Pub Date : 2001-10-01DOI: 10.1179/000705901101501613
B. Mercer
Mercer Innovation awards The first senior Brian Mercer award for innovation with a value of around £250 000 has been made to Professor Christopher Hall at the University of Edinburgh for a three year project on a new surface chemistry approach to the durability and conservation of building stone. Professor Hall said that the scientific core of this work would be to try to understand the micromechanics of chemical damage in stone. ‘I feel that this research will lead to a rather simple but novel technology for conserving heritage buildings and even preventing damage to new buildings in which stone is used.’ In the longer term, Hall’s research may help in improving durability in concrete as well as have an impact on how scientists view chemomechanical processes in many contexts, from landform weathering to oilfield engineering. The first post-doctoral Brian Mercer Awards for Innovation have been awarded to: Dr Alan Arthur at the University of Birmingham to demonstrate the viability of processing biodegradable material in place of conventional plastic parts used in domestic appliances; and to Dr Ambrose Taylor at Imperial College of Science, Technology and Medicine to develop materials that will increase safety and efficiency in the manufacture of aircrafts, automobiles, and trains. The Royal Society received £10 million from the estate of the late Brian Mercer FRS to support innovation in scientific, engineering and technological fields, which were of interest to him. Further information from: Soccy Ponsford or Bob Ward, Press and Public Relations, The Royal Society, London SW1, tel. 020 7451 2508/2516, email press@royalsoc. ac.uk.
{"title":"Corrosion news and views","authors":"B. Mercer","doi":"10.1179/000705901101501613","DOIUrl":"https://doi.org/10.1179/000705901101501613","url":null,"abstract":"Mercer Innovation awards The first senior Brian Mercer award for innovation with a value of around £250 000 has been made to Professor Christopher Hall at the University of Edinburgh for a three year project on a new surface chemistry approach to the durability and conservation of building stone. Professor Hall said that the scientific core of this work would be to try to understand the micromechanics of chemical damage in stone. ‘I feel that this research will lead to a rather simple but novel technology for conserving heritage buildings and even preventing damage to new buildings in which stone is used.’ In the longer term, Hall’s research may help in improving durability in concrete as well as have an impact on how scientists view chemomechanical processes in many contexts, from landform weathering to oilfield engineering. The first post-doctoral Brian Mercer Awards for Innovation have been awarded to: Dr Alan Arthur at the University of Birmingham to demonstrate the viability of processing biodegradable material in place of conventional plastic parts used in domestic appliances; and to Dr Ambrose Taylor at Imperial College of Science, Technology and Medicine to develop materials that will increase safety and efficiency in the manufacture of aircrafts, automobiles, and trains. The Royal Society received £10 million from the estate of the late Brian Mercer FRS to support innovation in scientific, engineering and technological fields, which were of interest to him. Further information from: Soccy Ponsford or Bob Ward, Press and Public Relations, The Royal Society, London SW1, tel. 020 7451 2508/2516, email press@royalsoc. ac.uk.","PeriodicalId":9349,"journal":{"name":"British Corrosion Journal","volume":"10 1","pages":"233 - 236"},"PeriodicalIF":0.0,"publicationDate":"2001-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80228894","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 : 2001-10-01DOI: 10.1179/000705901101501640
M. Challis, D. Worsley
Abstract Organically coated galvanised strip steel materials are increasingly important as construction materials. The effects of magnesium additions to the zinc spelter on the microstructure and cut edge corrosion mechanism of zinc aluminium alloy galvanising coatings on strip steels have been found to be significant. Galvanised specimens were prepared on 0.7 mm steel substrates using a hot dip bath composition of near eutectic 4.2 wt-% aluminium-ca. 95 8 wt-% zinc and trace levels of magnesium. Increasing the magnesium content in the metallic coating from 0.01 to 0.05 wt-% leads to the formation of significant areas of subsurface, dendritic, pro-eutectic zinc rich phases. The metallic coating substrates were over coated with asymmetric thicknesses of a 200 μm PVC based coating on one side and a 15 μm polyester coating on the other producing a range of model organically coated substrates identical in every way except for the magnesium level in the metallic coating. The kinetics and mechanism of cut edge corrosion in 5 vol.-%NaCl of these model systems have been investigated using the scanning vibrating electrode technique (SVET). The SVET data have shown that the increasing coating heterogeneity with increased magnesium content leads to increasing numbers of active and intense anodes on the exposed surface of the metallic coating at the cut edge. At magnesium levels of < 0.03 wt-%, asymmetry in the thickness of the organic coating induced localisation of anodic activity near to the thicker (PVC) organic layer, and of cathodic activity localised primarily on the steel/galvanising layer adjacent to the thinner (polyester) organic coating. However, as the magnesium content of the metallic coating was increased (to 0.04 and 0.05 wt-%) the location of anodic and cathodic activity was found to become independent of the geometry of the organic coating. Whilst the number of active anodes on the 20 mm exposed edge was found to be identical for both of the latter magnesium levels those in the 0 05 wt-%Mg specimen were more persistent. In the case of the 0 04 wt-%Mg specimen, 13 of the 21 active anodes deactivated over the first 12 h of immersion whereas with the highest magnesium level deactivation was only observed for 5 of the 21 anodes. Those that remained active in the latter specimen also had significantly greater levels of anodic activity. This appears to be related to interlinking between particles of the pro-eutectic zinc rich phase in specimen of the highest magnesium level, leading to crevice corrosion. The consequence of the microstructural changes induced by trace Mg additions in that the SVET measured total zinc losses over the 24 h exposure period increasing from 28 μg (with 0.01 wt-%Mg), to 44 μg (0.02 wt-%Mg), 61 μg (0.03 wt-%Mg), 67 μg (0.04 wt-%Mg) and 223 μg (0.05 wt-%Mg).
{"title":"Cut edge corrosion mechanisms in organically coated zinc–aluminium alloy galvanised steels","authors":"M. Challis, D. Worsley","doi":"10.1179/000705901101501640","DOIUrl":"https://doi.org/10.1179/000705901101501640","url":null,"abstract":"Abstract Organically coated galvanised strip steel materials are increasingly important as construction materials. The effects of magnesium additions to the zinc spelter on the microstructure and cut edge corrosion mechanism of zinc aluminium alloy galvanising coatings on strip steels have been found to be significant. Galvanised specimens were prepared on 0.7 mm steel substrates using a hot dip bath composition of near eutectic 4.2 wt-% aluminium-ca. 95 8 wt-% zinc and trace levels of magnesium. Increasing the magnesium content in the metallic coating from 0.01 to 0.05 wt-% leads to the formation of significant areas of subsurface, dendritic, pro-eutectic zinc rich phases. The metallic coating substrates were over coated with asymmetric thicknesses of a 200 μm PVC based coating on one side and a 15 μm polyester coating on the other producing a range of model organically coated substrates identical in every way except for the magnesium level in the metallic coating. The kinetics and mechanism of cut edge corrosion in 5 vol.-%NaCl of these model systems have been investigated using the scanning vibrating electrode technique (SVET). The SVET data have shown that the increasing coating heterogeneity with increased magnesium content leads to increasing numbers of active and intense anodes on the exposed surface of the metallic coating at the cut edge. At magnesium levels of < 0.03 wt-%, asymmetry in the thickness of the organic coating induced localisation of anodic activity near to the thicker (PVC) organic layer, and of cathodic activity localised primarily on the steel/galvanising layer adjacent to the thinner (polyester) organic coating. However, as the magnesium content of the metallic coating was increased (to 0.04 and 0.05 wt-%) the location of anodic and cathodic activity was found to become independent of the geometry of the organic coating. Whilst the number of active anodes on the 20 mm exposed edge was found to be identical for both of the latter magnesium levels those in the 0 05 wt-%Mg specimen were more persistent. In the case of the 0 04 wt-%Mg specimen, 13 of the 21 active anodes deactivated over the first 12 h of immersion whereas with the highest magnesium level deactivation was only observed for 5 of the 21 anodes. Those that remained active in the latter specimen also had significantly greater levels of anodic activity. This appears to be related to interlinking between particles of the pro-eutectic zinc rich phase in specimen of the highest magnesium level, leading to crevice corrosion. The consequence of the microstructural changes induced by trace Mg additions in that the SVET measured total zinc losses over the 24 h exposure period increasing from 28 μg (with 0.01 wt-%Mg), to 44 μg (0.02 wt-%Mg), 61 μg (0.03 wt-%Mg), 67 μg (0.04 wt-%Mg) and 223 μg (0.05 wt-%Mg).","PeriodicalId":9349,"journal":{"name":"British Corrosion Journal","volume":"25 1","pages":"297 - 303"},"PeriodicalIF":0.0,"publicationDate":"2001-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78241986","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.2001.36.3.191
A. el-Turki, G. Allen, K. Hallam
Abstract This paper reports a study of the composition and morphology of the corrosion products formed on galvanised steel specimens exposed to a swimming pool atmosphere. Two thicknesses of hot dip zinc coatings were investigated measuring 1·8 and 180 µm, respectively. Specimens were analysed throughout a 12 month exposure period and a reaction sequence identified using the techniques of X-ray diffraction, X-ray photoelectron spectroscopy, and SEM/EDX. The main phases determined were: zincite (ZnO), simonkolleite (Zn5(OH)8Cl2. H2O), hydrated zinc hydroxychlorosulphate (Zn4Cl2(OH)4SO4. 5H2O), and hydrated sodium zinc hydroxychlorosulphate (NaZn4Cl(OH)6SO4. 6H2O). Amarantite (FeSO4(OH). 3H2O) was found only on the specimens with the thinner zinc coating through which iron diffusion from the bulk steel could occur.
{"title":"Composition and morphology of corrosion products formed on galvanised steel exposed to a swimming pool atmosphere","authors":"A. el-Turki, G. Allen, K. Hallam","doi":"10.1179/bcj.2001.36.3.191","DOIUrl":"https://doi.org/10.1179/bcj.2001.36.3.191","url":null,"abstract":"Abstract This paper reports a study of the composition and morphology of the corrosion products formed on galvanised steel specimens exposed to a swimming pool atmosphere. Two thicknesses of hot dip zinc coatings were investigated measuring 1·8 and 180 µm, respectively. Specimens were analysed throughout a 12 month exposure period and a reaction sequence identified using the techniques of X-ray diffraction, X-ray photoelectron spectroscopy, and SEM/EDX. The main phases determined were: zincite (ZnO), simonkolleite (Zn5(OH)8Cl2. H2O), hydrated zinc hydroxychlorosulphate (Zn4Cl2(OH)4SO4. 5H2O), and hydrated sodium zinc hydroxychlorosulphate (NaZn4Cl(OH)6SO4. 6H2O). Amarantite (FeSO4(OH). 3H2O) was found only on the specimens with the thinner zinc coating through which iron diffusion from the bulk steel could occur.","PeriodicalId":9349,"journal":{"name":"British Corrosion Journal","volume":"5 1","pages":"191 - 196"},"PeriodicalIF":0.0,"publicationDate":"2001-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79388071","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.2001.36.3.184
F. El Shawesh, A. El Houd, O. Raghai
Abstract Several carbon steel flash chambers clad with type 316L austenitic stainless steel and operating in seawater at 80°C exhibited severe localised corrosion on the inner wall after three months of continuous service. Visual investigation, carried out on the corroded wall surfaces revealed that the corrosion attack was confined to mechanically damaged and iron-contaminated areas. Failure to keep the oxygen level within the allowable limit of 0·026 ppm had promoted the corrosion. Electrochemical studies confirmed the influence of surface condition apparent from the visual inspections. Various specimens of type 316L austenitic stainless steel with different surface finishes (as received, ground, mechanically scratched, and iron contaminated) were exposed to natural sea water at 80°C Metallographic examination revealed that pits which formed on the as received specimens were uniform in shape, while those on specimens with mechanically damaged surfaces were larger and irregular in shape. The results suggest that surface finish exerted a significant influence on the rapid corrosion of the flash chambers. Post-fabrication cleaning by acid pickling markedly improved the resistance of the type 316L specimens to localised corrosion (pitting). However, the results of acid pickling were dependent on the surface condition and, to a large extent, the temperature of the acid.
{"title":"Role of surface finish and post-fabrication cleaning on localised corrosion of type 316L austenitic stainless steel flash chambers","authors":"F. El Shawesh, A. El Houd, O. Raghai","doi":"10.1179/bcj.2001.36.3.184","DOIUrl":"https://doi.org/10.1179/bcj.2001.36.3.184","url":null,"abstract":"Abstract Several carbon steel flash chambers clad with type 316L austenitic stainless steel and operating in seawater at 80°C exhibited severe localised corrosion on the inner wall after three months of continuous service. Visual investigation, carried out on the corroded wall surfaces revealed that the corrosion attack was confined to mechanically damaged and iron-contaminated areas. Failure to keep the oxygen level within the allowable limit of 0·026 ppm had promoted the corrosion. Electrochemical studies confirmed the influence of surface condition apparent from the visual inspections. Various specimens of type 316L austenitic stainless steel with different surface finishes (as received, ground, mechanically scratched, and iron contaminated) were exposed to natural sea water at 80°C Metallographic examination revealed that pits which formed on the as received specimens were uniform in shape, while those on specimens with mechanically damaged surfaces were larger and irregular in shape. The results suggest that surface finish exerted a significant influence on the rapid corrosion of the flash chambers. Post-fabrication cleaning by acid pickling markedly improved the resistance of the type 316L specimens to localised corrosion (pitting). However, the results of acid pickling were dependent on the surface condition and, to a large extent, the temperature of the acid.","PeriodicalId":9349,"journal":{"name":"British Corrosion Journal","volume":"44 1","pages":"184 - 190"},"PeriodicalIF":0.0,"publicationDate":"2001-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89152735","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.2001.36.3.197
E. Khamis, S. Oun, S. Lyon
Abstract The effect of dicyclohexylamine nitrite (DCHN), a volatile corrosion inhibitor, on the corrosion behaviour of steel, zinc, and coupled steel and zinc was studied. Corrosion rates were determined using mass loss methods as well as potentiodynamic polarisation and ac impedance measurements. Potentiodynamic polarisation studies show that DCHN acts as an anodic inhibitor in the corrosion of mild steel. However, for zinc, DCHN acts to accelerate corrosion. This is attributed to surface chelation between DCHN and zinc, resulting in the formation of a soluble complex. Zero resistance ammetry was used to investigate the dissolution behaviour of a galvanic couple between steel and zinc in the presence of DCHN; in such as situation, the inhibitor effectiveness depends mainly on its concentration.
{"title":"Use of dicyclohexylamine nitrite in inhibition of coupled zinc and steel","authors":"E. Khamis, S. Oun, S. Lyon","doi":"10.1179/bcj.2001.36.3.197","DOIUrl":"https://doi.org/10.1179/bcj.2001.36.3.197","url":null,"abstract":"Abstract The effect of dicyclohexylamine nitrite (DCHN), a volatile corrosion inhibitor, on the corrosion behaviour of steel, zinc, and coupled steel and zinc was studied. Corrosion rates were determined using mass loss methods as well as potentiodynamic polarisation and ac impedance measurements. Potentiodynamic polarisation studies show that DCHN acts as an anodic inhibitor in the corrosion of mild steel. However, for zinc, DCHN acts to accelerate corrosion. This is attributed to surface chelation between DCHN and zinc, resulting in the formation of a soluble complex. Zero resistance ammetry was used to investigate the dissolution behaviour of a galvanic couple between steel and zinc in the presence of DCHN; in such as situation, the inhibitor effectiveness depends mainly on its concentration.","PeriodicalId":9349,"journal":{"name":"British Corrosion Journal","volume":"56 1","pages":"197 - 200"},"PeriodicalIF":0.0,"publicationDate":"2001-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77122187","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.2001.36.3.205
A. E. El Warraky
Abstract The films formed on Cu surfaces in 4% NaCl with 10 ppm FeSO4 solution for short immersion times of up to 4 h were analysed using X-ray photoelectron spectroscopy and Auger electron spectroscopy. Iron was detected on the copper surface after immersion for 30 min. The presence of Fe(OH)2 and α-FeOOH species on the surface supports the proposal that Fe2+ ions are transported to the cathodic sites to form Fe(OH)2 which is subsequently oxidised to α-FeOOH (lepidocrocite) by dissolved oxygen in solution. The presence of a peak corresponding to the approximate empirical formula HCuFe2O10 suggests that the iron is incorporated into Cu2O which is formed at the moment of immersion. Both the Fe/Cu ratio on the surface and the film thickness increased with increasing time of immersion up to 2 h and then decreased again because it depends on the concentration of dissolved oxygen in solution and the residual amount of Fe2+ in solution.
{"title":"Early stages of copper protection in chloride solution containing ferrous sulphate","authors":"A. E. El Warraky","doi":"10.1179/bcj.2001.36.3.205","DOIUrl":"https://doi.org/10.1179/bcj.2001.36.3.205","url":null,"abstract":"Abstract The films formed on Cu surfaces in 4% NaCl with 10 ppm FeSO4 solution for short immersion times of up to 4 h were analysed using X-ray photoelectron spectroscopy and Auger electron spectroscopy. Iron was detected on the copper surface after immersion for 30 min. The presence of Fe(OH)2 and α-FeOOH species on the surface supports the proposal that Fe2+ ions are transported to the cathodic sites to form Fe(OH)2 which is subsequently oxidised to α-FeOOH (lepidocrocite) by dissolved oxygen in solution. The presence of a peak corresponding to the approximate empirical formula HCuFe2O10 suggests that the iron is incorporated into Cu2O which is formed at the moment of immersion. Both the Fe/Cu ratio on the surface and the film thickness increased with increasing time of immersion up to 2 h and then decreased again because it depends on the concentration of dissolved oxygen in solution and the residual amount of Fe2+ in solution.","PeriodicalId":9349,"journal":{"name":"British Corrosion Journal","volume":"54 1","pages":"205 - 209"},"PeriodicalIF":0.0,"publicationDate":"2001-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80436088","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.2001.36.3.221
R. S. Dutta, R. Savalia, G. Dey
Abstract In order to evaluate the effects of microcrystalline phases and quenched in defects on the corrosion of rapidly solidified Ti47Cu53 and Ti50Cu50 alloys, electrochemical studies have been performed on each side of alloy ribbons separately in acidic chloride environments at room temperature. In the as solidified condition, air pockets were found to be the more detrimental defects from the view point of corrosion when compared with the microcrystalline phases that initially lie beneath a thick air formed oxide film on the air side surface. Compositional differences between the two sides of the alloy ribbons were found to play an insignificant role in influencing the corrosion of the alloys.
{"title":"Effects of microcrystalline phases and quenched in defects on corrosion of rapidly solidified Ti47Cu53 and Ti50Cu50 alloys","authors":"R. S. Dutta, R. Savalia, G. Dey","doi":"10.1179/bcj.2001.36.3.221","DOIUrl":"https://doi.org/10.1179/bcj.2001.36.3.221","url":null,"abstract":"Abstract In order to evaluate the effects of microcrystalline phases and quenched in defects on the corrosion of rapidly solidified Ti47Cu53 and Ti50Cu50 alloys, electrochemical studies have been performed on each side of alloy ribbons separately in acidic chloride environments at room temperature. In the as solidified condition, air pockets were found to be the more detrimental defects from the view point of corrosion when compared with the microcrystalline phases that initially lie beneath a thick air formed oxide film on the air side surface. Compositional differences between the two sides of the alloy ribbons were found to play an insignificant role in influencing the corrosion of the alloys.","PeriodicalId":9349,"journal":{"name":"British Corrosion Journal","volume":"18 1","pages":"221 - 226"},"PeriodicalIF":0.0,"publicationDate":"2001-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84540250","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.2001.36.3.201
R. Melchers
Abstract The present paper describes an interpretation of the variation in material loss of aluminium specimens in sea water immersion at 14 different locations worldwide. Careful examination of the conditions under which aluminium corrodes in very low velocity sea water suggests that the only significant variables are temperature and aeration. This allows the field observations obtained as part of an ASTM sponsored worldwide ‘round robin’ test programme to be viewed largely as a function of temperature. It is found that corrosion tends to be generally low except at temperatures around about 10°C and in the region 20–27°C with a local peak at around 23°C. This pattern applies for all exposures to 5 years.
{"title":"Influence of temperature on sea water immersion corrosion of aluminium (UNS A95086)","authors":"R. Melchers","doi":"10.1179/bcj.2001.36.3.201","DOIUrl":"https://doi.org/10.1179/bcj.2001.36.3.201","url":null,"abstract":"Abstract The present paper describes an interpretation of the variation in material loss of aluminium specimens in sea water immersion at 14 different locations worldwide. Careful examination of the conditions under which aluminium corrodes in very low velocity sea water suggests that the only significant variables are temperature and aeration. This allows the field observations obtained as part of an ASTM sponsored worldwide ‘round robin’ test programme to be viewed largely as a function of temperature. It is found that corrosion tends to be generally low except at temperatures around about 10°C and in the region 20–27°C with a local peak at around 23°C. This pattern applies for all exposures to 5 years.","PeriodicalId":9349,"journal":{"name":"British Corrosion Journal","volume":"32 1","pages":"201 - 204"},"PeriodicalIF":0.0,"publicationDate":"2001-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82273862","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.2001.36.3.210
Alan Turnbull, D. Coleman, A. Griffiths
Abstract In many service applications an excursion in solution chemistry, temporary loss of inhibitor or increase in temperature may give rise to localised corrosion. It is important to demonstrate that restoration of normal inhibitor levels or use of enhanced doses to restore passivity will be effective in retarding propagation. Accordingly, a number of methods have been explored as a basis for developing a standard test for conducting preliminary laboratory trials. The methods examined were based on galvanostatic pre-pitting, use of the pencil artificial pit, a differential flow system and an artificial crevice arrangement. Of these, the pencil artificial pit was found to provide the most efficient and practical method for evaluating inhibitor performance.
{"title":"Assessment of test methods for evaluating effectiveness of corrosion inhibitors in retarding propagation of localised corrosion","authors":"Alan Turnbull, D. Coleman, A. Griffiths","doi":"10.1179/bcj.2001.36.3.210","DOIUrl":"https://doi.org/10.1179/bcj.2001.36.3.210","url":null,"abstract":"Abstract In many service applications an excursion in solution chemistry, temporary loss of inhibitor or increase in temperature may give rise to localised corrosion. It is important to demonstrate that restoration of normal inhibitor levels or use of enhanced doses to restore passivity will be effective in retarding propagation. Accordingly, a number of methods have been explored as a basis for developing a standard test for conducting preliminary laboratory trials. The methods examined were based on galvanostatic pre-pitting, use of the pencil artificial pit, a differential flow system and an artificial crevice arrangement. Of these, the pencil artificial pit was found to provide the most efficient and practical method for evaluating inhibitor performance.","PeriodicalId":9349,"journal":{"name":"British Corrosion Journal","volume":"32 5","pages":"210 - 214"},"PeriodicalIF":0.0,"publicationDate":"2001-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91430448","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.2001.36.3.215
H. El Shayeb, F. Abd El Wahab, E. A. Abd El Meguid
Abstract The open circuit potential of Mo electrodes has been followed as a function of time in various aqueous solutions until steady state values Est were obtained. These varied with the logarithm of the molar concentration C as Est = a + b log C. The rate of oxide film thickening was determined from the linear relationship between the open circuit potential of Mo E and the logarithm of immersion time t as E = a1 + b1 log t. A plot of the final steady state potential of Mo as a function of the pH of buffered solutions fits the linear relationship Est = a2 - b2 pH. The oxide film formed on Mo provides the opportunity to use the metal-metal oxide as an indicator electrode for potentiometric acid–base and precipitation titrations. In the case of redox titrations, the Mo electrode could not be used successfully on its own, but when coupled with platinum as a bimetallic pair electrode, excellent results were obtained when used as an indicator electrode for oxidation–reduction reactions.
摘要研究了Mo电极在不同水溶液中的开路电位随时间的变化规律，直至得到稳态值Est。这些变化与摩尔浓度的对数C Est = a + b日志C .氧化膜增厚率确定的开路电位之间的线性关系莫E和浸泡时间的对数t E = a1 + b1日志t。情节的最终稳定状态的潜力莫作为缓冲溶液的pH值的函数符合线性关系Est = a2 - b2博士形成的氧化膜在密苏里州提供了使用-金属氧化物作为的机会电位酸碱滴定和沉淀滴定用指示电极。在氧化还原滴定中，Mo电极不能单独使用，但当与铂偶联作为双金属对电极时，作为氧化还原反应的指示电极时，获得了良好的效果。
{"title":"Electrochemical behaviour of molybdenum electrodes in various aqueous and buffered solutions and their use in titrations","authors":"H. El Shayeb, F. Abd El Wahab, E. A. Abd El Meguid","doi":"10.1179/bcj.2001.36.3.215","DOIUrl":"https://doi.org/10.1179/bcj.2001.36.3.215","url":null,"abstract":"Abstract The open circuit potential of Mo electrodes has been followed as a function of time in various aqueous solutions until steady state values Est were obtained. These varied with the logarithm of the molar concentration C as Est = a + b log C. The rate of oxide film thickening was determined from the linear relationship between the open circuit potential of Mo E and the logarithm of immersion time t as E = a1 + b1 log t. A plot of the final steady state potential of Mo as a function of the pH of buffered solutions fits the linear relationship Est = a2 - b2 pH. The oxide film formed on Mo provides the opportunity to use the metal-metal oxide as an indicator electrode for potentiometric acid–base and precipitation titrations. In the case of redox titrations, the Mo electrode could not be used successfully on its own, but when coupled with platinum as a bimetallic pair electrode, excellent results were obtained when used as an indicator electrode for oxidation–reduction reactions.","PeriodicalId":9349,"journal":{"name":"British Corrosion Journal","volume":"11 1","pages":"215 - 220"},"PeriodicalIF":0.0,"publicationDate":"2001-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86225721","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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