EXPERIMENTAL-STUDY OF THE TI-B-C SYSTEM USING LPCVD

The chemical system Ti-B-C-CI-H was explored experimentally under redu ced pressure (10 mbar) starting from a mixture of TiCl4, BCl3, CH4 and H-2. The rare of growth, the composition, and the microstructure of t he deposited solids were examined The formation of titanium diboride, present in the entire explored domain, directs the chemical system. Ca rbon is present only in a small domain and when the concentration of T iCl4 in the gas mixture is very low. Only rhombohedral boron carbide B 13C2 and a tetragonal phase noted 'Q' with the general formula B48Ti2- xC2-y identified, and always in the presence of TiB2. These solids are distinguished bq, their very unique and varied microstructures and wi th the notable existence of nanometric three phase composites.