Effect of lithium addition on density and oxide-phase morphology of Ag-ZnO electrical contact materials

The effect of trace additions of lithium as lithium nitrate, to spray-coprecipitated silver-zinc oxide powder, on density and oxide-phase morphology of Ag-ZnO contact materials has been investigated. The Li-treated powders are characterized by particle size analyser and ESCA. The pressed-sintered-hot pressed compacts with and without Li are evaluated for density, microhardness, electrical conductivity and microstructure. The morphological evaluation of ZnO phase is done using quantitative image analysis technique. The mechanism of activation due to Li and the resultant changes in oxide-phase morphology for Ag-ZnO composite system are analysed. (C) 199