COMPARING SEGREGATION PROFILES OF Sn AND Sb IN SINGLE AND POLYCRYSTALLINE Cu

The kinetics as well as the equilibrium segregation profiles of very low concentrations of Sn (0.14 at.%) and Sb (0.12 at.%) in a polycrystalline Cu sample were measured by Auger electron spectroscopy. These profiles were compared to those from a Cu(100), Sb, Sn ternary single crystal which was subjected to the same experimental conditions. The results are explained in terms of solute segregation to grain boundaries and surface interfaces. The comparison also indicate that not only bulk diffusion, interactions and segregation energies play a role in the surface enrichment of the species, but in polycrystalline samples, the doping order of the specimen is to be considered as well. The differences in interaction energies of Sn and Sb also suggest an indirect method of measuring the concentrations of nonsegregating impurities in polycrystalline samples.