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Ajouter le résultat dans votre panierCopper corrosion in drinking water systems – effect of pH and phosphate-dosage / J. Dartmann in Materials and corrosion, Vol. 61 N° 3 (Mars 2010)
in Materials and corrosion > Vol. 61 N° 3 (Mars 2010) . - pp. 189–198
Titre : Copper corrosion in drinking water systems – effect of pH and phosphate-dosage Type de document : texte imprimé Auteurs : J. Dartmann, Auteur ; B. Sadlowsky, Auteur ; T. Dorsch, Auteur Année de publication : 2010 Article en page(s) : pp. 189–198 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Copper release; deacidification; decarbonisation; DIN 50931-1; domestic plumbing installation; mechanisms; orthophosphate-dosage; total organic carbon Résumé : Copper corrosion in residential plumbing installations can lead to an increase in copper concentration in drinking water as well as to leakages. Central water treatment steps such as pH-adjustment or dosages of phosphate-based inhibitors are measures in reducing copper corrosion. Especially phosphate in drinking water is believed to work as a corrosion inhibitor, but it is currently uncertain as to how this inhibitor works. In some cases the phosphate dosage aggravated the copper corrosion. The mechanisms are not yet clear and the influence of phosphate and pH remain a question to be answered. The results of a German Gas and Water Works Association (DVGW) research project on copper corrosion are presented as follows. The influence and the mechanisms of decarbonisation, deacidification and phosphate dosing on copper release in residential plumbing installations were studied in pipe rig experiments according to the German standard DIN 50931-1. It shows that an increased pH-value can lead to a decrease in copper content and that a phosphate dosage can lead to both higher and lower copper concentrations. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905241/abstract [article] Copper corrosion in drinking water systems – effect of pH and phosphate-dosage [texte imprimé] / J. Dartmann, Auteur ; B. Sadlowsky, Auteur ; T. Dorsch, Auteur . - 2010 . - pp. 189–198.
Génie mécanique
Langues : Anglais (eng)
in Materials and corrosion > Vol. 61 N° 3 (Mars 2010) . - pp. 189–198
Mots-clés : Copper release; deacidification; decarbonisation; DIN 50931-1; domestic plumbing installation; mechanisms; orthophosphate-dosage; total organic carbon Résumé : Copper corrosion in residential plumbing installations can lead to an increase in copper concentration in drinking water as well as to leakages. Central water treatment steps such as pH-adjustment or dosages of phosphate-based inhibitors are measures in reducing copper corrosion. Especially phosphate in drinking water is believed to work as a corrosion inhibitor, but it is currently uncertain as to how this inhibitor works. In some cases the phosphate dosage aggravated the copper corrosion. The mechanisms are not yet clear and the influence of phosphate and pH remain a question to be answered. The results of a German Gas and Water Works Association (DVGW) research project on copper corrosion are presented as follows. The influence and the mechanisms of decarbonisation, deacidification and phosphate dosing on copper release in residential plumbing installations were studied in pipe rig experiments according to the German standard DIN 50931-1. It shows that an increased pH-value can lead to a decrease in copper content and that a phosphate dosage can lead to both higher and lower copper concentrations. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905241/abstract
in Materials and corrosion > Vol. 61 N° 3 (Mars 2010) . - pp. 199–204
Titre : Influence of cold work and sigma phase on the pitting corrosion behavior of 25 chromium super duplex stainless steel in 3.5% sodium chloride solution Type de document : texte imprimé Auteurs : A. Elhoud, Auteur ; H. Ezuber, Auteur ; W. Deans, Auteur Année de publication : 2010 Article en page(s) : pp. 199–204 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : 25 chromium SDSS; cold work; pitting corrosion; sigma phase Résumé : The effect of cold work (up to 16% strain) and sigma phase precipitation (at 850 °C for 10 and 60 min) on the pitting resistance of 25 chromium super duplex stainless steel were investigated in 3.5% sodium chloride solution at 70 and 90 °C. Anodic polarization scans for cold worked samples revealed immunity to pitting attack at 70 °C even with 16% strain. At 90 °C, the alloy still showed high pitting resistance, pitting occurring at about 600 mV (SCE) for the 16% plastic strain samples. A serious deterioration of the pitting corrosion resistance was found after heating the alloy at 850 °C for 10 min resulting in a clear drop in the pitting potential at 90 °C. After heating for 60 min, the material showed rapid deterioration of pitting corrosion resistance at 70 °C. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905312/abstract [article] Influence of cold work and sigma phase on the pitting corrosion behavior of 25 chromium super duplex stainless steel in 3.5% sodium chloride solution [texte imprimé] / A. Elhoud, Auteur ; H. Ezuber, Auteur ; W. Deans, Auteur . - 2010 . - pp. 199–204.
Génie mécanique
Langues : Anglais (eng)
in Materials and corrosion > Vol. 61 N° 3 (Mars 2010) . - pp. 199–204
Mots-clés : 25 chromium SDSS; cold work; pitting corrosion; sigma phase Résumé : The effect of cold work (up to 16% strain) and sigma phase precipitation (at 850 °C for 10 and 60 min) on the pitting resistance of 25 chromium super duplex stainless steel were investigated in 3.5% sodium chloride solution at 70 and 90 °C. Anodic polarization scans for cold worked samples revealed immunity to pitting attack at 70 °C even with 16% strain. At 90 °C, the alloy still showed high pitting resistance, pitting occurring at about 600 mV (SCE) for the 16% plastic strain samples. A serious deterioration of the pitting corrosion resistance was found after heating the alloy at 850 °C for 10 min resulting in a clear drop in the pitting potential at 90 °C. After heating for 60 min, the material showed rapid deterioration of pitting corrosion resistance at 70 °C. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905312/abstract
in Materials and corrosion > Vol. 61 N° 3 (Mars 2010) . - pp. 205–210
Titre : Characterization of two Roman coins from an archaeological site in Portugal Type de document : texte imprimé Auteurs : A. L. Mata, Auteur ; M. M. L. Salta, Auteur ; M. M. M. Neto, Auteur Année de publication : 2010 Article en page(s) : pp. 205–210 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : EDS; portuguese cultural heritage; roman coins; soil; XRD Résumé : This paper reports a study carried out on two Roman coins found in the archaeological site of São Pedro, in Fronteira (Alentejo, Portugal). One coin was in a quite well preserved state, allowing its reading and historical identification, while the other was quite deteriorated and its reading difficult. The coins have been identified as: an Antoninianus of Galilenus (267–268 A.D.) and an AE 3 (337–340 A.D.) in which is impossible to identify the emperor. Energy dispersive spectroscopy (EDS) has given the following average composition: 42%C + 30%O + 12%Cu + 1%Ag + 2%Sn + 4%Pb + 6%Si and 17%C + 31%O + 5%Cu + 7%Pb + 27%Fe + 5%Si, for the outer layers of the Antoninianus and of the AE 3, respectively. The exact substrate composition of the AE 3 could be determined: 84%Cu + 10%Pb + 2%Ag + 2%Sn + 2%Fe. The chemical composition found for the AE 3 is consistent with historical investigations, since silver-plated Cu–Pb–Sn alloys was the material used in the production of the AE 3. X-ray powder diffraction spectroscopy (XRD) has identified as possible crystalline compounds: a mixture of two silicates, namely the lead aluminium silicate, Pb4Al4Si3O16, and the lead copper silicate, Pb8Cu(Si2O7)3, pyromorphite, Pb5(PO4)3Cl, on the Antoninianus and only oxides, namely Cu2O, and iron oxides, Fe2O3 and/Fe3O4, on the AE 3 outer layer. The chemical composition of the corrosion products is related with the soil composition, a sandy neutral soil, rich in P, Mn, Si, K, Fe and organic matter (9%). The hydrogeological context plays also its role on the formation of the corrosion products. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905284/abstract [article] Characterization of two Roman coins from an archaeological site in Portugal [texte imprimé] / A. L. Mata, Auteur ; M. M. L. Salta, Auteur ; M. M. M. Neto, Auteur . - 2010 . - pp. 205–210.
Génie mécanique
Langues : Anglais (eng)
in Materials and corrosion > Vol. 61 N° 3 (Mars 2010) . - pp. 205–210
Mots-clés : EDS; portuguese cultural heritage; roman coins; soil; XRD Résumé : This paper reports a study carried out on two Roman coins found in the archaeological site of São Pedro, in Fronteira (Alentejo, Portugal). One coin was in a quite well preserved state, allowing its reading and historical identification, while the other was quite deteriorated and its reading difficult. The coins have been identified as: an Antoninianus of Galilenus (267–268 A.D.) and an AE 3 (337–340 A.D.) in which is impossible to identify the emperor. Energy dispersive spectroscopy (EDS) has given the following average composition: 42%C + 30%O + 12%Cu + 1%Ag + 2%Sn + 4%Pb + 6%Si and 17%C + 31%O + 5%Cu + 7%Pb + 27%Fe + 5%Si, for the outer layers of the Antoninianus and of the AE 3, respectively. The exact substrate composition of the AE 3 could be determined: 84%Cu + 10%Pb + 2%Ag + 2%Sn + 2%Fe. The chemical composition found for the AE 3 is consistent with historical investigations, since silver-plated Cu–Pb–Sn alloys was the material used in the production of the AE 3. X-ray powder diffraction spectroscopy (XRD) has identified as possible crystalline compounds: a mixture of two silicates, namely the lead aluminium silicate, Pb4Al4Si3O16, and the lead copper silicate, Pb8Cu(Si2O7)3, pyromorphite, Pb5(PO4)3Cl, on the Antoninianus and only oxides, namely Cu2O, and iron oxides, Fe2O3 and/Fe3O4, on the AE 3 outer layer. The chemical composition of the corrosion products is related with the soil composition, a sandy neutral soil, rich in P, Mn, Si, K, Fe and organic matter (9%). The hydrogeological context plays also its role on the formation of the corrosion products. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905284/abstract
in Materials and corrosion > Vol. 61 N° 3 (Mars 2010) . - pp. 211–217
Titre : Role of second phase particles in pitting corrosion of 3003 Al alloy in NaCl solution Type de document : texte imprimé Auteurs : Y. Liu, Auteur ; Y. F. Cheng, Auteur Année de publication : 2010 Article en page(s) : pp. 211–217 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Aluminum alloy; pitting corrosion; second phase particles Résumé : The second phase particles in 3003 aluminum (Al) alloy were characterized by scanning electron microscope, energy-dispersive X-ray analysis and X-ray diffraction techniques. The role of second phase particles in Al alloy pitting corrosion was investigated by cyclic polarization measurement, and scanning vibrating electrode technique. Results demonstrated that the second phase particles in 3003 Al alloy are mainly Alx(Fe,Mn) intermetallics, with an average diameter of about 5 µm. The enrichment of Mn in second phase particles forms a galvanic cell effect relative to the adjacent Al alloy substrate. The initiation of pitting corrosion of 3003 Al alloy is the local dissolution of Al substrate around the second phase particles. When a sufficient amount of Al is dissolved away, the second phase particles drop off from the Al substrate, forming large pitting cavities that are usually linked each other. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905308/abstract [article] Role of second phase particles in pitting corrosion of 3003 Al alloy in NaCl solution [texte imprimé] / Y. Liu, Auteur ; Y. F. Cheng, Auteur . - 2010 . - pp. 211–217.
Génie mécanique
Langues : Anglais (eng)
in Materials and corrosion > Vol. 61 N° 3 (Mars 2010) . - pp. 211–217
Mots-clés : Aluminum alloy; pitting corrosion; second phase particles Résumé : The second phase particles in 3003 aluminum (Al) alloy were characterized by scanning electron microscope, energy-dispersive X-ray analysis and X-ray diffraction techniques. The role of second phase particles in Al alloy pitting corrosion was investigated by cyclic polarization measurement, and scanning vibrating electrode technique. Results demonstrated that the second phase particles in 3003 Al alloy are mainly Alx(Fe,Mn) intermetallics, with an average diameter of about 5 µm. The enrichment of Mn in second phase particles forms a galvanic cell effect relative to the adjacent Al alloy substrate. The initiation of pitting corrosion of 3003 Al alloy is the local dissolution of Al substrate around the second phase particles. When a sufficient amount of Al is dissolved away, the second phase particles drop off from the Al substrate, forming large pitting cavities that are usually linked each other. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905308/abstract
in Materials and corrosion > Vol. 61 N° 3 (Mars 2010) . - pp. 218–221
Titre : Effect of ultrasound treatment of AlSi5 liquid alloy on corrosion resistance Type de document : texte imprimé Auteurs : A. Arrighini, Auteur ; M. Gelfi, Auteur ; A. Pola, Auteur Année de publication : 2010 Article en page(s) : pp. 218–221 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : AlSi5; corrosion; casting; electrochemical tests; ultrasound treatment Résumé : The application of power ultrasound to liquid alloys can be a simple and cost effective method to induce both degassing and grain refinement in a single step, without the need of inert gas or inoculants additions. In this paper, the treatment of liquid hypoeutectic AlSi5 alloy by ultrasound waves and its effects on microstructure were investigated. The corrosion behavior of ultrasound treated samples was compared to that of the non-treated ones by means of immersion and electrochemical tests. It was observed that the ultrasound treated alloy offers better quality, higher mechanical properties and improved corrosion resistance, as a consequence of a more uniform distribution of the solute. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905303/abstract [article] Effect of ultrasound treatment of AlSi5 liquid alloy on corrosion resistance [texte imprimé] / A. Arrighini, Auteur ; M. Gelfi, Auteur ; A. Pola, Auteur . - 2010 . - pp. 218–221.
Génie mécanique
Langues : Anglais (eng)
in Materials and corrosion > Vol. 61 N° 3 (Mars 2010) . - pp. 218–221
Mots-clés : AlSi5; corrosion; casting; electrochemical tests; ultrasound treatment Résumé : The application of power ultrasound to liquid alloys can be a simple and cost effective method to induce both degassing and grain refinement in a single step, without the need of inert gas or inoculants additions. In this paper, the treatment of liquid hypoeutectic AlSi5 alloy by ultrasound waves and its effects on microstructure were investigated. The corrosion behavior of ultrasound treated samples was compared to that of the non-treated ones by means of immersion and electrochemical tests. It was observed that the ultrasound treated alloy offers better quality, higher mechanical properties and improved corrosion resistance, as a consequence of a more uniform distribution of the solute. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905303/abstract
in Materials and corrosion > Vol. 61 N° 3 (Mars 2010) . - pp. 222–228
Titre : Study on the effect of corrosion on the tensile behavior of an AZ91 alloy Type de document : texte imprimé Auteurs : Q. Wang, Auteur ; Y. H. Liu, Auteur ; L. N. Zhang, Auteur Année de publication : 2010 Article en page(s) : pp. 222–228 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : AZ91 magnesium alloy; corrosion residual strength; estimation; fracture Résumé : The effect of corrosion on the tensile behavior of an as-cast AZ91 alloy was investigated via systematical experiments. The corrosion residual strength of the AZ91 magnesium alloy is approximately negative linear dependent on the extreme depth of corrosion pit, which was quantitatively obtained by the corrosion morphology analysis and the statistic analysis. Experimental results reveal that the corrosion residual strength of the AZ91 magnesium alloy dropped quickly in the first 40 h due to the initiation and development of the corrosion pit and subsequently decreased slowly as a result of the development of the corrosion pit encountered the β phase. The β phase at the grain boundary of the primary α phase acts as an effective barrier to prevent the development of the corrosion pit into the alloy matrix and thus remarkably prevents the drop of the corrosion residual strength. In general, the variation of the corrosion residual strength exhibits an exponential decay regulation within the testing time. Consequently, the empirical prediction of the corrosion residual strength was given with regard to the variation of the corrosion residual strength varied with the immersion time. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905317/abstract [article] Study on the effect of corrosion on the tensile behavior of an AZ91 alloy [texte imprimé] / Q. Wang, Auteur ; Y. H. Liu, Auteur ; L. N. Zhang, Auteur . - 2010 . - pp. 222–228.
Génie mécanique
Langues : Anglais (eng)
in Materials and corrosion > Vol. 61 N° 3 (Mars 2010) . - pp. 222–228
Mots-clés : AZ91 magnesium alloy; corrosion residual strength; estimation; fracture Résumé : The effect of corrosion on the tensile behavior of an as-cast AZ91 alloy was investigated via systematical experiments. The corrosion residual strength of the AZ91 magnesium alloy is approximately negative linear dependent on the extreme depth of corrosion pit, which was quantitatively obtained by the corrosion morphology analysis and the statistic analysis. Experimental results reveal that the corrosion residual strength of the AZ91 magnesium alloy dropped quickly in the first 40 h due to the initiation and development of the corrosion pit and subsequently decreased slowly as a result of the development of the corrosion pit encountered the β phase. The β phase at the grain boundary of the primary α phase acts as an effective barrier to prevent the development of the corrosion pit into the alloy matrix and thus remarkably prevents the drop of the corrosion residual strength. In general, the variation of the corrosion residual strength exhibits an exponential decay regulation within the testing time. Consequently, the empirical prediction of the corrosion residual strength was given with regard to the variation of the corrosion residual strength varied with the immersion time. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905317/abstract
in Materials and corrosion > Vol. 61 N° 3 (Mars 2010) . - pp. 229–237
Titre : Synergism between protocatechualdehyde and rare earth cerium(IV) ion on the corrosion of cold rolled steel in hydrochloric acid solution Type de document : texte imprimé Auteurs : X. H. Li, Auteur ; S. D. Deng, Auteur ; G. N. Mu, Auteur Année de publication : 2010 Article en page(s) : pp. 229–237 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Adsorption; cerium(IV) ion; cold rolled steel; corrosion inhibitor; hydrochloric acid; protocatechualdehyde; synergism Résumé : The synergism between protocatechualdehyde (PAL, 3,4-dihydroxy-benzaldehye) and rare earth cerium(IV) ion (Ce4+) on the corrosion of cold rolled steel (CRS) in 1.0 M hydrochloric acid (HCl) solution has been investigated by weight loss and potentiodynamic polarization methods. The results reveal that PAL has a moderate inhibitive effect, while Ce4+ has a poor effect. Incorporation of PAL with Ce4+ improves the inhibition performance significantly, and exhibits synergistic inhibition effect. The adsorption of individual PAL obeys the Temkin adsorption isotherm, and the adsorption of the complex of PAL and Ce4+ accords with the Temkin adsorption isotherm too. The thermodynamic parameters of adsorption heat (ΔH0), adsorption free energy (ΔG0), and adsorption entropy (ΔS0) are calculated and discussed. Polarization curves show that individual PAL acts as a mixed-type inhibitor, while Ce4+ slightly inhibits the corrosion reaction. The complex of PAL and Ce4+ acts as a mixed-type inhibitor, which drastically inhibits both anodic and cathodic reactions. Depending on the results, the synergism mechanism is proposed from the viewpoint of adsorption theory. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905283/abstract [article] Synergism between protocatechualdehyde and rare earth cerium(IV) ion on the corrosion of cold rolled steel in hydrochloric acid solution [texte imprimé] / X. H. Li, Auteur ; S. D. Deng, Auteur ; G. N. Mu, Auteur . - 2010 . - pp. 229–237.
Génie mécanique
Langues : Anglais (eng)
in Materials and corrosion > Vol. 61 N° 3 (Mars 2010) . - pp. 229–237
Mots-clés : Adsorption; cerium(IV) ion; cold rolled steel; corrosion inhibitor; hydrochloric acid; protocatechualdehyde; synergism Résumé : The synergism between protocatechualdehyde (PAL, 3,4-dihydroxy-benzaldehye) and rare earth cerium(IV) ion (Ce4+) on the corrosion of cold rolled steel (CRS) in 1.0 M hydrochloric acid (HCl) solution has been investigated by weight loss and potentiodynamic polarization methods. The results reveal that PAL has a moderate inhibitive effect, while Ce4+ has a poor effect. Incorporation of PAL with Ce4+ improves the inhibition performance significantly, and exhibits synergistic inhibition effect. The adsorption of individual PAL obeys the Temkin adsorption isotherm, and the adsorption of the complex of PAL and Ce4+ accords with the Temkin adsorption isotherm too. The thermodynamic parameters of adsorption heat (ΔH0), adsorption free energy (ΔG0), and adsorption entropy (ΔS0) are calculated and discussed. Polarization curves show that individual PAL acts as a mixed-type inhibitor, while Ce4+ slightly inhibits the corrosion reaction. The complex of PAL and Ce4+ acts as a mixed-type inhibitor, which drastically inhibits both anodic and cathodic reactions. Depending on the results, the synergism mechanism is proposed from the viewpoint of adsorption theory. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905283/abstract
in Materials and corrosion > Vol. 61 N° 3 (Mars 2010) . - pp. 238–244
Titre : Atmospheric corrosion of carbon steel at marine sites in Saudi Arabia Type de document : texte imprimé Auteurs : S. Syed, Auteur Année de publication : 2010 Article en page(s) : pp. 238–244 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Aggressiveness of atmospheres; atmospheric corrosion; carbon steel; kinetics; marine corrosion; xrd Résumé : Atmospheric corrosion tests, according to ASTM G50-76, have been carried out in Saudi Arabia, at eight marine sites representing different environmental conditions. Environmental factors such as average temperature, average relative humidity, and deposition rates of atmospheric pollutants (Cl− and SO2) was investigated. X-ray diffraction has been used to determine the composition of the corrosion products. Corrosion rates have been determined for each sample at each of the exposure sites via loss of weight. The obtained data were used for the classification of atmospheric aggressivity, according to ISO 9223. The results obeyed well with the empirical kinetics equation of the form C = Ktn, where K and C are the corrosion losses in mg/cm2 after 1 and t years of the exposure respectively, and n is constant. Based on n values, the corrosion mechanism of carbon steel is predicted. The major constituent of the rust formed in marine environment is goethite (α-FeOOH). Samples also show the presence of a large proportion of lepidocrocite (γ-FeOOH) and small amounts of ferrihydrite and maghemite (α-Fe203). En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905300/abstract [article] Atmospheric corrosion of carbon steel at marine sites in Saudi Arabia [texte imprimé] / S. Syed, Auteur . - 2010 . - pp. 238–244.
Génie mécanique
Langues : Anglais (eng)
in Materials and corrosion > Vol. 61 N° 3 (Mars 2010) . - pp. 238–244
Mots-clés : Aggressiveness of atmospheres; atmospheric corrosion; carbon steel; kinetics; marine corrosion; xrd Résumé : Atmospheric corrosion tests, according to ASTM G50-76, have been carried out in Saudi Arabia, at eight marine sites representing different environmental conditions. Environmental factors such as average temperature, average relative humidity, and deposition rates of atmospheric pollutants (Cl− and SO2) was investigated. X-ray diffraction has been used to determine the composition of the corrosion products. Corrosion rates have been determined for each sample at each of the exposure sites via loss of weight. The obtained data were used for the classification of atmospheric aggressivity, according to ISO 9223. The results obeyed well with the empirical kinetics equation of the form C = Ktn, where K and C are the corrosion losses in mg/cm2 after 1 and t years of the exposure respectively, and n is constant. Based on n values, the corrosion mechanism of carbon steel is predicted. The major constituent of the rust formed in marine environment is goethite (α-FeOOH). Samples also show the presence of a large proportion of lepidocrocite (γ-FeOOH) and small amounts of ferrihydrite and maghemite (α-Fe203). En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905300/abstract
in Materials and corrosion > Vol. 61 N° 3 (Mars 2010) . - pp. 245–251
Titre : Analysis of different factors affecting cathodic protection for deep well casings Type de document : texte imprimé Auteurs : I. A. Metwally, Auteur ; A. H. Al-Badi, Auteur Année de publication : 2010 Article en page(s) : pp. 245–251 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Cathodic protection; interference; oil well casing; pulse rectifier; simulation; stray current Résumé : This paper introduces a comparative theoretical investigation of the conventional cathodic protection (CP) and the pulse cathodic protection (PCP) systems to show how both of them behave under different operating conditions. The effectiveness of the PCP system is also highlighted for a typical large-scale configuration as well as some field measurements have been carried out. The performance of PCP system has been analyzed in the light of getting better protection-current distribution along the protected well casing at reduced anode current together with reducing the stray current (corrosion) at any nearby unprotected structure(s). Many factors have been investigated to show their effects on the performance of the CP system, namely, soil resistivity, voltage pulse waveform and frequency, and multi-layer soil. In addition, the performance of both the conventional CP and the PCP systems has been compared to that when utilizing unused/abandoned well casing as anode energized by the conventional CP system. The PCP system shows better performance than that of the conventional CP, and a similar performance at high soil resistivity to that when using unused/abandoned well casing. On the other hand, the utilization of the unused/abandoned well casing gives superior performance, especially at low soil resistivities, where the protection-current profiles of both the conventional CP and the PCP systems decay sharply. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905272/abstract [article] Analysis of different factors affecting cathodic protection for deep well casings [texte imprimé] / I. A. Metwally, Auteur ; A. H. Al-Badi, Auteur . - 2010 . - pp. 245–251.
Génie mécanique
Langues : Anglais (eng)
in Materials and corrosion > Vol. 61 N° 3 (Mars 2010) . - pp. 245–251
Mots-clés : Cathodic protection; interference; oil well casing; pulse rectifier; simulation; stray current Résumé : This paper introduces a comparative theoretical investigation of the conventional cathodic protection (CP) and the pulse cathodic protection (PCP) systems to show how both of them behave under different operating conditions. The effectiveness of the PCP system is also highlighted for a typical large-scale configuration as well as some field measurements have been carried out. The performance of PCP system has been analyzed in the light of getting better protection-current distribution along the protected well casing at reduced anode current together with reducing the stray current (corrosion) at any nearby unprotected structure(s). Many factors have been investigated to show their effects on the performance of the CP system, namely, soil resistivity, voltage pulse waveform and frequency, and multi-layer soil. In addition, the performance of both the conventional CP and the PCP systems has been compared to that when utilizing unused/abandoned well casing as anode energized by the conventional CP system. The PCP system shows better performance than that of the conventional CP, and a similar performance at high soil resistivity to that when using unused/abandoned well casing. On the other hand, the utilization of the unused/abandoned well casing gives superior performance, especially at low soil resistivities, where the protection-current profiles of both the conventional CP and the PCP systems decay sharply. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905272/abstract
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