EFFECT OF SRO ON DENSIFICATION AND MECHANICAL-PROPERTIES OF REACTION-SINTERED MULLITE ZIRCONIA

Abstract

Reaction sintering of mullite-zirconia ceramic composites using submicron alumina and zircon powders with small additions of strontium oxide was studied The powder mixture was ball-milled, biaxially pressed into disks and bars and then the samples were sintered at 1450, 1500 and 1600-degrees-C for 1, 2 and 4 h in air. Bulk densities were estimated using the mercury displacement method and apparent porosities by boiling the samples in water. Microstructural examinations were performed by SEM and EDAX studies. Flexural strength and fracture toughness values were measured at room temperature by three-point-bending and Vickers indentation techniques respectively. It was found that a certain amount of strontium oxide addition was considerably effective on the densification of the material studied.