No abstract

Thermomechanical properties of aluminum titanate‐mullite composites were studied for a wide composition range to develop material having high thermal shock resistance. The thermal shock resistance tended to increase with increasing aluminum titanate content. Composite having 82 vol% aluminum titanate can withstand water quench from above 1200°C and has a room‐temperature strength of 60 MPa. Composite with less aluminum titanate has lower thermal shock resistance but has higher strength. The relation between thermal shock resistance and strength, Young's modulus, and thermal expansion coefficient is discussed.

Materials having a higher thermal shock resistance are much needed in various fields of high-temperature application. Aluminium titanate composite recently developed [1] has a high thermal shock resistance comparable to aluminum titantate [2][3][4][5], and has a much higher strength than this material. However, those composites were prepared by conventional methods by mixing oxides and very little care was taken in processing. Improvement of the mechanical properties through better processing is expected for materials having a high thermal expansion anisotropy such as aluminium titanate [6] and mullite. In this study, processing using hydrolysis of alcohoxide was applied to develop a better aluminium titanate-mullite composite. The compositions containing 22, 63 and 91 vol % aluminium titanate were selected for examination, because high strength, moderate strength and thermal shock resistance, and high thermal shock resistance respectively, were expected.The starting materials used for synthesis were aluminium isopropoxide, titanium isopropoxide, and silica tetraethoxide. After weighing, they were dissolved in isobuthanol and heated at 80°C for 4h in a flowing dried air. After cooling to 20°C, the solution was droped into 1000 ml ion-exchanged water at 20 ml hand 50ml aqueous ammonia solution was added.

Studies of the thermochemical properties of the title composites over a wide composition range show that the thermal shock resistance tends to increase with increasing aluminum titanate content.