Effects of silver powder particle size on the microstructure and properties of Ag-Yb_2O_3 electrical contact materials prepared by spark plasma sintering

摘要

Ag-Yb2O3 electrical contact materials were fabricated by spark plasma sintering(SPS).The effects of silver powder particle size on the microstructure and properties of the samples were investigated.The surface morphologies of the sintered samples were examined by optical microscope(OM),and the fracture morphologies were observed by scanning electron microscopy(SEM).The physical and mechanical properties such as density,electrical resistivity,microhardness,and tensile strength were also tested.The results show that the silver powder particle size has evident effects on the sintered materials.Comparing with coarse silver powder(5 μm),homogeneous and fine microstructure was obtained by fine silver powder(≤0.5 μm).At the same time,the electrical conductivity,microhardness,and tensile strength of the sintered samples with fine silver powder were higher than those of the samples with coarse silver powder.However,silver powder particle size has little influence on the relative densities,which of all samples(both by fine and coarse silver powders) is more than 95%.The fracture characteristics are ductile.