화학공학소재연구정보센터
Journal of the Electrochemical Society, Vol.160, No.8, C345-C355, 2013
Analysis of Ag Corrosion Products
The corrosion behavior of Ag in outdoor environments and in a salt spray chamber was investigated. The coulometric reduction technique was applied to identify various silver corrosion products including Ag2SO4 and AgO. These corrosion products were observed on samples exposed in certain field environments. A plateau in the coulometric reduction curve associated with metastable hydrogen evolution was observed under conditions in which a considerable amount of Ag2S was formed and reduced. Soluble silver chloride complexes were the dominant corrosion product, instead of insoluble AgCl, when the chloride deposition rate was high enough. Under those conditions, the corrosion rate measured by coulometric reduction is lower than the actual corrosion rate. Ag particles formed on the surface during exposure to different environments. During exposure in a marine environment, photodecomposition of AgCl corrosion product resulted in the formation of Ag nanoparticles embedded in AgCl. Isolated Ag particles of a few micrometers in size formed during exposure in a salt spray chamber due to the high exchange current density for the Ag/Ag+ reaction. (C) 2013 The Electrochemical Society. All rights reserved.