Role of MgO and Cr2O3 additives on the properties of zirconia–mullite composites

Precursor powder for zirconia–mullite composite was synthesized by co-precipitation in aqueous medium taking inorganic salts of aluminium, silicon and zirconium in requisite amounts. The powder was thoroughly characterized in terms of chemical composition, surface area, DTG behavior and FT–IR spectra. Role of two additives, namely, MgO and Cr2O3, on the densification of the compacted powder at different elevated temperatures ca. 1300–1500 °C was studied by the measurement of different physico-mechanical properties, such as bulk density, apparent porosity, specific gravity, compressive strength, bending strength and fracture toughness. Phase analysis by XRD technique and phase distribution by SEM technique was carried out to evaluate the microstructure of the sintered materials.