Abstract
This paper reports the color and the tarnishing behavior of CuMn15Zn15Al1 alloy in a synthetic sweat medium quantitatively. German silver BZn15–20–0.3 was selected for comparison. The results indicated that CuMn15Zn15Al1 has a silvery color similar to BZn15–20–0.3 but the tarnishing resistance of CuMn15Zn15Al1 in sweat is not as good as that of BZn15–20–0.3. For CuMn15Zn15Al1, tarnishing in sweat results in the decrease of L∗ values and increase of a∗ values, when both L∗ and a∗ are parameters in the CIE system to express the color. In other words, the color gets darker and redder after the sweat test. The corrosion layers were analyzed by means of Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS). The tarnishing products primarily consist of Cu2O, ZnO and Mn oxides. Some chlorides and hydroxides are detected on the outmost surface.
