Effects of Radiation-Induced Segregation and Preferential Sputtering on the Sputtering Rate of Alloys

摘要

Changes in the surface composition and in the sputtering rate of binary alloys were calculated using a kinetic model that includes the effects of radiation-induced segregation and preferential sputtering. Numerical solutions were obtained for two dilute Ni-based model alloys, Ni--Cu and Ni--Mo, under 5-keV Ar exp + ion bombardment as functions of sputtering time, temperature, and initial alloy composition. In the temperature range 200 to 850 exp 0 C, the sputtering rate is initially affected by strong radiation-induced segregation. As the bombardment time increases, preferential sputtering becomes dominant; the surface composition and hence, the sputtering rate, approach the steady-state values determined entirely by the sputtering coefficients of the alloy components. Below 200 and above 850 exp 0 C, the sputtering rate is controlled by preferential sputtering only because radiation-induced segregation is insignificant in these temperature regimes. (ERA citation 04:037099)