Synthesis of nanocrystalline WCu powders via freeze-drying and hydrogen reduction

The preparation of nanocrystalline WCu powders plays a significant role in the production of high-performance WCu composites. The chemical reduction method is a promising approach for industrial nano-powder synthesis. However, the influence of various reduction parameters on the morphology and grain size of the reduced powders, as well as their underlying mechanisms, have remained unclear. In this study, we investigated the effects of reduction steps, temperature, duration, hydrogen inflow rate, and copper content on the grain size of the composite powders and disclosed the related mechanisms. Through optimization of reaction parameters, WCu powders with grain sizes below 50 nm were obtained. Moreover, the utilization of the synthesized nanocrystalline WCu powders as raw materials yielded a bulk W20Cu composite with an ultrahigh hardness of 600 HV30.