Effect of Variation of Lattice Constants on the Thermal Stability of Aluminium Titanate

The relationship was investigated between lattice constants and thermal stability ofaluminium titanate (Al_2TiO_5). Through studying the variation of lattice constants of Al_2TiO_5 withtemperature, the authors discovered am abnormal phenomenon that lattice constant c of Al_2TiO_5decreases with the increase of temperature. The authors proposed that the thermal stability ofAl_2TiO_5 is closely related to its lattice constant c. Different additives were added to Al_2TiO_5 tochange its lattice constants. The stability of Al_2TiO_5 can be reflected by its lattice constant c.The larger lattice constant of the more stable aluminium titanate. Lattice constant c correspondsto the height of the distorted [MeO_6] octahedra in the crystal structure of Al_2TiO_5 and its increasewill lead to a reduction of distortion of the octahedra, so that the stability of Al_2TiO_5 is improved.The effect of firing process on lattice constants and stability of Al_2TiO_5 was also explored. Theresult shows that with increase of firing temperature and extension of soaking time, aluminiumtitanate exhibits larger lattice constant c and its stability increases correspondingly.