Cubic boron nitride sintered material

Patent metadata

Field	Value
Publication number	US-11795113-B2
Application number	US-202217947627-A
Country	US
Kind code	B2
Filing date	Sep 19, 2022
Priority date	Nov 4, 2020
Publication date	Oct 24, 2023
Grant date	Oct 24, 2023

Abstract

A cubic boron nitride sintered material includes: more than or equal to 80 volume % and less than or equal to 96 volume % of cubic boron nitride grains; and a binder, wherein the binder includes tungsten carbide, cobalt, and an aluminum compound, and Ha/Hb≥0.40 is satisfied, where Hb represents a hardness of the cubic boron nitride sintered material and Ha represents a hardness of the cubic boron nitride sintered material after performing acid treatment onto the cubic boron nitride sintered material to substantially remove the binder in the cubic boron nitride sintered material.

First claim

The invention claimed is:

1. A cubic boron nitride sintered material comprising:
more than or equal to 80 volume % and less than or equal to 96 volume % of cubic boron nitride grains; and
a binder, wherein
the binder includes tungsten carbide, cobalt, and an aluminum compound, and
Ha/Hb≥0.40 is satisfied, where Hb represents a hardness of the cubic boron nitride sintered material and Ha represents a hardness of the cubic boron nitride sintered material after performing acid treatment onto the cubic boron nitride sintered material to substantially remove the binder in the cubic boron nitride sintered material.

2. The cubic boron nitride sintered material according to claim 1 , wherein Ha and Hb satisfy Ha/Hb≥0.53.

3. The cubic boron nitride sintered material according to claim 2 , wherein Ha and Hb satisfy Ha/Hb≥0.55.

4. The cubic boron nitride sintered material according to claim 1 , wherein Ka/Kb≥0.60 is satisfied, where Kb represents a thermal diffusivity of the cubic boron nitride sintered material before the acid treatment, and Ka represents a thermal diffusivity of the cubic boron nitride sintered material after the acid treatment.

5. The cubic boron nitride sintered material according to claim 4 , wherein Ka and Kb satisfy Ka/Kb≥0.90.

6. The cubic boron nitride sintered material according to claim 5 , wherein Ka and Kb satisfy Ka/Kb≥0.95.

7. The cubic boron nitride sintered material according to claim 1 , wherein Ta/Tb≥0.30 is satisfied, where Tb represents a bending test strength of the cubic boron nitride sintered material before the acid treatment and Ta represents a bending test strength of the cubic boron nitride sintered material after the acid treatment.

8. The cubic boron nitride sintered material according to claim 7 , wherein Ta and Tb satisfy Ta/Tb≥0.35.

9. The cubic boron nitride sintered material according to claim 8 , wherein Ta and Tb satisfy Ta/Tb≥0.40.

10. The cubic boron nitride sintered material according to claim 1 , wherein an average grain size of the cubic boron nitride grains is more than or equal to 0.4 μm and less than or equal to 5 μm.

11. The cubic boron nitride sintered material according to claim 10 , wherein the average grain size of the cubic boron nitride grains is more than or equal to 0.5 μm and less than or equal to 3.5 μm.

12. The cubic boron nitride sintered material according to claim 1 , wherein the cubic boron nitride sintered material is formed from a powder mixture comprising a cubic boron nitride source material powder including coarse cubic boron nitride particles with fine cubic boron nitride particles attached thereto by electrostatic adsorption.

13. The cubic boron nitride sintered material according to claim 12 , wherein the coarse cubic boron nitride particles have an average particle size of 0.2 to 8 μm and the fine cubic boron nitride particles have an average particle size of 0.05 to 0.1 μm.

14. The cubic boron nitride sintered material according to claim 13 , wherein a volume ratio of the fine cubic boron nitride particles and the coarse cubic boron nitride particles falls within a range of 20:80 to 1:99.

15. The cubic boron nitride sintered material according to claim 12 , wherein the powder mixture further comprises a binder source material powder.

16. The cubic boron nitride sintered material according to claim 14 wherein the binder source material powder comprises tungsten carbide, cobalt, and aluminum.

Assignees

• Sumitomo Electric Industries
• Sumitomo Electric Hardmetal Corp

Inventors

• Ishii Akito
• Okamura Katsumi
• Hama Hisaya
• Ishida Yuh
• Nagashima Issei

Classifications

• C04B35/5831 Primary

  based on cubic boron nitrides {or Wurtzitic boron nitrides, including crystal structure transformation of powder} · CPC title

• C04B35/64

  Burning or sintering processes (C04B33/32 takes precedence {; powder metallurgy B22F}) · CPC title

• C04B2235/386

  Boron nitrides · CPC title

• C04B2235/3847

  Tungsten carbides · CPC title

• C04B2235/402

  Aluminium · CPC title