Preparation and characterization of W–Cu nanopowders by a homogeneous precipitation process

Abstract

A novel homogeneous precipitation process was employed to prepare nanosized W–Cu powders. Precipitates of CuWO 4·2H 2O and Cu 2(OH) 2WO 4 were first obtained by adding sodium tungstate and copper chloride into aqueous ammonia solution, and then heating the solution to remove ammonia. The precipitates were subsequently washed, dried and dehydrated, followed by reducing in H 2 atmosphere to convert into W–Cu composite powders. Properties of the precipitates, as well as the W–Cu composite powders and their sintered parts were characterized. It was shown that W–Cu powders produced by the homogeneous precipitation process have a nearly spherical shape, with particle size ranging from 50 to 100 nm and a well-mixed state of W and Cu ingredients. Relative density of more than 94% and 98% was obtained for W–Cu samples sintered at 1050 and 1150 °C, respectively. Homogeneous microstructure, good physical and mechanical properties were also achieved for the sintered W–Cu parts.