Surface topography and composition of NiPd alloys under oblique and normal gas cluster ion beam irradiation

Abstract

Polycrystalline NiPd and Ni5Pd alloys were irradiated with argon gas cluster ion beam and atomic ion beam. In situ XPS measurements showed surface enrichment with Ni. For cluster ions, the degree of the enrichment was significantly higher, and the ion current density influenced on it. Under oblique cluster ion beam, ripples developed on the surface, and the elements of the alloy redistributed along the surface according to the ripple pattern. For normal cluster ion beam direction, sputtering rate was determined by a crystalline orientation, which limited the smoothing effect.