Chemisorption of Oxygen on Edges (100), (110), (111) of Fe-Ni Alloys - Effects of Orientation and Structure

摘要

A comparative Auger electron spectroscopic study of the kinetics of oxygen chemisorption on the (100), (110), (111) faces of Fe-36 percent Ni, Fe-75 percent Ni single crystal alloys and on polycrystalline Fe-75 percent Ni alloy has been carried out for O_2 exposures up to 5000 L. The initial adsorption rate and maximum amount of the chemisorbed oxygen were established to depend on the face orientation and ally composition, with the crystallographic effects being predominant. The rate and sign of the chemisorption induced surface segregation, taking place in the alloys, were shown to depend on the crystallographic orientation, alloy composition and oxygen exposure. The diffusion coefficients of a component segregating in the alloys were evaluated.