Effect of La2Sn2O7 content on Ag-La2Sn2O7/SnO2 arc erosion behavior and mechanism

Abstract

La2Sn2O7/SnO2 powder was synthesized by chemical co-precipitation method, and Ag-La2Sn2O7/SnO2 composites were prepared by hot-pressing sintering. The electrical resistivity, density, Brinell hardness and flexural strength of Ag-La2Sn2O7/SnO2 composites were measured. Moreover, the effect of La2Sn2O7 content on the arc erosion behavior of Ag-La2Sn2O7/SnO2 composites at 7 kV voltage was studied. With the increase of La2Sn2O7 content, the arc duration and arc energy decrease, and the breakdown strength increases. The surface morphology of Ag-La2Sn2O7/SnO2 composites after arc erosion was investigated using scanning electron microscopy and three-dimensional laser confocal scanning microscopy. With the increase of La2Sn2O7 content, the smaller the erosion damage, the better the anti-arc erosion performance. However, too much La2Sn2O7 results in the decrease of Ag-La2Sn2O7/SnO2 properties and severe arc erosion. X-ray photoelectron spectroscopy was used to determine the composition of the erosion region. The effect of La2Sn2O7 on wettability between Ag and SnO2 was investigated, and the erosion mechanism of Ag-La2Sn2O7/SnO2 composites was discussed systematically. This study can provide a reference for the application of Ag matrix electrical contact materials in high-voltage electrical appliances.