Documents disponibles écrits par cet auteur

Corrosion behaviour of Ti–Ta–Sn alloy systems in 0.9% NaCl solution / W. Q. Khan in Materials and corrosion, Vol. 63 N° 11 (Novembre 2012) 

Public ISBD [article]  in Materials and corrosion > Vol. 63 N° 11 (Novembre 2012) . - pp. 992–996 Titre : Corrosion behaviour of Ti–Ta–Sn alloy systems in 0.9% NaCl solution Type de document : texte imprimé Auteurs : W. Q. Khan, Auteur ; K. M. Deen, Auteur ; K. M. Ghauri, Auteur Année de publication : 2014 Article en page(s) : pp. 992–996 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Electrochemical;  electrochemical  impedance  spectroscopy;  microstructural;  passive  film;  X-ray  diffraction Résumé : Two alloys of varying contents of tantalum (Ta) and tin (Sn) were prepared and homogenized to evaluate their microstructural and electrochemical characteristics. The microstructural features were revealed through optical microscopy and X-ray diffraction methods. The formation and stability of passive film was studied by open circuit potential, potentiodynamic polarization and electrochemical scratch tests. The electrochemical impedance spectroscopy results simulated with equivalent electrical circuit suggested bilayer structure of outer porous and inner barrier oxide films. The quantitative data showed thick inner barrier oxide film retarded electrochemical reactions at low ‘Ta’ and ‘Sn’ concentration. The increased percentage of ‘Ta’ and ‘Sn’ deteriorated barrier properties by agglomeration of Ta2Sn3 and Ta0.15Ti0.85 precipitates within grains and at the grain boundaries. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201206523/abstract [article] Corrosion behaviour of Ti–Ta–Sn alloy systems in 0.9% NaCl solution [texte imprimé] / W. Q. Khan, Auteur ; K. M. Deen, Auteur ; K. M. Ghauri, Auteur . - 2014 . - pp. 992–996. Génie mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 63 N° 11 (Novembre 2012) . - pp. 992–996 Mots-clés : Electrochemical;  electrochemical  impedance  spectroscopy;  microstructural;  passive  film;  X-ray  diffraction Résumé : Two alloys of varying contents of tantalum (Ta) and tin (Sn) were prepared and homogenized to evaluate their microstructural and electrochemical characteristics. The microstructural features were revealed through optical microscopy and X-ray diffraction methods. The formation and stability of passive film was studied by open circuit potential, potentiodynamic polarization and electrochemical scratch tests. The electrochemical impedance spectroscopy results simulated with equivalent electrical circuit suggested bilayer structure of outer porous and inner barrier oxide films. The quantitative data showed thick inner barrier oxide film retarded electrochemical reactions at low ‘Ta’ and ‘Sn’ concentration. The increased percentage of ‘Ta’ and ‘Sn’ deteriorated barrier properties by agglomeration of Ta2Sn3 and Ta0.15Ti0.85 precipitates within grains and at the grain boundaries. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201206523/abstract

Impeding corrosion of sintered NdFeB magnets with titanium nitride coating / A. Ali in Materials and corrosion, Vol. 61 N° 2 (Fevrier 2010) 

Public ISBD [article]  in Materials and corrosion > Vol. 61 N° 2 (Fevrier 2010) . - pp. 130–135 Titre : Impeding corrosion of sintered NdFeB magnets with titanium nitride coating Type de document : texte imprimé Auteurs : A. Ali, Auteur ; A. Ahmad, Auteur ; K. M. Deen, Auteur Année de publication : 2010 Article en page(s) : pp. 130–135 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Electrochemical  impedance  spectroscopy;  pits  re-passivation;  sintered  NdFeB  Magnets Résumé : Sintered NdFeB magnets have poor corrosion resistance that renders them susceptible to corrosion in industrial and marine environments. This paper evaluates the properties of cathodic arc physical vapour deposited (CAPVD) titanium nitride coating for corrosion protection of sintered NdFeB permanent magnets. The performance of titanium nitride coating has been compared to the electrodeposited nickel–copper–nickel multilayer coating. The rates of coatings degradation in simulated marine environment were estimated with electrochemical impedance spectroscopy (EIS). Cyclic polarization was carried out to assess the pitting potential. The surface chemistry and coating morphologies were studied with scanning electron microscope (SEM). X-ray diffraction (XRD) was used for qualitative phase analyses of coatings and the substrate. It was figured out that the charge transfer resistance of CAPVD titanium nitride coating increased with exposure time. The negative rate of Rp-degradation for titanium nitride coating compared to the nickel–copper–nickel multilayer for equivalent exposure time is a unique and valuable result. Polarization results showed that ‘pits re-passivation’ of titanium nitride coating could be responsible for the extended corrosion protection of the NdFeB substrate. The magnetic properties remained comparable for both types of coatings. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905265/abstract [article] Impeding corrosion of sintered NdFeB magnets with titanium nitride coating [texte imprimé] / A. Ali, Auteur ; A. Ahmad, Auteur ; K. M. Deen, Auteur . - 2010 . - pp. 130–135. Génie mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 61 N° 2 (Fevrier 2010) . - pp. 130–135 Mots-clés : Electrochemical  impedance  spectroscopy;  pits  re-passivation;  sintered  NdFeB  Magnets Résumé : Sintered NdFeB magnets have poor corrosion resistance that renders them susceptible to corrosion in industrial and marine environments. This paper evaluates the properties of cathodic arc physical vapour deposited (CAPVD) titanium nitride coating for corrosion protection of sintered NdFeB permanent magnets. The performance of titanium nitride coating has been compared to the electrodeposited nickel–copper–nickel multilayer coating. The rates of coatings degradation in simulated marine environment were estimated with electrochemical impedance spectroscopy (EIS). Cyclic polarization was carried out to assess the pitting potential. The surface chemistry and coating morphologies were studied with scanning electron microscope (SEM). X-ray diffraction (XRD) was used for qualitative phase analyses of coatings and the substrate. It was figured out that the charge transfer resistance of CAPVD titanium nitride coating increased with exposure time. The negative rate of Rp-degradation for titanium nitride coating compared to the nickel–copper–nickel multilayer for equivalent exposure time is a unique and valuable result. Polarization results showed that ‘pits re-passivation’ of titanium nitride coating could be responsible for the extended corrosion protection of the NdFeB substrate. The magnetic properties remained comparable for both types of coatings. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905265/abstract