In this study, TiN-coated cBN (cubic-structure boron nitride) powders were successfully synthesized by a sol-gel method using titanium (IV) isopropoxide (TTIP) and by controlling the heat treatment conditions. After the sol-gel process, amorphous nano-sized TiOx was uniformly coated on the surface of cBN powder particles. The obtained TiOx-coated cBN powders were heated at 1,000~1,300℃ for 1 or 6 h in a flow of 95%N2-5%H2 mixed gas. With increasing temperature, the chemical composition of the TiOx coating layer changed in the order of TiO2→Ti6O11→Ti4O7→TiN due to reduction of the Ti ions. The TiN coating layer was observable in the samples heated at 1,200℃ and appeared as the main phase in the sample heated at 1,300℃. The resulting thickness of the TiN coating layer of the sample heated at 1,300℃ was approximately 45~50 nm.
