Characterization of Vapor Phase Copper Corrosion Products Using Electrochemical Methods

摘要

The copper corrosion products originated by the action of formic, acetic and propionic acid vapors at a 100% relative humidity were studied for a period of 21 days. Five formic, acetic and propionic vapor concentrations (10, 50, 100, 200 and 300 ppm) were tested. The corrosion-product layers were characterized using electrochemical methods. Some of the compounds identified were: cuprite (Cu_2O), for the three acids; cupric hydroxide monohydrate (Cu(OH)_2·H_2O) and copper formate tetrahydrate (Cu(HCOO)_2·4H_2O), for formic acid; copper acetate dihydrate (Cu(CH_3COO)_2·2H_2O) and copper hydroxide acetate dihydrate (Cu_4(OH)(CH_3COO)_7·2H_2O), for acetic acid; and copper propionate (Cu_4(OH)(CH_3CH_2COO)_7·2H_2O) for propionic acid.