COMPORTEMENT ELECTROCHIMIQUE ET FORMATION DE FILMS SUPERFICIELS SUR ALLIAGES A BASE DE NICKEL DANS DES SOLUTIONS REPRESENTATIVES DES EAUX GEOLOGIQUES
The present report deals with the studies on the passivation and depassivation processes of nickel base alloys in different geological waters. The depassivation in sulfuric acid solution shows that the films formed are relatively thin, especially for films formed in salt brine, and exhibit also three layers which were observed previously by Glow Discharge Spectrometry (GDS). In chloride rich solutions, like salt brine and 3 % NaCl solution, the pit nucleation potentials E-np depend on several physicochemical parameters such as the temperature, the chloride concentration and the inhibiting species concentrations and the alloy compositions. For the last parameter, the beneficial actions of the alloying elements, Mo and Cr, are pointed out.The surface analysis by SDL and SIMS, which show an accumulation of Mo at the film - matrix interface and inside the pit, are in good agreement with the hypothesis of the redeposition of dissolved Mo, on the matrix inside the pit.
Références bibliographiques: EUR 9669 FR (1985) MF, 50 P., BFR 150, BLOW-UP COPY BFR 250, EUROFFICE, LUXEMBOURG, POB 1003
Disponibilité: Can be ordered online
Numéro d'enregistrement: 1989123052100 / Dernière mise à jour le: 1987-01-01
Langues disponibles: fr