A Laboratory Study of the Effect of Acetic Acid Vapor on Atmospheric Copper Corrosion

A study was made of the copper corrosion rate and corrosion products originated by the action of acetic acid vapor at 100% relative humidity. Copper plates were exposed to an acetic acid contaminated atmosphere for a period of 21 days. Five acetic vapor concentration levels were used. The copper corrosion rate was in the range of 1 to 23 mg/dm 2 day. The corrosion‐product layers were characterized using electrochemical, X‐ray powder diffraction, Fourier transform infrared spectrometry, and scanning electron microscopy techniques. Thermal and calorimetric studies were also performed. Some of the compounds identified were cuprite , copper acetate hydrate , and copper hydroxide acetate . This last compound was also characterized. The thickness of the patina layers was 4 to 8 nm for amorphous cuprite, 11 to 48 nm for cuprite, and 225 nm for copper acetate. The patina, in which the cementation process of different corrosion‐product layers plays an important role, is formed by the reaction of acetic vapor with copper through porous cuprite paths.