Copper Corrosion Mechanism in the Presence of Formic Acid Vapor for Short Exposure Times

The rate of copper corrosion originated by the action of formic acid vapors at 100% relative humidity was studied. Five formic vapor concentration levels (10, 50, 100, 200, and 300 ppm) were used. A copper corrosion rate of up to was measured for a period of 21 days using a gravimetric method. The patina layers were characterized using cathodic reduction, X‐ray powder diffraction, Fourier transform infrared spectrometry, and scanning electron microscopy techniques. Some of the components identified in the corrosion‐product layers were cuprite , cupric hydroxide hydrate , and copper formate hydrate . The latter was formed by both cupric hydroxide and formic acid‐cuprous ion complex mechanisms. © 2000 The Electrochemical Society. All rights reserved.