Titanium Nitride (TiN) was deposited onto the SKH9 and STD11 tool steels by chemical vapor deposition (CVD) using a gas mixture of $TiCl_4$, $N_2$, and $H_2$. The heat treatment was performed in order to harden the substrate steels because the substrate steels had been thermally softened during the CVD process.
The effects of the deposition temperature and input gas composition on the deposition rate, microstructure, preferred orientation, microhardness, and wear resistance of TiN deposits were studied and the residual stress of TiN deposits was measured using X-ray diffractometer.
The experimental results show that the TiN deposition reaction is thermally activated process with an apparent activation energy of 22-27 Kcal/mole. The mechanical properties such as microhardness and wear resistance have close relation with the microstructure and preferred orientation of TiN deposits. It is suggested that the equiaxed structure with random orientation increases the microhardness and improves the wear resistance of TiN deposits. The residual stress of TiN deposits is always compressive in both as-deposited and heattreated state and the heat treatment have a little effect on the residual stress.
