HOMOGENEOUS FABRICATION AND DENSIFICATION OF CORDIERITE ZIRCONIA COMPOSITES BY A MIXED COLLOIDAL PROCESSING ROUTE

Abstract

Based on the electrokinetic properties of aqueous silica, boehmite, and ZrO2 dispersions, cordierite-ZrO2 composites were fabricated by a mixed colloidal processing route. The fabricated composite was characterized by a dense and homogeneous microstructure and by a uniform spatial distribution of submicrometer-sized tetragonal ZrO2 particles throughout the matrix. Increasing ZrO2 content enhanced densification and resulted in a full density composite at 20 wt% ZrO2. Fracture toughness was also increased with increasing ZrO2 content. The enhanced toughening was partly attributed to the martensitic transformation of the dispersed tetragonal ZrO2 particles in a cordierite matrix. The formation of zircon was suppressed by suitably adjusting the heating schedule during sintering.