THE EFFECT OF ADSORBED SULFUR ON THE SURFACE SELF-DIFFUSION OF COPPER.

Abstract : We have studied the effect of adsorbed sulfur on the surface self-diffusion of copper using eight different surface orientations and the grain boundary grooving method. The eight orientations studied were the four lying near the low index surfaces-(100), (111), and two directions in the (110) - plus four higher index surfaces. Surface diffusion measurements were made over a range of H2S concentrations (in H2) from 3 to 1500 ppm between 830 and 1050 C. The results can be divided into two groups - Group 1 contains the two (110) surfaces while Group 2 contains the remaining six surfaces. In Group 1, increasing the temperature increases the effect of H2S on D sub s for the H2S range equal to or less than 700 ppm. Q sub s and D sub o increase with increasing H2S concentration in this H2S range. Beyond this range, increasing the temperature decreased this effect on D sub s; also Q sub s and D sub o decreased. In Group 2, increasing the temperature decreases the effect of H2S on D sub s for the H2S range studied, and Q sub s and D sub o decrease with increasing H2S concentration. (Author)