Polycrystalline cubic boron nitride sintered compacts prepared from nanocrystalline TiN coated cBN powder

摘要

Polycrystalline cubic boron nitride (PcBN) samples were fabricated via high pressure high temperature (HPHT) sintering process using nanocrystalline TiN particle coated cBN powder. cBN powder was coated with TiN nanoparticles prior to sintering for the purpose of improving microstructural homogeneity. The effect of using coated cBN powders on the mechanical properties of the sintered compacts was investigated. Nano-sized TiN coated cBN powders resulted in a significant improvement in the homogeneity of the binder phase in bulk sintered compacts which would not have been obtainable by ordinary mechanical mixing technique. By using coated powders, TiN phase was found to be continuously distributed within the cBN network. Better distribution of TiN resulted in a complete reaction of TiN with cBN at the interface resulting in stronger bonding and higher interfacial strength. Compacts prepared using coated cBN powder exhibited improved mechanical properties and lower values of flank wear and surface roughness.