Pub Date : 2001-03-01DOI: 10.1179/bcj.2001.36.3.227
G. Brunoro, G. Laguzzi, L. Luvidi, C. Chiavari
Abstract This study concerns the corrosion behaviour of wrought 94 wt-%Cu–6 wt-%Sn (B6) bronze, whose composition is similar to materials used for outdoor bronze artefacts. In order to investigate the influence of the composition and microstructure on bronze corrosion processes, electrochemical ac and dc measurements in synthetic acid rain and chloride solutions were performed on the B6 binary alloy in comparison with an as cast bronze having a different degree of purity. Moreover, to perform thin layer activation (TLA) measurements of thickness loss, a suitable radio nuclide 65Zn (t½ = 244 days) was produced on B6 specimens by a high energy proton beam. Artificial weathering experiments have been carried out by exposing activated and non-activated B6 specimens: to selected pollutants including NOx and SO2 at different concentrations to simulate urban and industrial atmospheres; in a cyclic salt spray cabinet to investigate the effects of marine environments; to basic (NH4)2SO4 solutions reproducing the aggressiveness of ammonia containing wet deposits. At the end of each test, the B6 corrosion rates obtained by weight loss determinations have been compared with those arising from the TLA method. Finally, the nature and microstructure of the surface oxidation products were investigated.
{"title":"Corrosion evaluation of artificially aged 6 wt-% tin bronze","authors":"G. Brunoro, G. Laguzzi, L. Luvidi, C. Chiavari","doi":"10.1179/bcj.2001.36.3.227","DOIUrl":"https://doi.org/10.1179/bcj.2001.36.3.227","url":null,"abstract":"Abstract This study concerns the corrosion behaviour of wrought 94 wt-%Cu–6 wt-%Sn (B6) bronze, whose composition is similar to materials used for outdoor bronze artefacts. In order to investigate the influence of the composition and microstructure on bronze corrosion processes, electrochemical ac and dc measurements in synthetic acid rain and chloride solutions were performed on the B6 binary alloy in comparison with an as cast bronze having a different degree of purity. Moreover, to perform thin layer activation (TLA) measurements of thickness loss, a suitable radio nuclide 65Zn (t½ = 244 days) was produced on B6 specimens by a high energy proton beam. Artificial weathering experiments have been carried out by exposing activated and non-activated B6 specimens: to selected pollutants including NOx and SO2 at different concentrations to simulate urban and industrial atmospheres; in a cyclic salt spray cabinet to investigate the effects of marine environments; to basic (NH4)2SO4 solutions reproducing the aggressiveness of ammonia containing wet deposits. At the end of each test, the B6 corrosion rates obtained by weight loss determinations have been compared with those arising from the TLA method. Finally, the nature and microstructure of the surface oxidation products were investigated.","PeriodicalId":9349,"journal":{"name":"British Corrosion Journal","volume":"60 1","pages":"227 - 232"},"PeriodicalIF":0.0,"publicationDate":"2001-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81562146","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-03-01DOI: 10.1179/bcj.2001.36.3.179
M.C. Li, C. Zeng, H. Lin, C. Cao
Abstract The corrosion behaviour of type 316 stainless steel has been investigated in F- containing dilute hydrochloric acid and acetic acid solutions aerated with oxygen gas at 25°C using electrochemical measurement techniques. Both electrochemical impedance spectroscopy spectra and polarisation curves illustrate that 316 stainless steel can passivate in these solutions at the corrosion potential. The passive impedance decreases slightly with increasing F- concentration. The anodic polarisation curves show that low concentrations of F- ion have no significant influence on the passivity of 316 stainless steel, but the passivity is reduced by high concentrations of F- ions. In 0·1 M NaF solutions, an anodic current peak occurs at below the pitting potential. This does not appear in solutions with low concentrations of NaF, and is related to the F- accelerated reactions. During anodic polarisation, the selective dissolution of the Fe component takes place in the above solutions.
摘要采用电化学测量技术研究了316不锈钢在含F的稀盐酸和含氧乙酸溶液中25°C的腐蚀行为。电化学阻抗谱和极化曲线表明，316不锈钢在这些溶液中可以在腐蚀电位处钝化。无源阻抗随F-浓度的增加而略有下降。阳极极化曲线表明，低浓度的F离子对316不锈钢的钝化性没有显著影响，但高浓度的F离子降低了316不锈钢的钝化性。在0.1 M NaF溶液中，阳极电流峰值出现在点蚀电位以下。这在低浓度NaF溶液中不会出现，这与F加速反应有关。在阳极极化过程中，铁组分在上述溶液中选择性溶解。
{"title":"Electrochemical corrosion behaviour of type 316 stainless steel in acid media containing fluoride ions","authors":"M.C. Li, C. Zeng, H. Lin, C. Cao","doi":"10.1179/bcj.2001.36.3.179","DOIUrl":"https://doi.org/10.1179/bcj.2001.36.3.179","url":null,"abstract":"Abstract The corrosion behaviour of type 316 stainless steel has been investigated in F- containing dilute hydrochloric acid and acetic acid solutions aerated with oxygen gas at 25°C using electrochemical measurement techniques. Both electrochemical impedance spectroscopy spectra and polarisation curves illustrate that 316 stainless steel can passivate in these solutions at the corrosion potential. The passive impedance decreases slightly with increasing F- concentration. The anodic polarisation curves show that low concentrations of F- ion have no significant influence on the passivity of 316 stainless steel, but the passivity is reduced by high concentrations of F- ions. In 0·1 M NaF solutions, an anodic current peak occurs at below the pitting potential. This does not appear in solutions with low concentrations of NaF, and is related to the F- accelerated reactions. During anodic polarisation, the selective dissolution of the Fe component takes place in the above solutions.","PeriodicalId":9349,"journal":{"name":"British Corrosion Journal","volume":"18 1","pages":"179 - 183"},"PeriodicalIF":0.0,"publicationDate":"2001-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76395848","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-02-01DOI: 10.1179/000705901101501541
Xinqiang Wu, H. Jing, Yingkui Zheng, Z. Yao, W. Ke
Abstract Coke deposited on the inner wall of industrial HP cracker tubing during the cracking of ethane has been investigated in detail to elucidate the mechanism of the coking process. The outer wall of the deposit, adjacent to the metal tube, consists of filamentary coke. Lamellar coke occupies the central zone of the deposit, while the inner zone, adjacent to the reaction gases, is comprised of coke particles. The formation of the filamentary coke at the tube wall is closely related to composition of the tube material, but both the lamellar coke and the coke particles are derived from the gas phase reactions so bear no relation to the tube material. The difference in morphology between the lamellar and particulate types of coke is attributed to changes in the coking process. Possible ways to alleviate or prevent coking of the tube include reduction of the catalytic activity of the material at the inner wall of the tube and improvement of the ethylene steam cracking process.
{"title":"Coking of HP tubes in ethylene steam cracking plant and its mitigation","authors":"Xinqiang Wu, H. Jing, Yingkui Zheng, Z. Yao, W. Ke","doi":"10.1179/000705901101501541","DOIUrl":"https://doi.org/10.1179/000705901101501541","url":null,"abstract":"Abstract Coke deposited on the inner wall of industrial HP cracker tubing during the cracking of ethane has been investigated in detail to elucidate the mechanism of the coking process. The outer wall of the deposit, adjacent to the metal tube, consists of filamentary coke. Lamellar coke occupies the central zone of the deposit, while the inner zone, adjacent to the reaction gases, is comprised of coke particles. The formation of the filamentary coke at the tube wall is closely related to composition of the tube material, but both the lamellar coke and the coke particles are derived from the gas phase reactions so bear no relation to the tube material. The difference in morphology between the lamellar and particulate types of coke is attributed to changes in the coking process. Possible ways to alleviate or prevent coking of the tube include reduction of the catalytic activity of the material at the inner wall of the tube and improvement of the ethylene steam cracking process.","PeriodicalId":9349,"journal":{"name":"British Corrosion Journal","volume":"520 1","pages":"121 - 126"},"PeriodicalIF":0.0,"publicationDate":"2001-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77063308","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-02-01DOI: 10.1179/000705901101501587
F. H. Assaf, S. El-rehim, A. Zaky
Abstract The electrochemical behaviour of a brasses was studied in NaOH solutions using the cyclic voltammetric technique to establish the effect of such variables as alloy composition, reversal anodic potential, scan rate, NaOH concentration, and temperature. Compounds that formed on the surface during the anodic sweep were analysed using X-ray diffraction analysis (XRD). The data show that the voltammetric behaviour of – brass consists of two potential regions. The first or subcritical potential region was indicated by two anodic peaks designated A1 and A2. Within this potential region, selective dissolution of the less noble component, zinc, occurs (i.e. dezincification). The second potential region consists of three anodic peaks, designated A3, A4, and A5, where the two components of the alloy, namely copper and zinc, dissolve simultaneously. Alloying zinc with copper resulted in a decrease in the dissolution of zinc from the alloy. This behaviour could be explained on the basis that the dissolution is limited by the non-steady state diffusion of zinc atoms from the bulk of the alloy to the alloy solution interface, which implies that the rate determining step of dezincification is the diffusion of zinc atoms. The process of preferential dissolution of zinc leads to the formation of a layer rich in copper and depleted in zinc on the electrode surface.
{"title":"Cyclic voltammetric behaviour of – brass in alkaline media","authors":"F. H. Assaf, S. El-rehim, A. Zaky","doi":"10.1179/000705901101501587","DOIUrl":"https://doi.org/10.1179/000705901101501587","url":null,"abstract":"Abstract The electrochemical behaviour of a brasses was studied in NaOH solutions using the cyclic voltammetric technique to establish the effect of such variables as alloy composition, reversal anodic potential, scan rate, NaOH concentration, and temperature. Compounds that formed on the surface during the anodic sweep were analysed using X-ray diffraction analysis (XRD). The data show that the voltammetric behaviour of – brass consists of two potential regions. The first or subcritical potential region was indicated by two anodic peaks designated A1 and A2. Within this potential region, selective dissolution of the less noble component, zinc, occurs (i.e. dezincification). The second potential region consists of three anodic peaks, designated A3, A4, and A5, where the two components of the alloy, namely copper and zinc, dissolve simultaneously. Alloying zinc with copper resulted in a decrease in the dissolution of zinc from the alloy. This behaviour could be explained on the basis that the dissolution is limited by the non-steady state diffusion of zinc atoms from the bulk of the alloy to the alloy solution interface, which implies that the rate determining step of dezincification is the diffusion of zinc atoms. The process of preferential dissolution of zinc leads to the formation of a layer rich in copper and depleted in zinc on the electrode surface.","PeriodicalId":9349,"journal":{"name":"British Corrosion Journal","volume":"45 4 1","pages":"143 - 150"},"PeriodicalIF":0.0,"publicationDate":"2001-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79908956","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-02-01DOI: 10.1179/000705901101501523
S. Percival, J. Knapp, D. Wales, R. Edyvean
Abstract The aim of the present study was to estimate the concentrations of metal ions in biofilms within flowing and stagnant stainless steel systems since this could affect the suitability of stainless steel for use in potable water. There may be occasions when domestic plumbing systems are not used for long periods of time, leading to stagnation of the water, particularly if the supply system has been designed poorly. Stagnation can occur in dead-legs when water is left in the system for extended periods following pressure testing before going into service. It has been established that metal ions are leached from stainless steel in very low amounts. The highest detectable levels of metal ions leached from stainless steel into stagnant water and/or the biofilm were of iron, then molybdenum, nickel, and finally chromium. It seems unlikely that the concentrations of metal ions detected within both biofilms and flowing/stagnant water would adversely affect the suitability of stainless steel pipework for potable water supplies.
{"title":"Metal and inorganic ion accumulation in biofilms exposed to flowing and stagnant water","authors":"S. Percival, J. Knapp, D. Wales, R. Edyvean","doi":"10.1179/000705901101501523","DOIUrl":"https://doi.org/10.1179/000705901101501523","url":null,"abstract":"Abstract The aim of the present study was to estimate the concentrations of metal ions in biofilms within flowing and stagnant stainless steel systems since this could affect the suitability of stainless steel for use in potable water. There may be occasions when domestic plumbing systems are not used for long periods of time, leading to stagnation of the water, particularly if the supply system has been designed poorly. Stagnation can occur in dead-legs when water is left in the system for extended periods following pressure testing before going into service. It has been established that metal ions are leached from stainless steel in very low amounts. The highest detectable levels of metal ions leached from stainless steel into stagnant water and/or the biofilm were of iron, then molybdenum, nickel, and finally chromium. It seems unlikely that the concentrations of metal ions detected within both biofilms and flowing/stagnant water would adversely affect the suitability of stainless steel pipework for potable water supplies.","PeriodicalId":9349,"journal":{"name":"British Corrosion Journal","volume":"25 1","pages":"105 - 110"},"PeriodicalIF":0.0,"publicationDate":"2001-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85104049","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-02-01DOI: 10.1179/000705901101501604
S. Feliu, M. Morcillo, B. Chico
Abstract Several studies in the literature have shown a considerable effect of wind on marine aerosol production and atmospheric corrosion when the wind speed exceeds some 3–5 m s-1. However, the current work has shown that the wind effect is not so clear at the Tarragona testing station, on the Mediterranean coast of Spain, where marine winds are generally moderate. Apparently, factors other than marine wind speed at the coast exert a significant influence on the aerosol production. In addition to wind data, the study considers data on the state of the sea in the coast close to the Tarragona testing station obtained from records from an experimentation buoy. These latter data suggest a direct relationship between chloride aerosol deposition rate and the square of wave height. The effect of chloride deposition rate on atmospheric corrosion at the Tarragona testing station has also been studied. Using bimetallic ‘Climat’ type specimens a proportionality has been revealed between corrosion and atmospheric salinity.
文献中的一些研究表明，当风速超过约3-5 m s-1时，风对海洋气溶胶产生和大气腐蚀有相当大的影响。然而，目前的工作表明，在西班牙地中海沿岸的塔拉戈纳测试站，风的影响并不那么明显，那里的海风通常是温和的。显然，海岸风速以外的其他因素对气溶胶的产生也有重要影响。除了风力数据外，该研究还考虑了塔拉戈纳测试站附近海岸的海洋状况数据，这些数据来自一个实验浮标的记录。后者的数据表明氯离子气溶胶沉积速率与波高的平方之间有直接关系。研究了氯化物沉积速率对塔拉戈纳试验站大气腐蚀的影响。利用双金属“气候”型试样，揭示了腐蚀与大气盐度之间的比例关系。
{"title":"Effect of state of sea on atmospheric corrosion in coastal zones","authors":"S. Feliu, M. Morcillo, B. Chico","doi":"10.1179/000705901101501604","DOIUrl":"https://doi.org/10.1179/000705901101501604","url":null,"abstract":"Abstract Several studies in the literature have shown a considerable effect of wind on marine aerosol production and atmospheric corrosion when the wind speed exceeds some 3–5 m s-1. However, the current work has shown that the wind effect is not so clear at the Tarragona testing station, on the Mediterranean coast of Spain, where marine winds are generally moderate. Apparently, factors other than marine wind speed at the coast exert a significant influence on the aerosol production. In addition to wind data, the study considers data on the state of the sea in the coast close to the Tarragona testing station obtained from records from an experimentation buoy. These latter data suggest a direct relationship between chloride aerosol deposition rate and the square of wave height. The effect of chloride deposition rate on atmospheric corrosion at the Tarragona testing station has also been studied. Using bimetallic ‘Climat’ type specimens a proportionality has been revealed between corrosion and atmospheric salinity.","PeriodicalId":9349,"journal":{"name":"British Corrosion Journal","volume":"14 1","pages":"157 - 160"},"PeriodicalIF":0.0,"publicationDate":"2001-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88625313","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-02-01DOI: 10.1179/000705901101501550
A.M. Ai-Mayouf, A.K. Al-Ameery, A. Al‐Suhybani
Abstract Inhibition efficiencies have been investigated for two types of azole, namely 2-mercaptobenzoazole (CBA) and 2-methylbenzoazole (MBA), containing nitrogen, sulphur, oxygen, or selenium atoms, on the corrosion of type 304 stainless steel in 2M sulphuric acid (H2SO4) and 3M hydrochloric acid (HCl). The study was conducted using weight loss, gasometry, and polarisation methods. It was shown that some of the compounds tested provide 90% inhibition efficiency at a concentration of 5 × 10-4M and that the efficiency depends on the heteroatom and decreases in the order Se > S > N > O. These inhibitors were more efficient in H2SO4 than in HCl whereas the opposite is true for inhibitors with nitrogen alone. Adsorption isotherms were fitted to the experimental findings and some thermodynamics functions were obtained.
摘要研究了含氮、含硫、含氧、含硒的2-巯基苯并唑(CBA)和2-甲基苯并唑(MBA)对304型不锈钢在2M硫酸和3M盐酸中腐蚀的缓蚀效果。本研究采用失重法、气相测量法和极化法进行。结果表明，在5 × 10-4M的浓度下，部分化合物的抑菌效率为90%，且抑菌效率取决于杂原子的大小，并按Se > S > N > o的顺序递减。这些抑制剂在H2SO4中比在HCl中更有效，而在单独含氮的抑制剂中则相反。吸附等温线与实验结果拟合，得到了一些热力学函数。
{"title":"Comparison of inhibition efficiency of some azoles on corrosion of type 304 stainless steel in acidic solutions","authors":"A.M. Ai-Mayouf, A.K. Al-Ameery, A. Al‐Suhybani","doi":"10.1179/000705901101501550","DOIUrl":"https://doi.org/10.1179/000705901101501550","url":null,"abstract":"Abstract Inhibition efficiencies have been investigated for two types of azole, namely 2-mercaptobenzoazole (CBA) and 2-methylbenzoazole (MBA), containing nitrogen, sulphur, oxygen, or selenium atoms, on the corrosion of type 304 stainless steel in 2M sulphuric acid (H2SO4) and 3M hydrochloric acid (HCl). The study was conducted using weight loss, gasometry, and polarisation methods. It was shown that some of the compounds tested provide 90% inhibition efficiency at a concentration of 5 × 10-4M and that the efficiency depends on the heteroatom and decreases in the order Se > S > N > O. These inhibitors were more efficient in H2SO4 than in HCl whereas the opposite is true for inhibitors with nitrogen alone. Adsorption isotherms were fitted to the experimental findings and some thermodynamics functions were obtained.","PeriodicalId":9349,"journal":{"name":"British Corrosion Journal","volume":"30 1","pages":"127 - 132"},"PeriodicalIF":0.0,"publicationDate":"2001-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76936171","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-02-01DOI: 10.1179/000705901101501569
A.K. Maayta, M. B. Bitar, M. Al-Abdallah
Abstract The inhibitive efficiency of some nonionic, amphoteric, cationic, and anionic surface active agents (surfactants) on the dissolution of copper in 4·5M HNO3 was studied at 25°C by the weight loss method. The percentage inhibition I increases as the concentration of the cationic, nonionic, and amphoteric substances increases and reaches a limiting value. It is suggested that this is due to the formation of a monolayer on the surface of the metal; the Langmuir adsorption isotherm was confirmed. In the case of anionic surface agents, the percentage inhibition values were at their highest at low surfactant concentrations and decreased as the concentration of the surfactant increased.
{"title":"Inhibition effect of some surface active agents on dissolution of copper in nitric acid","authors":"A.K. Maayta, M. B. Bitar, M. Al-Abdallah","doi":"10.1179/000705901101501569","DOIUrl":"https://doi.org/10.1179/000705901101501569","url":null,"abstract":"Abstract The inhibitive efficiency of some nonionic, amphoteric, cationic, and anionic surface active agents (surfactants) on the dissolution of copper in 4·5M HNO3 was studied at 25°C by the weight loss method. The percentage inhibition I increases as the concentration of the cationic, nonionic, and amphoteric substances increases and reaches a limiting value. It is suggested that this is due to the formation of a monolayer on the surface of the metal; the Langmuir adsorption isotherm was confirmed. In the case of anionic surface agents, the percentage inhibition values were at their highest at low surfactant concentrations and decreased as the concentration of the surfactant increased.","PeriodicalId":9349,"journal":{"name":"British Corrosion Journal","volume":"124 1","pages":"133 - 135"},"PeriodicalIF":0.0,"publicationDate":"2001-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76696003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-02-01DOI: 10.1179/000705901101501578
A. Laachach, A. Srhiri, C. Fiaud, A. Benbachir
Abstract The behaviour of 70/30 Cu–Ni alloy in 3%NaCl medium, both pure and contaminated by 1 ppm S2-ions, has been studied in the absence and in the presence of aminotriazole at a concentration of 10-4M. Potentiodynamic and electrochemical impedance measurements showed that sulphides accelerate the corrosion of the alloy in 3%NaCl. The aminotriazole inhibited both anodic and cathodic corrosion processes. The inhibiting effect was higher when the solution contained the S2-ions. Analysis by scanning electron microscopy (SEM) showed that the inhibitor acts by establishing a very thin film on the metal surface. This film behaves as a barrier to the diffusion of dissolved oxygen and to the transport of the metal ions from the melt to the solution.
{"title":"Electrochemical behaviour of Cu–Ni alloy in 3%NaCl medium polluted by sulphides: effect of aminotriazole","authors":"A. Laachach, A. Srhiri, C. Fiaud, A. Benbachir","doi":"10.1179/000705901101501578","DOIUrl":"https://doi.org/10.1179/000705901101501578","url":null,"abstract":"Abstract The behaviour of 70/30 Cu–Ni alloy in 3%NaCl medium, both pure and contaminated by 1 ppm S2-ions, has been studied in the absence and in the presence of aminotriazole at a concentration of 10-4M. Potentiodynamic and electrochemical impedance measurements showed that sulphides accelerate the corrosion of the alloy in 3%NaCl. The aminotriazole inhibited both anodic and cathodic corrosion processes. The inhibiting effect was higher when the solution contained the S2-ions. Analysis by scanning electron microscopy (SEM) showed that the inhibitor acts by establishing a very thin film on the metal surface. This film behaves as a barrier to the diffusion of dissolved oxygen and to the transport of the metal ions from the melt to the solution.","PeriodicalId":9349,"journal":{"name":"British Corrosion Journal","volume":"49 1","pages":"136 - 142"},"PeriodicalIF":0.0,"publicationDate":"2001-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89068524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-02-01DOI: 10.1179/000705901101501532
J.A. Hearley, C. Liu, J. Little, A. Sturgeon
Abstract Corrosion of a thermal spray (HVOF) Ni–Al coating has been investigated at 600°C under both biomass generated fly ash and synthetic biomass ashes and has been monitored as a function of reaction time for up to 1000 h. Detailed microstructral and compositional analyses have been carried out to investigate the hot corrosion mechanism. Various microstructural defects and compositional inhomogeneities are found to play an important role in the initiation of hot corrosion. Deposition of molten reactants from the ashes creates the aggressive environment. Molten salts cause initial rapid hot corrosion via fluxing reactions between planar interlamellar porosity resulting in debonding of the surface lenticular splats followed by subsequent slow dissolution. Comparison between the performance of the coating in the fly ash and the synthetic ashes provides information for improved laboratory corrosion tests.
{"title":"Corrosion of Ni–Al high velocity oxyfuel (HVOF) thermal spray coating by fly ash and synthetic biomass ash deposits","authors":"J.A. Hearley, C. Liu, J. Little, A. Sturgeon","doi":"10.1179/000705901101501532","DOIUrl":"https://doi.org/10.1179/000705901101501532","url":null,"abstract":"Abstract Corrosion of a thermal spray (HVOF) Ni–Al coating has been investigated at 600°C under both biomass generated fly ash and synthetic biomass ashes and has been monitored as a function of reaction time for up to 1000 h. Detailed microstructral and compositional analyses have been carried out to investigate the hot corrosion mechanism. Various microstructural defects and compositional inhomogeneities are found to play an important role in the initiation of hot corrosion. Deposition of molten reactants from the ashes creates the aggressive environment. Molten salts cause initial rapid hot corrosion via fluxing reactions between planar interlamellar porosity resulting in debonding of the surface lenticular splats followed by subsequent slow dissolution. Comparison between the performance of the coating in the fly ash and the synthetic ashes provides information for improved laboratory corrosion tests.","PeriodicalId":9349,"journal":{"name":"British Corrosion Journal","volume":"3 1","pages":"111 - 120"},"PeriodicalIF":0.0,"publicationDate":"2001-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79062047","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：