Composite sintered body
AssigneeSumitomo Electric Hardmetal Corp.
InventorsKatsumi OKAMURA, Satoru KUKINO, Tomohiro FUKAYA
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Abstract
A composite sintered body according to the present invention contains at least cubic boron nitride and a binder. Cubic boron nitride has a continuous skeleton structure as a result of bonding of a plurality of first cubic boron nitride particles to each other. The binder has a continuous structure as a result of bonding of a plurality of binder particles to each other, that are present in a region except for a bonding interface where the first cubic boron nitride particles are bonded to each other. Second cubic boron nitride particles isolated from the first cubic boron nitride particles forming the skeleton structure are dispersed in the continuous structure of the binder particles.
Claims20
A composite sintered body, comprising at least cubic boron nitride and a binder, wherein:
- said cubic boron nitride has a continuous skeleton structure as a result of bonding of a plurality of first cubic boron nitride particles to each other,
- said binder has a continuous structure as a result of bonding of a plurality of binder particles to each other, that are present in a region except for a bonding interface where said first cubic boron nitride particles are bonded to each other,
- second cubic boron nitride particles isolated from said first cubic boron nitride particles forming said skeleton structure are dispersed in said continuous structure of said binder particles, and
- after said composite sintered body is subject to an acid treatment, said cubic boron nitride having the continuous skeleton structure in the treated composite sintered body maintains an original shape exhibited prior to the acid treatment, where the acid treatment is a treatment in which a mixed acid obtained by mixing concentrated 60% nitric acid, distilled water and concentrated 47% hydrofluoric acid at a volume ratio of 2:2:1 and the composite sintered body cut into a rectangular shape of length 6 mm×width 3 mm×thickness 0.5 mm are placed in an airtight container and the composite sintered body is treated under pressure for 48 hours at a temperature of 140° C.
A method of manufacturing a composite sintered body comprising at least cubic boron nitride and a binder, the method comprising:
- preparing mixed powders of cubic boron nitride particles and a binder;
- first sintering the mixed powder at a temperature in a range of 1000 to 1500° C. under a pressure in a range of 2 to 5 GPa, to obtain a first sintered body;
- and
- second sintering the first sintered body by increasing the temperature to and thereafter maintaining at a range of 1400 to 2000° C. under a pressure in a range of 5 to 8 GPa, to obtain the composite sintered body.
Dependencies are inferred from the claim text.