Mechanical characteristics of the Ag/SnO2 electrical contact materials with Cu2O and CuO additives

Abstract

To investigate the effect of oxide additives on the mechanical characteristics of Ag-based contact materials, the Ag/SnO2 tensile samples with CuO and Cu2O were prepared by powder metallurgy method. The mechanical properties of the prepared Ag/SnO2 materials were tested on a special tensile machine. And, the effect of cyclic loadings on the mechanical characteristics of the prepared samples was also studied. The tensile fractures of the Ag/SnO2 samples were analyzed by a Scanning Electron Microscope (SEM). The results showed that a small amount of CuO and Cu2O additives had remarkable influence on the mechanical characteristics of the Ag/SnO2 materials. The Ag/SnO2 samples with 0.5 wt% Cu2O exhibited the optimal mechanical property. The ultimate strength and uniform elongation were increased by 60% and 21%, respectively. The CuO and Cu2O additives suppressed the growth of intergranular cracks in the Ag/SnO2 materials by the formation of larger dimples around SnO2 particles. The cyclic creeps of the Ag/SnO2 samples with copper oxides were also obviously decreased. These results indicated that a moderate amount of cupper oxides especially Cu2O was beneficial for improving the processability of Ag/SnO2 contact materials.