High-pressure synchrotron studies on TiO2-II nanocrystallite doped withSnO2

Abstract

We have studied the high-pressure and high-temperature behaviour of α-PbO2-typeTiO2–SnO2 (5 mol%) nanocomposite up to 62.3 GPa and 1700 K in a laser-heateddiamond-anvil cell by means of synchrotron energy-dispersive x-ray diffraction.We found that it transforms to the baddeleyite phase at 19.4 GPa at roomtemperature. This phase was stable up to about 40 GPa. At 62.3 GPa and 1700K, the diffraction pattern showed that there exists another nonquenchable phase.We discussed the mechanisms for these high-pressure transformations in α-PbO2-typeTiO2–SnO2 (5 mol%) nanocomposite.