004-01-01

    The effect of surface corrosion product layer on the stress corrosion cracking (SCC) susceptibility of type 304 stainless steel with Cu was studied in 1 kmol/m 3 (1 M) sulfuric acid at 353 K temperature. Studies based on the intermittent removal of surface corrosion product layer indicated that the surface film governs the SCC behavior of the alloy by accelerating both the crack initiation and propagation stages. The electrochemical impedance and polarization studies showed the surface layer to be promoting SCC initiation by lowering the uniform corrosion rate and the propagation by shifting the surface corrosion potential to a more noble direction. The elemental analysis of the corrosion product both by the energy dispersive X-ray (EDX) spectroscopy and by X-ray diffraction (XRD) analysis along with the thermodynamic calculations showed the layer to be constituted mainly of metallic copper (Cu) and the mono-hydrated iron sulfate which acts as cathode promoting SCC

  16. Effects of high temperature surface oxides on room temperature aqueous corrosion and environmental embrittlement of iron aluminides

    Energy Technology Data Exchange (ETDEWEB)

    Buchanan, R.A.; Perrin, R.L.

    1996-09-01

    Studies were conducted to determine the effects of high-temperature surface oxides, produced during thermomechanical processing, heat treatment (750 {degrees}C in air, one hour) or simulated in-service-type oxidation (1000{degrees}C in air, 24 hours) on the room-temperature aqueous-corrosion and environmental-embrittlement characteristics of iron aluminides. Materials evaluated included the Fe{sub 3}Al-based iron aluminides, FA-84, FA-129, FAL and FAL-Mo, a FeAl-based iron aluminide, FA-385, and a disordered low-aluminum Fe-Al alloy, FAPY. Tests were performed in a mild acid-chloride solution to simulate aggressive atmospheric corrosion. Cyclic-anodic-polarization tests were employed to evaluate resistances to localized aqueous corrosion. The high-temperature oxide surfaces consistently produced detrimental results relative to mechanically or chemically cleaned surfaces. Specifically, the pitting corrosion resistances were much lower for the as-processed and 750{degrees} C surfaces, relative to the cleaned surfaces, for FA-84, FA-129, FAL-Mo, FA-385 and FAPY. Furthermore, the pitting corrosion resistances were much lower for the 1000{degrees}C surfaces, relative to cleaned surfaces, for FA-129, FAL and FAL-Mo.

  17. [The effect of hydrogen peroxide on the electrochemical corrosion properties and metal ions release of nickel-chromium dental alloys].

    Science.gov (United States)

    Wang, Jue; Qiao, Guang-yan

    2013-04-01

    To investigate the effect of hydrogen peroxide on the electrochemical corrosion and metal ions release of nickel-chromium dental alloys. The corrosion resistance of nickel-chromium dental alloys was compared by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curve (PD) methods in artificial saliva after immersed in different concentrations of hydrogen peroxide for 112 h. The metal ions released from nickel-chromium dental alloys to the artificial saliva were detected after electrochemical measurements using inductively coupled plasma mass spectrometry (ICP-MS). The data was statistically analyzed by analysis of variance (ANOVA) using SPSS 13.0 software package. The electrochemical experiment showed that the sequence of polarization resistance in equivalent circuit (Rct), corrosion potential (Ecorr), pitting breakdown potential (Eb), and the difference between Ecorr and Eb representing the "pseudo-passivation" (δE) of nickel-chromium alloys in artificial saliva was 30% alloys to the artificial saliva, and the order of the concentrations of metal ions was 0% corrosion resistance of nickel-chromium dental alloys decrease after immersed in different concentrations of hydrogen peroxide for 112 h. Nickel-chromium dental alloys are more prone to corrosion in the artificial saliva with the concentration of hydrogen peroxide increased, and more metal ions are released in the artificial saliva.

  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. Effect of Cu addition on microstructure and corrosion behavior of spray-deposited Zn–30Al alloy

    International Nuclear Information System (INIS)

    Wang Feng; Xiong Baiqing; Zhang Yongan; Liu Hongwei; Li Zhihui; Li Xiwu; Qu Chu

    2012-01-01

    Highlights: ► Zn–30Al–xCu alloys were synthesized by the spray atomization and deposition technique. ► Immersion test and electrochemical measurements have been used to estimate the corrosion rate and the behavior. ► The result indicates that the 1 wt.% Cu addition displays superior corrosion resistance. - Abstract: In this study, one binary Zn–30Al and three ternary Zn–30Al–Cu alloys were synthesized by the spray atomization and deposition technique. The microstructures of the spray-deposited alloys were investigated by means of scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD). Immersion test, potentiodynamic polarization and electrochemical impedance measurements have been used to estimate the corrosion rate and the behavior. The results indicate that the 1 wt.% Cu addition to spray-deposited Zn–30Al alloy does not make significant change in microstructure. However, with the 2, 4 wt.% Cu additions to the alloy, some ε-CuZn 4 compounds with particle or irregular shapes were observed on the grain boundaries in the microstructures. Immersion test and electrochemical measurements confirmed that the 1 wt.% Cu addition displays superior corrosion resistance, whereas the 2, 4 wt.% Cu additions have a baneful effect on the corrosion behavior.

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

    Science.gov (United States)

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

    2002-05-01

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

  1. Effect of dissolved oxygen, hydrazine and pH outside the crevice on the galvanic corrosion of support plate alloys

    International Nuclear Information System (INIS)

    McKubre, M.C.H.

    1985-01-01

    A study has been performed of the initial corrosion of support structure alloys in crevices of various geometries, when galvanically coupled to alloy 600. Corrosion rates were monitored continuously by measuring the galvanic current flowing in each couple, transduced by a zero impedance ammeter. Experiments were performed in a single-pass flowing electrolyte system, with AVT water pumped through alloy 600 tubing past the orifice of each crevice. Fourteen crevices were studied simultaneously in two parallel flow arms containing seven specimens each. The steady state AVT water pH/hydrazine/oxygen concentrations were controlled by microcomputer, allowing the effect of secondary water chemistry on the corrosion rate to be studied easily. Control of the crevice electrolyte composition was achieved by separately pumping electrolyte, at a low rate, directly into the crevices of the seven specimens in the lower flow arm. In addition, a high pressure syringe was used to introduce chemicals directly into the secondary or crevice electrolyte flow streams, in order to rapidly evaluate the influence of potential corrodent or corrosion control agents on the galvanic corrosion rates. Specimens were studied in the five basic geometries

  2. Modeling the effects of evolving redox conditions on the corrosion of copper containers

    International Nuclear Information System (INIS)

    Kng, F.; LeNeveu, D.M.; Jobe, D.J.

    1994-01-01

    The corrosive environment around the containers in a Canadian nuclear fuel waste disposal vault will change over time from open-quotes warm and oxidizingclose quotes to open-quotes cool and anoxic.close quotes As the conditions change, so too will the corrosion behaviour of the containers. For copper containers, uniform corrosion and, possibly, pitting will occur during the initial aggressive phase, to be replaced by slow uniform corrosion during the long-term anoxic period. The corrosion behaviour of copper has been studied over a range of conditions representing all phases in the evolution of the vault environment. The results of these studies are summarized and used to illustrate how a model can be developed to predict the corrosion behaviour and container lifetimes over long periods of time. Lifetimes in excess of 10 6 a are predicted for 25-mm-thick copper containers under Canadian disposal conditions

  3. The effect of sulphide and moisture content on steel corrosion during transport of fine wet coal

    International Nuclear Information System (INIS)

    Waanders, F. B.; Vorster, S. W.

    2013-01-01

    In the present investigation the influence of compaction pressure (stress) on the corrosivity of wet coal was investigated. Two coal samples, one high in sulphur content (3 %) and the other low in sulphur content (0.6 %) were used to determine the influence of compaction stress on the corrosion rates of steel samples in contact with compacted coal. It was found that the pressure exerted on finely divided wet coal is an important factor in determining its water content and corrosivity towards mild steel. Corrosion of the steel was typically in the form of pitting and the sulphur content of the coal was an important factor in determining the corrosivity of the coal. The corrosion rate of the high sulphur content coal was higher than that of the low sulphur coal. Mössbauer spectroscopy showed that a FeS species developed on the steel surface.

  4. Corrosion in low dielectric constant Si-O based thin films: Buffer concentration effects

    International Nuclear Information System (INIS)

    Zeng, F. W.; Lane, M. W.; Gates, S. M.

    2014-01-01

    Organosilicate glass (OSG) is often used as an interlayer dielectric (ILD) in high performance integrated circuits. OSG is a brittle material and prone to stress-corrosion cracking reminiscent of that observed in bulk glasses. Of particular concern are chemical-mechanical planarization techniques and wet cleans involving solvents commonly encountered in microelectronics fabrication where the organosilicate film is exposed to aqueous environments. Previous work has focused on the effect of pH, surfactant, and peroxide concentration on the subcritical crack growth of these films. However, little or no attention has focused on the effect of the conjugate acid/base concentration in a buffer. Accordingly, this work examines the “strength” of the buffer solution in both acidic and basic environments. The concentration of the buffer components is varied keeping the ratio of acid/base and therefore pH constant. In addition, the pH was varied by altering the acid/base ratio to ascertain any additional effect of pH. Corrosion tests were conducted with double-cantilever beam fracture mechanics specimens and fracture paths were verified with ATR-FTIR. Shifts in the threshold fracture energy, the lowest energy required for bond rupture in the given environment, G TH , were found to shift to lower values as the concentration of the base in the buffer increased. This effect was found to be much larger than the effect of the hydroxide ion concentration in unbuffered solutions. The results are rationalized in terms of the salient chemical bond breaking process occurring at the crack tip and modeled in terms of the chemical potential of the reactive species

  5. Corrosion evaluation technology

    International Nuclear Information System (INIS)

    Kim, Uh Chul; Han, Jeong Ho; Nho, Kye Ho; Lee, Eun Hee; Kim, Hong Pyo; Hwang, Seong Sik; Lee, Deok Hyun; Hur, Do Haeng; Kim, Kyung Mo.

    1997-09-01

    A multifrequency ACPD system was assembled which can measure very small crack. Stress corrosion cracking test system with SSRT operating high temperature was installed. Stress corrosion cracking test of newly developed alloy 600 and existing alloy 600 was carried out in steam atmosphere of 400 deg C. No crack was observed in both materials within a test period of 2,000 hrs. Corrosion fatigue test system operating at high temperature was installed in which fatigue crack was measured by CDPD. Lead enhanced the SCC of the Alloy 600 in high temperature water, had a tendency to modify a cracking morphology from intergranular to transgranular. Pit initiation preferentially occurred at Ti-rich carbide. Resistance to pit initiation decreased with increasing temperature up to 300 deg C. Test loop for erosion corrosion was designed and fabricated. Thin layer activation technique was very effective in measuring erosion corrosion. Erosion corrosion of a part of secondary side pipe was evaluated by the Check Family Codes of EPRI. Calculated values of pipe thickness by Check Family Codes coincided with the pipe thickness measured by UT with an error of ± 20%. Literature review on turbine failure showed that failure usually occurred in low pressure turbine rotor disc and causes of failure are stress corrosion cracking and corrosion fatigue. (author). 12 refs., 20 tabs., 77 figs

  6. The effect of crystallographic orientation on the active corrosion of pure magnesium

    International Nuclear Information System (INIS)

    Liu Ming; Qiu Dong; Zhao Mingchun; Song, Guangling; Atrens, Andrej

    2008-01-01

    An improved method was used to investigate the influence of crystallographic orientation on the corrosion of pure magnesium in 0.1 N HCl. The corrosion depth and orientation of surface features were mapped against crystallographic orientation (obtained by electron backscatter diffraction) for many off-principal magnesium crystals. The grains near (0 0 0 1) orientation are the most corrosion resistant. Most grains exhibited a striated structure of long and narrow hillocks with a unique direction

  7. Effect of water chemistry and fuel operation parameters on Zr + 1% Nb cladding corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Kritsky, V G; Petrik, N G; Berezina, I G; Doilnitsina, V V [VNIPIET, St. Petersburg (Russian Federation)

    1997-02-01

    In-pile corrosion of Zr + 1%Nb fuel cladding has been studied. Zr-oxide and hydroxide solubilities at various temperatures and pH values have been calculated and correlations obtained between post-transition corrosion and the solubilities nodular corrosion and fuel operation parameters, as well as between the rate of fuel cladding degradation and water chemistry. Extrapolations of fuel assemblies behaviour to higher burnups have also performed. (author). 12 refs, 11 figs.

  8. Effect of deformation on densification and corrosion behavior of Al-ZrB2 composite

    Directory of Open Access Journals (Sweden)

    Sai Mahesh Yadav Kaku

    2017-03-01

    Full Text Available In the present investigation, aluminium based metal matrix composites (MMCs were produced through powder metallurgical route. Different composites were processed by adding different amount of ZrB2 (0, 2, 4 and 6 wt. % at three aspect ratios of 0.35, 0.5, and 0.65, respectively. The powder mixture was compacted and pressureless sintered at 550 °C for 1 h in controlled atmosphere (argon gas. The relative density of the sintered preforms was found to be 90%, approximately. Sintered preforms are used as workpiece materials for deformation study at different temperatures in order to find the effect of temperature on the densification behaviour. Potentio-dynamic polarization studies were performed on the deformed preforms to find the effect of mechanical working. The corrosion rate was found to decrease with increase in deformation.

  9. Structural Response to Blast Loading: The Effects of Corrosion on Reinforced Concrete Structures

    Directory of Open Access Journals (Sweden)

    Hakan Yalciner

    2014-01-01

    Full Text Available Structural blast design has become a necessary part of the design with increasing terrorist attacks. Terrorist attacks are not the one to make the structures important against blast loading where other explosions such as high gas explosions also take an important place in structural safety. The main objective of this study was to verify the structural performance levels under the impact of different blast loading scenarios. The blast loads were represented by using triangular pulse for single degree of freedom system. The effect of blast load on both corroded and uncorroded reinforced concrete buildings was examined for different explosion distances. Modified plastic hinge properties were used to ensure the effects of corrosion. The results indicated that explosion distance and concrete strength were key parameters to define the performance of the structures against blast loading.

  10. The effect of mucin, fibrinogen and IgG on the corrosion behaviour of Ni-Ti alloy and stainless steel.

    Science.gov (United States)

    Chao, Zhang; Yaomu, Xiao; Chufeng, Liu; Conghua, Liu

    2017-06-01

    In this study, Ni-Ti alloy and stainless steal were exposed to artificial saliva containing fibrinogen, IgG or mucin, and the resultant corrosion behavior was studied. The purpose was to determine the mechanisms by which different types of protein contribute to corrosion. The effect of different proteins on the electrochemical resistance of Ni-Ti and SS was tested by potentiodynamic polarization, and the repair capacity of passivation film was tested by cyclic polarization measurements. The dissolved corrosion products were determined by ICP-OES, and the surface was analyzed by SEM and AFM. The results showed fibrinogen, IgG or mucin could have different influences on the susceptibility to corrosion of the same alloy. Adding protein lead to the decrease of corrosion resistance of SS, whereas protein could slow down the corrosion process of Ni-Ti. For Ni-Ti, adding mucin could enhance the corrosion stability and repair capacity of passivation film. The susceptibility to pitting corrosion of Ni-Ti and stainless steal in fibrinogen AS is not as high as mucin and IgG AS. There are different patterns of deposition formation on the metal surface by different types of protein, which is associated with their effects on the corrosion process of the alloys.

  11. Measuring the corrosion rate of steel in concrete – effect of measurement technique, polarisation time and current

    DEFF Research Database (Denmark)

    Nygaard, Peter Vagn; Geiker, Mette Rica

    2012-01-01

    , are in some studies considered the main reasons for the variations. This paper presents an experimental study on the quantitative effect of polarisation time and current on the measured polarisation resistance – and thus the corrosion current density – of passively and actively corroding steel. Two...... electrochemical techniques often used in instruments for on-site corrosion rate measurements are investigated. On passively corroding reinforcement the measured polarisation resistance was for both techniques found to be highly affected by the polarisation time and current and no plateaus at either short or long...... rate for actively corroding steel. For both techniques guidelines for polarisation times and currents are given for (on-site) non-destructive corrosion rate measurements on reinforcement steel in concrete....

  12. Effect of electrochemical corrosion on the subsurface microstructure evolution of a CoCrMo alloy in albumin containing environment

    International Nuclear Information System (INIS)

    Wang, Zhongwei; Yan, Yu; Su, Yanjing; Qiao, Lijie

    2017-01-01

    Highlights: • Accelerated electrochemical corrosion results in severer plastic deformation with finer grains. • Lower applied potential can increase protein adsorption on sample surfaces. • The tribo-film decreases the shear stresses and relief subsurface deformation. • Tribocorrosion induced passive film can suppress the annihilation of stacking faults. - Abstract: The subsurface microstructures of metallic implants play a key role in bio-tribocorrosion. Due to wear or change of local environment, the implant surface can have inhomogeneous electrochemical corrosion properties. In this work, the effect of electrochemical corrosion conditions on the subsurface microstructure evolution of CoCrMo alloys for artificial joints was investigated. Transmission electron microscope (TEM) was employed to observe the subsurface microstructures of worn areas at different applied potentials in a simulated physiological solution. The results showed that applied potentials could affect the severity of the subsurface deformation not only by changing the surface passivation but also affecting the adsorption of protein on the alloy surface.

  13. Effect of electrochemical corrosion on the subsurface microstructure evolution of a CoCrMo alloy in albumin containing environment

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhongwei; Yan, Yu, E-mail: yanyu@ustb.edu.cn; Su, Yanjing; Qiao, Lijie

    2017-06-01

    Highlights: • Accelerated electrochemical corrosion results in severer plastic deformation with finer grains. • Lower applied potential can increase protein adsorption on sample surfaces. • The tribo-film decreases the shear stresses and relief subsurface deformation. • Tribocorrosion induced passive film can suppress the annihilation of stacking faults. - Abstract: The subsurface microstructures of metallic implants play a key role in bio-tribocorrosion. Due to wear or change of local environment, the implant surface can have inhomogeneous electrochemical corrosion properties. In this work, the effect of electrochemical corrosion conditions on the subsurface microstructure evolution of CoCrMo alloys for artificial joints was investigated. Transmission electron microscope (TEM) was employed to observe the subsurface microstructures of worn areas at different applied potentials in a simulated physiological solution. The results showed that applied potentials could affect the severity of the subsurface deformation not only by changing the surface passivation but also affecting the adsorption of protein on the alloy surface.

  14. A Statistical Study on the Effect of Hydrostatic Pressure on Metastable Pitting Corrosion of X70 Pipeline Steel.

    Science.gov (United States)

    Yang, Zixuan; Kan, Bo; Li, Jinxu; Qiao, Lijie; Volinsky, Alex A; Su, Yanjing

    2017-11-14

    Hydrostatic pressure effects on pitting initiation and propagation in X70 steel are investigated by evaluating metastable pitting probability using electrochemical methods and immersion corrosion tests in containing chlorine ion solution. Potentiodynamic tests indicated that hydrostatic pressure can decrease the breakdown potential and lead to a reduced transpassivity region. Metastable test results revealed that hydrostatic pressure can increase metastable pitting formation frequency and promote stabilization of metastable pitting growth. Electrochemical impedance spectroscopy (EIS) results indicate that Hydrostatic pressure decreases the charge transfer resistance and increases the dissolution rate within the cavities. Corrosion test results also indicated that pitting initiation and propagation are accelerated by hydrostatic pressure. Result validity was verified by evaluating metastable pitting to predict pitting corrosion resistance.

  15. Effect of cloric acid concentration on corrosion behavior of Ni/Cr coated on carbon steel

    Science.gov (United States)

    Desiati, Resetiana Dwi; Sugiarti, Eni; Thosin, K. A. Zaini

    2018-05-01

    Corrosion is one of the causes of metal degradation. Carbon steel (Fe) is easy to corrode in the extreme environment. Coating on carbon steel is required to improve corrosion resistance owing to protection or hindrance to extreme environmental conditions. In this present work, carbon steel was coated by electroplating techniques for nickel and pack cementation for chrome. The corrosion rate test was performed by Weight Loss method on FeNiCr, FeNi, FeCr and uncoated Fe as comparator which was dyed in 37% HCl and 25% HCl which had previously been measured dimension and mass. The immersion test result of FeNiCr and FeNi specimen were better than FeCr and uncoated Fe in terms of increasing corrosion resistance. The corrosion rate for 56 hours in 37% HCl for FeNiCr was 1.592 mm/y and FeNi was 3.208 mm/y, FeCr only lasted within 32 hours with corrosion rate was 6.494 mm/y. Surface of the sample after the corrosion test there was pitting, crevice corrosion and alloy cracking caused by chloride. The higher the concentration of HCl the faster the corrosion rate.

  16. Characterization of the corrosion resistance of biologically active solutions: The effects of anodizing and welding

    Science.gov (United States)

    Walsh, Daniel W.

    1991-01-01

    An understanding of fabrication processes, metallurgy, electrochemistry, and microbiology is crucial to the resolution of microbiologically influenced corrosion (MIC) problems. The object of this effort was to use AC impedance spectroscopy to characterize the corrosion resistance of Type II anodized aluminum alloy 2219-T87 in sterile and biologically active media and to examine the corrosion resistance of 316L, alloy 2219-T87, and titanium alloy 6-4 in the welded and unwelded conditions. The latter materials were immersed in sterile and biologically active media and corrosion currents were measured using the polarization resistance (DC) technique.

  17. The effect of heat treatment and test parameters on the aqueous stress corrosion cracking of D6AC steel

    Science.gov (United States)

    Gilbreath, W. P.; Adamson, M. J.

    1974-01-01

    The crack growth behavior of D6AC steel as a function of stress intensity, stress and corrosion history and test technique, under sustained load in natural seawater, 3.3 percent NaCl solution, distilled water, and high humidity air was investigated. Reported investigations of D6AC were considered with emphasis on thermal treatment, specimen configuration, fracture toughness, crack-growth rates, initiation period, threshold, and the extension of corrosion fatigue data to sustained load conditions. Stress history effects were found to be most important in that they controlled incubation period, initial crack growth rates, and apparent threshold.

  18. Effects of Dy and Nb on the magnetic properties and corrosion resistance of sintered NdFeB

    International Nuclear Information System (INIS)

    Yu, L.Q.; Wen, Y.H.; Yan, M.

    2004-01-01

    Dy and Nb were added into the sintered NdFeB magnets with the aim of improving their magnetic properties and corrosion resistance. It was found that intrinsic coercivity of magnets is promoted whilst remanence is reduced as a result of Dy addition. Simultaneous addition of Dy and Nb not only gives rise to greatly improved coercivity, but also suppresses the undesirable effect of Dy on the remanence. The optimum magnetic properties were achieved when 1.0% Dy and 1.5% Nb were incorporated. Moreover, corrosion resistance of NdFeB magnets improves with the increase in the content of Dy and Nb

  19. Effect of agressive medium movement of local corrosion of the steel - 12Kh18N10T

    International Nuclear Information System (INIS)

    Makartsev, V.V.; Pakhomov, V.S.; Abramova, I.M.

    1980-01-01

    The effect of agressive medium movement on the formation of pitting corrosion of the 12Kh18N10T stainless steel in the acidic chloride-nitrate solution at room temperature is studied. It is established that the agressive medium movement hinders the formation of pitting corrosion at potentials more negative than +0.4 V and practically does not affect it at more positive potentials. The investigations have been carried out on a disc electrode rotating at a speed from 0 to 2000 rot./min

  20. Review on stress corrosion and corrosion fatigue failure of centrifugal compressor impeller

    Science.gov (United States)

    Sun, Jiao; Chen, Songying; Qu, Yanpeng; Li, Jianfeng

    2015-03-01

    Corrosion failure, especially stress corrosion cracking and corrosion fatigue, is the main cause of centrifugal compressor impeller failure. And it is concealed and destructive. This paper summarizes the main theories of stress corrosion cracking and corrosion fatigue and its latest developments, and it also points out that existing stress corrosion cracking theories can be reduced to the anodic dissolution (AD), the hydrogen-induced cracking (HIC), and the combined AD and HIC mechanisms. The corrosion behavior and the mechanism of corrosion fatigue in the crack propagation stage are similar to stress corrosion cracking. The effects of stress ratio, loading frequency, and corrosive medium on the corrosion fatigue crack propagation rate are analyzed and summarized. The corrosion behavior and the mechanism of stress corrosion cracking and corrosion fatigue in corrosive environments, which contain sulfide, chlorides, and carbonate, are analyzed. The working environments of the centrifugal compressor impeller show the behavior and the mechanism of stress corrosion cracking and corrosion fatigue in different corrosive environments. The current research methods for centrifugal compressor impeller corrosion failure are analyzed. Physical analysis, numerical simulation, and the fluid-structure interaction method play an increasingly important role in the research on impeller deformation and stress distribution caused by the joint action of aerodynamic load and centrifugal load.

  1. Effect of 1,2,4-triazole on galvanic corrosion between cobalt and copper in CMP based alkaline slurry

    Science.gov (United States)

    Fu, Lei; Liu, Yuling; Wang, Chenwei; Han, Linan

    2018-04-01

    Cobalt has become a new type of barrier material with its unique advantages since the copper-interconnects in the great-large scale integrated circuits (GLSI) into 10 nm and below technical nodes, but cobalt and copper have severe galvanic corrosion during chemical–mechanical flattening. The effect of 1,2,4-triazole on Co/Cu galvanic corrosion in alkaline slurry and the control of rate selectivity of copper and cobalt were investigated in this work. The results of electrochemical experiments and polishing experiments had indicated that a certain concentration of 1,2,4-triazole could form a layer of insoluble and dense passive film on the surface of cobalt and copper, which reduced the corrosion potential difference between cobalt and copper. Meantime, the removal rate of cobalt and copper could be effectively controlled according to demand during the CMP process. When the study optimized slurry was composed of 0.5 wt% colloidal silica, 0.1 %vol. hydrogen peroxide, 0.05 wt% FA/O, 345 ppm 1,2,4-triazole, cobalt had higher corrosion potential than copper and the galvanic corrosion could be reduced effectively when the corrosion potential difference between them decreased to 1 mV and the galvanic corrosion current density reached 0.02 nA/cm2. Meanwhile, the removal rate of Co was 62.396 nm/min, the removal rate of Cu was 47.328 nm/min, so that the removal rate ratio of cobalt and copper was 1.32 : 1, which was a good amendment to the dishing pits. The contact potential corrosion of Co/Cu was very weak, which could be better for meeting the requirements of the barrier CMP. Project supported by the Major National Science and Technology Special Projects (No. 2016ZX02301003-004-007), the Natural Science Foundation of Hebei Province, China (No. F2015202267), and the Outstanding Young Science and Technology Innovation Fund of Hebei University of Technology (No. 2015007).

  2. Stress corrosion mechanisms of alloy-600 polycrystals and monocrystals in primary water: effect of hydrogen

    International Nuclear Information System (INIS)

    Foct, F.

    1999-01-01

    The aim of this study is to identify the mechanisms involved in Alloy 600 primary water stress corrosion cracking. Therefore, this work is mainly focussed on the two following points. The first one is to understand the influence of hydrogen on SCC of industrial Alloy 600 and the second one is to study the crack initiation and propagation on polycrystals and single crystals. A cathodic potential applied during slow strain rate tests does not affect crack initiation but increases the slow crack growth rate by a factor 2 to 5. Cathodic polarisation, cold work and 25 cm 3 STP/kg hydrogen content increase the slow CGR so that the K ISCC (and therefore fast CGR) is reached. The influence of hydrogenated primary water has been studied for the first time on Alloy 600 single crystals. Cracks cannot initiate on tensile specimens but they can propagate on pre-cracked specimens. Transgranular cracks present a precise crystallographic aspect which is similar to that of 316 alloy in MgCl 2 solutions. Moreover, the following results improve the description of the cracking conditions. Firstly, the higher the hydrogen partial pressure, the lower the Alloy 600 passivation current transients. Since this result is not correlated with the effect of hydrogen on SCC, cracking is not caused by a direct effect of dissolved hydrogen on dissolution. Secondly, hydrogen embrittlement of Alloy 600 disappears at temperatures above 200 deg.C. Thirdly, grain boundary sliding (GBS) does not directly act on SCC but shows the mechanical weakness of grain boundaries. Regarding the proposed models for Alloy 600 SCC, it is possible to draw the following conclusions. Internal oxidation or absorbed hydrogen effects are the most probable mechanisms for initiation. Dissolution, internal oxidation and global hydrogen embrittlement models cannot explain crack propagation. On the other hand, the Corrosion Enhanced Plasticity Model gives a good description of the SCC propagation. (author)

  3. Effect of sulfide on the corrosion behavior of pure copper under anaerobic condition and possibility of super long lifetime for copper overpacks

    International Nuclear Information System (INIS)

    Taniguchi, Naoki; Naitou, Morimasa; Kawasaki, Manabu

    2007-03-01

    In general, copper is thermodynamically stable under anaerobic condition, so that corrosion due to water reduction can not be occurred on copper. In the presence of sulfide, however, this property of immunity to corrosion is lost and corrosion as copper sulfide is occurred. Therefore, it is necessary to understand the effect of sulfide on the corrosion behavior of copper for using the copper as a material for overpacks. In this study, immersion tests and stress corrosion cracking tests were carried out using synthetic seawater containing sodium sulfide. Based on the experimental results, the possibility of super long lifetime for copper overpacks was discussed. The results were summarized as follows; 1) As the results of the immersion tests of copper in buffer material for 2 years, the corrosion rates became large with increase in the concentration of sodium sulfide. The corrosion rates of copper in sodium sulfide of 0.001M, 0.005M and 0.1M were estimated to be 0.55μm/y, 2.2μm/y, 15μm/y respectively. 2) Corrosion product film with black or dark-gray was formed on the surface of copper specimens, and it was identified as Cu 2 S(Chalcocite) by the X-ray diffraction. 3) As the results of stress corrosion cracking experiments by means of slow strain rate technique, copper has little susceptibility to crack initiation for the specimen of the experiment under 0.001M-Na 2 S condition. Obvious cracks were observed for the specimens of the experiment over 0.005M Na 2 S condition. 4) According to the results of immersion tests and stress corrosion cracking tests, copper overpacks have a potential to accomplish super long lifetime far over 1000 years owing to very low corrosion rate and no stress corrosion cracking if the sulfide concentration in repository environment is promised to be less than 0.001M. (author)

  4. The effect of fly ashes in the corrosion and durability in concretes; Efecto de las Cenizas Volantes en la Durabilidad y en la Corrosion en Armaduras del Hormigon

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-12-31

    From the beginning of this century, fly ashes have been the object of a variety of studies and research-looking for different ways of application. The construction industry reuses the highest volume of the fly ash actually produced. Researches carried out on the behaviour of hydraulic blended materials mixed with fly ash have supported the progressive use of these by-products, and simultaneously have opened new ways of application. Spanish fly ash producers together with research centers, as IETcc, have been involved in investigations since 70`s. The last important research carried out has been the one dealing with the durability of concrete made with fly ash and its interaction with the corrosion of reinforcements. In this work five fly ashes of silicon-aluminous type were mixed with portland cement containing low alkali and aluminates in order to enhance the effect of those components from the fly ash. The main goal was to study the degradation mechanisms of concretes made with fly ashes, substituting partially the cement (15 and 35%) in several aggressive media: containing sulfates, chlorides or sea water. The effect to these aggressive media on the durability has also been considered regarding reinforcements. Different type of tests were carried out in laboratory and under natural exposure. In the case of laboratory studies the objectives were: 1) to stablish the mechanisms of hardening. The effect of fly ashes in pozolanic reaction and in the microstructure of the material. 2) Resistance of the addition of fly ashes against chloride and sulfates. Definition of the deterioration mechanisms. 3) Effect of fly ashes on the corrosion of reinforcements. Influence on the passivation process. Resistance against carbonation and chloride attack. (Author)

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

    Science.gov (United States)

    Dur, Ender

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

  6. Understanding corrosion behavior of Mg-Zn-Ca alloys from subcutaneous mouse model: effect of Zn element concentration and plasma electrolytic oxidation.

    Science.gov (United States)

    Jang, Yongseok; Tan, Zongqing; Jurey, Chris; Xu, Zhigang; Dong, Zhongyun; Collins, Boyce; Yun, Yeoheung; Sankar, Jagannathan

    2015-03-01

    Mg-Zn-Ca alloys are considered as suitable biodegradable metallic implants because of their biocompatibility and proper physical properties. In this study, we investigated the effect of Zn concentration of Mg-xZn-0.3Ca (x=1, 3 and 5wt.%) alloys and surface modification by plasma electrolytic oxidation (PEO) on corrosion behavior in in vivo environment in terms of microstructure, corrosion rate, types of corrosion, and corrosion product formation. Microstructure analysis of alloys and morphological characterization of corrosion products were conducted using x-ray computed tomography (micro-CT) and scanning electron microscopy (SEM). Elemental composition and crystal structure of corrosion products were determined using x-ray diffraction (XRD) and electron dispersive x-ray spectroscopy (EDX). The results show that 1) as-cast Mg-xZn-0.3Ca alloys are composed of Mg matrix and a secondary phase of Ca2Mg6Zn3 formed along grain boundaries, 2) the corrosion rate of Mg-xZn-0.3Ca alloys increases with increasing concentration of Zn in the alloy, 3) corrosion rates of alloys treated by PEO sample are decreased in in vivo environment, and 4) the corrosion products of these alloys after in vivo tests are identified as brucite (Mg(OH)2), hydroxyapatite (Ca10(PO4)6(OH)2), and magnesite (MgCO3·3H2O). Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Stress Corrosion Cracking of Zircaloy-4 in Halide Solutions: Effect of Temperature

    Directory of Open Access Journals (Sweden)

    Farina S.B.

    2002-01-01

    Full Text Available Zircaloy-4 was found to be susceptible to stress corrosion cracking in 1 M NaCl, 1 M KBr and 1 M KI aqueous solutions at potentials above the pitting potential. In all the solutions tested crack propagation was initially intergranular and then changed to transgranular. The effect of strain rate and temperature on the SCC propagation was investigated. An increase in the strain rate was found to lead to an increase in the crack propagation rate. The crack propagation rate increases in the three solutions tested as the temperatures increases between 20 and 90 °C. The Surface-Mobility SCC mechanism accounts for the observation made in the present work, and the activation energy predicted in iodide solutions is similar to that found in the literature.

  8. Effect of heat treatment on the corrosion behaviour of Al-Zn alloys in seawater

    International Nuclear Information System (INIS)

    Siti Radiah Mohd Kamarudin; Muhamad Daud; Nur Ubaidah Saidin; Zaifol Samsu

    2010-01-01

    A study has been carried out to investigate the effect of heat treatment on the corrosion behaviour of Al-Zn alloys in seawater environment. The microstructure, potential and current capacity of the samples were studied. Open circuit potential (OCP) of 96 hours was measured against saturated calomel electrode (SCE) and estimating current capacity of the alloys were calculated by using protective current generated from the capacity test. For the microstructure study, optical microscope is used to examine the surface morphology before and after test. The results show that the heat treated samples of 2 hours at 550 degree Celsius and variation in alloys composition affected the values of alloys OCP, current capacity and microstructure. (author)

  9. Effects of Organic Corrosion Inhibitor and Chloride Ion Concentration on Steel Depassivation and Repassivation in Solution

    Institute of Scientific and Technical Information of China (English)

    WANG Zixiao; YU Lei; LIU Zhiyong; SONG Ning

    2015-01-01

    Effect of an organic corrosion inhibitor (OCI) named PCI-2014 added in chloride solution on the critical chlo-ride concentration of mild steel depassivation and the critical OCI concentrations for repairing the steel in different chlo-ride solution were investigated. The results show that the critical chloride concentration increases exponentially with raises of PCI-2014 concentration in the solution. Within a certain chloride ion concentration range, the critical PCI-2014 concentration for repairing the corroded steel is also increases exponentially with enhancement of chloride content in the solution. Atomic force microscopy images display the molecular particles of inhibitor are adsorbed on the steel surface and formed a protective layer. Analysis of X-ray photoelectron spectroscopy shows the chloride ions at the surface of steel are displaced by atoms or molecules of the inhibitor in chloride condition.

  10. Effect of Schiff's Bases as Corrosion Inhibitors on Mild Steel in Sulphuric Acid

    Directory of Open Access Journals (Sweden)

    R. K. Upadhyay

    2007-01-01

    Full Text Available Mass loss and thermometric methods have been used to study the corrosion inhibitory effect of synthesised Schiff's bases viz. N-(furfurilidine – 4- methoxy aniline (SB1, N-(furfurilidine – 4- methylaniline (SB2, N-(salicylidine – 4- methoxy aniline (SB3, N-(cinnamalidine – 4 –methoxy aniline (SB4 and N-(cinnamalidine - 2-methylaniline (SB5 on mild steel in sulphuric acid solutions. Results show that both methods have good agreement with each other and inhibition efficiency depends upon the concentration of inhibitor as well as that of acid. Maximum inhibition efficiency is shown at highest concentration of Schiff's bases at the highest strength of acid.

  11. The effects of Ti implantation on corrosion and adhesion of TiN coated stainless steel

    Science.gov (United States)

    Baba, K.; Nagata, S.; Hatada, R.; Daikoku, T.; Hasaka, M.

    1993-06-01

    Thin titanium nitride (TiN) films of 40 and 70 nm in thickness were deposited on austenitic-type 304 stainless steel substrates by a rf ion plating process, and these specimens were irradiated with 70 kV titanium ions at a fluence of 1 × 10 17/cm 2 by use of MEVVA IV metallic ion source at room temperature. After that TiN films of 2 μm were deposited by the same method. The results of X-ray photoelectron spectroscopy and Auger electron spectroscopy revealed that implanted titanium penetrated into the substrate and interfacial mixing was verified. The adhesion strength was estimated by a scratch test. It was found that ion implantation can enhance the adhesion strength between the film and the substrate. The corrosion resistance of the specimens was evaluated in aqueous solutions of sulfuric acid by an electrochemical method. Titanium implantation was extremely effective in suppressing the anodic dissolution of stainless steel.

  12. The Inhibition Effect of Potassium Iodide on the Corrosion of Pure Iron in Sulphuric Acid

    Directory of Open Access Journals (Sweden)

    Tarik Attar

    2014-01-01

    Full Text Available The use of inorganic inhibitors as an alternative to organic compounds is based on the possibility of degradation of organic compounds with time and temperature. The inhibition effect of potassium iodide on the corrosion of pure iron in 0.5 M H2SO4 has been studied by weight loss. It has been observed from the results that the inhibition efficiency (IE% of KI increases from 82.17% to 97.51% with the increase in inhibitor concentration from 1·10−4 to 2·10−3 M. The apparent activation energy (Ea and the equilibrium constant of adsorption (Kads were calculated. The adsorption of the inhibitor on the pure iron surface is in agreement with Langmuir adsorption isotherm.

  13. Mass transfer effects in feeder flow-accelerated corrosion wall thinning

    International Nuclear Information System (INIS)

    Pietralik, J.

    2008-01-01

    Flow conditions play a dominant role in Flow-Accelerated Corrosion (FAC) under certain conditions, e.g., in CANDU feeders. While chemistry and materials set the overall potential for FAC, flow conditions determine the local distribution of wall thinning. Recent plant data of feeders and laboratory tests confirms that there is a close relationship between local flow conditions, expressed by mass transfer coefficient, and FAC rate in CANDU feeder bends. The knowledge of local effects can be useful for minimizing the number of inspected components, predicting the location of the highest FAC rate for a given piping component, and determining what components or feeders should be replaced. A similar evaluation applies also to FAC in heat transfer equipment such as heat exchangers and steam generators. The objective of this paper is to examine the relationship between FAC rate and local mass transfer parameters. For FAC where the flow is dominant, the FAC rate is proportional to mass flux of ferrous ions. The mass flux is the product of the mass transfer coefficient and the concentration difference, or degree of saturation. The mass transfer coefficient describes the intensity of the transport of corrosion products (ferrous ions) from the oxide-water interface into the bulk water. Therefore, this parameter can be used for predicting the local distribution of FAC rate in the mass-transfer controlled FAC. The degree of saturation reduces the mass flux, thus reducing the FAC rate. This effect can be significant in long piping, e.g., in outlet feeders. The paper presents plant and laboratory evidence for the relationship between local mass transfer conditions and the FAC rate. It shows correlations for mass transfer coefficient in components that are highly susceptible to FAC and most important flow parameters that affect mass transfer coefficient. The role of surface roughness, wall shear stress, and local turbulence is also discussed. (author)

  14. Corrosion Inhibitors for Aluminum.

    Science.gov (United States)

    Muller, Bodo

    1995-01-01

    Describes a simple and reliable test method used to investigate the corrosion-inhibiting effects of various chelating agents on aluminum pigments in aqueous alkaline media. The experiments that are presented require no complicated or expensive electronic equipment. (DDR)

  15. Microscopic analysis of effect of shot peening on corrosion fatigue behavior of aluminum alloy

    International Nuclear Information System (INIS)

    Kim, Jong Cheon; Cheong, Seong Kyun

    2012-01-01

    The object of this study considers corrosion fatigue improvement of 7075-T6 aluminum by using shot peening treatment on 3.5% NaCl solution at room temperature. Aluminum alloy is generally used in aerospace structural components because of the light weight and high strength characteristics. Many studies have shown that an aluminum alloy can be approximately 50% lighter than other materials. Mostly, corrosion leads to earlier fatigue crack propagation under tensile conditions and severely reduces the life of structures. Therefore, the technique to improve material resistance to corrosion fatigue is required. Shot peening technology is widely used to improve fatigue life and other mechanical properties by induced compressive residual stress. Even the roughness of treated surface causes pitting corrosion, the compressive residual stress, which is induced under the surface layer of material by shot peening, suppersses the corrosion and increases the corrosion resistance. The experimental results for shot peened specimens were compared with previous work for non treated aluminum alloy. The results show that the shot peening treatment affects the corrosion fatigue improvement of aluminum alloys and the induced compressive residual stress by shot peening treatment improves the resistance to corrosion fatigue

  16. Effect of alloy elements on the anti-corrosion properties of low alloy ...

    Indian Academy of Sciences (India)

    Unknown

    2.2b Specimens installation: The specimens were installed vertically facing southward in plastic frames, as shown in figure 1, and were connected to each other with lead wires in order to simulate well the practical corrosion conditions in the open sea. The welding point was covered with epoxy resin to prevent corrosion due ...

  17. Effect of Chemical Environment and pH on AC Corrosion of Cathodically Protected Structures

    DEFF Research Database (Denmark)

    Junker-Holst, Andreas; Vendelbo Nielsen, Lars; Møller, Per

    2017-01-01

    and corrosion products is made using scanning electron microscopy and energy dispersive x-ray spectroscopy (SEM/EDS) and x-ray diffraction (XRD). The findings suggest an AC corrosion mechanism highly dependent on the build-up and break-down of calcareous deposits at high CP, which is clearly reflected...

  18. Effect of Admixed Micelles on the Microstructure Alterations of Reinforced Mortar Subjected to Chloride Induced Corrosion

    NARCIS (Netherlands)

    Hu, J.; Koleva, D.A.; Van Breugel, K.

    2011-01-01

    This paper reports the main results from the influence of the initially admixed nano-aggregates (0.5 g/l PEO113-b-PS70 micelles previously dissolved in demi-water) on microstructural alterations of the reinforced mortar subjected to chloride induced corrosion. The morphology of hydration/corrosion

  19. Effect of Plasma Nitriding Process Conditions on Corrosion Resistance of 440B Martensitic Stainless Steel

    Directory of Open Access Journals (Sweden)

    Łępicka Magdalena

    2014-09-01

    Full Text Available Martensitic stainless steels are used in a large number of various industrial applications, e.g. molds for plastic injections and glass moldings, automotive components, cutting tools, surgical and dental instruments. The improvement of their tribological and corrosion properties is a problem of high interest especially in medical applications, where patient safety becomes a priority. The paper covers findings from plasma nitrided AISI 440B (PN-EN or DIN X90CrMoV18 stainless steel corrosion resistance studies. Conventionally heat treated and plasma nitrided in N2:H2 reaction gas mixture (50:50, 65:35 and 80:20, respectively in two different temperature ranges (380 or 450°C specimens groups were examined. Microscopic observations and electrochemical corrosion tests were performed using a variety of analytical techniques. As obtained findings show, plasma nitriding of AISI 440B stainless steel, regardless of the process temperature, results in reduction of corrosion current density. Nevertheless, applying thermo-chemical process which requires exceeding temperature of about 400°C is not recommended due to increased risk of steel sensitization to intergranular and stress corrosion. According to the results, material ion nitrided in 450°C underwent leaching corrosion processes, which led to significant disproportion in chemical composition of the corroded and corrosion-free areas. The authors suggest further research into corrosion process of plasma nitrided materials and its degradation products.

  20. The Effect of Friction Stir Welding on Corrosion Behavior of Ti-6Al-4V

    Science.gov (United States)

    Nasresfahani, Ali Reza; Soltanipur, Abdol Reza; Farmanesh, Khosro; Ghasemi, Ali

    2017-09-01

    Fusion welding can deteriorate corrosion behavior of Ti-6Al-4V alloy. However, the use of friction stir welding leads to a more appropriate corrosion resistance. In this study, the corrosion resistance of welded zones of Ti-6Al-4V alloy using friction stir welding technique is evaluated. For these purposes, the study of structural characteristics using SEM and FESEM equipped with EDS micro-analyses was conducted. Micro-hardness test was also employed to estimate the hardness of welded zones. Corrosion behavior was investigated by a potentiostat instrument. SEM micrographs, EDS and XRD analyses confirmed non-uniformity of chemical composition within the welded zones. The results reveal that the stir zone contains typical alpha and prior beta phases. Nevertheless, thermomechanical zone included equiaxed and bimodal lamellae structure. Furthermore, the presence of different types of phases and microstructure in the thermomechanical zone led to reduced corrosion resistance. The corresponding values of corrosion current density in the stir zone, thermomechanical zone and base metal were 0.048, 0.55 and 0.032 µA, respectively. Corresponding corrosion potential for these zones was estimated as -207, -110 and -157 mV. Evidently, the results show that corrosion resistance of thermomechanical zone is less than that of the stir zone and both zones have lower value than the base metal.

  1. Microscopic analysis of effect of shot peening on corrosion fatigue behavior of aluminum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong Cheon; Cheong, Seong Kyun [Seoul Nat' l Univ. of Science and Technology, Seoul (Korea, Republic of)

    2012-11-15

    The object of this study considers corrosion fatigue improvement of 7075-T6 aluminum by using shot peening treatment on 3.5% NaCl solution at room temperature. Aluminum alloy is generally used in aerospace structural components because of the light weight and high strength characteristics. Many studies have shown that an aluminum alloy can be approximately 50% lighter than other materials. Mostly, corrosion leads to earlier fatigue crack propagation under tensile conditions and severely reduces the life of structures. Therefore, the technique to improve material resistance to corrosion fatigue is required. Shot peening technology is widely used to improve fatigue life and other mechanical properties by induced compressive residual stress. Even the roughness of treated surface causes pitting corrosion, the compressive residual stress, which is induced under the surface layer of material by shot peening, suppersses the corrosion and increases the corrosion resistance. The experimental results for shot peened specimens were compared with previous work for non treated aluminum alloy. The results show that the shot peening treatment affects the corrosion fatigue improvement of aluminum alloys and the induced compressive residual stress by shot peening treatment improves the resistance to corrosion fatigue.

  2. The effect of laser treatment on the wear resistance of steel in corrosive media

    International Nuclear Information System (INIS)

    Plyatsko, G.V.; Porter, A.I.; Prejs, G.A.; Mojsa, M.I.

    1975-01-01

    The corrosion mechanical wearing properties of steel 45 treated with a laser beam (H 100 =7800 Mn/sq.m) under friction with nitrated steel 40KhNMA (HV=7000 Mn/sq.m), chrome cast iron Kh15M (hardened and low-temperature tempered, modified), perlite cast iron and bronze are studied. The aqueous buffers with pH=6 and 11 are used as a corrosion active media. In a weakly acid medium the most intensive wearing of steel 40KhNMA is observed at P=8 Mn/sq.m. Its wearing reduces due to increase of pressure to 12 Mn/sq.m. Extent of steel 45 wearing increases with pressure increase from 8 to 12 Mn/sg.m. Friction coefficient of this pair changes by jumps at an increase of normal pressure and its variation range is smaller than that observed in an alkaline medium. The maximum value of friction coefficient is shifted to the higher pressure. The wearing of cast iron Kh15M-steel 45 pair has an alternative pattern. In an alkaline medium the cast iron wearing intensity shows a linear increase with the normal contact pressure but that of the steel changes jumpwise attaining extreme at 8 and 12 Mn/sq.m. In a weak acid medium the intensity of grasping and graphitization at the friction surface of cast iron Kh15M-steel 45 pair is higher than that in the alkaline medium. Experiments demonstrate an effectiveness of the laser beam treatment of steel 45 for its friction in the alkaline medium with nitrated steel 40KhNMA and with hardened low-temperature tempered cast iron 45 under friction contact pressure as high as 8 Mn/sq.m, and in acid medium at 12 and 8 Mn/sq.m respectively. The laser treatment provides high corrosion-mechanical stability of steel 45 and the counterbodies described, as well as the low friction coefficient of these pairs

  3. Effect of heat treatments and minor elements on caustic stress corrosion cracking of type 304 stainless steel

    International Nuclear Information System (INIS)

    Yamanaka, Kazuo; Kowaka, Masamichi

    1983-01-01

    The effect of heat treatments and minor elements (C, S, P, N) on caustic stress corrosion cracking of Type 304 stainless steel in boiling 34% NaOH solution at 393 K was studied. The results obtained as follows: (1) Susceptibility to IGSCC (intergranular stress corrosion cracking) in NaOH solution was increased with the intergranular precipitation of chromium carbides by the sensitizing heat treatments, but was not completely consistent with the susceptibility to IGC (intergranular corrosion) by Strauss test in H 2 SO 4 + CuSO 4 solution. (2) SCC in NaOH solution took place in three potential ranges of about -100 to +150 mV (vs SCE), -600 to -300 mV and -1100 to -900 mV. Transglanular cracking predominantly occurred in the first region and intergranular cracking occurred in the latter two regions. IGC occurred in the potential range of about -400 to 0 mV. No IGC was observed at corrosion potential. (3) Among minor elements carbon and sulfur had a detrimental effect on SCC, but no effect of phosphorus and nitrogen was almost observed on SCC in NaOH solution. (author)

  4. The Effect of General Corrosion on the Guided Wave Inspection of the Pipeline

    Directory of Open Access Journals (Sweden)

    Zhang Jin Heng

    2016-01-01

    Full Text Available The guided wave method can inspect pipelines very quickly and widely. For instance, it can inspect the overall pipelines by digging several detection pits or removing part of coating material to set the array ring. However, it will make the guided wave attenuate more seriously and make the signals hard to identify when setting the array ring on the general corrosion. In this study, the wave propagation will be discussed when the general corrosion is under the array ring and the severe localized corrosion is inside the general corrosion via experiment and finite element method. The results showed that the excitation energy will be lower when the array ring set on the pipe surface with the general corrosion. By two-dimensional Fourier transform analysis, its non-uniform contact surface will increase asymmetric modal and mix signals. The energy attenuation will increase when the corrosion depth is deepened or the inspection frequency is risen. For example, the 2 mm deep general corrosion will attenuate −1.09 dB/m at 20 kHz and attenuate −3.01 dB/m at 40 kHz; the 4 mm deep general corrosion will attenuation −5.76 dB/m at 20 kHz and attenuation −23.19 dB/m at 40 kHz. However, the coherent signals which were caused by the general corrosion will decay with increasing frequency. For example, the coherent signals of 2 mm deep general corrosion are −23.67 dB at 20 kHz and −35.44 dB at 40 kHz; then, the 20 mm long and 3.5 mm deep localized corrosion which signal is −26.34 dB at 20 kHz and −26.94 dB at 40 kHz will be detected easily at high frequency. It can provide detectors to understand the impact when the array ring set on the area of general corrosion and the way to distinguish the localized corrosion which is inside the area of general corrosion.

  5. Effects of Friction Stir Welding on Corrosion Behaviors of AA2024-T4 Aluminum Alloy

    Directory of Open Access Journals (Sweden)

    Ales Steve Korakan

    2017-01-01

    Full Text Available In this work, the corrosion behavior of welded joints of AA2024-T4 Al alloy produced by friction stir welding process has been investigated. Tests were performed in an aerated 3.5% NaCl aqueous solution with pH = 7 at 20±2°C. Corrosion rate and corrosion morphology of weld regions were evaluated and compared to those of the parent metal. The microstructure of weld nugget, thermomechanical affected zone, heated affected zone, and parent metal were analyzed using scanning electron microscopy and energy dispersive spectroscopy. It was observed that corrosion initiated at FSW related spots and the sizes of local corrosion increased with time.

  6. Temperature factors effect on occurrence of stress corrosion cracking of main gas pipeline

    Science.gov (United States)

    Nazarova, M. N.; Akhmetov, R. R.; Krainov, S. A.

    2017-10-01

    The purpose of the article is to analyze and compare the data in order to contribute to the formation of an objective opinion on the issue of the growth of stress corrosion defects of the main gas pipeline. According to available data, a histogram of the dependence of defects due to stress corrosion on the distance from the compressor station was constructed, and graphs of the dependence of the accident density due to stress corrosion in the winter and summer were also plotted. Data on activation energy were collected and analyzed in which occurrence of stress corrosion is most likely constructed, a plot of activation energy versus temperature is plotted, and the process of occurrence of stress corrosion by the example of two different grades of steels under the action of different temperatures was analyzed.

  7. Effect of water impurities on stress corrosion cracking in a boiling water reactor

    International Nuclear Information System (INIS)

    Ljungbery, L.G.; Cubicciotti, D

    1985-01-01

    A series of stress corrosion tests, including corrosion potential and water chemistry measurements, has been performed in the Swedish Ringhals-1 boiling water reactor. Tests have been run under reactor start-up and reactor power operation with normal reactor water conditions and with alternate water chemistry in which hydrogen is added to the feedwater to suppress stress corrosion cracking. During one alternate water chemistry test, there was significant intergranular corrosion cracking of sensitized stainless specimens. It is shown that nitrate and sulfate, arising from an accidental resin intrusion, are likely causes. Nitrate increases the oxidizing power of the water, and sulfate enhances cracking under oxidizing conditions. During another test under start-up conditions, enhanced transgranular stress corrosion cracking in low alloy steels and possibly initiation of cracking in a nickel base alloy was observed as a result of resin intrusion into the reactor water. The intrusion produced acid and sulfate, which are believed to enhance hydrogen cracking conditions

  8. Effects of simulated inflammation on the corrosion of 316L stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Brooks, Emily K.; Brooks, Richard P. [Department of Biomedical Engineering, State University of New York at Buffalo (United States); Ehrensberger, Mark T., E-mail: mte@buffalo.edu [Department of Biomedical Engineering, State University of New York at Buffalo (United States); Department of Orthopaedics, State University of New York at Buffalo (United States)

    2017-02-01

    Stainless steel alloys, including 316L, find use in orthopaedics, commonly as fracture fixation devices. Invasive procedures involved in the placement of these devices will provoke a local inflammatory response that produces hydrogen peroxide (H{sub 2}O{sub 2}) and an acidic environment surrounding the implant. This study assessed the influence of a simulated inflammatory response on the corrosion of 316L stainless steel. Samples were immersed in an electrolyte representing either normal or inflammatory physiological conditions. After 24 h of exposure, electrochemical impedance spectroscopy (EIS) and inductively coupled plasma mass spectroscopy (ICPMS) were used to evaluate differences in corrosion behavior and ion release induced by the inflammatory conditions. Scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDX) were used to evaluate surface morphology and corrosion products formed on the sample surface. Inflammatory conditions, involving the presence of H{sub 2}O{sub 2} and an acidic pH, significantly alter the corrosion processes of 316L stainless steel, promoting aggressive and localized corrosion. It is demonstrated that particular consideration should be given to 316L stainless steel implants with crevice susceptible areas (ex. screw-head/plate interface), as those areas may have an increased probability of rapid and aggressive corrosion when exposed to inflammatory conditions. - Highlights: • The corrosion of 316L exposed to simulated inflammation is examined. • Inflammation is replicated with an acidic electrolyte containing hydrogen peroxide. • Inflammatory conditions increase 316L corrosion compared to normal conditions. • Accelerated corrosion under inflammation is likely due to crevice corrosion. • Care should be taken using 316L in devices with crevice susceptible areas.

  9. Oxidation effect on steel corrosion and thermal loads during corium melt in-vessel retention

    Energy Technology Data Exchange (ETDEWEB)

    Granovsky, V.S.; Khabensky, V.B.; Krushinov, E.V.; Vitol, S.A.; Sulatsky, A.A.; Almjashev, V.I. [Alexandrov Scientific-Research Technology Institute (NITI), Sosnovy Bor (Russian Federation); Bechta, S.V. [KTH, Stockholm (Sweden); Gusarov, V.V. [SPb State Technology University (SPbGTU), St. Petersburg (Russian Federation); Barrachin, M. [Institut de Radioprotection et de Sûreté Nucléaire (IRSN), St Paul lez Durance (France); Bottomley, P.D., E-mail: paul.bottomley@ec.europa.eu [EC-Joint Research Centre, Institute for Transuranium Elements (ITU), Karlsruhe (Germany); Fischer, M. [AREVA GmbH, Erlangen (Germany); Piluso, P. [Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA), Cadarache, St Paul lez Durance (France)

    2014-10-15

    Highlights: • The METCOR facility simulates vessel steel corrosion in contact with corium. • Steel corrosion rates in UO{sub 2+x}–ZrO{sub 2}–FeO{sub y} coria accelerate above 1050 K. • However corrosion rates can also be limited by melt O{sub 2} supply. • The impact of this on in-vessel retention (IVR) strategy is discussed. - Abstract: During a severe accident with core meltdown, the in-vessel molten core retention is challenged by the vessel steel ablation due to thermal and physicochemical interaction of melt with steel. In accidents with oxidizing atmosphere above the melt surface, a low melting point UO{sub 2+x}–ZrO{sub 2}–FeO{sub y} corium pool can form. In this case ablation of the RPV steel interacting with the molten corium is a corrosion process. Experiments carried out within the International Scientific and Technology Center's (ISTC) METCOR Project have shown that the corrosion rate can vary and depends on both surface temperature of the RPV steel and oxygen potential of the melt. If the oxygen potential is low, the corrosion rate is controlled by the solid phase diffusion of Fe ions in the corrosion layer. At high oxygen potential and steel surface layer temperature of 1050 °C and higher, the corrosion rate intensifies because of corrosion layer liquefaction and liquid phase diffusion of Fe ions. The paper analyzes conditions under which corrosion intensification occurs and can impact on in-vessel melt retention (IVR)

  10. 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.

  11. 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

  12. Smart Coatings for Corrosion Protection

    Science.gov (United States)

    Calle, Luz Marina; Li, Wendy; Buhrow, Jerry W.; Johnsey, Marissa N.

    2016-01-01

    Nearly all metals and their alloys are subject to corrosion that causes them to lose their structural integrity or other critical functionality. It is essential to detect corrosion when it occurs, and preferably at its early stage, so that action can be taken to avoid structural damage or loss of function. Protective coatings are the most commonly used method of corrosion control. However, progressively stricter environmental regulations have resulted in the ban of many commercially available corrosion protective coatings due to the harmful effects of their solvents or corrosion inhibitors. This work concerns the development of a multifunctional, smart coating for the autonomous control of corrosion. This coating is being developed to have the inherent ability to detect the chemical changes associated with the onset of corrosion and respond autonomously to indicate it and control it.

  13. Effect of H{sub 2}O{sub 2} on the corrosion behavior of 304L stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Song, Taek Ho

    1994-02-15

    In connection with the safe storage of high level nuclear waste, effect of H{sub 2}O{sub 2} on the corrosion behavior of 304L stainless steel was examined. Open circuit potentials and polarization curves were measured with and without H{sub 2}O{sub 2}. The experimental results show that H{sub 2}O{sub 2} increased corrosion potential and decreased pitting potential. The passive range, therefore, decreased as H{sub 2}O{sub 2} concentration increased, indicating that pitting resistance was decreased by the existence of H{sub 2}O{sub 2} in the electrolyte. These effects of H{sub 2}O{sub 2} on corrosion of 304L stainless steel are considered to be similar to those of γ-irradiation. To compare the effects of H{sub 2}O{sub 2} with those of O{sub 2}, cathodic and anodic polarization curves were made in three types of electrolyte such as aerated, deaerated, and stirred electrolyte. The experimental results show that the effects of H{sub 2}O{sub 2} on the corrosion behavior were very similar to those of O{sub 2} such as increase of corrosion potential, decrease of pitting resistance, and increase of repassivation potential. Further, H{sub 2}O{sub 2} played much greater role in controlling cathodic reaction rate in neutral water environment. In acid and alkaline media, potential shifts by H{sub 2}O{sub 2} were restricted by the large current density of proton reduction and by the le Chatelier's principle respectively.

  14. TEM characterisation of stress corrosion cracks in nickel based alloys: effect of chromium content and chemistry of environment

    International Nuclear Information System (INIS)

    Delabrouille, F.

    2004-11-01

    Stress corrosion cracking (SCC) is a damaging mode of alloys used in pressurized water reactors, particularly of nickel based alloys constituting the vapour generator tubes. Cracks appear on both primary and secondary sides of the tubes, and more frequently in locations where the environment is not well defined. SCC sensitivity of nickel based alloys depends of their chromium content, which lead to the replacement of alloy 600 (15 % Cr) by alloy 690 (30 % Cr) but this phenomenon is not yet very well understood. The goal of this thesis is two fold: i) observe the effect of chromium content on corrosion and ii) characterize the effect of environment on the damaging process of GV tubes. For this purpose, one industrial tube and several synthetic alloys - with controlled chromium content - have been studied. Various characterisation techniques were used to study the corrosion products on the surface and within the SCC cracks: SIMS; TEM - FEG: thin foil preparation, HAADF, EELS, EDX. The effect of chromium content and surface preparation on the generalised corrosion was evidenced for synthetic alloys. Moreover, we observed the penetration of oxygen along triple junctions of grain boundaries few micrometers under the free surface. SCC tests show the positive effect of chromium for contents varying from 5 to 30 % wt. Plastic deformation induces a modification of the structure, and thus of the protective character, of the internal chromium rich oxide layer. SCC cracks which developed in different chemical environments were characterised by TEM. The oxides which are formed within the cracks are different from what is observed on the free surface, which reveals a modification of medium and electrochemical conditions in the crack. Finally we were able to evidence some structural characteristics of the corrosion products (in the cracks and on the surface) which turn to be a signature of the chemical environment. (author)

  15. Solubility of oxygen in liquid sodium: effect on interpretation of corrosion data

    International Nuclear Information System (INIS)

    Claxton, K.T.

    1976-01-01

    No solubility correlation relating the equilibrium oxygen concentration with the sodium saturation temperature has yet been derived which has gained general acceptance. A statistical analysis of all the available data which directly or indirectly may be taken as representing a measurement of solubility has been made. The results indicate that a real and seemingly permanent difference is apparent between the assumed equilibrium levels of oxygen measured at different saturation temperatures as reported by UK and US workers. Data analysis procedures producing sub-sets of culled data which are then used to derive a compromise solubility function are considered less than adequate. It is considered preferable and more realistic to distinguish data sub-sets by the analytical technique employed. The established vacuum distillation method is shown to yield results differing among themselves by up to a factor of four at cold trap temperatures of relevance to fast reactor operation. The vanadium wire and electrochemical cell techniques are shown to give the lowest solubility values. Appropriate factors relating UK oxygen levels to values derived from alternative methods are presented. The divergent positions prevailing for oxygen-in-sodium analysis can lead to apparent anomalies when comparisons of corrosion rates from different sources have to be made. It is shown that this situation is, in part, apparently resolved by effecting comparisons at the equivalent cold trap temperature instead of the equivalent oxygen level. It is recognised that the approach presumes equilibrium of the oxygen in the sodium with the cold trap and reference is made to alternative ''sinks'' for oxygen. It is demonstrated, by comparison of a number of recommended and observed corrosion rates from US and European sources, that, in spite of the above and other qualifications, the approach is reasonable

  16. Effects of lipopolysaccharides on the corrosion behavior of Ni-Cr and Co-Cr alloys.

    Science.gov (United States)

    Yu, Weiqiang; Qian, Chao; Weng, Weimin; Zhang, Songmei

    2016-08-01

    Lipopolysaccharides (LPS) are constituents of gingival crevicular fluid and may affect the base metal alloys used in metal ceramic crowns. The role of LPS in base metal alloys is currently unknown. The purpose of this in vitro study was to evaluate the effects of gram-negative bacterial LPS on the electrochemical behavior of Ni-Cr and Co-Cr alloys. Alloy specimens were divided into 4 groups according to Escherichia coli LPS concentration (0, 0.15, 15, and 150 μg/mL) in acidic saliva (pH 5). Open circuit potential (OCP) and potentiodynamic polarization behavior were examined using a computer-controlled potentiostat. Metal ions released from the 2 alloys were measured by immersion in LPS-free solution and 150 μg/mL LPS solution and analyzed by inductively coupled plasma atomic emission spectrometry (ICP-AES). Data were evaluated using 1-way ANOVA (α=.05). Compared with control groups, medium LPS concentration (15 μg/mL) accelerated Ni-Cr alloy corrosion (Palloy corrosion (Pcorrosion current density, and polarization resistance parameters. After immersion in high LPS concentrations (150 μg/mL), a slight increase in Ni ion release (P >.05) was observed for the Ni-Cr alloy, while a more significant Co ion release (Palloy. LPS negatively affected the electrochemical behavior of both the Ni-Cr and Co-Cr alloys. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.