SINTERED CUBIC BORON NITRIDE TOOL

摘要

A cubic boron nitride sintered body tool (1) of the present invention, in which a cubic boron nitride sintered body (2) is joined to a tool base material (4) via a joining layer (3), has the following feature. The cubic boron nitride sintered body (2) contains cubic boron nitride particles by not less than 30 volume % and not more than 95 volume %, and a binder phase (6) by not less than 5 volume % and not more than 70 volume %. In at least one cross sectional surface of the cubic boron nitride sintered body tool (1) taken along a plane perpendicular to a joining surface having the largest area in joining surfaces between the cubic boron nitride sintered body (2) and the joining layer (3), a point C and a point D are assumed to represent points away by 1/4 of the length of a line segment connecting a point A and a point B shown in a figure. A value obtained when an area of a region surrounded by a line segment connecting the point C and the point D, the first cubic boron nitride particle (7), the second cubic boron nitride particle (8), and the binder phase (6) is divided by the length of the line segment connecting the point A and point B to each other is not less than 0.14 µm and not more than 0.6 µm.