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°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°C is proposed. At this temperature, carbon can react to yield a binary phase, TiC, or a ternary phase, Ti2SnC. The structure of Ti2SnC is proposed on the basis of powder diffraction X-ray data (space group: P63/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.