Thermal expansion and stability of Ti2SC in air and inert atmospheres

The thermal expansion and stability of predominantly single-phase Ti2SC powders in argon and air was investigated by Rietveld analysis of synchrotron X–ray diffraction spectra. When the sample was heated in an Ar atmosphere, it started to dissociate into TiS2 (see footnote 1) at ≈400 °C. At 8.5 (5) × 10−6 °C−1 and 8.8 (2) × 10−6 °C−1 the thermal expansion coefficients along the a and c-directions, respectively, are quite similar. The volumetric thermal expansion is 25.2 (5) × 10−6 °C−1. When Ti2SC was heated in air, it started to oxidize, at 400 °C, first to anatase, which converts, at higher temperatures, to rutile. The sulfur and carbon atoms presumably diffuse outward and escape as gases.