| abstract |
The cubic boron nitride sintered body is a cubic boron nitride sintered body comprising 50% to 75% by volume of cubic boron nitride (1) and 25% to 50% by volume of binder phase and inevitable impurities. The binder phase includes an Al compound (3) and a Zr compound (2), and the Al compound (3) includes Al and at least one element selected from N, O, and B, and a Zr compound (2) contains Zr and at least one element selected from C, N, O and B, and the Zr compound (2) has a center of gravity (4) to Zr on the polished surface of the cubic boron nitride sintered body. The number of the plurality of line segments (5) that reach the composition other than the compound (2) and are drawn at equal intervals in the radial direction is N, and among the line segments (5), the Zr compound and the cubic boron nitride are When the number of line segments (5) in contact is n, the relationship of n / N is 0.25 or more and 0 The number of Zr compound (2) to satisfy the 8 less, 40% or more relative to the total number of Zr compound (2). |