Combustion synthesis of aluminium titanate: thermal stability

Abstract

Initial interest in aluminium titanate, Al2TiO5, was due to its low thermal expansion coefficient, but further research was soon discouraged following the discovery of the expansion anisotropy and the instability of the compound over the temperature range of ~800-1280°C. Research studies aimed at improving the mechanical strength and counteracting the thermal instability require the synthesis of the compound, most commonly carried out using the solid state route or wet-chemical reaction methods. In the present work the combustion synthesis technique was used to prepare sub-micron Al2TiO5 from the corresponding metal salts-urea mixtures, at low temperature, short reaction times and without the intermediate decomposition and/or calcining steps. The effect of the reaction variables on the phase formation and the characteristics of the powder produced are reported and compared with those of aluminium titanate obtained with the usual solid state route technique.