Corrosion Mechanism of Ag in H₂S/NO₂ Mixed Gas

Abstract

Sulfidation corrosion rate of Ag in H₂S/NO₂ mixed gas atmosphere was evaluated using resistance measurement method. As a result, the corrosion of Ag was accelerated about 100 times in H₂S/NO₂ mixed gas compared with H₂S single gas. The corrosion behavior changes at the concentration ratio of H₂S : NO₂＝1 : 2, and the corrosion rate shows a negative temperature dependence and no humidity dependence. It was also confirmed that S₈ was detected in the H₂S/NO₂ mixed gas using HPLC （High Performance Liquid Chromatography） method. Based on these results, mechanisms of Ag sulfidation corrosion by H₂S/NO₂ mixed gas atmosphere were proposed.