Abstract
In order to study the applicability of a slip-casting technique to preparation of ceramic composites consisting of powders with different specific gravity, the technique was applied to ZrO2-WC system. During casting process, ZrO2 and WC were afraid to separate due to the difference in their specific gravity, that is, 6.07 for ZrO2 and 15.6 for WC.. For preparing fluidal and thick slurry, the optimum amounts of water and dispersant were determined on the basis of the viscosity and the density of green compacts. The optimum amounts of water and dispersant were 60vol% and 0.35mass%, respectively. The dispersibility was estimated by an EDX analysis and SEM observation. WC powders were found to disperse uniformly in ZrO2 matrix, when the thick slurry consisting of raw powders was cast. The prepared compacts were sintered at a temperature from 1400°C to 1700°C. The density and mechanical properties of composites were improved with an increase in sintering temperature. The bending strength and fracture toughness of the composites sintered at 1700°C were 820MPa and 7.4MPa⋅m1/2, respectively. The improvement of the boundary between ZrO2 and WC was guessed to make their properties enhanced further.
