Formation, Decomposition and Thermal Stability of Al2TiO5 Ceramics

The thermal instability of Al2TiO5 can be mitigated using solid solutions of MgO, Fe2O3, TiO2, and ZrO2 in the Al2TiO5 lattice or grain boundary solutions with additives such as SiO2, ZrO2, ZrTiO4, or mullite, most of which do not form solid solutions with Al2TiO5 but rather restrain the tendency of Al2TiO5 toward decomposition. The additives SiO2 and ZrO2 do not have a significant effect on the thermal stability of Al2TiO5, even after long annealing at the critical temperature of 1100 degrees C. Mullite retarded decomposition and increased thermal stability between 750 and 1300 degrees C. Literature regarding the formation, decomposition and thermal stability of Al2TiO5 ceramics with different inorganic materials exhibiting thermal expansion and excellent thermal shock resistance is discussed with regard to the application of the materials at high temperature, especially as diesel particulate filters.