COMBUSTION SYNTHESIS AND PROPERTIES OF ZIRCONIA-ALUMINA POWDERS

Fine zirconia-alumina composite powders with 10-80% ZrO2 have been pre pared by the combustion of aqueous solutions containing stoichiometric amounts of aluminium nitrate, zirconyl nitrate and carbohydrazide. Th e combustion-derived powders are of submicron size, with 40-65 m2/g BE T surface area. The cold-pressed powders, when sintered at 1650-degree s-C for 3 h achieved 94-99% theoretical density. The sintered body of 10% t-ZrO2-Al2O3 has room-temperature Vickers hardness, Hv = 21.1 GPa and fracture toughness, K(c) = 8.9 MPa m1/2.