Synthesis and consolidation of nanostructured W–10–40 wt.% Cu powders

Nanostructured W–(10–40)% Cu composite powders were prepared by calcinations of a spray dried W–Cu salt and a subsequent reduction treatment. The sintering of these powders was investigated as a function of copper content and temperature. W–Cu composites with 20–40 wt.% Cu could be consolidated to high densities (>98%) when sintered at 1250 °C for 1 h. However, the sintering of samples with lower copper content (10 wt.%) did not result in high densities (a maximum of 92% at 1450 °C for 2 h). The addition of WO3 prior to the reduction step was found to markedly enhance the sinterability of these composites. Samples can be densified to >98% by sintering at 1400 °C with zero hold time. A proposed role played by the added oxide is given. The electrical conductivity of the composites was measured and the values were consistent with theoretical calculations for composites with Cu content between 10 and 40 wt.%.