THE EFFECTS OF SILICA SAND (Si02) AND ZIRCONIA (Zr02) ON THE MECHANICAL AND THERMAL PROPERTIES OF THE PRESSURELESS SINTERED Al203-Si02-Zr02 COMPOSITE

The research work presents an investigation on the pressureless sintering,
microstructure and mechanical properties of three component ceramic composite
material consisting of alumina, silica and zirconia for structural applications. The
effect of each component composition on the physical and mechanical properties was
studied. Mechanical properties including fracture toughness, flexural strength, and
hardness at ambient temperature were determined and thermal shock resistance
properties up to 950°C were also investigated. These properties were compared
among the monolithic A1203, Al203-Zr02 (AZ) and Al203-Si02-Zr02 (ASZ)
composites. The microstructure of sintered, thermal shocked and fractured surface
states was investigated using FESEM and AFM. A three phase microstructure was
adopted with a composition of 70% by weight of alumina, 10% by weight of silica
and 20% by weight of zirconia. The reinforcements of the Si02 and Zr02 contributed
in improving the mechanical properties of the composite.