Effect of Grain Size and Controlled Atmospheres on the Thermal Stability of Aluminium Titanate

Abstract

Aluminium titanate (Al2TiO5) is an excellent refractory and thermal shock resistant material due to 25 its relatively low thermal expansion coefficient and high melting point. However, Al2TiO5 is only 25 thermodynamically stable above 1280° C and undergoes a eutectoid-like decomposition to α-Al2O3 and TiO2 (rutile) at the temperature range of 900-1280° C. Hitherto, the effect of grain size and 2 atmosphere on the kinetics of decomposition is poorly understood but experimental evidences suggest a nucleation and growth controlled process. In this paper, we describe the role of grain size and controlled atmospheres on the thermal stability of Al2TiO5. In particular, the effects of grain size 25 and oxygen partial pressure on the rate of isothermal decomposition of Al2TiO at 1100° C have been 25 investigated. Results show that the thermal stability of Al0TiO5 increases as the grain size and 25 oxygen partial pressure increases. However, both the on-set temperature nor the temperature range of Al2TiO5 thermal decomposition are not affected by the variation of oxygen partial pressure 25 present in the furnace atmosphere.