Phase equilibria in the system Li2O-TiO2

The system Li2O-TiO2 contains four stable phases: Li4TiO4, Li2TiO3, Li4Ti5O12 and Li2Ti3O7, and one metastable phase, H. Li2TiO3 undergoes an order-disorder phase transition at 1215°C. High Li2TiO3 forms an extensive range of solid solution between ∼44 and 66 mole % TiO2 and low Li2TiO3 forms a more limited range of solid solution between ∼47 and 51% TiO2. The temperature of the order-disorder transition decreases to either side of the Li2TiO3 composition. The spinel phase Li4Ti5O12, has an upper limit of stability at 1015 ± 5°C, above which it decomposes to high Li2TiO3 ss and Li2Ti3O7. Li2Ti3O7 has a lower limit of stability at 957 ± 20°C, below which it decomposes to Li4Ti5O12 and rutile. During this decomposition of Li2Ti3O7, phase H, a metastable phase of unknown composition, forms as an intermediate. Li2Ti3O7 forms a short range of solid solutions between ∼74 and 76% TiO2. A phase diagram for the system Li2O-TiO2 has been constructed using a combination of results determined here and those reported by GICQUEL, MAYER and BOUAZIZ. X-ray powder diffraction data are given for Li2Ti3O7, Li4Ti5O12 and phase H.