SPUTTERING OF THE ALLOY SYSTEMS Ag-Au, Au-Cu AND Ag-Cu STUDIED BY AUGER ELECTRON SPECTROSCOPY.

Preferential sputtering has been studied for the binary systems Ag-Au, Au-Cu, and Ag-Cu. Several alloys of each system with given bulk compositions have been sputtered by 1 keV argon ions while the surface composition was analyzed by Auger electron spectroscopy. In the system Ag-Au, sputtering yields an enrichment of Au caused by preferential sputtering of Ag. The enrichment of Au is in qualitative agreement with the sputter coefficients of the pure elements. For Au-Cu alloys, no enrichment is detected, in accordance with a ratio of one for the sputter coefficients of pure Au and pure Cu. The ratio of the sputter coefficients for the systems Ag-Au and Au-Cu was found to be essentially constant over the whole concentration range. All sputtered Ag-Cu alloys show an enrichment in Cu.