| 主权项 |
1. A tool made of a cubic boron nitride sintered body, comprising a cubic boron nitride sintered body at least at a tool working point,
said tool satisfying an Equation (I) and any one of an Equation (II) and an Equation (III)×
20≦X≦98 (I)Y≦0.6×X+3 (where 20≦X<88) (II)Y≦5.8×X−455 (where 88≦X≦98) (III)where a ratio of the volume of cubic boron nitride contained in said cubic boron nitride sintered body to that of said cubic boron nitride sintered body is denoted as X volume % and thermal conductivity of said cubic boron nitride sintered body is denoted as Y (W/m·K),
said cubic boron nitride sintered body containing a binder phase in addition to said cubic boron nitride, the composition used for said binder phase being a compound of both Al and at least one type of carbide, boride, carbonitride, oxide, and solid solution including at least Co, said cubic boron nitride sintered body contains a heat insulating phase in addition to said cubic boron nitride and said binder phase, said heat insulating phase contains one or more types of first compound composed of one or more types of element selected from the group consisting of Al, Si, Ti, Zr, Mo, Ni, and Cr and one or more types of element selected from the group consisting of N, C, O, and B, and said first compound is contained in said cubic boron nitride sintered body by not less than 1 mass % and not more than 20 mass % and has an average particle size smaller than 100 nm. |
