Corrosion Products Formed on Silver and Copper Plates Exposed in a Volcanic Area

• Main Authors: Watanabe, Masamitsu, Handa, Takao, Ichino, Toshihiro, Kuwaki, Nobuo
• Format: Conference Proceeding
• Language: English
• ISSN: 1938-5862; 1938-6737
• DOI: 10.1149/1.2838451

Corrosion products formed on silver and copper plates exposed in a volcanic area were analyzed to get a better understanding of silver and copper corrosion in harsh environments. Both Ag2S and AgCl were detected in the X-ray diffraction (XRD) patterns of silver plates exposed for either 22 or 212 days. Cuprite (Cu2O) and posnjakite (Cu4SO4(OH)6•H2O) were detected in the XRD pattern of a copper plate exposed for 22 days. Brochantite (Cu4SO4(OH)6), antlerite (Cu3SO4(OH)4), and geerite (Cu8S5) were detected as well in that of a copper plate exposed for 212 days. Surface observation revealed that the surface Corrosion products formed on silver and copper plates exposed in a volcanic area were analyzed to get a better understanding of silver and copper corrosion in harsh environments. Both silver sulfide (Ag2S) and silver chloride (AgCl) were detected in the X-ray diffraction (XRD) patterns of silver plates exposed for either 22 or 212 days. Cuprite (Cu2O) and posnjakite (Cu4SO4(OH)6•H2O) were detected in the XRD pattern of a copper plate exposed for 22 days. Brochantite (Cu4SO4(OH) 6), antlerite (Cu3SO4(OH)4), and geerite (Cu8S5) were detected as well in that of a copper plate exposed for 212 days. Surface observation revealed that the surface morphologies of silver and copper plates exposed for 212 days differed from those exposed for 22 days. Chemical state analysis by X-ray photoelectron spectroscopy showed that sulfur existed mainly as sulfide on the silver plates, while it existed mainly as sulfate on the copper plates. This agrees well with the XRD results.