Abstract: The relationship was investigated between lattice constants and thermal stability of
aluminium titanate (Al₂TiO₅). Through studying the variation of lattice constants of Al₂TiO₅ with temperature, the authors discovered an abnormal
phenomenon that lattice constant c of Al₂TiO₅ decreases with the increase of temperature. The authors proposed that the thermal stability of
Al₂TiO₅ is closely related to its lattice constant c. Different additives were added to Al₂TiO₅ to change its lattice constants.
The stability of Al₂TiO₅ can be reflected by its lattice constant c. The larger lattice constant c, the more stable aluminium titanate. Lattice constant c corresponds to the height of the
distorted [MeO₆] octahedra in the crystal structure of Al₂TiO₅ and its increase will lead to a reduction of distortion of the octahedra,
so that the stability of Al₂TiO₅ is improved. The effect of firing process on lattice constants and stability of Al₂TiO₅ was also explored.
The result shows that with increase of firing temperature and extension of soaking time, aluminium titanate exhibits larger lattice constant c and its
stability increases correspondingly.

Key words: aluminum titanate, thermal stability, thermal decomposition, lattice constants