Oxidation on the current-carrying rolling surface and its subsequent impact on the damage of Cu contact pairs in O2/N2 mixture

Abstract The oxidation of copper surface under current-carrying conditions were investigated by using a disc-disc rolling tribometer in different oxygen contents. Energy-dispersive X-ray spectrometry on rolling surface showed that the increase of oxygen content promoted surface oxidation. An interesting phenomenon was that the friction coefficient increased with the oxygen content. Contact angle tests indicated that the surface with a higher oxidation degree had a better hydrophilicity, which would cause a higher friction coefficient because of the additional meniscus force. Meanwhile, material damage styles changed from adhesive wear to lamellar fatigue wear due to the shear deformation induced by high friction coefficient, which has been demonstrated by electron back-scattered diffraction observation.