The effect of SiO2 addition on physical properties of Al2TiO5 ceramics

Aluminum Titanate (Al2TiO5) is a ceramic material with coefficient of low thermal conductivity and high thermal shock resistance. The micro cracks formed during the sintering of Al2TiO5 lead to low mechanical strength. Various oxide additives are used to improve mechanical properties. In this study, SiO2 was used as additive and its effects on porosity, phase composition, bending strength and microstructure were investigated. The compositions were prepared by adding up to 10% (by wt) quartz (SiO2) to the equimolar mixture of alpha-Al2O3 and rutile (TiO2). The powder mixture was shaped by an uniaxial press and sintered at 1450 degrees C for 3 hours. Experimental results show that porosity decreases and mechanical strength increases with the addition of SiO2. It was determined that mullite formation occurred and the number of cracks decreased with the addition of SiO2. The bending strength of the pure Al2TiO5 was 6.80 MPa, while the bending strength of 38.43 MPa was obtained by addition of 10% SiO2. As a result the addition of SiO2 has played an active role in improving the physical and microstructural properties of Al2TiO5 ceramics.