Microstructure and Properties of ZrO₂/Cu Composites Prepared by Internal Oxidation for Spot-Welding Electrode

ZrO2/Cu composites for spot-welding electrode were prepared by a modified internal oxidation method, then plastic deformation and heat treatment were carried out for the composite. The microstructure, hardness and conductivity of the composite treated in different conditions were studied. The results show that the composites had fine and homogeneous microstructure, and ZrO2 particles distributed dispersively in copper substrate. The hardness of the composite increased, but the conductivity decreased with the increase of deformation degree in cold drawing, and the best deformation degree was 60%. The hardness of the composite cold drawn with deformation degree of 60%, reached 100 HV and its conductivity reached 86%IACS. With the increase of temperature and the prolongation of holding time, the composite still had a high conductivity and few changes in hardness, whose high temperature resistance was better than that of CuCrZr alloy. So the ZrO2/Cu composite was a good material for spot-welding electrode.