Abstract: A sintered compact has a first material, a second material, and a third material. The first material is cubic boron nitride. The second material is a compound including zirconium. The third material is an aluminum oxide and the aluminum oxide includes a fine-particle aluminum oxide. The sintered compact has a first region in which not less than 5 volume % and not more than 50 volume % of the fine-particle aluminum oxide is dispersed in the second material. On arbitrary straight lines in the first region, an average value of continuous distances occupied by the fine-particle aluminum oxide is not more than 0.08 ?m and a standard deviation of the continuous distances occupied by the fine-particle aluminum oxide is not more than 0.1 ?m.

Abstract: A sintered compact according to the present invention includes: a first material that is cubic boron nitride; a second material that is an oxide of zirconium; and a third material that is an oxide of aluminum, the second material including cubic ZrO2 and ZrO, the third material including ?-Al2O3, and the sintered compact satisfying the following relation: 0.9?Izro2(111)/Ial(110)?30; and 0.3?Izro(111)/Ial(110)?3, where Ial(110), Izro2(111), and Izro(111) respectively represent X-ray diffraction intensities of a (110) plane of the ?-Al2O3, a (111) plane of the cubic ZrO2, and a (111) plane of the ZrO.

Abstract: A sintered compact according to the present invention includes: a first material that is cubic boron nitride; a second material that is an oxide of zirconium; and a third material that is an oxide of aluminum, the second material including cubic ZrO2 and ZrO, the third material including ?-Al2O3, and the sintered compact satisfying the following relation: 0.9?Izro2(111)/Ial(110)?30; and 0.3?Izro(111)/Ial(110)?3, where Ial(110), Izro2(111), and Izro(111) respectively represent X-ray diffraction intensities of a (110) plane of the ?-Al2O3, a (111) plane of the cubic ZrO2, and a (111) plane of the ZrO.

Abstract: A sintered compact has a first material, a second material, and a third material. The first material is cubic boron nitride. The second material is a compound including zirconium. The third material is an aluminum oxide and the aluminum oxide includes a fine-particle aluminum oxide. The sintered compact has a first region in which not less than 5 volume % and not more than 50 volume % of the fine-particle aluminum oxide is dispersed in the second material. On arbitrary straight lines in the first region, an average value of continuous distances occupied by the fine-particle aluminum oxide is not more than 0.08 ?m and a standard deviation of the continuous distances occupied by the fine-particle aluminum oxide is not more than 0.1 ?m.