Abstract
Single-phase (binderless) nano-polycrystalline cBN consisting of small cBN grains of less than several tens or hundreds nanometers in size without any binder materials has successfully synthesized by direct conversion from hBN under high pressure and high temperature. The nano-polycrystalline cBN has high hardness, high strength and high thermal stability. In order to clarify its potentiality for industrial uses in high-precision cutting tools, the mechanical properties of the nano-polycrystalline cBN were systematically investigated. The basic performance tests for high-precison cutting tools on a hardened steel were also evaluated. These results revealed that the nano-polycrystalline cBN has an extremely high potential for high-precision cutting tools for high strength ferrous material.
