Thermal expansion and stability of Ti2SC in air and inert atmospheres

Abstract

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. © 2008 Elsevier B.V. All rights reserved.