Preparation and Sintering Properties of Nanometer W-30Cu-La2O3 Composite Powder

Tungsten copper alloy has high strength, good wear resistance and excellent high-temperature conductivity, and is widely used in electronic packaging and high-voltage electrical contact materials. Tungsten copper oxide precursor powder was prepared by low temperature self-propagation method with tungstic acid, copper nitrate, cerium nitrate hexahydrate as raw materials, glycine as fuel, ammonium nitrate as accelerant. Nano-tungsten copper composite powder was obtained by hydrogen reduction, and W-30Cu-La2O3 alloy was prepared by sintering. The effects of different molar ratios of tungstate, glycine and ammonium nitrate on phase, morphology and properties of precursor powder and composite powder were investigated by XRD and SEM. The density, microstructure and comprehensive properties of W-30Cu-La2O3 alloy at different sintering temperatures were analyzed. The experimental results show that the optimal molar ratio of tungstic acid to glycine and ammonium nitrate was 1:10 and 1:25, respectively. The powders have good uniformity, the specific surface area is 6.6271 m2·g-1, and the powder size is 100~200 nm. The density, bending strength, Vickers hardnesses, and coefficient of thermal expansion of the alloy sintered at 1350℃ are 99.0%, 1205MPa, 307HV, and 9.17×10-6 K-1, respectively. The microstructure is fine and uniform, and the fracture morphology is ductile.