THE TI-B-C-H-CL SYSTEM - A THERMODYNAMIC APPROACH

The heterogeneous chemical system TiCl4-BCl3-CH4-H-2 has been thermody namically examined. The influence of various parameters on deposition domains and formation rates has been investigated. The affinity betwee n boron and titanium controls the system and TiB2, which is a very imp ortant phase, is often deposited. Although in theory methane dissociat ion is often complete, its influence is smaller. In consequence, titan ium diboride can be associated, in condensed phase, to titanium carbid e or boron carbide. On the other hand, titanium monoboride and the TiC + B4C biphased mixture are not formed at equilibrium from the gaseous system considered.