Numerical investigation on interface enhancement mechanism of Ag-SnO2 contact materials with Cu additiveCu添加剂对Ag-SnO2触点材料界面增强机理的数值模拟

The electrical contact and mechanical performances of Ag-SnO2 contact materials are often improved by additives, especially Cu and its oxides. To reveal the improvement mechanism of metal additive, the effects of Cu nanoparticles on the interface strength and failure behavior of the Ag-SnO2 contact materials are investigated by numerical simulations and experiments. Three-dimensional representative volume element (RVE) models for the Ag-SnO2 materials without and with Cu nanoparticles are established, and the cohesive zone model is used to simulate the interface debonding process. The results show that the stress—strain relationships and failure modes predicted by the simulation agree well with the experimental ones. The adhesion strengths of the Ag/SnO2 and Ag/Cu interfaces are respectively predicted to be 100 and 450 MPa through the inverse method. It is found that the stress concentration around the SnO2 phase is the primary reason for the interface debonding, which leads to the failure of Ag-SnO2 contact material. The addition of Cu particles not only improves the interface strength, but also effectively suppresses the initiation and propagation of cracks. The results have an reference value for improving the processability of Ag based contact materials.