| abstract |
(57) [Summary] [PROBLEMS] While maintaining mechanical properties and thermal properties, cBN particles fall off during cutting of high hardness hardened steel or cast iron, tool wear and chipping due to abrasion and falling off of the binder. The present invention provides a cubic boron nitride sintered compact cutting tool with high performance. A cubic boron nitride having an average particle size of 1 μm or less is contained in an amount of 30 to 90% by volume and a cubic boron nitride having an average particle size of 2 to 10 μm is contained in an amount of 10 to 70% by volume. A cubic boron nitride sintered body containing 2 O 3 , wherein the sintered body is a boride containing an element from Groups 4a, 5a and 6a of the Periodic Table in X-ray diffraction measurement using Kα1 ray of Cu Ratio I1 / I2 of the intensity (I1) of the first peak of the first peak to the intensity (I2) of the first peak of the cubic boron nitride; The ratio I1 / I3 of the intensity (I1) of the first peak and the intensity (I3) of the first peak of the non-borated compound containing the element is both in the range of 0.05 to 0.5. |