Effects of Surface Oxidation on Vacancy Defects in beta Nickel-Aluminum Alloys

摘要

Transmission Electron Microscopy and Auger Electron Spectroscopy have been used to make observations of the oxidation process in beta -NiAl alloys annealed under controlled conditions of temperature and oxygen partial pressure. Binary Ni-Al alloys, with nominally 47.5, 50.4 and 52.5 at. % Al, were examined. The Auger spectroscopy analysis showed that the predominant oxide formed on these alloys is Al sub 2 O sub 3 , with a possible thin intermediate layer of spinel. Bulk oxidation experiments indicate that the oxide grows by outward diffusion of cations to the oxide/gas interface. (ERA citation 05:010369)