Properties of W-Cu composite powder produced by a thermo-mechanical method

In order to improve the process of co-reduction of oxide powder, a new thermo-mechanical method was designed to produce high-dispersed W-Cu composite powder by high temperature oxidation, short time high-energy milling and reduction. The properties of W-Cu composite powder are analyzed in terms of oxygen contents, BET specific surface (BET-S), particle size distributions, morphology of final powder and their sintering behaviors. The results show that the oxygen content of W-Cu composite powder decreases with the increase of milling time, while the BET-S of final powder increases with the milling time. The distributions of final powder are more uniform after reduction at 630 °C than at 700 °C. After milling of the oxide powder for about 3-10 h, W-Cu composite powder with very low oxygen content can be achieved at the reduction temperature of 630 °C owning to the increasing of BET-S of W-Cu oxide powder. The particle size of W-Cu powder after reduction is lower than 0. 5 μm and smaller than that reduced at 700 °C. After sintering at 1200 °C for 60 min, the relative density and thermal conductivity of final products (W-20Cu) can attain 99.5% and 210 Wm^-1K^-1 respectively.