Pub Date : 2002-07-01DOI: 10.1179/000705902225002376
M. Athar, H. Ali, M. Quraishi
Abstract Three organic inhibitors containing heteroatoms, namely: undecenoic acid hydrazide (UAH); 2-mercaptobenzothiazole (MBT); and 2-hydrazinobenzothiazole (HBT) have been synthesised in the lab and their inhibiting action on the corrosion of carbon steel in 1N HCl was investigated by means of two different techniques, namely weight loss and potentiodynamic studies. The weight loss studies were conducted in 1MHCl at different temperatures (30, 45, and 60°C) using various concentrations (25–500 ppm) of the inhibitor, and the inhibitor with the highest efficiency (HBT) was also tested for different immersion times (1/2, 3, 6, and 24 h) at the optimum concentration (500 ppm) at room temperature (30°C). The results show that the inhibitor efficiency increases with increased temperature, from room temperature (30°C) to 60°C at the most effective concentration (500 ppm). Inhibitor efficiency (IE) also increases with increase in the inhibitor concentration from 25 to 500 ppm at a given temperature and time. The effect of immersion time on the inhibition efficiency (IE) for HBT was also studied, and the results show that the inhibition efficiency (IE) increases with immersion time. The potentiodynamic polarisation studies revealed that UAH is a mixed type of inhibitor whereas MBT and H BT are predominantly anodic inhibitors. The adsorption of these inhibitors on the metal surface obeys the Temkin adsorption isotherm.
{"title":"Corrosion inhibition of carbon steel in hydrochloric acid by organic compounds containing heteroatoms","authors":"M. Athar, H. Ali, M. Quraishi","doi":"10.1179/000705902225002376","DOIUrl":"https://doi.org/10.1179/000705902225002376","url":null,"abstract":"Abstract Three organic inhibitors containing heteroatoms, namely: undecenoic acid hydrazide (UAH); 2-mercaptobenzothiazole (MBT); and 2-hydrazinobenzothiazole (HBT) have been synthesised in the lab and their inhibiting action on the corrosion of carbon steel in 1N HCl was investigated by means of two different techniques, namely weight loss and potentiodynamic studies. The weight loss studies were conducted in 1MHCl at different temperatures (30, 45, and 60°C) using various concentrations (25–500 ppm) of the inhibitor, and the inhibitor with the highest efficiency (HBT) was also tested for different immersion times (1/2, 3, 6, and 24 h) at the optimum concentration (500 ppm) at room temperature (30°C). The results show that the inhibitor efficiency increases with increased temperature, from room temperature (30°C) to 60°C at the most effective concentration (500 ppm). Inhibitor efficiency (IE) also increases with increase in the inhibitor concentration from 25 to 500 ppm at a given temperature and time. The effect of immersion time on the inhibition efficiency (IE) for HBT was also studied, and the results show that the inhibition efficiency (IE) increases with immersion time. The potentiodynamic polarisation studies revealed that UAH is a mixed type of inhibitor whereas MBT and H BT are predominantly anodic inhibitors. The adsorption of these inhibitors on the metal surface obeys the Temkin adsorption isotherm.","PeriodicalId":9349,"journal":{"name":"British Corrosion Journal","volume":"01 1","pages":"155 - 158"},"PeriodicalIF":0.0,"publicationDate":"2002-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86501072","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 : 2002-07-01DOI: 10.1179/000705902225004383
Hongkai Fan, C. Fu, H.‐L. Wang, X. Guo, J.S. Zheng
Abstract The effect of sodium n,n-diethyl dithiocarbamate (SDEDTC) on the corrosion of mild steel in 0·5 mol L-1 HCl solution was studied using weight loss and potentiodynamic polarisation methods. Experimental data revealed that SDEDTC acted as an inhibitor in the acid environment and, furthermore, that the compound was a mixed type inhibitor, predominating as a cathodic inhibitor. It was found that the inhibition efficiency increased with an increase in SDEDTC concentration at temperatures in the range 303–333 K. The experimental data for the inhibitor fitted the Flory–Huggins adsorption isotherm and the El–Awady thermodynamic kinetic model. The corrosion inhibition mechanism of SDEDTC on mild steel in HCl solution was also investigated by infrared spectra and electron probe microanalysis methods. The process of inhibition is attributed to the formation of an adsorbed film on the metal surface, which protects the metal against corrosive agents.
{"title":"Inhibition of corrosion of mild steel by sodium n,n-diethyl dithiocarbamate in hydrochloric acid solution","authors":"Hongkai Fan, C. Fu, H.‐L. Wang, X. Guo, J.S. Zheng","doi":"10.1179/000705902225004383","DOIUrl":"https://doi.org/10.1179/000705902225004383","url":null,"abstract":"Abstract The effect of sodium n,n-diethyl dithiocarbamate (SDEDTC) on the corrosion of mild steel in 0·5 mol L-1 HCl solution was studied using weight loss and potentiodynamic polarisation methods. Experimental data revealed that SDEDTC acted as an inhibitor in the acid environment and, furthermore, that the compound was a mixed type inhibitor, predominating as a cathodic inhibitor. It was found that the inhibition efficiency increased with an increase in SDEDTC concentration at temperatures in the range 303–333 K. The experimental data for the inhibitor fitted the Flory–Huggins adsorption isotherm and the El–Awady thermodynamic kinetic model. The corrosion inhibition mechanism of SDEDTC on mild steel in HCl solution was also investigated by infrared spectra and electron probe microanalysis methods. The process of inhibition is attributed to the formation of an adsorbed film on the metal surface, which protects the metal against corrosive agents.","PeriodicalId":9349,"journal":{"name":"British Corrosion Journal","volume":"83 1","pages":"122 - 125"},"PeriodicalIF":0.0,"publicationDate":"2002-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91207829","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 : 2002-07-01DOI: 10.1179/000705902225004365
J. M. Romero, C. Angeles-Chávez, L. Martínez, M. Amaya
Abstract A study of microbiologically induced corrosion has been conducted on X52 pipeline steel using bioelements which were located in a bioprobe located at the inner surface of a sea water pipeline and exposed for 60 days. Severely attacked surfaces with pits of various diameters and depths and a great deal of metal loss were observed after removing the biofilm that had deposited on the bioelement surfaces. This behaviour was not expected under the normal operating conditions of the pipeline. Pit depths were measured and a depth distribution curve was obtained. Different aerobic or facultative bacteria types were cultured from the biofilm removed from the X52 steel bioelement surface while a negative growth in the anaerobic bacteria culture was observed. The morphological and chemical characteristics of the aerobic bacteria were determined and results based on 16S rRNA gene sequence similarity suggest that these aerobic or facultative bacteria could be a new species in this kind of environment.
{"title":"Localised biological corrosion of X52 steel exposed within sea water pipelines","authors":"J. M. Romero, C. Angeles-Chávez, L. Martínez, M. Amaya","doi":"10.1179/000705902225004365","DOIUrl":"https://doi.org/10.1179/000705902225004365","url":null,"abstract":"Abstract A study of microbiologically induced corrosion has been conducted on X52 pipeline steel using bioelements which were located in a bioprobe located at the inner surface of a sea water pipeline and exposed for 60 days. Severely attacked surfaces with pits of various diameters and depths and a great deal of metal loss were observed after removing the biofilm that had deposited on the bioelement surfaces. This behaviour was not expected under the normal operating conditions of the pipeline. Pit depths were measured and a depth distribution curve was obtained. Different aerobic or facultative bacteria types were cultured from the biofilm removed from the X52 steel bioelement surface while a negative growth in the anaerobic bacteria culture was observed. The morphological and chemical characteristics of the aerobic bacteria were determined and results based on 16S rRNA gene sequence similarity suggest that these aerobic or facultative bacteria could be a new species in this kind of environment.","PeriodicalId":9349,"journal":{"name":"British Corrosion Journal","volume":"1 1","pages":"117 - 121"},"PeriodicalIF":0.0,"publicationDate":"2002-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84443575","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 : 2002-07-01DOI: 10.1179/000705902225004347
H. Awad, S. Turgoose
Abstract The action of 1-hydrox yethylidene-1, 1-diphosphonic acid (HEDP) in combination with zinc ions as a corrosion inhibitor for mild steel in oxygen containing aqueous solutions has been investigated in relation to the presence of different zinc levels, the presence of aggressive anions, and different pH values. The highest inhibition effect was obtained at a 2·7:1 zinc/HEDP molar ratio, corresponding to 60 ppm zinc, and was associated with a significant anodic effect. In the absence of chloride and with no free forms of the inhibitor components, the zinc-HEDP mixture exhibited good protection over a wide range of pH (6·5-9·5). However, in a weakly acidic medium, protection could not be achieved. Calculations based on the dissociation constants of the HEDP and the stability constants of the possible zinc-HEDP complexes showed that this inhibition can be attributed to the presence of the 2:1 zinc-HEDP complex (Zn2H-1L-) at a sufficient level. It is found that this anionic complex can behave as an anodic, passivating, inhibitor at a concentration as low as 0·00015M (20 ppm zinc-32 ppm HEDP mix ture). This passivity is prevented by the presence of sufficient chloride. The critical chloride concentration in these studies is approximately ten times higher than the complex concentration, in molar terms. It is also found that free phosphonate is aggressive and can prevent passivity due to the preferential formation of soluble iron-HEDP complex. The tolerance of the 2:1 complex to free phosphonate is substantially less than to chloride, approx imately equimolar.
{"title":"Role of complexes in inhibition of mild steel by zinc–1-hydroxyethylidene-1, 1-diphosphonic acid mixtures","authors":"H. Awad, S. Turgoose","doi":"10.1179/000705902225004347","DOIUrl":"https://doi.org/10.1179/000705902225004347","url":null,"abstract":"Abstract The action of 1-hydrox yethylidene-1, 1-diphosphonic acid (HEDP) in combination with zinc ions as a corrosion inhibitor for mild steel in oxygen containing aqueous solutions has been investigated in relation to the presence of different zinc levels, the presence of aggressive anions, and different pH values. The highest inhibition effect was obtained at a 2·7:1 zinc/HEDP molar ratio, corresponding to 60 ppm zinc, and was associated with a significant anodic effect. In the absence of chloride and with no free forms of the inhibitor components, the zinc-HEDP mixture exhibited good protection over a wide range of pH (6·5-9·5). However, in a weakly acidic medium, protection could not be achieved. Calculations based on the dissociation constants of the HEDP and the stability constants of the possible zinc-HEDP complexes showed that this inhibition can be attributed to the presence of the 2:1 zinc-HEDP complex (Zn2H-1L-) at a sufficient level. It is found that this anionic complex can behave as an anodic, passivating, inhibitor at a concentration as low as 0·00015M (20 ppm zinc-32 ppm HEDP mix ture). This passivity is prevented by the presence of sufficient chloride. The critical chloride concentration in these studies is approximately ten times higher than the complex concentration, in molar terms. It is also found that free phosphonate is aggressive and can prevent passivity due to the preferential formation of soluble iron-HEDP complex. The tolerance of the 2:1 complex to free phosphonate is substantially less than to chloride, approx imately equimolar.","PeriodicalId":9349,"journal":{"name":"British Corrosion Journal","volume":"48 1","pages":"147 - 154"},"PeriodicalIF":0.0,"publicationDate":"2002-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88692176","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 : 2002-07-01DOI: 10.1179/000705902225004356
R. Jeffrey, R. Melchers
Abstract The conventional wisdom in corrosion testing is that the size of the coupon and its perimeter/area ratio (the surface area of the perimeter expressed as a percentage of the total surface area) are important parameters and that these will have an effect on the results obtained. In order to test this proposition, sets of mild steel coupons of the same exposed areas but having different perimeters were immersed in a marine environment. Corrosion mass loss was observed for area/perimeter ratios in the range 3·52-6·03%. Mass loss observations were taken at various times to 12 months. Sets of rectangular coupons of different sizes (50 × 100 mm and 100 × 200 mm) were also immersed. The results indicate that any variation caused by shape or size falls within the expected variability of corrosion at a test location.
{"title":"Shape and size effects for marine immersion coupons","authors":"R. Jeffrey, R. Melchers","doi":"10.1179/000705902225004356","DOIUrl":"https://doi.org/10.1179/000705902225004356","url":null,"abstract":"Abstract The conventional wisdom in corrosion testing is that the size of the coupon and its perimeter/area ratio (the surface area of the perimeter expressed as a percentage of the total surface area) are important parameters and that these will have an effect on the results obtained. In order to test this proposition, sets of mild steel coupons of the same exposed areas but having different perimeters were immersed in a marine environment. Corrosion mass loss was observed for area/perimeter ratios in the range 3·52-6·03%. Mass loss observations were taken at various times to 12 months. Sets of rectangular coupons of different sizes (50 × 100 mm and 100 × 200 mm) were also immersed. The results indicate that any variation caused by shape or size falls within the expected variability of corrosion at a test location.","PeriodicalId":9349,"journal":{"name":"British Corrosion Journal","volume":"29 1","pages":"104 - 99"},"PeriodicalIF":0.0,"publicationDate":"2002-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81393599","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 : 2002-07-01DOI: 10.1179/000705902225004374
A. Szyprowski
Abstract Seven homologous imidazoline inhibitors, the derivatives of cyclopentylic and cyclohexylonaphthenic acids, have been synthesised. The effectiveness of these inhibitors for St3S carbon steel and 1H18N9T austenitic stainless steel was tested using the impedance method in 2 wt-% sodium chloride solution in the presence of a hydrocarbon phase. The solution was saturated with hydrogen sulphide. It was found that the inhibitors and their mix tures displayed high inhibition efficiencies, reaching 93% for carbon steel and 94% for the austenitic steel. Inhibitors with the shortest hydrocarbon side chains on the imidazoline ring were found to offer the lowest level of protection, the inhibition efficiency increasing with the length of the side chain. The capacitance measured on the surface decreased linearly as the coverage of the steel surface by inhibitor increased. The results of impedance measurements with commercial inhibitors have confirmed the conclusions from the tests on the pure chemical species.
{"title":"Impedance study of imidazoline inhibitors against hydrogen sulphide corrosion of steel","authors":"A. Szyprowski","doi":"10.1179/000705902225004374","DOIUrl":"https://doi.org/10.1179/000705902225004374","url":null,"abstract":"Abstract Seven homologous imidazoline inhibitors, the derivatives of cyclopentylic and cyclohexylonaphthenic acids, have been synthesised. The effectiveness of these inhibitors for St3S carbon steel and 1H18N9T austenitic stainless steel was tested using the impedance method in 2 wt-% sodium chloride solution in the presence of a hydrocarbon phase. The solution was saturated with hydrogen sulphide. It was found that the inhibitors and their mix tures displayed high inhibition efficiencies, reaching 93% for carbon steel and 94% for the austenitic steel. Inhibitors with the shortest hydrocarbon side chains on the imidazoline ring were found to offer the lowest level of protection, the inhibition efficiency increasing with the length of the side chain. The capacitance measured on the surface decreased linearly as the coverage of the steel surface by inhibitor increased. The results of impedance measurements with commercial inhibitors have confirmed the conclusions from the tests on the pure chemical species.","PeriodicalId":9349,"journal":{"name":"British Corrosion Journal","volume":"190 1","pages":"141 - 146"},"PeriodicalIF":0.0,"publicationDate":"2002-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75003542","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 : 2002-07-01DOI: 10.1179/000705902225002411
S. M. A. Shibli, Sony George, V. Gireesh
Abstract Ruthenium oxide, one of the excellent electrocatalysts having high conductivity and high chemical and thermodynamic stability, has been coated onto the surface of an electrode made from a Al–5 wt-%Zn alloy. The activated aluminium ion was able to diffuse through the porous catalytic hydrophilic layer. Ruthenium oxide coated Al–Zn alloy anodes displayed high open circuit potential and high closed circuit potential during galvanic exposure with mild steel cathodes. A galvanic efficiency as high as 86% with an actual current capacity of 2573 A h kg-1 was achieved. The RuO2 film underwent very little deterioration and a considerable mass of the ruthenium oxide film persisted on the anode surface, even after the electrode size had been reduced to one third of its original size owing to galvanic dissolution. These electrodes are economically efficient, as convenient to prepare, install and use as other conventional electrodes, are tolerable of very aggressive media and highly efficient, even under high galvanic current loads.
摘要在Al-5 wt-%Zn合金电极表面涂覆了一层氧化钌，它是一种具有高导电性和高化学和热力学稳定性的优良电催化剂。活性铝离子能够通过多孔的催化亲水性层扩散。氧化钌包覆Al-Zn合金阳极在低碳钢阴极电暴露过程中表现出高开路电位和高闭合电位。电流效率高达86%，实际电流容量为2573 A h kg-1。RuO2膜几乎没有变质，即使在电极尺寸由于电溶而缩小到原来尺寸的三分之一之后，仍有相当数量的氧化钌膜保留在阳极表面。这些电极具有经济效益，与其他传统电极一样方便准备，安装和使用，即使在高电流负载下，也能耐受非常腐蚀性的介质并且效率很高。
{"title":"Ruthenium oxide for effective activation of aluminium sacrificial anodes: a new approach","authors":"S. M. A. Shibli, Sony George, V. Gireesh","doi":"10.1179/000705902225002411","DOIUrl":"https://doi.org/10.1179/000705902225002411","url":null,"abstract":"Abstract Ruthenium oxide, one of the excellent electrocatalysts having high conductivity and high chemical and thermodynamic stability, has been coated onto the surface of an electrode made from a Al–5 wt-%Zn alloy. The activated aluminium ion was able to diffuse through the porous catalytic hydrophilic layer. Ruthenium oxide coated Al–Zn alloy anodes displayed high open circuit potential and high closed circuit potential during galvanic exposure with mild steel cathodes. A galvanic efficiency as high as 86% with an actual current capacity of 2573 A h kg-1 was achieved. The RuO2 film underwent very little deterioration and a considerable mass of the ruthenium oxide film persisted on the anode surface, even after the electrode size had been reduced to one third of its original size owing to galvanic dissolution. These electrodes are economically efficient, as convenient to prepare, install and use as other conventional electrodes, are tolerable of very aggressive media and highly efficient, even under high galvanic current loads.","PeriodicalId":9349,"journal":{"name":"British Corrosion Journal","volume":"15 1","pages":"126 - 128"},"PeriodicalIF":0.0,"publicationDate":"2002-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87408512","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 : 2002-02-01DOI: 10.1179/000705902225002448
A. Zaky, F. Assaf
Abstract The electrochemical behaviour of two copper nickel alloys; cu-20 wt-%Ni and Cu-80 wt-%Ni, was studied in alkaline solution using the cyclic voltammetric technique. The voltammograms of the alloys were compared with those of the pure copper and pure nickel recorded under the same conditions. The influence of different variables such as switching potential Es, scan rate, NaOH concentration, solution temperature, and repetitive cycling was also studied. The forward sweep was characterised by the appearance of five anodic peaks: A1, A2, A3, A4, and A5, which are related to the formation of Ni(OH)2, Cu2O, Cu(OH)2, CuO, and Ni2O3, respectively. The activity of copper dissolution and, hence, the heights of the corresponding anodic peaks decreased as the nickel content in the alloy increased. X-ray diffraction analysis of the surface of the 80% nickel alloy after polarisation in the anodic direction confirmed the existence of only nickel corrosion compounds. Increasing the nickel content in the alloy retards the dissolution of copper via the formation of a very protective nickel hydroxide passive film. The addition of chloride ions, owing to their ease of adsorption, increases dissolution from the alloy. When the ratio of [Cl-]/[OH-] ex ceeds 1·5, the chloride ions initiate pitting attack. To examine the alloy surface for pit formation SEM was used.
{"title":"Cyclic voltammetric behaviour of copper–nickel alloys in alkaline media","authors":"A. Zaky, F. Assaf","doi":"10.1179/000705902225002448","DOIUrl":"https://doi.org/10.1179/000705902225002448","url":null,"abstract":"Abstract The electrochemical behaviour of two copper nickel alloys; cu-20 wt-%Ni and Cu-80 wt-%Ni, was studied in alkaline solution using the cyclic voltammetric technique. The voltammograms of the alloys were compared with those of the pure copper and pure nickel recorded under the same conditions. The influence of different variables such as switching potential Es, scan rate, NaOH concentration, solution temperature, and repetitive cycling was also studied. The forward sweep was characterised by the appearance of five anodic peaks: A1, A2, A3, A4, and A5, which are related to the formation of Ni(OH)2, Cu2O, Cu(OH)2, CuO, and Ni2O3, respectively. The activity of copper dissolution and, hence, the heights of the corresponding anodic peaks decreased as the nickel content in the alloy increased. X-ray diffraction analysis of the surface of the 80% nickel alloy after polarisation in the anodic direction confirmed the existence of only nickel corrosion compounds. Increasing the nickel content in the alloy retards the dissolution of copper via the formation of a very protective nickel hydroxide passive film. The addition of chloride ions, owing to their ease of adsorption, increases dissolution from the alloy. When the ratio of [Cl-]/[OH-] ex ceeds 1·5, the chloride ions initiate pitting attack. To examine the alloy surface for pit formation SEM was used.","PeriodicalId":9349,"journal":{"name":"British Corrosion Journal","volume":"12 1","pages":"48 - 55"},"PeriodicalIF":0.0,"publicationDate":"2002-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82896829","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 : 2002-02-01DOI: 10.1179/000705902225002330
R. George, S. Venkatachalam, K. Ninan
Abstract Both electroless nickel coated and chromated surfaces of magnesium alloy AZ 31 and hydrothermally sealed anodised surfaces of unalloyed aluminium Al-2S and aluminium alloy 6061 have been prepared and the corrosion behaviour of these surfaces in aqueous K Cl and K2SO4 solutions has been studied using electrochemical impedance spectroscopy (EIS). The effect of the concentration of hypophosphite in the plating bath used for electroless plating on the Ni-P layers formed and their corrosion behaviour has also been studied. The EIS studies have shown that the diffusion of ionic species is less for yellow chromated surfaces of magnesium alloy than for black chromated ones. In the case of anodised aluminium surfaces, impedance values are much higher in KCl than in K2SO4 solutions. The effect of anodising time on pore resistance R po and barrier capacitance Cb has also been studied. Data from EIS indicate that the pore resistance of aluminium alloys A1-2S and AA 6061 attains a saturation value after anodisation for ~45 min.
{"title":"Electrochemical impedance measurements on Ni–P coated magnesium alloy, chromated magnesium alloy, and anodised aluminium alloys in aqueous salt solutions","authors":"R. George, S. Venkatachalam, K. Ninan","doi":"10.1179/000705902225002330","DOIUrl":"https://doi.org/10.1179/000705902225002330","url":null,"abstract":"Abstract Both electroless nickel coated and chromated surfaces of magnesium alloy AZ 31 and hydrothermally sealed anodised surfaces of unalloyed aluminium Al-2S and aluminium alloy 6061 have been prepared and the corrosion behaviour of these surfaces in aqueous K Cl and K2SO4 solutions has been studied using electrochemical impedance spectroscopy (EIS). The effect of the concentration of hypophosphite in the plating bath used for electroless plating on the Ni-P layers formed and their corrosion behaviour has also been studied. The EIS studies have shown that the diffusion of ionic species is less for yellow chromated surfaces of magnesium alloy than for black chromated ones. In the case of anodised aluminium surfaces, impedance values are much higher in KCl than in K2SO4 solutions. The effect of anodising time on pore resistance R po and barrier capacitance Cb has also been studied. Data from EIS indicate that the pore resistance of aluminium alloys A1-2S and AA 6061 attains a saturation value after anodisation for ~45 min.","PeriodicalId":9349,"journal":{"name":"British Corrosion Journal","volume":"6 1","pages":"37 - 42"},"PeriodicalIF":0.0,"publicationDate":"2002-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79518154","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}
This session was organised by Professor Michael SchuÈtze of the Karl Winnacker Institute (KWI) of Dechema in Frankfurt, who is Chairman if EFC WP 3 on `Corrosion by hot gases and combustion products’. This was a one and a half day session with a dozen oral presentations and some posters. Germany is a focal point for high temperature corrosion research at present, and this is where 50% of the presentations in this session had originated, split equally between KWI and the Max Planck Institute (MPI) in DuÈsseldorf. This is where Professor Hans Grabke, Professor SchuÈtze’s predecessor as Chairman of WP 3, conducted his seminal work on metal dusting over the past decade. The metal dusting phenomenon and ways to alleviate it figured prominently in this session, as did problems in coal gasification and combustion processes, particularly those using high sulphur fuels, and in waste incineration plants.
{"title":"Eurocorr 2001","authors":"","doi":"10.1179/bcj.2002.37.1.8","DOIUrl":"https://doi.org/10.1179/bcj.2002.37.1.8","url":null,"abstract":"This session was organised by Professor Michael SchuÈtze of the Karl Winnacker Institute (KWI) of Dechema in Frankfurt, who is Chairman if EFC WP 3 on `Corrosion by hot gases and combustion products’. This was a one and a half day session with a dozen oral presentations and some posters. Germany is a focal point for high temperature corrosion research at present, and this is where 50% of the presentations in this session had originated, split equally between KWI and the Max Planck Institute (MPI) in DuÈsseldorf. This is where Professor Hans Grabke, Professor SchuÈtze’s predecessor as Chairman of WP 3, conducted his seminal work on metal dusting over the past decade. The metal dusting phenomenon and ways to alleviate it figured prominently in this session, as did problems in coal gasification and combustion processes, particularly those using high sulphur fuels, and in waste incineration plants.","PeriodicalId":9349,"journal":{"name":"British Corrosion Journal","volume":"8 1","pages":"17 - 8"},"PeriodicalIF":0.0,"publicationDate":"2002-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91239553","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}
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