High energy ball milling was used in order to improve dispersion of metal
oxide in Ag-SnO2 electrical contact materials. The processed Ag-SnO2 (92:8)
and Ag-SnO2In2O3 (87.8:9.30:2.9) powder mixtures were subsequently
consolidated to bulk solid pieces by conventional powder metallurgy method.
The characterization of the prepared samples included microstructural
analysis by XRD and SEM, as well as measurements of physical properties such
as density, hardness and electrical conductivity. The results of X-Ray
analysis point to reduction of crystallite size after milling of about ten
times. Microstructures of sintered Ag-SnO2 and Ag-SnO2 In2O3 materials
display very fine dispersion of the oxide components in silver matrix.
Somewhat higher uniformity was obtained for Ag-SnO2 In2O3 material which was
illustrated by results of SEM analysis and more consistent microhardness
values. The obtained values of studied physical properties were found to be
in accordance with observed higher dispersion of metal oxide particles and
comparable to properties of commercial electrical contact materials of this
type.