Internal oxidation of rapidly solidified silver-tin-indium alloy powders

Abstract

The internal oxidation behaviour of rapidly solidified silver-tin-indium (Ag-Sn-In) alloy powders is described. Internal oxidation of Ag-Sn-ln alloy has gained importance in view of the possible replacement of toxic silver-cadmium oxide (Ag-CdO) material by a better property silver-tin oxide (Ag-SnO₂) electrical contact material. Rapidly solidified Ag-Sn-In alloy powders of composition Ag-6.0Sn-3.0In were prepared by gas atomization. The important characteristics of alloy and powders, from the point of view of internal oxidation, were determined. The powders were internally oxidized and subsequently processed by conventional powder metallurgy techniques. The important physical properties, such as electrical conductivity, hardness, density and microstructure, were determined. The physical properties, especially the microstructure and rate of internal oxidation, were compared with the materials prepared by the conventional internal oxidation route.