Cubic boron nitride containing group sintered material cutting tool made

A intermittent cutting of hardened steel, excellent chipping resistance, providing cubic boron nitride containing group sintered material cutting tool made to exhibit chipping resistance. In A cubic containing groups sintered material cutting tool made boron nitride, the average particle size of the cubic boron nitride particles is 0.5 to 8 m. Surface of the front Symbol cubic boron nitride particles are coated with an aluminum oxide film having an average thickness of 10~90nm partially rift was formed. The average formation ratio h / H of the rift satisfies the 0.02 ≦ h / H ≦ 0.08. Here, h is rifts length of the aluminum oxide film, H is indicative of the ambient length of the cubic boron nitride particles. .FIELD 1