Improved fracture resistance of the Ag/SnO2 contact materials using Cu nanoparticles as additive

Abstract

For improving fracture resistance, metal Cu nanoparticles were used as additive in Ag/SnO2 contact materials. The fracture behaviors and mechanical properties of the Ag-8wt%SnO2 contact materials adding nano Cu additive were investigated by tensile tests. The fracture morphologies and strain distributions of the tensile samples were characterized using a scanning electron microscope (SEM) equipped with an EBSD system. The test results showed that the uniform elongation and yield stress of the Ag/SnO2 materials were significantly increased with the addition of nano Cu additive. Many dimples with different sizes were generated around SnO2 particles, indicating an obvious improvement of plastic deformation ability. The results of EBSD analysis revealed that the highest misorientation value occurred in the interfaces between SnO2 and Ag matrix. And, the plastic deformation region was mainly distributed near the larger SnO2-rich phase during tension. Due to the existence of fine Cu phase at the interfaces of SnO2 and Ag, the initiation and propagation of the intergranular cracks were effectively suppressed. More importantly, the Ag/SnO2 contact materials with nano Cu additive exhibited an excellent creep resistance because of the increased interfacial strength and plastic strain.