The Topotactic Transformation of Ti3SiC2 into a Partially Ordered Cubic Ti ( C 0.67Si0.06 ) Phase by the Diffusion of Si into Molten Cryolite

Abstract

Immersion of Ti 3 SiC 2 samples in molten cryolite at 960°C resulted in the preferential diffusion of Si atoms out of the basal planes to form a partially ordered, cubic phase with approximate chemistry Ti(C 0.67 , Si 0.06 ). The latter forms in domains, wherein the (111) planes are related by mirror planes; i.e., the loss of Si results in the de-twinning of the Ti 3 C 2 layers. Raman spectroscopy. X-ray diffraction, optical, scanning and transmission electron microscopy all indicate that the Si exits the structure topotactically, in such a way that the C atoms remain partially in their ordered oosition in the cubic chase. © 1999 The Electrochemical Society. All rights reserved.