Cubic boron nitride sintered body, coated cubic boron nitride sintered body, and tool having same

A cubic boron nitride sintered body comprising:

• cubic boron nitride;
• and
• a binder phase,
• wherein when a cross-sectional structure of the cubic boron nitride sintered body is observed, a content ratio of the cubic boron nitride is 10.0 area % or more and 60.0 area % or less, and a content ratio of the binder phase is 40.0 area % or more and 90.0 area % or less, based on 100 area % in total of the cubic boron nitride sintered body,
• the binder phase comprises an Al compound phase and a Ti compound phase,
• the Al compound phase comprises a compound of Al and at least one element selected from the group consisting of C, N, O, and B,
• the Ti compound phase comprises at least one selected from the group consisting of a compound of Ti and at least one element selected from the group consisting of C, N, O, and B and a compound of Ti, at least one element selected from the group consisting of V, Cr, Zr, Nb, Mo, Hf, Ta, and W, and at least one element selected from the group consisting of C, N, O, and B,
• the Ti compound phase comprises a composite compound phase,
• the composite compound phase comprises at least one selected from the group consisting of a carbide, a nitride, and a carbonitride each comprising Ti and at least one element selected from the group consisting of V, Cr, Zr, Nb, Mo, Hf, Ta, and W,
• in the cross-sectional structure, a content ratio of the Al compound phase is more than 0.0 area % and 20.0 area % or less, and a content ratio of the Ti compound phase is 80.0 area % or more and less than 100.0 area %, based on 100 area % in total of the binder phase, and
• in the cross-sectional structure, when a content ratio of the composite compound phase based on 100 area % in total of the binder phase is indicated by a content ratio X1, and a content ratio of the composite compound phase based on 100 area % in total of the binder phase in a range from an interface between the cubic boron nitride and the binder phase to a distance of 300 nm toward the binder phase is indicated by a content ratio X2, the content ratio X2 is larger than the content ratio X1.