Segregation of atoms in NixPdy alloys during ion irradiation

Sputtering of Ni5Pd and NiPd5 alloys by 10 keV Ar ions has been studied using the binary-collision simulation. Special attention was given to the angular distributions of sputtered atoms at the steady-state conditions. The results of simulations were compared with the experimental data published recently. For both targets, the concentrations of Ni and Pd atoms in the top monolayer were extracted from the experimental data. The results of simulations favor segregation of Pd in Ni5Pd and segregation of Ni in NiPd5. The total concentration of surface vacancies was found to be about 10–30%.