Abstract:The effect of particle size distributions (PSDs) on the properties of zirconia ceramic mould for TiAl investment casting was described. The relationship between the zirconia powder characteristics and properties of the ceramic moulds was investigated. The particle size distribution, morphology of particles, viscosity of slurries, mechanical properties and fracture surfaces of ceramic moulds were examined. The effect of PSDs on the viscosity was observed through the measurement of slurries prepared from zirconia and binder. The morphology of the fracture surface of the zirconia moulds with different PSDs was also investigated. The measurement of bend strength shows that the mechanical behaviors of the green and fired zirconia ceramic moulds are comparable for all systems. The preliminary results illustrate that the PSDs play an important role in determining the quality of ceramic moulds and thus on the metallurgical quality of TiAl components produced by investment casting process.

Key words: particle size distribution; investment casting; TiAl; zirconia ceramic mould; properties