Dépouillements

Electrochemical and surface analytical studies of synergistic effect of phosphonate, Zn2+ and ascorbate in corrosion control of carbon steel / B. V. Appa Rao in Materials and corrosion, Vol. 61 N° 4 (Avril 2010) 

Public ISBD [article]  in Materials and corrosion > Vol. 61 N° 4 (Avril 2010) . - pp. 285–301 Titre : Electrochemical and surface analytical studies of synergistic effect of phosphonate, Zn2+ and ascorbate in corrosion control of carbon steel Type de document : texte imprimé Auteurs : B. V. Appa Rao, Auteur ; S. Srinivasa Rao, Auteur Année de publication : 2010 Article en page(s) : pp. 285–301 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Ascorbate;  carbon  steel;  corrosion  inhibition;  EIS;  FTIR;  PBTC;  polarisation;  XPS;  Zn2+ Résumé : Synergistic inhibition of corrosion of carbon steel in low chloride environment using ascorbate as a synergist along with 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC) and Zn2+ is presented. The synergistic effect of ascorbate has been established from the present studies. In the presence of ascorbate, lower concentrations of PBTC and Zn2+ are sufficient in order to obtain good inhibition, thus making this formulation more environmentally friendly. Potentiodynamic polarisation studies inferred that this mixture functions as a mixed inhibitor, predominantly cathodic. Impedance studies revealed that an immersion period of 24 h is necessary for the formation of the protective film, with a very high charge transfer resistance. The film is stable even at 60 °C in the presence of the inhibitor in the corrosive environment. The surface analysis by X-ray photoelectron spectroscopy (XPS) showed the presence of iron, oxygen, phosphorus, carbon and zinc in the protective film. The XPS spectra inferred the presence of oxides/hydroxides of iron(III), Zn(OH)2 and [Zn(II)–PBTC–ascorbate] complex in the surface film. This inference was further supported by the reflection absorption Fourier transform infrared spectrum of the surface film. A plausible mechanism of corrosion inhibition has been proposed. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905333/abstract [article] Electrochemical and surface analytical studies of synergistic effect of phosphonate, Zn2+ and ascorbate in corrosion control of carbon steel [texte imprimé] / B. V. Appa Rao, Auteur ; S. Srinivasa Rao, Auteur . - 2010 . - pp. 285–301. Génie mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 61 N° 4 (Avril 2010) . - pp. 285–301 Mots-clés : Ascorbate;  carbon  steel;  corrosion  inhibition;  EIS;  FTIR;  PBTC;  polarisation;  XPS;  Zn2+ Résumé : Synergistic inhibition of corrosion of carbon steel in low chloride environment using ascorbate as a synergist along with 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC) and Zn2+ is presented. The synergistic effect of ascorbate has been established from the present studies. In the presence of ascorbate, lower concentrations of PBTC and Zn2+ are sufficient in order to obtain good inhibition, thus making this formulation more environmentally friendly. Potentiodynamic polarisation studies inferred that this mixture functions as a mixed inhibitor, predominantly cathodic. Impedance studies revealed that an immersion period of 24 h is necessary for the formation of the protective film, with a very high charge transfer resistance. The film is stable even at 60 °C in the presence of the inhibitor in the corrosive environment. The surface analysis by X-ray photoelectron spectroscopy (XPS) showed the presence of iron, oxygen, phosphorus, carbon and zinc in the protective film. The XPS spectra inferred the presence of oxides/hydroxides of iron(III), Zn(OH)2 and [Zn(II)–PBTC–ascorbate] complex in the surface film. This inference was further supported by the reflection absorption Fourier transform infrared spectrum of the surface film. A plausible mechanism of corrosion inhibition has been proposed. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905333/abstract

Concerning the use of constant phase elements (CPEs) in the analysis of impedance data / Y. Huang in Materials and corrosion, Vol. 61 N° 4 (Avril 2010) 

Public ISBD [article]  in Materials and corrosion > Vol. 61 N° 4 (Avril 2010) . - pp. 302–305 Titre : Concerning the use of constant phase elements (CPEs) in the analysis of impedance data Type de document : texte imprimé Auteurs : Y. Huang, Auteur ; H. Shih, Auteur ; F. Mansfeld, Auteur Année de publication : 2010 Article en page(s) : pp. 302–305 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Constant  phase  element;  equivalent  circuit;  oxide  coatings Résumé : Impedance spectra obtained for Al6061 samples that had been anodized and sealed in two different processes and subjected to thermal cycling at three different temperatures have been analyzed using the Equivcrt software using a three-time constant model with four constant phase elements (CPEs). Excellent agreement has been observed between the experimental and the fit data. The high-frequency data have also been analyzed using the ANODAL software. Excellent agreement between the experimental data and the fit data was found in both cases; however, the fit parameters were quite different. The relationship between the CPEs and the surface properties of the anodized samples has been discussed. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905385/abstract [article] Concerning the use of constant phase elements (CPEs) in the analysis of impedance data [texte imprimé] / Y. Huang, Auteur ; H. Shih, Auteur ; F. Mansfeld, Auteur . - 2010 . - pp. 302–305. Génie mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 61 N° 4 (Avril 2010) . - pp. 302–305 Mots-clés : Constant  phase  element;  equivalent  circuit;  oxide  coatings Résumé : Impedance spectra obtained for Al6061 samples that had been anodized and sealed in two different processes and subjected to thermal cycling at three different temperatures have been analyzed using the Equivcrt software using a three-time constant model with four constant phase elements (CPEs). Excellent agreement has been observed between the experimental and the fit data. The high-frequency data have also been analyzed using the ANODAL software. Excellent agreement between the experimental data and the fit data was found in both cases; however, the fit parameters were quite different. The relationship between the CPEs and the surface properties of the anodized samples has been discussed. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905385/abstract

A stochastic analysis of the effect of magnetic field on the pitting corrosion susceptibility of pure magnesium / J. Li in Materials and corrosion, Vol. 61 N° 4 (Avril 2010) 

Public ISBD [article]  in Materials and corrosion > Vol. 61 N° 4 (Avril 2010) . - pp. 306–312 Titre : A stochastic analysis of the effect of magnetic field on the pitting corrosion susceptibility of pure magnesium Type de document : texte imprimé Auteurs : J. Li, Auteur ; T. Zhang, Auteur ; Y. Shao, Auteur Année de publication : 2010 Article en page(s) : pp. 306–312 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Magnesium;  magnetic  field;  pitting  corrosion;  potentiostatic;  stochastic  analysis Résumé : The effect of magnetic field on the pitting corrosion susceptibility of pure magnesium was investigated by stochastic approaches. Stochastic models had been applied to simulate pitting corrosion as the combination of two physical processes: pit initiation and pit growth. The results revealed that magnetic field increased the pitting corrosion susceptibility of pure magnesium. For the pit initiation process, the presence of magnetic field changed the mechanism of pit initiation from the parallel birth and death stochastic model (B1) to the parallel birth stochastic model (A3). Magnetic field increased the pit generation rate λ while decreased the repassivation rate µ, which indicated that magnetic field accelerated the pit initiation process of pure magnesium. For the pit growth process, magnetic field didn't change the pit growth mechanism, but it could decrease the ability of repassivation of pitting corrosion resulting in a great probability for the stable pitting corrosion to grow up with a higher growth rate and finally develop into larger pit cavity. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905290/abstract [article] A stochastic analysis of the effect of magnetic field on the pitting corrosion susceptibility of pure magnesium [texte imprimé] / J. Li, Auteur ; T. Zhang, Auteur ; Y. Shao, Auteur . - 2010 . - pp. 306–312. Génie mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 61 N° 4 (Avril 2010) . - pp. 306–312 Mots-clés : Magnesium;  magnetic  field;  pitting  corrosion;  potentiostatic;  stochastic  analysis Résumé : The effect of magnetic field on the pitting corrosion susceptibility of pure magnesium was investigated by stochastic approaches. Stochastic models had been applied to simulate pitting corrosion as the combination of two physical processes: pit initiation and pit growth. The results revealed that magnetic field increased the pitting corrosion susceptibility of pure magnesium. For the pit initiation process, the presence of magnetic field changed the mechanism of pit initiation from the parallel birth and death stochastic model (B1) to the parallel birth stochastic model (A3). Magnetic field increased the pit generation rate λ while decreased the repassivation rate µ, which indicated that magnetic field accelerated the pit initiation process of pure magnesium. For the pit growth process, magnetic field didn't change the pit growth mechanism, but it could decrease the ability of repassivation of pitting corrosion resulting in a great probability for the stable pitting corrosion to grow up with a higher growth rate and finally develop into larger pit cavity. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905290/abstract

Influence of microstructure on the corrosion resistance of hyperduplex stainless steel / S. S. M. Tavares in Materials and corrosion, Vol. 61 N° 4 (Avril 2010) 

Public ISBD [article]  in Materials and corrosion > Vol. 61 N° 4 (Avril 2010) . - pp. 313–317 Titre : Influence of microstructure on the corrosion resistance of hyperduplex stainless steel Type de document : texte imprimé Auteurs : S. S. M. Tavares, Auteur ; J. M. Pardal, Auteur ; E. Ponzio, Auteur Année de publication : 2010 Article en page(s) : pp. 313–317 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Critical  pitting  temperature;  hyperduplex  stainless  steel;  pitting  corrosion Résumé : Hyperduplex UNS S32707 is a newly developed austenitic–ferritic stainless steel. The steel contains about 27%Cr, 7%Ni, 4.5%Mo, and 0.4%N, which results in a pitting resistance equivalent factor (PRE) equal to 49. In this study, the pitting corrosion resistance of this new grade of stainless steel was investigated by varying the microstructure using different thermal processes. The critical pitting temperature measurement and cyclic polarization tests confirm the high corrosion resistance of the hyperduplex steel in the solution treated condition. However, deleterious phases form easily during thermal processing and cause a drastic decrease in the corrosion resistance. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905386/abstract [article] Influence of microstructure on the corrosion resistance of hyperduplex stainless steel [texte imprimé] / S. S. M. Tavares, Auteur ; J. M. Pardal, Auteur ; E. Ponzio, Auteur . - 2010 . - pp. 313–317. Génie mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 61 N° 4 (Avril 2010) . - pp. 313–317 Mots-clés : Critical  pitting  temperature;  hyperduplex  stainless  steel;  pitting  corrosion Résumé : Hyperduplex UNS S32707 is a newly developed austenitic–ferritic stainless steel. The steel contains about 27%Cr, 7%Ni, 4.5%Mo, and 0.4%N, which results in a pitting resistance equivalent factor (PRE) equal to 49. In this study, the pitting corrosion resistance of this new grade of stainless steel was investigated by varying the microstructure using different thermal processes. The critical pitting temperature measurement and cyclic polarization tests confirm the high corrosion resistance of the hyperduplex steel in the solution treated condition. However, deleterious phases form easily during thermal processing and cause a drastic decrease in the corrosion resistance. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905386/abstract

The effect of calcination on the corrosion performance of TiO2 sol–gel coatings doped with benzotriazole on steel CK45 / S. M. Madani in Materials and corrosion, Vol. 61 N° 4 (Avril 2010) 

Public ISBD [article]  in Materials and corrosion > Vol. 61 N° 4 (Avril 2010) . - pp. 318–323 Titre : The effect of calcination on the corrosion performance of TiO2 sol–gel coatings doped with benzotriazole on steel CK45 Type de document : texte imprimé Auteurs : S. M. Madani, Auteur ; M. Ehteshamzadeh, Auteur ; H. H. Rafsanjani, Auteur Année de publication : 2010 Article en page(s) : pp. 318–323 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Calcinations;  corrosion  inhibition;  EIS;  sol–gel;  steel Résumé : Sol–gel method under dip coating process and tetra-n-butyle orthotitanate as precursor were used to produce titanium oxide coating on steel CK45. The effect of calcination at 400 °C, after drying at 120 °C, on the morphology and corrosion performance of the coatings was investigated. Benzotriazole (BTA) as an inhibitor was doped on titanium oxide coatings to improve corrosion performance of the coatings as well as its self-healing properties. The morphology and structure of the coatings were studied by X-ray diffraction (XRD), scanning electron microscope (SEM), and energy dispersive X-ray spectroscopy (EDS) techniques. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques were used to study the corrosion behavior of the coatings. The results revealed that after calcination the dominant crystalline phase was anatase. The results obtained from potentiodynamic polarization curves and electrochemical impedance spectra showed that the calcinated and doped with BTA coatings possessed higher corrosion resistance than non-calcinated although doped with BTA coatings. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905306/abstract [article] The effect of calcination on the corrosion performance of TiO2 sol–gel coatings doped with benzotriazole on steel CK45 [texte imprimé] / S. M. Madani, Auteur ; M. Ehteshamzadeh, Auteur ; H. H. Rafsanjani, Auteur . - 2010 . - pp. 318–323. Génie mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 61 N° 4 (Avril 2010) . - pp. 318–323 Mots-clés : Calcinations;  corrosion  inhibition;  EIS;  sol–gel;  steel Résumé : Sol–gel method under dip coating process and tetra-n-butyle orthotitanate as precursor were used to produce titanium oxide coating on steel CK45. The effect of calcination at 400 °C, after drying at 120 °C, on the morphology and corrosion performance of the coatings was investigated. Benzotriazole (BTA) as an inhibitor was doped on titanium oxide coatings to improve corrosion performance of the coatings as well as its self-healing properties. The morphology and structure of the coatings were studied by X-ray diffraction (XRD), scanning electron microscope (SEM), and energy dispersive X-ray spectroscopy (EDS) techniques. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques were used to study the corrosion behavior of the coatings. The results revealed that after calcination the dominant crystalline phase was anatase. The results obtained from potentiodynamic polarization curves and electrochemical impedance spectra showed that the calcinated and doped with BTA coatings possessed higher corrosion resistance than non-calcinated although doped with BTA coatings. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905306/abstract

Energy storage ability and anti-corrosion protection properties of TiO2–SnO2 system / M.-J. Zhou in Materials and corrosion, Vol. 61 N° 4 (Avril 2010) 

Public ISBD [article]  in Materials and corrosion > Vol. 61 N° 4 (Avril 2010) . - pp. 324–327 Titre : Energy storage ability and anti-corrosion protection properties of TiO2–SnO2 system Type de document : texte imprimé Auteurs : M.-J. Zhou, Auteur ; Z.-O. Zeng, Auteur ; L. Zhong, Auteur Année de publication : 2010 Article en page(s) : pp. 324–327 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : anti-corrosion  protection;  energy  storage;  photocathodic  protection;  TiO2/SnO2;  TiO2–SnO2 Résumé : TiO2/SnO2 and TiO2–SnO2 coatings were prepared on type 304 stainless steel by sol–gel method, respectively. TiO2/SnO2 coating is compared with TiO2–SnO2 coating in terms of energy storage ability and anti-corrosion property. The two coatings can be charged with reductive energy under UV irradiation in 3 wt% aqueous NaCl. The self-discharging time of the TiO2/SnO2 coating is slower than that of the TiO2–SnO2 coating. The slow discharging may be suitable for an anti-corrosion application for metal. In the case where TiO2/SnO2 coating electrode is electrochemically charged at −0.38 V (vs. SCE) for 1 h, it can maintain a good cathodic protection for type 304 stainless steel for 7 h in the dark, while the TiO2–SnO2 coating electrode can only maintain a good cathode protection for 0.5 h in the dark. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905347/abstract [article] Energy storage ability and anti-corrosion protection properties of TiO2–SnO2 system [texte imprimé] / M.-J. Zhou, Auteur ; Z.-O. Zeng, Auteur ; L. Zhong, Auteur . - 2010 . - pp. 324–327. Génie mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 61 N° 4 (Avril 2010) . - pp. 324–327 Mots-clés : anti-corrosion  protection;  energy  storage;  photocathodic  protection;  TiO2/SnO2;  TiO2–SnO2 Résumé : TiO2/SnO2 and TiO2–SnO2 coatings were prepared on type 304 stainless steel by sol–gel method, respectively. TiO2/SnO2 coating is compared with TiO2–SnO2 coating in terms of energy storage ability and anti-corrosion property. The two coatings can be charged with reductive energy under UV irradiation in 3 wt% aqueous NaCl. The self-discharging time of the TiO2/SnO2 coating is slower than that of the TiO2–SnO2 coating. The slow discharging may be suitable for an anti-corrosion application for metal. In the case where TiO2/SnO2 coating electrode is electrochemically charged at −0.38 V (vs. SCE) for 1 h, it can maintain a good cathodic protection for type 304 stainless steel for 7 h in the dark, while the TiO2–SnO2 coating electrode can only maintain a good cathode protection for 0.5 h in the dark. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905347/abstract

Effect of corrosion on bond strength of steel and non-metallic reinforcement / S. Demis in Materials and corrosion, Vol. 61 N° 4 (Avril 2010) 

Public ISBD [article]  in Materials and corrosion > Vol. 61 N° 4 (Avril 2010) . - pp. 328–331 Titre : Effect of corrosion on bond strength of steel and non-metallic reinforcement Type de document : texte imprimé Auteurs : S. Demis, Auteur ; K. Pilakoutas, Auteur ; Ch. Alk. Apostolopoulos, Auteur Année de publication : 2010 Article en page(s) : pp. 328–331 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : accelerated  carbonation;  bond  strength;  corrosion;  fiber  reinforced  polymers Résumé : Research attempts on the effect of environmental corrosion on bond between steel bars and concrete, report considerable losses of bond strength. Alternative solutions to the corrosion problem include the use of non-metallic reinforcement. In this paper the effects of environmental corrosion (through accelerated carbonation) on the bond properties of fiber reinforced polymer (FRP) bars with the surrounding concrete are investigated. The work presented is part of an extensive project addressing the durability of FRP in concrete 1. It was found out that, in contrast to what is generally believed, concrete alkalinity does not have a major impact on the durability of FRP bar and its bond strength. The expected bond deterioration due to carbonation is more than compensated by the increase in compressive strength due to time and carbonation, contrary to the case when steel reinforcement is used. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905324/abstract [article] Effect of corrosion on bond strength of steel and non-metallic reinforcement [texte imprimé] / S. Demis, Auteur ; K. Pilakoutas, Auteur ; Ch. Alk. Apostolopoulos, Auteur . - 2010 . - pp. 328–331. Génie mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 61 N° 4 (Avril 2010) . - pp. 328–331 Mots-clés : accelerated  carbonation;  bond  strength;  corrosion;  fiber  reinforced  polymers Résumé : Research attempts on the effect of environmental corrosion on bond between steel bars and concrete, report considerable losses of bond strength. Alternative solutions to the corrosion problem include the use of non-metallic reinforcement. In this paper the effects of environmental corrosion (through accelerated carbonation) on the bond properties of fiber reinforced polymer (FRP) bars with the surrounding concrete are investigated. The work presented is part of an extensive project addressing the durability of FRP in concrete 1. It was found out that, in contrast to what is generally believed, concrete alkalinity does not have a major impact on the durability of FRP bar and its bond strength. The expected bond deterioration due to carbonation is more than compensated by the increase in compressive strength due to time and carbonation, contrary to the case when steel reinforcement is used. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905324/abstract

Studies on corrosion inhibition of copper by alkanethiol SAMs prepared in aqueous micellar solution / P. Wang in Materials and corrosion, Vol. 61 N° 4 (Avril 2010) 

Public ISBD [article]  in Materials and corrosion > Vol. 61 N° 4 (Avril 2010) . - pp. 332–337 Titre : Studies on corrosion inhibition of copper by alkanethiol SAMs prepared in aqueous micellar solution Type de document : texte imprimé Auteurs : P. Wang, Auteur ; C. Liang, Auteur ; Huang, N., Auteur Année de publication : 2010 Article en page(s) : pp. 332–337 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : copper;  corrosion;  inhibition;  SAMs Résumé : The character of 1-dodecanethiol (DT) self-assembled monolayers (SAMs) formed on copper surface in aqueous micellar solution is investigated by means of contact angle measurement, electrochemical impedance spectroscopy (EIS), and polarization curves. The contact angle measurement shows that the SAMs formed in aqueous micellar solution are oriented and compact. According to the electrochemical measurements, it is found that both the concentration of DT and temperature can significantly affect the property of SAMs. The DT SAMs can prevent the corrosion of copper in chloride-containing solution effectively because the inhibition efficiency can reach 99.59% at the DT concentration of 10−2 M. The adsorption of DT in aqueous micellar solution obeys to the Langmuir adsorption isotherm, and the value of the free energy of adsorption calculated indicates that the adsorption of DT molecule is a spontaneous process and a typical of chemical adsorption. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905285/abstract [article] Studies on corrosion inhibition of copper by alkanethiol SAMs prepared in aqueous micellar solution [texte imprimé] / P. Wang, Auteur ; C. Liang, Auteur ; Huang, N., Auteur . - 2010 . - pp. 332–337. Génie mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 61 N° 4 (Avril 2010) . - pp. 332–337 Mots-clés : copper;  corrosion;  inhibition;  SAMs Résumé : The character of 1-dodecanethiol (DT) self-assembled monolayers (SAMs) formed on copper surface in aqueous micellar solution is investigated by means of contact angle measurement, electrochemical impedance spectroscopy (EIS), and polarization curves. The contact angle measurement shows that the SAMs formed in aqueous micellar solution are oriented and compact. According to the electrochemical measurements, it is found that both the concentration of DT and temperature can significantly affect the property of SAMs. The DT SAMs can prevent the corrosion of copper in chloride-containing solution effectively because the inhibition efficiency can reach 99.59% at the DT concentration of 10−2 M. The adsorption of DT in aqueous micellar solution obeys to the Langmuir adsorption isotherm, and the value of the free energy of adsorption calculated indicates that the adsorption of DT molecule is a spontaneous process and a typical of chemical adsorption. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905285/abstract

Evaluation of the uniform current density assumption in cathodic protection systems with close anode-to-cathode arrangement / S. Martinez in Materials and corrosion, Vol. 61 N° 4 (Avril 2010) 

Public ISBD [article]  in Materials and corrosion > Vol. 61 N° 4 (Avril 2010) . - pp. 338–342 Titre : Evaluation of the uniform current density assumption in cathodic protection systems with close anode-to-cathode arrangement Type de document : texte imprimé Auteurs : S. Martinez, Auteur Année de publication : 2010 Article en page(s) : pp. 338–342 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : boundary  element  method;  current  distribution;  cathodic  protection;  potential  distribution Résumé : Cathodic protection modelling often involves making assumptions about geometric features and material characteristics that directly impact accuracy of solutions. In the present paper, predictive power of the model using approximate uniform current boundary condition on the cathode is validated against the model using nonlinear cathode polarization curves representative of low-carbon steel structure of common geometry, buried in soil or immersed in seawater. In order to explore the worst case scenario, the present example deals with a large diameter pipeline (Ø 1.2 m) and a wire anode (Ø 0.05 m), separated by a distance d, both embedded in an infinite space of conductivity κ. The calculation is performed for the two sets of parameters – κ and limiting current density of oxygen reduction, il. For simulation of CP systems in seawater κ = 4.79 S/m and il = −86 µA/cm2 and for CP system in soil, κ = 10−3 S/m and il = −1.1 µA/cm2. The other physical parameters were identical for both systems (Tafel slopes ba = 60 mV/dec, bc = 120 mV/dec and equilibrium potentials equation image, equation image). The results were visualized to best exemplify the general trends in potential and current distributions that appear upon switch between uniform and nonlinear cathodic boundary conditions. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905350/abstract [article] Evaluation of the uniform current density assumption in cathodic protection systems with close anode-to-cathode arrangement [texte imprimé] / S. Martinez, Auteur . - 2010 . - pp. 338–342. Génie mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 61 N° 4 (Avril 2010) . - pp. 338–342 Mots-clés : boundary  element  method;  current  distribution;  cathodic  protection;  potential  distribution Résumé : Cathodic protection modelling often involves making assumptions about geometric features and material characteristics that directly impact accuracy of solutions. In the present paper, predictive power of the model using approximate uniform current boundary condition on the cathode is validated against the model using nonlinear cathode polarization curves representative of low-carbon steel structure of common geometry, buried in soil or immersed in seawater. In order to explore the worst case scenario, the present example deals with a large diameter pipeline (Ø 1.2 m) and a wire anode (Ø 0.05 m), separated by a distance d, both embedded in an infinite space of conductivity κ. The calculation is performed for the two sets of parameters – κ and limiting current density of oxygen reduction, il. For simulation of CP systems in seawater κ = 4.79 S/m and il = −86 µA/cm2 and for CP system in soil, κ = 10−3 S/m and il = −1.1 µA/cm2. The other physical parameters were identical for both systems (Tafel slopes ba = 60 mV/dec, bc = 120 mV/dec and equilibrium potentials equation image, equation image). The results were visualized to best exemplify the general trends in potential and current distributions that appear upon switch between uniform and nonlinear cathodic boundary conditions. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905350/abstract

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