Dépouillements

In-situ investigation of the surface-topography during anodic dissolution of copper under near-ECM conditions / M. Schneider in Materials and corrosion, Vol. 63 N° 2 (Fevrier 2012) 

Public ISBD [article]  in Materials and corrosion > Vol. 63 N° 2 (Fevrier 2012) . - pp. 96–104 Titre : In-situ investigation of the surface-topography during anodic dissolution of copper under near-ECM conditions Type de document : texte imprimé Auteurs : M. Schneider, Auteur ; S. Schroth, Auteur ; N. Schubert, Auteur Année de publication : 2012 Article en page(s) : pp. 96–104 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : anodic  copper  dissolution;  electrochemical  machining;  in-situ  microscopy Résumé : Electrochemical machining is characterized by deliberate high speed anodic dissolution. The distance between anode and cathode are only a few hundred microns. Additionally, the electrolyte flow rate is in the range of approximately meter/second. A special electrochemical cell design was developed to investigate the surface topography during the anodic dissolution simultaneously and in-situ under near-ECM conditions. The anode was directly placed under the cathode with a gap of 350 µm. We carried out pulse experiments at 15 A/cm2 and 25 A/cm2 with an electrolyte flow rate of 4m/s. First-time it was possible to observe the surface changing of the anode directly during current pulses by using a video camera. Different stages e.g. roughening, film formation or gas evolution could be distinguished. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005716/abstract [article] In-situ investigation of the surface-topography during anodic dissolution of copper under near-ECM conditions [texte imprimé] / M. Schneider, Auteur ; S. Schroth, Auteur ; N. Schubert, Auteur . - 2012 . - pp. 96–104. Génie mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 63 N° 2 (Fevrier 2012) . - pp. 96–104 Mots-clés : anodic  copper  dissolution;  electrochemical  machining;  in-situ  microscopy Résumé : Electrochemical machining is characterized by deliberate high speed anodic dissolution. The distance between anode and cathode are only a few hundred microns. Additionally, the electrolyte flow rate is in the range of approximately meter/second. A special electrochemical cell design was developed to investigate the surface topography during the anodic dissolution simultaneously and in-situ under near-ECM conditions. The anode was directly placed under the cathode with a gap of 350 µm. We carried out pulse experiments at 15 A/cm2 and 25 A/cm2 with an electrolyte flow rate of 4m/s. First-time it was possible to observe the surface changing of the anode directly during current pulses by using a video camera. Different stages e.g. roughening, film formation or gas evolution could be distinguished. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005716/abstract

Electrochemical corrosion behaviour of innovative mould steels in a chloride-containing environment / F. Rosalbino in Materials and corrosion, Vol. 63 N° 2 (Fevrier 2012) 

Public ISBD [article]  in Materials and corrosion > Vol. 63 N° 2 (Fevrier 2012) . - pp. 105–110 Titre : Electrochemical corrosion behaviour of innovative mould steels in a chloride-containing environment Type de document : texte imprimé Auteurs : F. Rosalbino, Auteur ; G. Scavino, Auteur ; G. Mortarino, Auteur Année de publication : 2012 Article en page(s) : pp. 105–110 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : bainitic  microstructure;  corrosion  behaviour;  electrochemical  impedance  spectroscopy  (EIS);  mould  steels;  polarization  curves Résumé : Investigations concerning the electrochemical corrosion behaviour of mould steels are scarce and limited. In the present study the corrosion resistance of an innovative mould steel (a microalloyed steel, steel 2), devoted to the fabrication of large size moulds, and a steel having the same composition without microalloying elements (B, Zr, Nb, steel 3), proposed for small size moulds, was assessed in a chloride-containing environment and compared with that of the traditional 1.2738 steel. Potentiodynamic polarization and electrochemical impedance spectroscopy measurements were carried out on the investigated steel samples in a 0.1 M NaCl solution at 25 °C. Scanning electron microscopy and electron probe microanalysis were used to characterize the specimens surface after the electrochemical tests. Despite having a bainitic microstructure, the electrochemical corrosion behaviour of the investigated steels is quite different. Results showed that the steel 3 and the 1.2738 steel samples exhibit the best and the worst electrochemical corrosion behaviours compared to the steel 2 sample. The presence of pearlite is considered as the main reason for the poor corrosion behaviour showed by the 1.2738 steel sample, due to galvanic coupling phenomena between this phase and the bainitic matrix which experiences preferential dissolution. The coarse bainitic microstructure characterizing the steel 2 sample is responsible for its lower corrosion resistance as compared with the steel 3 sample exhibiting a finer bainitic microstructure. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005794/abstract [article] Electrochemical corrosion behaviour of innovative mould steels in a chloride-containing environment [texte imprimé] / F. Rosalbino, Auteur ; G. Scavino, Auteur ; G. Mortarino, Auteur . - 2012 . - pp. 105–110. Génie mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 63 N° 2 (Fevrier 2012) . - pp. 105–110 Mots-clés : bainitic  microstructure;  corrosion  behaviour;  electrochemical  impedance  spectroscopy  (EIS);  mould  steels;  polarization  curves Résumé : Investigations concerning the electrochemical corrosion behaviour of mould steels are scarce and limited. In the present study the corrosion resistance of an innovative mould steel (a microalloyed steel, steel 2), devoted to the fabrication of large size moulds, and a steel having the same composition without microalloying elements (B, Zr, Nb, steel 3), proposed for small size moulds, was assessed in a chloride-containing environment and compared with that of the traditional 1.2738 steel. Potentiodynamic polarization and electrochemical impedance spectroscopy measurements were carried out on the investigated steel samples in a 0.1 M NaCl solution at 25 °C. Scanning electron microscopy and electron probe microanalysis were used to characterize the specimens surface after the electrochemical tests. Despite having a bainitic microstructure, the electrochemical corrosion behaviour of the investigated steels is quite different. Results showed that the steel 3 and the 1.2738 steel samples exhibit the best and the worst electrochemical corrosion behaviours compared to the steel 2 sample. The presence of pearlite is considered as the main reason for the poor corrosion behaviour showed by the 1.2738 steel sample, due to galvanic coupling phenomena between this phase and the bainitic matrix which experiences preferential dissolution. The coarse bainitic microstructure characterizing the steel 2 sample is responsible for its lower corrosion resistance as compared with the steel 3 sample exhibiting a finer bainitic microstructure. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005794/abstract

Metallurgical and environmental factors affecting the pitting behavior of UNS S 32205 duplex stainless steel in chloride solutions / H. M. Ezuber in Materials and corrosion, Vol. 63 N° 2 (Fevrier 2012) 

Public ISBD [article]  in Materials and corrosion > Vol. 63 N° 2 (Fevrier 2012) . - pp. 111–118 Titre : Metallurgical and environmental factors affecting the pitting behavior of UNS S 32205 duplex stainless steel in chloride solutions Type de document : texte imprimé Auteurs : H. M. Ezuber, Auteur Année de publication : 2012 Article en page(s) : pp. 111–118 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : CO2;  fluid  flow;  pitting  corrosion;  sigma  phase;  UNS  S  32205  stainless  steel Résumé : The effect of temperatures up to 80 °C, dissolved CO2 (sat.), and flow (agitation) up to 1000 rpm on the breakdown potential of mill-annealed UNS S 32205 duplex stainless steel (DSS) has been evaluated in 1 M NaCl solution using potentiodynamic polarization technique. The results were compared with heat-treated samples (furnace heated at 850 °C for 10 or 60 min followed by water quench). The aim of the heat treatment is to simulate sigma phase precipitation. The results show dependence of pitting potential on the various factors (sigma phase, test temperature, dissolved CO2 (sat.), or solution flow) being studied. In general, the mill annealed or heat-treated UNS S 32205 DSS alloys are immune to pitting at room temperature (23 °C). At 50 °C however, pitting corrosion is evident and the intensity of such attack is increased with the presence of dissolved CO2, increasing isotherm held duration and/or seawater temperature. In contrast, agitation speed of 350 rpm (Re of 12 880) or above (sufficiently to yield turbulent flow) has shifted the pitting potential to more positive values. Lower speed of 100 rpm, however, is negligibly different from the stagnant conditions. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005667/abstract [article] Metallurgical and environmental factors affecting the pitting behavior of UNS S 32205 duplex stainless steel in chloride solutions [texte imprimé] / H. M. Ezuber, Auteur . - 2012 . - pp. 111–118. Génie mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 63 N° 2 (Fevrier 2012) . - pp. 111–118 Mots-clés : CO2;  fluid  flow;  pitting  corrosion;  sigma  phase;  UNS  S  32205  stainless  steel Résumé : The effect of temperatures up to 80 °C, dissolved CO2 (sat.), and flow (agitation) up to 1000 rpm on the breakdown potential of mill-annealed UNS S 32205 duplex stainless steel (DSS) has been evaluated in 1 M NaCl solution using potentiodynamic polarization technique. The results were compared with heat-treated samples (furnace heated at 850 °C for 10 or 60 min followed by water quench). The aim of the heat treatment is to simulate sigma phase precipitation. The results show dependence of pitting potential on the various factors (sigma phase, test temperature, dissolved CO2 (sat.), or solution flow) being studied. In general, the mill annealed or heat-treated UNS S 32205 DSS alloys are immune to pitting at room temperature (23 °C). At 50 °C however, pitting corrosion is evident and the intensity of such attack is increased with the presence of dissolved CO2, increasing isotherm held duration and/or seawater temperature. In contrast, agitation speed of 350 rpm (Re of 12 880) or above (sufficiently to yield turbulent flow) has shifted the pitting potential to more positive values. Lower speed of 100 rpm, however, is negligibly different from the stagnant conditions. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005667/abstract

Influence of water vapour on high temperature oxidation of steels used in petroleum refinery heaters / A. Sultan in Materials and corrosion, Vol. 63 N° 2 (Fevrier 2012) 

Public ISBD [article]  in Materials and corrosion > Vol. 63 N° 2 (Fevrier 2012) . - pp. 119–126 Titre : Influence of water vapour on high temperature oxidation of steels used in petroleum refinery heaters Type de document : texte imprimé Auteurs : A. Sultan, Auteur ; I. Karakaya, Auteur ; M. Erdogan, Auteur Année de publication : 2012 Article en page(s) : pp. 119–126 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : corrosion;  high  temperature;  oxidation;  petroleum  refinery  heaters;  thermogravimetric  analysis Résumé : The oxidation behaviours of three different steels used in the construction of petroleum refinery heaters were investigated by thermogravimetric analysis (TGA) technique. C-5, P-11 and P-22 steel samples were tested in two different environments: air and CO2 + 2H2O + 7.52N2, a gas composition which simulates the combustion products of natural gas, at 450 and 500 °C. P-22 steel had the best oxidation resistance at both temperatures in air. In CO2 + 2H2O + 7.52N2 environment, the oxidations of all the steels were accelerated and C-5 exhibited better oxidation resistance than P-22 and P-11. Analyses of oxidation products by optical microscopy, SEM-EDX and XRD were carried out to correlate TGA results to oxide composition and morphology. The lower oxidation rate of P-22 in air was explained with reference to the formation of a protective Cr-containing oxide layer between the steel and the iron oxide scale. The higher oxidation rates of chromium containing steels in CO2 + 2H2O + 7.52N2 environment were attributed to the depletion of protective Cr-containing oxide scale, which was deduced from the lower Cr content of this layer than that formed in air oxidation, as a result of probably faster oxidation of Cr even inside the steel. Therefore, the oxidation mechanisms of Fe[BOND]Cr alloys with intermediate Cr contents at higher temperatures could also be valid for steels with low chromium contents such as P-22 (2.25%) even at 450 and 500 °C. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905429/abstract [article] Influence of water vapour on high temperature oxidation of steels used in petroleum refinery heaters [texte imprimé] / A. Sultan, Auteur ; I. Karakaya, Auteur ; M. Erdogan, Auteur . - 2012 . - pp. 119–126. Génie mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 63 N° 2 (Fevrier 2012) . - pp. 119–126 Mots-clés : corrosion;  high  temperature;  oxidation;  petroleum  refinery  heaters;  thermogravimetric  analysis Résumé : The oxidation behaviours of three different steels used in the construction of petroleum refinery heaters were investigated by thermogravimetric analysis (TGA) technique. C-5, P-11 and P-22 steel samples were tested in two different environments: air and CO2 + 2H2O + 7.52N2, a gas composition which simulates the combustion products of natural gas, at 450 and 500 °C. P-22 steel had the best oxidation resistance at both temperatures in air. In CO2 + 2H2O + 7.52N2 environment, the oxidations of all the steels were accelerated and C-5 exhibited better oxidation resistance than P-22 and P-11. Analyses of oxidation products by optical microscopy, SEM-EDX and XRD were carried out to correlate TGA results to oxide composition and morphology. The lower oxidation rate of P-22 in air was explained with reference to the formation of a protective Cr-containing oxide layer between the steel and the iron oxide scale. The higher oxidation rates of chromium containing steels in CO2 + 2H2O + 7.52N2 environment were attributed to the depletion of protective Cr-containing oxide scale, which was deduced from the lower Cr content of this layer than that formed in air oxidation, as a result of probably faster oxidation of Cr even inside the steel. Therefore, the oxidation mechanisms of Fe[BOND]Cr alloys with intermediate Cr contents at higher temperatures could also be valid for steels with low chromium contents such as P-22 (2.25%) even at 450 and 500 °C. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905429/abstract

Exfoliation corrosion of Al–Zn–Mg–Cu–Zr alloy containing Sc examined by electrochemical impedance spectroscopy / Y. P. Xiao in Materials and corrosion, Vol. 63 N° 2 (Fevrier 2012) 

Public ISBD [article]  in Materials and corrosion > Vol. 63 N° 2 (Fevrier 2012) . - pp. 127–133 Titre : Exfoliation corrosion of Al–Zn–Mg–Cu–Zr alloy containing Sc examined by electrochemical impedance spectroscopy Type de document : texte imprimé Auteurs : Y. P. Xiao, Auteur ; Q. L. Pan, Auteur ; W.B. Li, Auteur Année de publication : 2012 Article en page(s) : pp. 127–133 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Al–Zn–Mg–Cu–Zr  alloy  containing  Sc;  electrochemical  impedance  spectroscopy  (EIS);  exfoliation  corrosion;  equivalent  circuit  (EC) Résumé : The exfoliation corrosion behavior of an Al–Zn–Mg–Cu–Zr alloy containing Sc artificially aged at 120 °C for 24 h is studied by macroscopic observation techniques and electrochemical impedance spectroscopy (EIS) measurements. After 48 h immersion, the blisters start bursting and delamination initiates, along with the appearance of two time constants in the impedance diagrams. According to the simulation by equivalent circuit, the corrosion rate decreases sharply and then reaches a steady state, which is due to the change of the solution pH and oxide layer thickness, as well as the accumulation of corrosion products. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005696/abstract [article] Exfoliation corrosion of Al–Zn–Mg–Cu–Zr alloy containing Sc examined by electrochemical impedance spectroscopy [texte imprimé] / Y. P. Xiao, Auteur ; Q. L. Pan, Auteur ; W.B. Li, Auteur . - 2012 . - pp. 127–133. Génie mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 63 N° 2 (Fevrier 2012) . - pp. 127–133 Mots-clés : Al–Zn–Mg–Cu–Zr  alloy  containing  Sc;  electrochemical  impedance  spectroscopy  (EIS);  exfoliation  corrosion;  equivalent  circuit  (EC) Résumé : The exfoliation corrosion behavior of an Al–Zn–Mg–Cu–Zr alloy containing Sc artificially aged at 120 °C for 24 h is studied by macroscopic observation techniques and electrochemical impedance spectroscopy (EIS) measurements. After 48 h immersion, the blisters start bursting and delamination initiates, along with the appearance of two time constants in the impedance diagrams. According to the simulation by equivalent circuit, the corrosion rate decreases sharply and then reaches a steady state, which is due to the change of the solution pH and oxide layer thickness, as well as the accumulation of corrosion products. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005696/abstract

Corrosion behavior of Ti–6Al–4V alloy weldment in hydrochloric acid / M. Atapour in Materials and corrosion, Vol. 63 N° 2 (Fevrier 2012) 

Public ISBD [article]  in Materials and corrosion > Vol. 63 N° 2 (Fevrier 2012) . - pp. 134–139 Titre : Corrosion behavior of Ti–6Al–4V alloy weldment in hydrochloric acid Type de document : texte imprimé Auteurs : M. Atapour, Auteur ; M. H. Fathi, Auteur ; M. Shamanian, Auteur Année de publication : 2012 Article en page(s) : pp. 134–139 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Corrosion;  electrochemical  impedance  spectroscopy;  hydrochloric  acid;  Ti–6Al–4V;  weldment Résumé : The corrosion behavior of a thin sheet of Ti–6Al–4V alloy was investigated in hydrochloric acid solution after welding by gas tungsten arc welding. The resulting microstructure of the weld metal (WM) consisted of coarse prior β grains containing fine acicular α platelets. It was found that both base metal (BM) and WM exhibited active–passive behavior after surface activation in open circuit potential experiments. The corrosion resistance of the BM and WM was found to decrease with increasing the temperature and acid concentration. However, the WM exhibited higher corrosion rate than the BM in all examined conditions. These results were also corroborated by electrochemical impedance spectroscopy measurements. Furthermore, it was revealed that the activation energy of the corrosion process for the WM was lower as compared to the BM, which confirmed the inferior corrosion behavior of the WM. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005821/abstract [article] Corrosion behavior of Ti–6Al–4V alloy weldment in hydrochloric acid [texte imprimé] / M. Atapour, Auteur ; M. H. Fathi, Auteur ; M. Shamanian, Auteur . - 2012 . - pp. 134–139. Génie mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 63 N° 2 (Fevrier 2012) . - pp. 134–139 Mots-clés : Corrosion;  electrochemical  impedance  spectroscopy;  hydrochloric  acid;  Ti–6Al–4V;  weldment Résumé : The corrosion behavior of a thin sheet of Ti–6Al–4V alloy was investigated in hydrochloric acid solution after welding by gas tungsten arc welding. The resulting microstructure of the weld metal (WM) consisted of coarse prior β grains containing fine acicular α platelets. It was found that both base metal (BM) and WM exhibited active–passive behavior after surface activation in open circuit potential experiments. The corrosion resistance of the BM and WM was found to decrease with increasing the temperature and acid concentration. However, the WM exhibited higher corrosion rate than the BM in all examined conditions. These results were also corroborated by electrochemical impedance spectroscopy measurements. Furthermore, it was revealed that the activation energy of the corrosion process for the WM was lower as compared to the BM, which confirmed the inferior corrosion behavior of the WM. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005821/abstract

Mildew growth on automotive coatings influencing the results of outdoor weathering / V. Wachtendorf in Materials and corrosion, Vol. 63 N° 2 (Fevrier 2012) 

Public ISBD [article]  in Materials and corrosion > Vol. 63 N° 2 (Fevrier 2012) . - pp. 140–147 Titre : Mildew growth on automotive coatings influencing the results of outdoor weathering Type de document : texte imprimé Auteurs : V. Wachtendorf, Auteur ; U. Schulz, Auteur ; A. Geburtig, Auteur Année de publication : 2012 Article en page(s) : pp. 140–147 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : coatings;  mildew;  weathering Résumé : As the results of a 14 weeks outdoor exposure of a series of automotive coatings in South Florida, the panels were found to be overgrown with an almost closed layer of mildew. Pinholes remained as permanent surface damage after removing the mildew mycelium. The extent of the damage differed in dependence of the kind of the coating. By tracing the images and profiles of the coating surfaces systematically over all phases of weathering and the subsequent cleaning procedure, a connection between formation of pinholes and mildew growth could be found. Outdoor weathering tests in other regions of Florida as well as in Europe and Australia showed that pinholes caused by mildew attack could also be found in all other locations, but always to a lower extent than in South Florida. The standardised mildew tests EN ISO 846 and MIL-STD 810F for laboratory exposure failed to reproduce the formation of pinholes. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005784/abstract [article] Mildew growth on automotive coatings influencing the results of outdoor weathering [texte imprimé] / V. Wachtendorf, Auteur ; U. Schulz, Auteur ; A. Geburtig, Auteur . - 2012 . - pp. 140–147. Génie mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 63 N° 2 (Fevrier 2012) . - pp. 140–147 Mots-clés : coatings;  mildew;  weathering Résumé : As the results of a 14 weeks outdoor exposure of a series of automotive coatings in South Florida, the panels were found to be overgrown with an almost closed layer of mildew. Pinholes remained as permanent surface damage after removing the mildew mycelium. The extent of the damage differed in dependence of the kind of the coating. By tracing the images and profiles of the coating surfaces systematically over all phases of weathering and the subsequent cleaning procedure, a connection between formation of pinholes and mildew growth could be found. Outdoor weathering tests in other regions of Florida as well as in Europe and Australia showed that pinholes caused by mildew attack could also be found in all other locations, but always to a lower extent than in South Florida. The standardised mildew tests EN ISO 846 and MIL-STD 810F for laboratory exposure failed to reproduce the formation of pinholes. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005784/abstract

Corrosion electrochemical behaviors of silane coating coated magnesium alloy in NaCl solution containing cerium nitrate / F. Luo in Materials and corrosion, Vol. 63 N° 2 (Fevrier 2012) 

Public ISBD [article]  in Materials and corrosion > Vol. 63 N° 2 (Fevrier 2012) . - pp. 148–154 Titre : Corrosion electrochemical behaviors of silane coating coated magnesium alloy in NaCl solution containing cerium nitrate Type de document : texte imprimé Auteurs : F. Luo, Auteur ; Q. Li, Auteur ; X. K. Zhong, Auteur Année de publication : 2012 Article en page(s) : pp. 148–154 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Cerium  nitrate;  corrosion  inhibition;  magnesium  alloy;  sol–gel  coating Résumé : Sol–gel coatings cannot provide adequate corrosion protection for metal/alloys in the corrosive environments due to their high crack-forming potential. This paper demonstrates the possibility to employ cerium nitrate as inhibitor to decrease the corrosion development of sol–gel-based silane coating on the magnesium alloy in NaCl solution. Cerium nitrate was added into the NaCl solution where the silane coating coated magnesium alloy was immersed. Scanning electron microcopy (SEM) was used to examine surface morphology of the silane coating coated magnesium alloy immersed in NaCl solutions doped and undoped with cerium nitrate. The corrosion electrochemical behaviors were investigated using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) tests. The results showed that the introduction of cerium nitrate into NaCl solution could effectively inhibit the corrosion of the silane coating coated magnesium alloy. Moreover, the influence of concentration of cerium nitrate on the corrosion inhibition and the possible inhibiting mechanism were also discussed in detail. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005706/abstract [article] Corrosion electrochemical behaviors of silane coating coated magnesium alloy in NaCl solution containing cerium nitrate [texte imprimé] / F. Luo, Auteur ; Q. Li, Auteur ; X. K. Zhong, Auteur . - 2012 . - pp. 148–154. Génie mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 63 N° 2 (Fevrier 2012) . - pp. 148–154 Mots-clés : Cerium  nitrate;  corrosion  inhibition;  magnesium  alloy;  sol–gel  coating Résumé : Sol–gel coatings cannot provide adequate corrosion protection for metal/alloys in the corrosive environments due to their high crack-forming potential. This paper demonstrates the possibility to employ cerium nitrate as inhibitor to decrease the corrosion development of sol–gel-based silane coating on the magnesium alloy in NaCl solution. Cerium nitrate was added into the NaCl solution where the silane coating coated magnesium alloy was immersed. Scanning electron microcopy (SEM) was used to examine surface morphology of the silane coating coated magnesium alloy immersed in NaCl solutions doped and undoped with cerium nitrate. The corrosion electrochemical behaviors were investigated using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) tests. The results showed that the introduction of cerium nitrate into NaCl solution could effectively inhibit the corrosion of the silane coating coated magnesium alloy. Moreover, the influence of concentration of cerium nitrate on the corrosion inhibition and the possible inhibiting mechanism were also discussed in detail. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005706/abstract

Electrochemical characterization for polybithiophene film on porous oxide layer of 304 stainless steel formed by square wave passivation / C. Liang in Materials and corrosion, Vol. 63 N° 2 (Fevrier 2012) 

Public ISBD [article]  in Materials and corrosion > Vol. 63 N° 2 (Fevrier 2012) . - pp. 155–160 Titre : Electrochemical characterization for polybithiophene film on porous oxide layer of 304 stainless steel formed by square wave passivation Type de document : texte imprimé Auteurs : C. Liang, Auteur ; W. Chen, Auteur ; Huang, N., Auteur Année de publication : 2012 Article en page(s) : pp. 155–160 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Electrochemical  impedance  spectroscopy;  electropolymerization;  polybithiophene;  square  wave  passivation Résumé : A bilayer coating was prepared by electrodepositing a polybithiophene (PBT) film on the top of square wave passivated 304 stainless steel (304SS). The structure of the PBT layer was characterized by FTIR spectroscopy and suggested to be composed of α–α coupling thiophene units. The electrochemical properties of the coating were investigated in 1 mol/L sulfuric acid solution by anodic polarization and electrochemical impedance spectroscopy measurements. The results indicated that the bilayer could provide an effective barrier and maintain the metal substrate in a passive state during the immersion time. The interfacial shear strength of the polythiophene film on untreated and passivated 304SS were 0.81 and 5.1 MPa, respectively. The better result given by treated one may be due to PBT growing within the pores formed on the square wave passivated 304SS. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905351/abstract [article] Electrochemical characterization for polybithiophene film on porous oxide layer of 304 stainless steel formed by square wave passivation [texte imprimé] / C. Liang, Auteur ; W. Chen, Auteur ; Huang, N., Auteur . - 2012 . - pp. 155–160. Génie mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 63 N° 2 (Fevrier 2012) . - pp. 155–160 Mots-clés : Electrochemical  impedance  spectroscopy;  electropolymerization;  polybithiophene;  square  wave  passivation Résumé : A bilayer coating was prepared by electrodepositing a polybithiophene (PBT) film on the top of square wave passivated 304 stainless steel (304SS). The structure of the PBT layer was characterized by FTIR spectroscopy and suggested to be composed of α–α coupling thiophene units. The electrochemical properties of the coating were investigated in 1 mol/L sulfuric acid solution by anodic polarization and electrochemical impedance spectroscopy measurements. The results indicated that the bilayer could provide an effective barrier and maintain the metal substrate in a passive state during the immersion time. The interfacial shear strength of the polythiophene film on untreated and passivated 304SS were 0.81 and 5.1 MPa, respectively. The better result given by treated one may be due to PBT growing within the pores formed on the square wave passivated 304SS. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905351/abstract

The co-operative effect of chloride ions and some natural extracts in retarding corrosion of steel in neutral media / A. M. Abdel-Gaber in Materials and corrosion, Vol. 63 N° 2 (Fevrier 2012) 

Public ISBD [article]  in Materials and corrosion > Vol. 63 N° 2 (Fevrier 2012) . - pp. 161–167 Titre : The co-operative effect of chloride ions and some natural extracts in retarding corrosion of steel in neutral media Type de document : texte imprimé Auteurs : A. M. Abdel-Gaber, Auteur ; B. A. Abdel-Nabey, Auteur ; M. Saadawy, Auteur Année de publication : 2012 Article en page(s) : pp. 161–167 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Corrosion;  neutral  extract;  steel Résumé : Effect of lupine and damsissa extracts on the corrosion of steel in 0.5 M Na2SO4 solution free from and containing 0.01 or 0.1 M NaCl were examined by potentiodynamic and electrochemical impedance spectroscopy techniques. Potentiodynamic polarization curves measurements indicated that damsissa and lupine extracts behave as anodic type inhibitors. Nyquist impedance plots showed type of distorted semicircle whose size increases with increasing concentrations of lupine or damsissa extract. Increasing chloride ion concentration in the solution led to increase of the inhibition efficiency of the extract and this behaviour was explained on the basis of co-operative mechanism of adsorption. Kinetic–thermodynamic model was used to clarify the nature of adsorption and showed good fit to the experimental data. The results indicated that lupine extract is more effective as corrosion inhibitor for steel in neutral media containing chloride ions than damsissa extract. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005678/abstract [article] The co-operative effect of chloride ions and some natural extracts in retarding corrosion of steel in neutral media [texte imprimé] / A. M. Abdel-Gaber, Auteur ; B. A. Abdel-Nabey, Auteur ; M. Saadawy, Auteur . - 2012 . - pp. 161–167. Génie mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 63 N° 2 (Fevrier 2012) . - pp. 161–167 Mots-clés : Corrosion;  neutral  extract;  steel Résumé : Effect of lupine and damsissa extracts on the corrosion of steel in 0.5 M Na2SO4 solution free from and containing 0.01 or 0.1 M NaCl were examined by potentiodynamic and electrochemical impedance spectroscopy techniques. Potentiodynamic polarization curves measurements indicated that damsissa and lupine extracts behave as anodic type inhibitors. Nyquist impedance plots showed type of distorted semicircle whose size increases with increasing concentrations of lupine or damsissa extract. Increasing chloride ion concentration in the solution led to increase of the inhibition efficiency of the extract and this behaviour was explained on the basis of co-operative mechanism of adsorption. Kinetic–thermodynamic model was used to clarify the nature of adsorption and showed good fit to the experimental data. The results indicated that lupine extract is more effective as corrosion inhibitor for steel in neutral media containing chloride ions than damsissa extract. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005678/abstract

Lab and field investigations on localized corrosion of casing / C. Q. Ren in Materials and corrosion, Vol. 63 N° 2 (Fevrier 2012) 

Public ISBD [article]  in Materials and corrosion > Vol. 63 N° 2 (Fevrier 2012) . - pp. 168–172 Titre : Lab and field investigations on localized corrosion of casing Type de document : texte imprimé Auteurs : C. Q. Ren, Auteur ; X. Wang, Auteur ; L. Liu, Auteur Année de publication : 2012 Article en page(s) : pp. 168–172 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Localized  corrosion;  microstructure;  steel Résumé : The corrosion of casing was investigated in the laboratory and oilfield by series methods of EIS, SEM, EDS, well logging, and field coupon test. Data reveal the middle vertical profile along the casing is greatly threatened by localized form rather than generalized corrosion. The pit initiates in the micro-pore of the corrosion scale on the surface of the steel. The development of pitting depends on the water type classified by geochemist. The calcium chloride water shows highest acceleration to pitting due to the two orders of magnitude higher concentration of chloride ion by comparing sodium sulfate and sodium bicarbonate water types. The element analysis and microstructure observation were used to further describe the pit propagation. It is proposed to get a better understanding of the corrosion damage of casing in the petroleum industry. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005713/abstract [article] Lab and field investigations on localized corrosion of casing [texte imprimé] / C. Q. Ren, Auteur ; X. Wang, Auteur ; L. Liu, Auteur . - 2012 . - pp. 168–172. Génie mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 63 N° 2 (Fevrier 2012) . - pp. 168–172 Mots-clés : Localized  corrosion;  microstructure;  steel Résumé : The corrosion of casing was investigated in the laboratory and oilfield by series methods of EIS, SEM, EDS, well logging, and field coupon test. Data reveal the middle vertical profile along the casing is greatly threatened by localized form rather than generalized corrosion. The pit initiates in the micro-pore of the corrosion scale on the surface of the steel. The development of pitting depends on the water type classified by geochemist. The calcium chloride water shows highest acceleration to pitting due to the two orders of magnitude higher concentration of chloride ion by comparing sodium sulfate and sodium bicarbonate water types. The element analysis and microstructure observation were used to further describe the pit propagation. It is proposed to get a better understanding of the corrosion damage of casing in the petroleum industry. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005713/abstract

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