Abstract:
This research involves the preparation of alumina-based composites reinforced by tungsten carbide and cobalt particles. Main chemical compositions of the composites contained 80wt% and 90wt% alumina while the rest were tungsten carbide and cobalt situated with various ratios. In the composites with 90wt% alumina, 10wt% of the reinforced particles consisted of cobalt from 0.6, 1 to 3wt%, meanwhile the batch with 80wt% alumina, 20 wt% of the reinforced particles comprised cobalt from 2, 4 to 6wt%. The powder mixtures were pressed into pellets, followed by pressureless sintered in argon, respectively. Parameters including sintering temperature and chemical compositions, based on cobalt content, which affected on mechanical and physical properties as well as microstructure were considered. The results suggested that the sintering temperature of 1600 ℃ for 2 hours provided superior density, strength, hardness together with toughness compared to those sintered at 1500 ℃. The addition of tungsten carbide-cobalt particles into alumina enhanced toughness according to the amount of cobalt content. Hardness of the WC-Co containing products were in the range of 17-20 GPa whereas toughness were 5 -10 MPa m½.