Documents disponibles écrits par cet auteur

Corrosion behaviour in physiological fluids of surface films formed on titanium alloys / J. C. Mirza Rosca in Materials and corrosion, Vol. 63 N° 6 (Juin 2012) 

Public ISBD [article]  in Materials and corrosion > Vol. 63 N° 6 (Juin 2012) . - pp. 527–533 Titre : Corrosion behaviour in physiological fluids of surface films formed on titanium alloys Type de document : texte imprimé Auteurs : J. C. Mirza Rosca, Auteur ; E. Vasilescu, Auteur ; P. Drob, Auteur Année de publication : 2012 Article en page(s) : pp. 527–533 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Chemical  and  heat  treatments;  EIS;  microhardness;  open  circuit  potentials Résumé : The properties of the surface films formed on Ti and its Ti–5Al–4V and Ti–6Al–3.5Fe alloys by chemical (immersion in 10 M NaOH) and thermal treatment (500 °C) were studied in this paper. Their corrosion behaviour in Ringer solution was investigated. After treatments, the sample microhardness was measured. Also, the sample surfaces were observed by an optical microscope before and after immersion in Ringer solutions. The electrochemical behaviour of the surface films obtained by the chemical and thermal treatments was studied using the methods of the electrochemical impedance spectroscopy (EIS) and monitoring of open circuit potentials at different immersion periods (up to 60 days) in Ringer solution. Microhardness increased with the increasing loads for the studied materials, showing the existence of a compact protective layer. Microscopic observations exhibited more compact coatings after 60 days of exposure in Ringer solution, due to the formation of an apatite layer. EIS spectra revealed surface films with two layers: an inner, barrier protective layer and an outer, porous apatite layer. The impedance increases in time denoting that the films have grown by apatite nucleation. Also, EIS spectra showed that the complex treatment by chemical + heat method is the most efficiently. For the samples treated by the two processes (chemical + heat) the values of the open circuit potentials are nobler than of the chemical treated samples, denoting better protective, bioactive films. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201106102/abstract [article] Corrosion behaviour in physiological fluids of surface films formed on titanium alloys [texte imprimé] / J. C. Mirza Rosca, Auteur ; E. Vasilescu, Auteur ; P. Drob, Auteur . - 2012 . - pp. 527–533. Génie mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 63 N° 6 (Juin 2012) . - pp. 527–533 Mots-clés : Chemical  and  heat  treatments;  EIS;  microhardness;  open  circuit  potentials Résumé : The properties of the surface films formed on Ti and its Ti–5Al–4V and Ti–6Al–3.5Fe alloys by chemical (immersion in 10 M NaOH) and thermal treatment (500 °C) were studied in this paper. Their corrosion behaviour in Ringer solution was investigated. After treatments, the sample microhardness was measured. Also, the sample surfaces were observed by an optical microscope before and after immersion in Ringer solutions. The electrochemical behaviour of the surface films obtained by the chemical and thermal treatments was studied using the methods of the electrochemical impedance spectroscopy (EIS) and monitoring of open circuit potentials at different immersion periods (up to 60 days) in Ringer solution. Microhardness increased with the increasing loads for the studied materials, showing the existence of a compact protective layer. Microscopic observations exhibited more compact coatings after 60 days of exposure in Ringer solution, due to the formation of an apatite layer. EIS spectra revealed surface films with two layers: an inner, barrier protective layer and an outer, porous apatite layer. The impedance increases in time denoting that the films have grown by apatite nucleation. Also, EIS spectra showed that the complex treatment by chemical + heat method is the most efficiently. For the samples treated by the two processes (chemical + heat) the values of the open circuit potentials are nobler than of the chemical treated samples, denoting better protective, bioactive films. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201106102/abstract