High-Gravity combustion synthesis of Al ₂TiO ₅/mullite ceramic composites

Al₂TiO₅/mullite ceramic composites were fabricated by high-gravity combustion synthesis. The co-existence of mullite was helpful to increase the thermal stability of Al₂TiO₅ and retard its decomposition. In the samples with less SiO₂, coarse Al ₂TiO₅ crystals were predominant and the other phases existed at the boundaries of Al₂TiO₅ crystals. With increasing SiO₂ content to 30%, plate-like mullite crystals became the major product. The hardness of the Al₂TiO₅/mullite ceramic composites increased with increasing content of mullite, and the maximum hardness was 7.4 GPa.