Abstract
Binderless cBN compacts were synthesized by the direct conversion method from hexagonal BN under high pressure and high temperature without additives or catalyst, and cutting performances of them have been investigated. The fine-grained (<1μm) and high purity (>99.9%) compact has high hardness and high-temperature strength. In addition, this compact has high thermal conductivity above 300W/m. K. The cutting tool of the binderless cBN compact shows good wear resistance in the high speed milling of cast iron or steel, because of the excellent thermal properties of the compact. The cutting edge is cooled down rapidly during the non-cutting time of milling due to the high thermal conductivity of the compact. As the result, this cBN compacts are applicable to cutting tools of high speed milling for gray cast iron at over 25m/s in both dry and wet condition and for steel at 16.7m/s in dry condition.
