Effects of Lubricants and Nano-Inclusions on Copper Corrosion Behavior and Their Electrical Conductivity

In this work, the corrosion behavior of copper with inclusions in rolling oil is investigated via potentiodynamic polarization, electrochemical impedance spectroscopy and weight loss experiments. The relationships among surface morphologies of the corroded copper, their microstructure characteristics and electrical conductivity are discussed. The results show that the inclusions in copper were mainly copper oxides with grain size of about 40 nm. Etch pitting corrosion of copper was initiated by nano-inclusions assembled along grain and sub-grain boundaries. Dislocations and other crystallographic defects were found to accelerate corrosion reactions of copper. Compared with the relatively light corrosion, the worst corrosion electrical conductivity drop was about 35%. The worst corrosion induced the largest electrical conductivity drop to 51% after 21 h when specimens were immersed in rolling base oil with phosphate agent.