Study of Anti-Tarnishing Synergistic Effect of Inhibitors for Silver

The inhibition performance of 1-phenyl-5-mercaptotetrazole (PMTA), 2-mercaptobenzoxazole (MBO), 2-mercaptobenzimidazole (MBI) and the built inhibitor (PMM) were evaluated for silver in HSCH sub 2 COOH solution by polarization curve and AC impedance method. Results showed that PMM was the most prominent among above four inhibitors and took on the synergistic effect. Results from Auger Electron Spectroscopy (AES) and X-ray Photoelectron Spectroscopy (XPS) showed that the anti-tarnishing film formed by PMM was more compact and stabilized than that of mono-component inhibitor so that the mixed anti-tarnishing inhibitor was more effective.