Cryst. Res. Technol. 35 2000 11-12 1295–1303 The results of TiC crystals and cobalt matrix microstructure studies by means of transmission electron microscope are presented. TiC crystals were obtained by the HTS method using cobalt as a high- temperature solvent. The morphology of the obtained crystals was studied by physical metallurgy methods. X-ray phase analysis of the obtained samples was also performed. It was found that TiC crystals are the primary crystals during solidification of the Co-Ti-C melt. No dislocation loops were revealed in the boundary region: TiC – martensitic cobalt matrix. Keywords: Titanium carbide crystals, cobalt matrix microstructure, high temperature solutions (Received July 22, 2000; Accepted September 6, 2000) 1. Introduction Titanium carbide (TiC) belongs to interstitial compounds that crystallise in B1 type structure, Fm3m space group. It is distinguished by a very high melting point (3067ºC), a good thermal and electrical conductivity as well as a high hardness (TOTH). These properties make that it is widely used in manufacturing of MMC (metal matrix composite) type composites, where dispersively distributed TiC particles fulfil the role of metal matrix filler (JARFORS, JARFORS and FREDRIKSSON, TERRY and CHINYAMAKOBVU). In the case of TiC single crystals they are used as cold field emission (FE) electron sources (OTANI and ISHIZAWA). Such sources have been applied to high-resolution scanning electron microscopes and other microelectron probe instruments. TiC crystals were obtained by Verneuil (WILLIAMS and SCHAAL), CVD (Chemical Vapour Deposition) (KATO and TAMARI, WOKULSKI and WOKULSKA 1983) and HTS (High Temperature Solution) (HIGASHI et al., POPOV and GURIN, SHIMADA and WATANABE, WOKULSKI and WOKULSKA 1995, WOKULSKI et al. 1995, 1998) methods. HIGASHI et al. used Al as a high-temperature solvent for TiC crystallisation. They performed crystallisation processes at 1500ºC for 10 hours. The obtained crystals were in the form of regular octahedrons of the maximum size of 2 mm. To obtain TiC crystals POPOV and GURIN used Al and Mg as high-temperature solvents. The size of obtained TiC crystals did not exceed 0.4 mm. SHIMADA et al. obtained TiC crystals using Ni and Co as high-temperature solvents. Crystals of about 1.5 mm maximum size were obtained using Ni while using Co the size of obtained crystals did not exceed 0.5 mm. WOKULSKI and WOKULSKA (1995), WOKULSKI et al. (1995, 1998) and STRZECIWILK and WOKULSKI (1999 a) studied usability of Al, Co and Ni as high-temperature solvents for TiC crystallisation. Crystallisation processes were carried out at temperatures 1500 – 1700ºC for 6 – 8 hours at cooling rates of 2.5 – 5.0ºC/min. The obtained TiC crystals were in the form of cubes, octahedrons or irregular crystals and their size did not exceed 1 mm. D. STRZECIWILK, P. TKACZ, Z. WOKULSKI Institute of Physics and Chemistry of Metals, University of Silesia, Katowice, Poland Transmission Electron Microscope Studies of TiC Crystals