The Optimum Preparation of WC-Co Composite Powders by Sol-Gel and Hydrogen Reduction

Abstract

In order to improve the uniformity of Co distribution in the WC-Co mixture, the WC-Co composite powders were prepared by the sol-gel chemistry and hydrogen reduction process. WC-Co composite powders were characterized by thermogravimetric analysis(TGA), differential scanning analysis (DSC), scanning electron microscopy (SEM) and chemistry analysis. The results indicated that the optimum mol ratio of TEA:Co²⁺ was 0. 4:1, and the sucrose was no benefit to properties of the WC-Co composite powders. The optimum reduction technology parameter were as below: the preheating temperature was 300°C, and the transition temperature was 400 °C, and the final reduction temperature was 650 °C for two hours. Based on this new method, the WC-Co mixture particles were more homogeneous than those by conventional method. Furthermore, the distribution of Co-phase of WC-6%Co mixture produced by the new method is more uniform than that of WC-6%Co mixture produced by the conventional method.