Documents disponibles écrits par cet auteur

Effects of coolant chemistry on corrosion of 3003 aluminum alloy in automotive cooling system / Y. Liu in Materials and corrosion, Vol. 61 N° 7 (Juillet 2010) 

Public ISBD [article]  in Materials and corrosion > Vol. 61 N° 7 (Juillet 2010) . - pp. 574–579 Titre : Effects of coolant chemistry on corrosion of 3003 aluminum alloy in automotive cooling system Type de document : texte imprimé Auteurs : Y. Liu, Auteur ; Y. F. Cheng, Auteur Année de publication : 2010 Article en page(s) : pp. 574–579 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : aluminum  alloys;  automotive  cooling  system;  cation  impurities;  corrosion;  ethylene  glycol Résumé : In this work, effects of coolant chemistry, including concentrations of chloride ions and ethylene glycol and addition of various ions, on corrosion of 3003 Al alloy were investigated by electrochemical impedance spectroscopy measurements and scanning electron microscopy characterization. In chloride-free, ethylene glycol–water solution, a layer of Al-alcohol film is proposed to form on the electrode surface. With the increase of ethylene glycol concentration, more Al-alcohol film is formed, resulting in the increase in film resistance and charge-transfer resistance. In the presence of Cl− ions, they would be involved in the film formation, decreasing the stability of the film. In 50% ethylene glycol–water solution, the threshold value of Cl− concentration for pitting initiation is within the range of 100 ppm to 0.01 M. When the ethylene glycol concentration increases to 70%, the threshold Cl− concentration for pitting is from 0.01 to 0.1 M. In 100% ethylene glycol, there is no pitting of 3003 Al alloy even at 0.1 M of Cl−. Even a trace amount of impurity cation could affect significantly the corrosion behavior of 3003 Al alloy in ethylene glycol–water solution. Addition of Zn2+ is capable of increasing the corrosion resistance of Al alloy electrode, while Cu2+ ions containing in the solution would enhance corrosion, especially pitting corrosion, of Al alloy. The effect of Mg2+ on Al alloy corrosion is only slight. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905323/abstract [article] Effects of coolant chemistry on corrosion of 3003 aluminum alloy in automotive cooling system [texte imprimé] / Y. Liu, Auteur ; Y. F. Cheng, Auteur . - 2010 . - pp. 574–579. Génie mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 61 N° 7 (Juillet 2010) . - pp. 574–579 Mots-clés : aluminum  alloys;  automotive  cooling  system;  cation  impurities;  corrosion;  ethylene  glycol Résumé : In this work, effects of coolant chemistry, including concentrations of chloride ions and ethylene glycol and addition of various ions, on corrosion of 3003 Al alloy were investigated by electrochemical impedance spectroscopy measurements and scanning electron microscopy characterization. In chloride-free, ethylene glycol–water solution, a layer of Al-alcohol film is proposed to form on the electrode surface. With the increase of ethylene glycol concentration, more Al-alcohol film is formed, resulting in the increase in film resistance and charge-transfer resistance. In the presence of Cl− ions, they would be involved in the film formation, decreasing the stability of the film. In 50% ethylene glycol–water solution, the threshold value of Cl− concentration for pitting initiation is within the range of 100 ppm to 0.01 M. When the ethylene glycol concentration increases to 70%, the threshold Cl− concentration for pitting is from 0.01 to 0.1 M. In 100% ethylene glycol, there is no pitting of 3003 Al alloy even at 0.1 M of Cl−. Even a trace amount of impurity cation could affect significantly the corrosion behavior of 3003 Al alloy in ethylene glycol–water solution. Addition of Zn2+ is capable of increasing the corrosion resistance of Al alloy electrode, while Cu2+ ions containing in the solution would enhance corrosion, especially pitting corrosion, of Al alloy. The effect of Mg2+ on Al alloy corrosion is only slight. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905323/abstract

Electrochemical corrosion behavior of X80 pipeline steel in a near-neutral pH solution / H. B. Xue in Materials and corrosion, Vol. 61 N° 9 (Septembre 2010) 

Public ISBD [article]  in Materials and corrosion > Vol. 61 N° 9 (Septembre 2010) . - pp. 756–761 Titre : Electrochemical corrosion behavior of X80 pipeline steel in a near-neutral pH solution Type de document : texte imprimé Auteurs : H. B. Xue, Auteur ; Y. F. Cheng, Auteur Année de publication : 2011 Article en page(s) : pp. 756–761 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Corrosion;  electrochemical  impedance  spectroscopy;  near-neutral  pH  solution;  photo-electrochemical  measurement;  pipeline  steel Résumé : In this work, the electrochemical corrosion behavior of X80 pipeline steel was investigated in a near-neutral pH solution using electrochemical impedance spectroscopy (EIC) and photo-electrochemical (PEC) measurements as well as X-ray photo-electron spectroscopy (XPS) technique. The effects of hydrogen-charging and stress were considered. The results show that the steel is in an active dissolution state, and a layer of corrosion product is formed and deposited on the electrode surface, which is subjected to further oxidation to form ferric oxide and hydroxide. Photo-illumination enhances anodic dissolution of the steel when it is under anodic polarization due to destroying of the corrosion product film. When the steel is under cathodic polarization, the cathodic current density decreases upon laser illumination due to the photo-oxidation of hydrogen atoms generated during cathodic reactions, which behaves as an anodic reaction to offset the cathodic current density. Hydrogen-charging and stress decrease the corrosion resistance of the steel and enhance the dissolution rate of the steel. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905430/abstract [article] Electrochemical corrosion behavior of X80 pipeline steel in a near-neutral pH solution [texte imprimé] / H. B. Xue, Auteur ; Y. F. Cheng, Auteur . - 2011 . - pp. 756–761. Génie mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 61 N° 9 (Septembre 2010) . - pp. 756–761 Mots-clés : Corrosion;  electrochemical  impedance  spectroscopy;  near-neutral  pH  solution;  photo-electrochemical  measurement;  pipeline  steel Résumé : In this work, the electrochemical corrosion behavior of X80 pipeline steel was investigated in a near-neutral pH solution using electrochemical impedance spectroscopy (EIC) and photo-electrochemical (PEC) measurements as well as X-ray photo-electron spectroscopy (XPS) technique. The effects of hydrogen-charging and stress were considered. The results show that the steel is in an active dissolution state, and a layer of corrosion product is formed and deposited on the electrode surface, which is subjected to further oxidation to form ferric oxide and hydroxide. Photo-illumination enhances anodic dissolution of the steel when it is under anodic polarization due to destroying of the corrosion product film. When the steel is under cathodic polarization, the cathodic current density decreases upon laser illumination due to the photo-oxidation of hydrogen atoms generated during cathodic reactions, which behaves as an anodic reaction to offset the cathodic current density. Hydrogen-charging and stress decrease the corrosion resistance of the steel and enhance the dissolution rate of the steel. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905430/abstract

Role of second phase particles in pitting corrosion of 3003 Al alloy in NaCl solution / Y. Liu in Materials and corrosion, Vol. 61 N° 3 (Mars 2010) 

Public ISBD [article]  in Materials and corrosion > Vol. 61 N° 3 (Mars 2010) . - pp. 211–217 Titre : Role of second phase particles in pitting corrosion of 3003 Al alloy in NaCl solution Type de document : texte imprimé Auteurs : Y. Liu, Auteur ; Y. F. Cheng, Auteur Année de publication : 2010 Article en page(s) : pp. 211–217 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Aluminum  alloy;  pitting  corrosion;  second  phase  particles Résumé : The second phase particles in 3003 aluminum (Al) alloy were characterized by scanning electron microscope, energy-dispersive X-ray analysis and X-ray diffraction techniques. The role of second phase particles in Al alloy pitting corrosion was investigated by cyclic polarization measurement, and scanning vibrating electrode technique. Results demonstrated that the second phase particles in 3003 Al alloy are mainly Alx(Fe,Mn) intermetallics, with an average diameter of about 5 µm. The enrichment of Mn in second phase particles forms a galvanic cell effect relative to the adjacent Al alloy substrate. The initiation of pitting corrosion of 3003 Al alloy is the local dissolution of Al substrate around the second phase particles. When a sufficient amount of Al is dissolved away, the second phase particles drop off from the Al substrate, forming large pitting cavities that are usually linked each other. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905308/abstract [article] Role of second phase particles in pitting corrosion of 3003 Al alloy in NaCl solution [texte imprimé] / Y. Liu, Auteur ; Y. F. Cheng, Auteur . - 2010 . - pp. 211–217. Génie mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 61 N° 3 (Mars 2010) . - pp. 211–217 Mots-clés : Aluminum  alloy;  pitting  corrosion;  second  phase  particles Résumé : The second phase particles in 3003 aluminum (Al) alloy were characterized by scanning electron microscope, energy-dispersive X-ray analysis and X-ray diffraction techniques. The role of second phase particles in Al alloy pitting corrosion was investigated by cyclic polarization measurement, and scanning vibrating electrode technique. Results demonstrated that the second phase particles in 3003 Al alloy are mainly Alx(Fe,Mn) intermetallics, with an average diameter of about 5 µm. The enrichment of Mn in second phase particles forms a galvanic cell effect relative to the adjacent Al alloy substrate. The initiation of pitting corrosion of 3003 Al alloy is the local dissolution of Al substrate around the second phase particles. When a sufficient amount of Al is dissolved away, the second phase particles drop off from the Al substrate, forming large pitting cavities that are usually linked each other. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905308/abstract