A novel approach to in situ synthesis of WC-Al2O3 composite by high energy reactive milling

Abstract

In-situ synthesis of WC-Al2O3 composite by milling and its subsequent heat treatment were investigated. Mixtures of Al, W, and C with stoichiometric ratio of W3AlC2 were ball milled up to 20h. Then, the 20-hour ball milled powder was heat treated at different temperatures of 900 and 1200°C. The reaction path was investigated by X-ray diffractometry (XRD). The particle size and microstructure of powders after milling was investigated by field emission scanning electron microscope (FESEM) equipped with energy-dispersive spectroscopy (EDS). Also, in order to analyze the heating behavior of 20h ball milled powder mixture during heat treatment, simultaneous thermal analysis (STA) was used. The results showed that after milling for 20h, the reactants reacted together and new phases including W2C and (W,Al)C1−x were formed. After heat treatment, the semi-stable compounds synthesized at the milling stage, were transferred to more stable compounds including WC and Al2O3.