Preparation of alumina-tungsten carbide nanocomposite by mechano-chemical reduction of WO3 with aluminum and graphite

Alumina-tungsten carbide composite powders were successfully obtained through reactive milling of WO3, Al and graphite as precursor at room temperature. The structural and morphological evolutions of the powders were studied by X-ray diffraction (XRD) and scanning electron microscopy. Physical properties such as density, surface area and micro-hardness of the ball milled powders were also measured. Results showed that the mechano-chemical reactions began in the first 5 h of milling and completed by the end of the milling (80 h). Very fine particles with a homogeneous microstructure with the hardness of 1450 kg/mm2 were obtained at the end of milling. An annealing step did not lead to extensive grain growth, and the as-annealed sample still maintained its nanocrystalline characteristics with a minimum lattice strain.