The mechanism of corrosion inhibition of copper in NaCl solution by benzotriazole studied by electron spectroscopy

Surface films formed by benzotriazole on copper in 3% brine solution were investigated using X-ray photoelectron spectroscopy (XPS or ESCA) and X-ray induced Auger spectroscopy (X-AES). This combination proved to be quite useful for such studies. Based on the results obtained, a model for the inhibition mechanism is proposed. According to this model, disproportionation of the Cu(I) ions followed by formation of a CuCl layer constitutes a suitable base for Cu—inhibitor complex formation. The thickness of the final complex layer is mainly governed by an intermediate stage of CuCl formation.