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

•very high enrichment with one of the alloy components if found•the steady state dose for cluster ions higher than for atomic ones;•ripples develop under oblique cluster incidence•alloy components distribution along surface repeats the ripple pattern•etching rate depends on the crystallite orientation 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. [Display omitted]