Electrochemical investigation and ab initio computation of passive film properties on copper in anaerobic sulphide solutions

Electrochemical measurements based on the point defect model and ab initio calculations were employed to investigate the properties of passive films formed on copper in anaerobic sulphide-containing solutions at different temperatures. P-type semiconductor characteristics were observed at potentials more positive than −0.75 VSCE, which is consistent with copper vacancies being the dominant defect, but n-type behaviour was observed at lower potentials. The density of copper vacancies (approximately 1022 cm−3) increases with temperature and formation potential, and the diffusion coefficient of copper vacancies lies within the range of 10−15 to 10−14 cm2/s based on ab initio computations and electrochemical measurements.