Influence of oxidant and sample state on oxides distribution of Ag-4.93Sn-3.56In alloy powders

Abstract

Ag/SnO2In2O3 materials prepared by internal oxidation have excellent resistance to welding and arc erosion. However, oxides distribution will have a significant influence on its final performance. Here influence mechanism of oxidant (air, air+Ag2O) and sample state (powders, green compacts) on the oxidation behavior of Ag-4.93Sn-3.56In alloy powders is discussed. Oxides accumulate on the surface when Ag-4.93Sn-3.56In alloy powders are oxidized in air while they uniformly distribute in inner when they are oxidized in air+Ag2O. In the sample with Ag2O, oxygen in atomic state can be supplied by the decomposition of Ag2O and easily absorbed into the Ag-alloy matrix to perform the oxidization of alloy elements, but in the case of O2 in air there is a high barrier at the surface of Ag-alloy powders for O2 to become [O] in the atomic state to be absorbed into the Ag-matrix. In air, Ag-4.93Sn-3.56In alloy powders are oxidized more fully than the green compacts, their oxidation behavior is similar but the oxidation mechanism is different. However, in air+Ag2O, Ag-4.93Sn-3.56In alloy powders and green compacts both are oxidized fully, and their oxidation behavior and mechanism are similar.