Abstract
Normalized ionization probabilities α+ are reported for binary Fe‐Ni alloys under O+2 bombardment at a 45° incidence angle. It is shown that the dependence of α+ on the composition is much smaller than at normal incidence. Photoemission spectroscopy reveals that both nickel and iron remain essentially metallic under oblique‐incidence bombardment, whereas almost complete oxidation occurs at normal incidence. This is attributed to our observation that sputter yields under oxygen bombardment increase much faster than cos α−1.