Nanocrystalline TIN Coating Prepared by Reactive Plasma Spraying

A gas-tunnel plasma spraying gun was self-designed. The titanium powders and nitrogen gas were used as the reactants to produce dense TiN coating by means of the reactive plasma spraying (RPS) technique. RPS is a promising technique that enables the fabrication of dense composite coatings with a metallic or an intermetallic matrix and finely dispersed ceramic phases. The TiN coating is of great thickness (> 500 mu m) and composed of nanocrystallities. In this respect, a new nano-materials fabrication technology was developed. The nanocrystalline TiN coating was examined using XRD, TEM and HRTEM. Results show that the coating is of well-stoichiometry, which is composed of TiN crystals of about 50-70nm in diameter, as well as the amorphous TiN phase. The nanocrystallities are separated by small-angle (about 7) grain boundaries.