Chemical interaction between carbon and titanium dissolved in liquid tin:: crystal structure and reactivity of Ti2SnC with Al

Chemical interaction between carbon and titanium dissolved in liquid tin was studied at temperatures higher than 1000 degrees C. The phase equilibria in the ternary system graphite-titanium-tin were investigated by thermal analysis, metallography, X-ray diffraction and electron microprobe analysis. The isothermal section at 1200 degrees C is proposed. At this temperature, carbon can react to yield a binary phase, TIG, or a ternary phase, Ti2SnC. The structure of Ti2SnC is proposed on the basis of powder diffraction X-ray data (space group: P6(3)/m.m.c, hexagonal axes a = 0.31626 nm, c = 1.36789 nm). Some experiments realized by immersion of T300 fibres in Sn-Ti alloys show that the chemical reaction leads to either a single layer of TiC or a double-layer, TiC-Ti2SnC. The results demonstrate that the ternary phase is not stable in liquid aluminium. (C) 1998 Elsevier Science S.A. All rights reserved.