Tungaloy Corporation

Kentaro Shiro

Yusuke Hirano

A cubic boron nitride sintered body has between 50% and 75% cubic boron nitride by volume and between 25% and 50% binder phase by volume, and inevitable impurities. The binder phase contains an Al compound and a Zr compound. The Al compound contains Al and one or more of N, O and B; and the Zr compound contains Zr and one or more of C, N, O and B. At a polished surface of the cubic boron nitride sintered body, 40% or more of the Zr compounds satisfy the ratio 0.25&#x2264;n/N&#x2264;0.8, where: N represents the number of line segments drawn radially at equal intervals from a center of gravity of a given Zr compound to a boundary with a non-Zr compound; and n represents the number among those N line segments which intersect a boundary between the given Zr compound and cubic boron nitride.

Cubic boron nitride sintered body and coated cubic boron nitride sintered body

A cBN sintered body has 40%-85% cBN by volume and 15% to 60% binder phase by volume. and inevitable impurities. The binder phase has an Al compound including Al and at least one element selected from N, O and B, and a Zr compound including Zr and at least one element selected from C, N, O and B. The Zr compound includes ZrO, or ZrO and ZrO. In an X-ray diffraction, where a peak intensity of a (111) plane of the ZrO is I, a peak intensity of a (101) plane of tetragonal ZrOis Iand a peak intensity of a (111) plane of cubic ZrOis I, a ratio of the intensity of Ito total intensities of I, Iand Iis 0.6-1.0, and an average grain size of the Al compound is 80 nm-300 nm.

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Iwaki, Japan

Kentaro Shiro