Effects of nickel addition on properties of Ag-W electrical contact materials

Tungsten and silver powders doped with small amounts of nickel were milled in a heavy duty attritor For 150 min to constitute the W-35 wt-%Ap composit ion. Milled powders were compacted, sintered, furnace cooled, and re-sinter ed using industrial conditions. Scanning electron microscopy (SEM) investig ations revealed homogeneous dispersions of silver and tungsten regions both in the as milled powders and the as milled compacts. The X-ray results tak en from the milled powders and the as milled compacts showed the presence o f the characteristic W and Ag peaks. Bulk hardness values of the sintered c ompacts increased with increases in nickel additions. the are erosion chara cteristics of the W-35 wt-%Ag compacts indicated that the erosion rate of t he contact material declined with nickel additions. Contact life expectancy increases about 10 fold for the W-35 Wt-%Ag compact containing 1 wt-%Ni fr om the one with no Ni content.