Phase transformations in the TiO2–SiO2 system at high pressures and temperatures

Abstract

In situ X-ray diffraction study of a sol–gel-produced SiO2–TiO2 glass and intimately mixed ultrafine powders of SiO2 and TiO2 was used to investigate the effect of TiO2 on the high-pressure phase transformations of SiO2 and specifically on the change in the p,T-conditions of the formation of coesite and stishovite. Our findings have shown that at pressures to 7.5 GPa and temperatures up to 1300 K the presence of TiO2 does not favor the formation of stishovite. †On leave from the Institute for Superhard Materials, Kiev, Ukraine.