EXAFS study of passive films on Ni and Ni-Mo alloy electrodes

Abstract
The specular reflectivity of x‐rays at sufficiently small grazing angles is absorption‐coefficient‐dependent so that the EXAFS technique can be used to probe the surface. This method allows in situ measurements. Applications to the study of passive films on nickel and nickel‐molybdenum alloy electrodes are presented. In both cases, the passive films is found to be composed of NiO entities probably ordered perpendicularly to the electrode. Molybdenum enrichment in the surface layer is confirmed by an increase of the Mo k edge signal.