The inhibition of copper corrosion by azole compounds in humid environments

Abstract

The ability of azole compounds, benzotriazole (BTA), 2-undecylimidazole (UDI) and poly- N-vinylimidazole (PVI-1) to inhibit copper corrosion in humid environments is studied using Fourier transform infrared reflection-absorption spectroscopy (FT-IR RAS). The corrosion product of bare Cu is shown to be Cu 2O even when moisture is present. The appearance and intensity of its characteristic vibration frequency can be used to monitor corrosion. It is found that dissolution of the Cu substrate, caused by local anodic and cathodic sites set up on the surface, accelerates the degradation process of BTA, UDI and PVI-1. The degradation of UDI on Cu apparently follows the same mechanism in both dry and wet environments while the degradation of PVI-1 on Cu does not. The BTA film is a better corrosion inhibitor than UDI or PVI-1 in this environment although some corrosion is observed. It is concluded that the inhibition ability of an inhibitor compound depends on the stability of the compound in the environment.