Cubic boron nitride-based sintered material and cutting tool made of cubic boron nitride-based sintered material
A cubic boron nitride-based sintered material includes cubic boron nitride particles of 70 to 95 vol %, in which in a structure of a cross-section of the sintered material, a binder phase with a width of 1 nm to 30 nm is present between the adjacent cubic boron nitride particles, the binder phase being made of a compound containing at least Al, B, and N and having a ratio of an oxygen content to an Al content of 0.1 or less in terms of atomic ratio.
1. A cubic boron nitride-based sintered material comprising:
cubic boron nitride particles of 70 to 95 vol %,
wherein in a structure of a cross-section of the sintered material, a binder phase with a width of 1 nm to 30 nm is present between the adjacent cubic boron nitride particles, the binder phase being made of a compound containing at least Al, B, and N and having a ratio of an oxygen content to an Al content of 0.1 or less in terms of atomic ratio.
2. A cubic boron nitride-based sintered material comprising;
cubic boron nitride particles of 70 to 95 vol %,
wherein in a structure of a cross-section of the sintered material, there is a region where an interval between the adjacent cubic boron nitride particles is 30 nm or less, where a binder phase is made of a nitride containing at least one of Al and B, or both Al and B, and an Al oxide, and where a ratio of an oxygen content to an Al content in the binder phase is 0.1 or less in terms of atomic ratio.
3. The cubic boron nitride-based sintered material according to claim 1 ,
wherein the average particle diameter of the cubic boron nitride particles is 0.5 to 8.0 μm,
in at least five fields of view of the structure of the cross-section of the cubic boron nitride-based sintered material with a field of view of 5 times×5 times the average particle diameter of the cubic boron nitride particles as one field of view, the cubic boron nitride particles having a binder phase with a width of 1 nm to 30 nm between the adjacent cubic boron nitride particle are observed in fields of view of 60% or more of the total number of the fields of view, the binder phase having a ratio of an oxygen content to an Al content of 0.1 or less.
4. The cubic boron nitride-based sintered material according to claim 1 ,
wherein in the structure of the cross-section of the cubic boron nitride-based sintered material:
an average particle number ratio of the number of the cubic boron nitride particles having the binder phase with a width of 1 nm to 30 nm between the adjacent cubic boron nitride particle with respect to the total number of the cubic boron nitride particles in the observed cross-section is 0.4 or more; and
among the cubic boron nitride particles having the binder phase with a width of 1 nm to 30 nm between the adjacent cubic boron nitride particle, an average ratio of the number of the cubic boron nitride particles having the binder phase with a ratio of an oxygen content to an Al content of 0.1 or less with respect to the number of the cubic boron nitride particles having the binder phase with a width of 1 nm to 30 nm between the adjacent cubic boron nitride particle is 0.5 or more.
5. The cubic boron nitride-based sintered material according to claim 1 ,
wherein the binder phases which are present between the adjacent cubic boron nitride particles and have a width of 1 nm to 30 nm are dotted between the adjacent cubic boron nitride particles.
6. A cutting tool made of cubic boron nitride-based sintered material comprising:
a cutting edge portion made of the cubic boron nitride-based sintered material according to claim 1 .
7. The cubic boron nitride-based sintered material according to claim 2 ,
wherein the average particle diameter of the cubic boron nitride particles is 0.5 to 8.0 μm,
in at least five fields of view of the structure of the cross-section of the cubic boron nitride-based sintered material with a field of view of 5 times×5 times the average particle diameter of the cubic boron nitride particles as one field of view, the cubic boron nitride particles having a binder phase with a width of 1 nm to 30 nm between the adjacent cubic boron nitride particle are observed in fields of view of 60% or more of the total number of the fields of view, the binder phase having a ratio of an oxygen content to an Al content of 0.1 or less.
8. The cubic boron nitride-based sintered material according to claim 2 ,
wherein in the structure of the cross-section of the cubic boron nitride-based sintered material:
an average particle number ratio of the number of the cubic boron nitride particles having the binder phase with a width of 1 nm to 30 nm between the adjacent cubic boron nitride particle with respect to the total number of the cubic boron nitride particles in the observed cross-section is 0.4 or more; and
among the cubic boron nitride particles having the binder phase with a width of 1 nm to 30 nm between the adjacent cubic boron nitride particle, an average ratio of the number of the cubic boron nitride particles having the binder phase with a ratio of an oxygen content to an Al content of 0.1 or less with respect to the number of the cubic boron nitride particles having the binder phase with a width of 1 nm to 30 nm between the adjacent cubic boron nitride particle is 0.5 or more.
9. The cubic boron nitride-based sintered material according to claim 7 ,
wherein in the structure of the cross-section of the cubic boron nitride-based sintered material:
an average particle number ratio of the number of the cubic boron nitride particles having the binder phase with a width of 1 nm to 30 nm between the adjacent cubic boron nitride particle with respect to the total number of the cubic boron nitride particles in the observed cross-section is 0.4 or more; and
among the cubic boron nitride particles having the binder phase with a width of 1 nm to 30 nm between the adjacent cubic boron nitride particle, an average ratio of the number of the cubic boron nitride particles having the binder phase with a ratio of an oxygen content to an Al content of 0.1 or less with respect to the number of the cubic boron nitride particles having the binder phase with a width of 1 nm to 30 nm between the adjacent cubic boron nitride particle is 0.5 or more.
10. The cubic boron nitride-based sintered material according to claim 2 ,
wherein the binder phases which are present between the adjacent cubic boron nitride particles and have a width of 1 nm to 30 nm are dotted between the adjacent cubic boron nitride particles.
11. A cutting tool made of cubic boron nitride-based sintered material comprising:
a cutting edge portion made of the cubic boron nitride-based sintered material according to claim 2 .