Deposits of titanium carbide (TiC) were formed on the tool steel, STD 11, substrate by chemical vapor deposition using a $TiCl_4$, $C_3H_8$ and $H_2$ gas mixture. In order to determine the optimum deposition conditions, the deposition rates and the morphologies of TiC coated layers were studied.
The deposition thickness was increased linearly with time. The deposition rate was increased with temperature until 950℃, but at 1000℃ the deposition rate was reduced by displacement reaction between $TiCl_4$ gas and Fe component in the steel substrate. The deposition rate was decreased above $m^{\frac{C}{Ti}}$ = 1.3. This showed that the pyrolytic carbon precluded further TiC deposition. The deposition rate was increased with the square root of the total flow rate from 350 cc/min to 840 cc/min, however, the deposition rate was constant with the flow rate from 840 cc/min to 1000 cc/min. The reduced deposition pressure resulted in reduced deposition rate and finer particle size.
Experimental results indicated that deposition temperature 850℃-900℃, deposition pressure 100-200 Torr and $m^{\frac{C}{Ti}}$ = 1 are the optimum deposition conditions.
