Material properties of tungsten carbide–alumina composites fabricated by spark plasma sintering

The densification behavior of WC–Al2O3 composites prepared via spark plasma sintering (SPS) was investigated. The initial materials were fabricated using a metal-organic chemical vapor deposition process in which W(CO)6 was used as a precursor and Al2O3 powder was used as the matrix in a spouted bed. The decomposed W(CO)6 produced W species that coated Al2O3. Then, carburization, using a mixture of CH4–H2 gas, was used to form tungsten carbide–alumina composite powder. This powder was sintered via SPS in the temperature range of 1200–1350 °C, which produced several secondary phases, namely W, WC, and W2C. At the highest sintering temperature (1350 °C), the intermediate phase WC decomposed to form W2C. The material properties of the SPS-treated samples, including density, hardness, and electrical resistivity, were investigated. The hardness and electrical resistivity of WC–Al2O3 composites were found to be approximately 22.4 GPa and 4.9×109 Ω cm, respectively.