SIMS and TM-AFM Studies on Weathered Cu, Zn, and Brass (CuZn10, CuZn30) Surfaces

Abstract Polished samples of Cu, Zn and two brasses (CuZn10 and CuZn30) have been treated in synthetic air with 80% relative humidity (RH) and alternatively with 250 ppb SO2 added to the moist air stream in a weathering box. Depth profiles of the corroded surfaces were made with dynamic-SIMS and the courses of the S- and O-signals were traced. The decay of the S- and the O-signal exhibited different behavior. While the O-signal decreased continuously through the corroded layer, the S-signal decreased much faster until it reached the background level at the half of the thickness of the altered layer. Surface features could be found with comparative TM-AFM-measurements that confirmed these SIMS results. The height of these features (measured with TM-AFM) matched with the determined thickness of the S enriched layer.