Growth mechanism of chromia scales on a model Ni-30Cr alloy at high temperatures
Résumé
Oxidation tests with markers and tracers were carried out to investigate the growth mechanism of chromia scale on a model Ni-30Cr alloy. The location of oriented grains characterized by TEM-ASRAR indicated that the scale grew predominantly outward at 800 and 900 • C. Experiments using 18 O and 54 Cr tracers confirmed a cationic transport via grain boundaries at these temperatures, using SIMS and NanoSIMS analyses. In the light of this and previous studies, we propose that the scales grow via diffusion of chromium vacancies at 900 • C and oxygen vacancies at 500 • C.
Domaines
ChimieOrigine | Fichiers éditeurs autorisés sur une archive ouverte |
---|---|
licence |