| 摘要 |
A cubic boron nitride sintered body includes cubic boron nitride, a binder, and a metal catalyst element, a content by percentage of the cubic boron nitride is 50 vol% or more and 85 vol% or less, a content by percentage of the catalyst is 0.5 mass% or more and 5 mass% or less. An image obtained through observation of a 8 µm × 8 µm region of a structure of the cubic boron nitride sintered body with a scanning transmission electron microscope is divided along line segments into partial regions in four rows and four columns, a composition analysis is performed on the line segments, a sum of a detected peak value of nitrogen and a detected peak value of boron at each of arbitrary measurement points on the line segments is calculated, a measurement point at which the sum is a half or less of a maximum value among the sums at all measurement points respectively is identified as a binder-portion measurement point, and a ratio of the number of measurement points at which the catalyst element is not detected among the binder-portion measurement points, to a total number of all binder-portion measurement points, is 30% or less |
