Titanium nitride (TiN) was deposited onto TiC-coated WC-Co substrates by chemical vapor deposition (CVD) using $TiCl_4$, $H_2$, $N_2$ gas mixture. In this work, the effects of deposition temperature, total flow rate of reactant gases. deposition time, $TiCl_4$ partial pressure and $H_2$ partial pressure on the deposition rate, final structure and the preferred orientation of TiN deposit were investigated. The controlling mechanism of TiN deposition reaction depending on deposition temperature and total flow rate of reactant gases was also investigated.
The deposition rate of TiW is increased with an increase in $TiCl_4$ partial pressure. The deposition rate shows a maximum at the $H_2$ partial pressure of 0.70 atm. Equiaxed grain structure is obtained under all experimental conditions, and (220) preferred orientation is obtained except some conditions. Particle size of TiN deposit is reduced with an increase in $TiCl_4$ partial pressure. The deposition reaction of TiN is controlled by the mass transport mechanism when deposition temperature is higher than 1000℃ and total flow rate of reactant gases is less than 700 cc/min. On the other hand, the reaction is controlled by the surface reaction mechanism when deposition temperature is lower than 1000℃ and total flow rate is larger than 700 cc/min.
