Synthesis and densification of W-30 wt%Cu composite powders using ammonium meta tungstate and copper nitrate as precursors

W-30 wt%Cu composite powders were prepared by a novel precipitation process using ammonium meta tungstate and copper nitrate as precursors. The initial precipitates were obtained by adding aqueous ammonia to a mixture of ammonium meta tungstate and copper nitrate solutions and then heating the solution up to 95 degrees C. In order to synthesis W-Cu composite powders, the dried precipitates were calcined in air at 500 degrees C and then reduced by hydrogen. The calcination temperature was determined by thermogravimetry analysis. The powders were characterized by X-ray diffraction technique and scanning electron microscopy analysis. The effect of sintering temperature was investigated on densification of the synthesized powders. Relative density over 98% was achieved for the samples which were sintered at 1150 degrees C. Good electrical conductivity and relatively high hardness were achieved for the samples which sintered above melting point of copper. (C) 2009 Elsevier Ltd. All rights reserved.