Processes of atom mixing at the boundary in Ag-Cu and Ag-Mo systems under argon ion bombardment

Abstract

Analysis of some aspects for dynamic ion mixing at the film-substrate boundary in Ag-Cu and Ag-Mo systems under argon ion bombardment during Ag film growth has been carried out. Evaluations of vacancy concentration formed in unit time under ion beam action show that without taking into account recombination and annealing the low energy ions are capable of creating a defect concentration in the film-substrate interface 1-2 orders of magnitude smaller than high energy ions. In this case the concentration is comparable with the thermo-dynamical equilibrium concentration at temperatures close to the Ag melting temperature. Proceeding from the comparison of diffusion activation energies, vacancy migration rates as well as taking into consideration mechanical characteristics of material, a conclusion has been drawn about mutual penetration and preferential penetration of substrate material into Ag coating as the result of radiation enhanced processes. Experimental results have confirmed these estimations revealing the considerably larger Ag films adhesion to Mo substrate than to Cu under the same conditions of film formation. The friction tests have shown that wear of Ag-Cu and Ag-Mo solid solutions produced under Ar ion bombardment of the growing Ag film is much lower than the wear of Ag film without ion irradiation.