| abstract |
The cubic boron nitride sintered body is a cubic boron nitride sintered body comprising 50% by volume or more and less than 80% by volume of cubic boron nitride particles and a bonding phase of more than 20% by volume and 50% by volume or less. The bonded phase is composed of at least one element selected from the group consisting of Group 4 elements, Group 5 elements, Group 6 elements and aluminum in the periodic table, and the group consisting of nitrogen, carbon, boron and oxygen. It contains a compound consisting of at least one selected element and at least one selected from the group consisting of a solid solution derived from the compound, and is perpendicular to the interface between the cubic boron nitride particles using TEM-EDX. When the oxygen content is measured in the direction, there is a first region having an oxygen content larger than the average value of the oxygen content of the cubic boron nitride particles, the interface exists in the first region, and the oxygen content is present. The length of the first region along the direction perpendicular to the interface is 0.1 nm or more and 10 nm or less. |