Dépouillements

Self-healing properties of TiO2 particle–polymer composite coatings for protection of aluminum alloys against corrosion in seawater / A. Yabuki in Materials and corrosion, Vol. 62 N° 10 (Octobre 2011) 

Public ISBD [article]  in Materials and corrosion > Vol. 62 N° 10 (Octobre 2011) . - pp. 907–912 Titre : Self-healing properties of TiO2 particle–polymer composite coatings for protection of aluminum alloys against corrosion in seawater Type de document : texte imprimé Auteurs : A. Yabuki, Auteur ; W. Urushihara, Auteur ; J. Kinugasa, Auteur Année de publication : 2012 Article en page(s) : pp. 907–912 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Aluminum  Composite  coating  Particle  Polymer  Self-healing Résumé : TiO2 particle–polymer composite coatings were applied to the surface of a 5083 aluminum alloy. After using a knife to create an artificial defect, polarization resistance was monitored in artificial seawater at a temperature of 30 °C. The polarization resistance of the specimen coated with the composite polymer containing 3 vol% TiO2 particles increased significantly over time, suggesting that the composite coating had self-healing properties. A carbon-containing 2-µm thick film was found on the coated aluminum substrate at the site of the artificial defect. The formation of the film was related to the dissolution of bisphenol A (BPA), which is a chemical precursor of the polymer coating that behaved as an inhibiting agent. DEWEY : 620.1 ISSN : 0947-5117 En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005756/abstract [article] Self-healing properties of TiO2 particle–polymer composite coatings for protection of aluminum alloys against corrosion in seawater [texte imprimé] / A. Yabuki, Auteur ; W. Urushihara, Auteur ; J. Kinugasa, Auteur . - 2012 . - pp. 907–912. Génie Mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 62 N° 10 (Octobre 2011) . - pp. 907–912 Mots-clés : Aluminum  Composite  coating  Particle  Polymer  Self-healing Résumé : TiO2 particle–polymer composite coatings were applied to the surface of a 5083 aluminum alloy. After using a knife to create an artificial defect, polarization resistance was monitored in artificial seawater at a temperature of 30 °C. The polarization resistance of the specimen coated with the composite polymer containing 3 vol% TiO2 particles increased significantly over time, suggesting that the composite coating had self-healing properties. A carbon-containing 2-µm thick film was found on the coated aluminum substrate at the site of the artificial defect. The formation of the film was related to the dissolution of bisphenol A (BPA), which is a chemical precursor of the polymer coating that behaved as an inhibiting agent. DEWEY : 620.1 ISSN : 0947-5117 En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005756/abstract

Nanostructured surface pre-treatment based on self-assembled molecules for corrosion protection of Alclad 7475-T761 aluminum alloy / S. De Souza in Materials and corrosion, Vol. 62 N° 10 (Octobre 2011) 

Public ISBD [article]  in Materials and corrosion > Vol. 62 N° 10 (Octobre 2011) . - pp. 913–919 Titre : Nanostructured surface pre-treatment based on self-assembled molecules for corrosion protection of Alclad 7475-T761 aluminum alloy Type de document : texte imprimé Auteurs : S. De Souza, Auteur ; D. S. Yoshikawa, Auteur ; W. A. S. Izaltino, Auteur Année de publication : 2012 Article en page(s) : pp. 913–919 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Aluminum  Chromate  Corrosion  protection  EIS  Self-assembled  molecules  Surface  treatment Résumé : Coatings based on self-assembled molecules (SAMs) for corrosion protection of aircraft aluminum alloys have been studied to evaluate their potentialities as replacements to yellow chromate conversion coatings (CCC), due to the toxicity of these leading to environmental problems. In this work, the influence of alkane diphosphonates self-assembling molecules on the corrosion resistance of the AA7475-T761 cladded with AA7072 was investigated by electrochemical impedance spectroscopy and cathodic and anodic polarization curves, in naturally aerated 0.5 mol/L Na2SO4 aqueous solution, with pH adjusted to 4. Corrosion accelerated experiments (salt spray tests) were also carried out to examine the resistance of the SAM treated samples against corrosion. The results suggested that the development of boehmite (aluminum oxide) layer with incorporation of SAM was beneficial to the corrosion resistance of the tested aluminum alloy. Samples surface treated with SAM or aluminum oxide/SAM (without and with subsequent polyester layer) showed better corrosion resistance results than samples with CCC, indicating that this last type of coating containing hexavalent chromium could be replaced by the environmentally friendly pre-treatment corresponding to boehmite growth followed by incorporation of SAM. DEWEY : 620.1 ISSN : 0947-5117 En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005631/abstract [article] Nanostructured surface pre-treatment based on self-assembled molecules for corrosion protection of Alclad 7475-T761 aluminum alloy [texte imprimé] / S. De Souza, Auteur ; D. S. Yoshikawa, Auteur ; W. A. S. Izaltino, Auteur . - 2012 . - pp. 913–919. Génie Mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 62 N° 10 (Octobre 2011) . - pp. 913–919 Mots-clés : Aluminum  Chromate  Corrosion  protection  EIS  Self-assembled  molecules  Surface  treatment Résumé : Coatings based on self-assembled molecules (SAMs) for corrosion protection of aircraft aluminum alloys have been studied to evaluate their potentialities as replacements to yellow chromate conversion coatings (CCC), due to the toxicity of these leading to environmental problems. In this work, the influence of alkane diphosphonates self-assembling molecules on the corrosion resistance of the AA7475-T761 cladded with AA7072 was investigated by electrochemical impedance spectroscopy and cathodic and anodic polarization curves, in naturally aerated 0.5 mol/L Na2SO4 aqueous solution, with pH adjusted to 4. Corrosion accelerated experiments (salt spray tests) were also carried out to examine the resistance of the SAM treated samples against corrosion. The results suggested that the development of boehmite (aluminum oxide) layer with incorporation of SAM was beneficial to the corrosion resistance of the tested aluminum alloy. Samples surface treated with SAM or aluminum oxide/SAM (without and with subsequent polyester layer) showed better corrosion resistance results than samples with CCC, indicating that this last type of coating containing hexavalent chromium could be replaced by the environmentally friendly pre-treatment corresponding to boehmite growth followed by incorporation of SAM. DEWEY : 620.1 ISSN : 0947-5117 En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005631/abstract

Corrosion behaviour of electrodeposited Ni/Al2O3 composite coating covered with a NaCl salt film at 800 °C / L. M. Chang in Materials and corrosion, Vol. 62 N° 10 (Octobre 2011) 

Public ISBD [article]  in Materials and corrosion > Vol. 62 N° 10 (Octobre 2011) . - pp. 920–925 Titre : Corrosion behaviour of electrodeposited Ni/Al2O3 composite coating covered with a NaCl salt film at 800 °C Type de document : texte imprimé Auteurs : L. M. Chang, Auteur ; J. H. Liu, Auteur ; R. J. Zhang, Auteur Année de publication : 2012 Article en page(s) : pp. 920–925 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Corrosion  behaviour  Electrodeposit  NaCl  salt  film  Ni/Al2O3  composite  coatings Résumé : The electrodeposited Ni/Al2O3 composite coatings were prepared by direct current (DC), pulse current (PC) and pulse reversal current (PRC) deposition, respectively. The corrosion behaviour of electrodeposited Ni/Al2O3 composite coatings covered with NaCl salt films at 800 °C in air was investigated by SEM/EDX, XRD and thermogravimetric analysis. It is found that corrosion of the three types of coatings is seriously aggravated with a present NaCl salt film, and a corrosion layer with a poor adherence to the matrix has been formed. Furthermore, chlorine enrichment at the interface between the matrix and the corrosion product has been observed. The corrosion resistance of the three types of coatings has improved with the increase of Al2O3 content. The corrosion resistance of the Ni/Al2O3 composite coatings prepared by PRC deposition is the best, and that by DC deposition is the worst. The corrosion mechanism of Ni/Al2O3 composite coatings will also be discussed. DEWEY : 620.1 ISSN : 0947-5117 En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905617/abstract [article] Corrosion behaviour of electrodeposited Ni/Al2O3 composite coating covered with a NaCl salt film at 800 °C [texte imprimé] / L. M. Chang, Auteur ; J. H. Liu, Auteur ; R. J. Zhang, Auteur . - 2012 . - pp. 920–925. Génie Mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 62 N° 10 (Octobre 2011) . - pp. 920–925 Mots-clés : Corrosion  behaviour  Electrodeposit  NaCl  salt  film  Ni/Al2O3  composite  coatings Résumé : The electrodeposited Ni/Al2O3 composite coatings were prepared by direct current (DC), pulse current (PC) and pulse reversal current (PRC) deposition, respectively. The corrosion behaviour of electrodeposited Ni/Al2O3 composite coatings covered with NaCl salt films at 800 °C in air was investigated by SEM/EDX, XRD and thermogravimetric analysis. It is found that corrosion of the three types of coatings is seriously aggravated with a present NaCl salt film, and a corrosion layer with a poor adherence to the matrix has been formed. Furthermore, chlorine enrichment at the interface between the matrix and the corrosion product has been observed. The corrosion resistance of the three types of coatings has improved with the increase of Al2O3 content. The corrosion resistance of the Ni/Al2O3 composite coatings prepared by PRC deposition is the best, and that by DC deposition is the worst. The corrosion mechanism of Ni/Al2O3 composite coatings will also be discussed. DEWEY : 620.1 ISSN : 0947-5117 En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905617/abstract

Effects of rare earth cerium addition on the synthesis and corrosion resistance of electroless Ni–PTFE–P coating / D. Liu in Materials and corrosion, Vol. 62 N° 10 (Octobre 2011) 

Public ISBD [article]  in Materials and corrosion > Vol. 62 N° 10 (Octobre 2011) . - pp. 926–931 Titre : Effects of rare earth cerium addition on the synthesis and corrosion resistance of electroless Ni–PTFE–P coating Type de document : texte imprimé Auteurs : D. Liu, Auteur ; L. Zhou, Auteur ; J. Yu, Auteur Année de publication : 2012 Article en page(s) : pp. 926–931 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Corrosion  resistance  Electroless  plating  Morphology  Rare  earth  metal  Ni–PTFE–P  coatings Résumé : Electroless Ni–PTFE–P coatings have been successfully deposited on the surface of mild steel shaft from plating baths containing various concentrations of rare earth metal cerium (RE Ce). Surface morphology, Ce fraction, and thickness of the coatings were characterized by scanning electron microscope, inductively coupled plasma optical emission spectrometry, and reflection optical microscope, respectively. Salt spray test was used to determine the corrosion resistance of the coating. Results revealed that structure, compactness, and deposition rate of the Ni–PTFE–P coatings were increased significantly by addition of a small amount of RE Ce (10–20 ppm) to the plating bath. Electroless Ni–PTFE–P coating deposited from plating baths with 20 ppm Ce shows the highest corrosion resistance, owing to its high compactness and thickness. Deposition rate and corrosion resistance of the Ni–PTFE–P coating were deteriorated greatly as concentration of RE Ce in the plating baths exceeds 100 ppm. DEWEY : 620.1 ISSN : 0947-5117 En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905523/abstract [article] Effects of rare earth cerium addition on the synthesis and corrosion resistance of electroless Ni–PTFE–P coating [texte imprimé] / D. Liu, Auteur ; L. Zhou, Auteur ; J. Yu, Auteur . - 2012 . - pp. 926–931. Génie Mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 62 N° 10 (Octobre 2011) . - pp. 926–931 Mots-clés : Corrosion  resistance  Electroless  plating  Morphology  Rare  earth  metal  Ni–PTFE–P  coatings Résumé : Electroless Ni–PTFE–P coatings have been successfully deposited on the surface of mild steel shaft from plating baths containing various concentrations of rare earth metal cerium (RE Ce). Surface morphology, Ce fraction, and thickness of the coatings were characterized by scanning electron microscope, inductively coupled plasma optical emission spectrometry, and reflection optical microscope, respectively. Salt spray test was used to determine the corrosion resistance of the coating. Results revealed that structure, compactness, and deposition rate of the Ni–PTFE–P coatings were increased significantly by addition of a small amount of RE Ce (10–20 ppm) to the plating bath. Electroless Ni–PTFE–P coating deposited from plating baths with 20 ppm Ce shows the highest corrosion resistance, owing to its high compactness and thickness. Deposition rate and corrosion resistance of the Ni–PTFE–P coating were deteriorated greatly as concentration of RE Ce in the plating baths exceeds 100 ppm. DEWEY : 620.1 ISSN : 0947-5117 En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905523/abstract

Polarization resistance measurements of bars embedded in concrete with different chloride concentrations / Martinez, I. in Materials and corrosion, Vol. 62 N° 10 (Octobre 2011) 

Public ISBD [article]  in Materials and corrosion > Vol. 62 N° 10 (Octobre 2011) . - pp. 932–942 Titre : Polarization resistance measurements of bars embedded in concrete with different chloride concentrations : EIS and DC comparison Type de document : texte imprimé Auteurs : Martinez, I., Auteur ; C. Andrade, Auteur Année de publication : 2012 Article en page(s) : pp. 932–942 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Concrete  Corrosion  Electrochemical  impedance  spectroscopy  Galvanostatic  pulse  Ohmic  drop  Polarization  Resistance  Potentiodynamic  tests  Potentiostatic  pulse Résumé : The experimental conditions for corrosion rate measurements of reinforcement by means of the polarization resistance technique, Rp, in order to obtain reliable values (in accordance with the gravimetric losses simultaneously measured) must consider some factors as are: the need to subtract ohmic drop generated by the high resistivity of the concrete, the need to wait a certain time after application of the current, the use of a certain sweep rate in order to obtain a quasi-steady-state value of the conjugated variable (potential/current), the need to avoid the overlapping with other processes, and the need to use a correct B value in Stern formula. These experimental requirements should be optimized for the individual kinetic of each system. From time to time several papers are published wondering whether Rp measurements in concrete are reliable. Present paper extends the study of the experimental conditions influence in the Rp determination in order to look more in detail to the accuracy of Rp technique. Several sweep rates in potentiodynamic tests, different waiting times with galvanostatic and potentiostatic pulses and different frequencies in electrochemical impedance spectroscopy, EIS, were tested in order to compare the most suitable parameters that provide correct values of the corrosion rate, Icorr. DEWEY : 620.1 ISSN : 0947-5117 En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905596/abstract [article] Polarization resistance measurements of bars embedded in concrete with different chloride concentrations : EIS and DC comparison [texte imprimé] / Martinez, I., Auteur ; C. Andrade, Auteur . - 2012 . - pp. 932–942. Génie Mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 62 N° 10 (Octobre 2011) . - pp. 932–942 Mots-clés : Concrete  Corrosion  Electrochemical  impedance  spectroscopy  Galvanostatic  pulse  Ohmic  drop  Polarization  Resistance  Potentiodynamic  tests  Potentiostatic  pulse Résumé : The experimental conditions for corrosion rate measurements of reinforcement by means of the polarization resistance technique, Rp, in order to obtain reliable values (in accordance with the gravimetric losses simultaneously measured) must consider some factors as are: the need to subtract ohmic drop generated by the high resistivity of the concrete, the need to wait a certain time after application of the current, the use of a certain sweep rate in order to obtain a quasi-steady-state value of the conjugated variable (potential/current), the need to avoid the overlapping with other processes, and the need to use a correct B value in Stern formula. These experimental requirements should be optimized for the individual kinetic of each system. From time to time several papers are published wondering whether Rp measurements in concrete are reliable. Present paper extends the study of the experimental conditions influence in the Rp determination in order to look more in detail to the accuracy of Rp technique. Several sweep rates in potentiodynamic tests, different waiting times with galvanostatic and potentiostatic pulses and different frequencies in electrochemical impedance spectroscopy, EIS, were tested in order to compare the most suitable parameters that provide correct values of the corrosion rate, Icorr. DEWEY : 620.1 ISSN : 0947-5117 En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905596/abstract

Modelling the corrosion-induced cracking of reinforced concrete structures exposed to the atmosphere / V. L'Hostis in Materials and corrosion, Vol. 62 N° 10 (Octobre 2011) 

Public ISBD [article]  in Materials and corrosion > Vol. 62 N° 10 (Octobre 2011) . - pp. 943–947 Titre : Modelling the corrosion-induced cracking of reinforced concrete structures exposed to the atmosphere Type de document : texte imprimé Auteurs : V. L'Hostis, Auteur ; A. Millard, Auteur ; S. Perrin, Auteur Année de publication : 2012 Article en page(s) : pp. 943–947 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Atmospheric  corrosion  Cementitious  materials  Modelling  Oxygen  reduction Résumé : The prediction of concrete cracking due to corrosion in atmospheric/carbonated conditions is a major issue for the evaluation of the durability of structures and the choice of maintenance policies. Because of the complexity of the phenomenon, a fully predictive approach is still missing. The proposed work can be considered as one step in this direction. It deals with a modelling study achieved at the Commissariat à l'Energie Atomique (CEA) with the CAST3M finite elements software. Model is constituted of three components: (1) concrete hydric behaviour, (2) rebar corrosion and (3) mechanical consequences on concrete (mainly concrete cracking). Actual developments consider analogies between rebar corrosion mechanisms and atmospheric corrosion ones, assuming that corrosion processes are influenced by the relative humidity evolution of atmosphere and/or of concrete. DEWEY : 620.1 ISSN : 0947-5117 En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905578/abstract [article] Modelling the corrosion-induced cracking of reinforced concrete structures exposed to the atmosphere [texte imprimé] / V. L'Hostis, Auteur ; A. Millard, Auteur ; S. Perrin, Auteur . - 2012 . - pp. 943–947. Génie Mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 62 N° 10 (Octobre 2011) . - pp. 943–947 Mots-clés : Atmospheric  corrosion  Cementitious  materials  Modelling  Oxygen  reduction Résumé : The prediction of concrete cracking due to corrosion in atmospheric/carbonated conditions is a major issue for the evaluation of the durability of structures and the choice of maintenance policies. Because of the complexity of the phenomenon, a fully predictive approach is still missing. The proposed work can be considered as one step in this direction. It deals with a modelling study achieved at the Commissariat à l'Energie Atomique (CEA) with the CAST3M finite elements software. Model is constituted of three components: (1) concrete hydric behaviour, (2) rebar corrosion and (3) mechanical consequences on concrete (mainly concrete cracking). Actual developments consider analogies between rebar corrosion mechanisms and atmospheric corrosion ones, assuming that corrosion processes are influenced by the relative humidity evolution of atmosphere and/or of concrete. DEWEY : 620.1 ISSN : 0947-5117 En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905578/abstract

Corrosion behaviour of a new Ti-6Al-2Nb-1Ta alloy in various solutions / C. Pirvu in Materials and corrosion, Vol. 62 N° 10 (Octobre 2011) 

Public ISBD [article]  in Materials and corrosion > Vol. 62 N° 10 (Octobre 2011) . - pp. 948–955 Titre : Corrosion behaviour of a new Ti-6Al-2Nb-1Ta alloy in various solutions Type de document : texte imprimé Auteurs : C. Pirvu, Auteur ; I. Demetrescu, Auteur ; P. Drob, Auteur Année de publication : 2012 Article en page(s) : pp. 948–955 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Corrosion  rates  EIS  Neutral  corrosive  environment  Pitting  corrosion  Titanium  alloy Résumé : A new Ti-6Al-2Nb-1Ta alloy was obtained for to satisfy the mechanical and anticorrosion requirements in neutral corrosive environment. The corrosion behaviour of this new Ti-6Al-2Nb-1Ta alloy in 0.1 M Na2SO4, 3% NaCl solutions and synthetic sea water was studied in this paper, using potentiodynamic and linear polarisation method, electrochemical impedance spectroscopy (EIS) and monitoring of the open circuit potentials. The structure of the alloy represents an α + β uniform structure with un-oriented grains. From the potentiodynamic polarisation curves it resulted that the studied alloy is self-passivated in all three solutions having a very good and very easy tendency to passivation. The most favourable values of the electrochemical parameters were registered in 0.1 M Na2SO4 solution due to its reduced corrosivity. EIS measurements proved the improvement of the passive layer resistance with the immersion time. An electric equivalent circuit with two time constants was fitted. The values of the polarisation resistances showed very good protective capacities which improved in time. The open circuit potentials have the general tendency to ennoble in time, suggesting the thickening of the passive films and the increase of their protective capacities. DEWEY : 620.1 ISSN : 0947-5117 En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201006041/abstract [article] Corrosion behaviour of a new Ti-6Al-2Nb-1Ta alloy in various solutions [texte imprimé] / C. Pirvu, Auteur ; I. Demetrescu, Auteur ; P. Drob, Auteur . - 2012 . - pp. 948–955. Génie Mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 62 N° 10 (Octobre 2011) . - pp. 948–955 Mots-clés : Corrosion  rates  EIS  Neutral  corrosive  environment  Pitting  corrosion  Titanium  alloy Résumé : A new Ti-6Al-2Nb-1Ta alloy was obtained for to satisfy the mechanical and anticorrosion requirements in neutral corrosive environment. The corrosion behaviour of this new Ti-6Al-2Nb-1Ta alloy in 0.1 M Na2SO4, 3% NaCl solutions and synthetic sea water was studied in this paper, using potentiodynamic and linear polarisation method, electrochemical impedance spectroscopy (EIS) and monitoring of the open circuit potentials. The structure of the alloy represents an α + β uniform structure with un-oriented grains. From the potentiodynamic polarisation curves it resulted that the studied alloy is self-passivated in all three solutions having a very good and very easy tendency to passivation. The most favourable values of the electrochemical parameters were registered in 0.1 M Na2SO4 solution due to its reduced corrosivity. EIS measurements proved the improvement of the passive layer resistance with the immersion time. An electric equivalent circuit with two time constants was fitted. The values of the polarisation resistances showed very good protective capacities which improved in time. The open circuit potentials have the general tendency to ennoble in time, suggesting the thickening of the passive films and the increase of their protective capacities. DEWEY : 620.1 ISSN : 0947-5117 En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201006041/abstract

Corrosion study of copper in the presence of benzotriazole and its hydroxy derivative / M. Finšgar in Materials and corrosion, Vol. 62 N° 10 (Octobre 2011) 

Public ISBD [article]  in Materials and corrosion > Vol. 62 N° 10 (Octobre 2011) . - pp. 956–966 Titre : Corrosion study of copper in the presence of benzotriazole and its hydroxy derivative Type de document : texte imprimé Auteurs : M. Finšgar, Auteur ; I. Milošev, Auteur Année de publication : 2012 Article en page(s) : pp. 956–966 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Benzotriazole  Copper  Corrosion  1-hydroxy-benzotriazole  Inhibition Résumé : The inhibitory properties of benzotriazole (BTAH) and its hydroxy derivative, 1-hydroxy-benzotriazole (BTAOH) on copper corrosion, were compared in 3% NaCl solution using cyclic voltammetry (CV), immersion tests, profilometry and scanning electron microscopy (SEM) combined with energy dispersive spectroscopy (EDX). CV experiments showed rapid interaction of both inhibitors with a Cu surface, but only at high concentrations. Immersion tests under stationary conditions showed that BTAOH offered corrosion protection only at concentration of 10 mM. Moreover, it was not effective under stirring conditions at any of the concentrations investigated. In contrast, BTAH exhibited good corrosion inhibition ability in all immersion tests. BTAOH, at up to 1 mM, increased the surface roughness of Cu more than 3% NaCl solution alone, but a significant reduction of surface roughening was observed when BTAH was present. Porous cross-linked acicular structures and star-like structures were observed using SEM/EDX in the case of BTAOH treatment. When Cu was treated with BTAH, roundish surface structures composed of bent plates with toothed-like edges, acicular structures and non-porous few hundred nm thick plates were observed. DEWEY : 620.1 ISSN : 0947-5117 En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005645/abstract [article] Corrosion study of copper in the presence of benzotriazole and its hydroxy derivative [texte imprimé] / M. Finšgar, Auteur ; I. Milošev, Auteur . - 2012 . - pp. 956–966. Génie Mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 62 N° 10 (Octobre 2011) . - pp. 956–966 Mots-clés : Benzotriazole  Copper  Corrosion  1-hydroxy-benzotriazole  Inhibition Résumé : The inhibitory properties of benzotriazole (BTAH) and its hydroxy derivative, 1-hydroxy-benzotriazole (BTAOH) on copper corrosion, were compared in 3% NaCl solution using cyclic voltammetry (CV), immersion tests, profilometry and scanning electron microscopy (SEM) combined with energy dispersive spectroscopy (EDX). CV experiments showed rapid interaction of both inhibitors with a Cu surface, but only at high concentrations. Immersion tests under stationary conditions showed that BTAOH offered corrosion protection only at concentration of 10 mM. Moreover, it was not effective under stirring conditions at any of the concentrations investigated. In contrast, BTAH exhibited good corrosion inhibition ability in all immersion tests. BTAOH, at up to 1 mM, increased the surface roughness of Cu more than 3% NaCl solution alone, but a significant reduction of surface roughening was observed when BTAH was present. Porous cross-linked acicular structures and star-like structures were observed using SEM/EDX in the case of BTAOH treatment. When Cu was treated with BTAH, roundish surface structures composed of bent plates with toothed-like edges, acicular structures and non-porous few hundred nm thick plates were observed. DEWEY : 620.1 ISSN : 0947-5117 En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005645/abstract

Acidic/caustic alternating corrosion on carbon steel pipes in heat exchanger of ethylene plant / Y. Gong in Materials and corrosion, Vol. 62 N° 10 (Octobre 2011) 

Public ISBD [article]  in Materials and corrosion > Vol. 62 N° 10 (Octobre 2011) . - pp. 967–978 Titre : Acidic/caustic alternating corrosion on carbon steel pipes in heat exchanger of ethylene plant Type de document : texte imprimé Auteurs : Y. Gong, Auteur ; C. Yang, Auteur ; C. Yao, Auteur Année de publication : 2012 Article en page(s) : pp. 967–978 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Acidic/caustic  alternating  corrosion  Carbon  steel  pipes  Caustic  embrittlement  Heat  exchanger  Pitting Résumé : Caustic embrittlement, a kind of stress corrosion cracking (SCC), is always encountered on materials under stresses amid caustic environment. Acidic corrosion is another familiar degradation on materials contacting acidic media. However, it has been seldom studied what effect would be resulted in on materials that are exposed to an acidic/caustic alternating environment. In this paper, failure events were discovered on the carbon steel pipes under such an alternating service condition due to frequent sharp fluctuations of the heat medium's (process water) pH values in a heat exchanger. What is more, even chloride ions and sulfur element were detected, i.e., pitting corrosion was involved as well. In order to identify the causes of the failure, matrix materials of the pipes were examined, failure defects on pipe surfaces were investigated, particularly the process water was thoroughly inspected via a series of characterization methods. Based on the analysis results, a novel four-level mechanism from microscopic scale to macroscopic scale was tentatively proposed to explain such an acidic/caustic alternating corrosion. DEWEY : 620.1 ISSN : 0947-5117 En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005741/abstract [article] Acidic/caustic alternating corrosion on carbon steel pipes in heat exchanger of ethylene plant [texte imprimé] / Y. Gong, Auteur ; C. Yang, Auteur ; C. Yao, Auteur . - 2012 . - pp. 967–978. Génie Mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 62 N° 10 (Octobre 2011) . - pp. 967–978 Mots-clés : Acidic/caustic  alternating  corrosion  Carbon  steel  pipes  Caustic  embrittlement  Heat  exchanger  Pitting Résumé : Caustic embrittlement, a kind of stress corrosion cracking (SCC), is always encountered on materials under stresses amid caustic environment. Acidic corrosion is another familiar degradation on materials contacting acidic media. However, it has been seldom studied what effect would be resulted in on materials that are exposed to an acidic/caustic alternating environment. In this paper, failure events were discovered on the carbon steel pipes under such an alternating service condition due to frequent sharp fluctuations of the heat medium's (process water) pH values in a heat exchanger. What is more, even chloride ions and sulfur element were detected, i.e., pitting corrosion was involved as well. In order to identify the causes of the failure, matrix materials of the pipes were examined, failure defects on pipe surfaces were investigated, particularly the process water was thoroughly inspected via a series of characterization methods. Based on the analysis results, a novel four-level mechanism from microscopic scale to macroscopic scale was tentatively proposed to explain such an acidic/caustic alternating corrosion. DEWEY : 620.1 ISSN : 0947-5117 En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005741/abstract

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