METHOD OF SOLID PCBN SYTHESIS

• US 20100069225A1
• Filed: 09/18/2009
• Published: 03/18/2010
• Est. Priority Date: 09/18/2008
• Status: Active Grant

• Current Assignee: Diamond Innovations Incorporated (Sandvik AB)
• Original Assignee: Diamond Innovations Incorporated (Sandvik AB)
• Inventors: Kountanya, Raja, Dole, Stephen
• Granted Patent: US 8,148,282 B2
• Time in Patent Office: Days
• US Class Current: 501/96.400
• CPC Class Codes: B01J 3/065 Presses for the formation of diamonds or boronitrides
• CPC Class Codes: C04B 2235/3804 Borides
• CPC Class Codes: C04B 2235/3821 Boron carbides
• CPC Class Codes: C04B 2235/3865 Aluminium nitrides
• CPC Class Codes: C04B 2235/402 Aluminium
• CPC Class Codes: C04B 2235/5436 micrometer sized, i.e. from 1 to 100 micron
• CPC Class Codes: C04B 2235/5472 Bimodal, multi-modal or multi-fraction
• CPC Class Codes: C04B 2235/783 Bimodal, multi-modal or multi-fractional
• CPC Class Codes: C04B 2235/784 Monomodal
• CPC Class Codes: C04B 2235/80 Phases present in the sintered or melt-cast ceramic products other than the main phase
• CPC Class Codes: C04B 2235/85 Intergranular or grain boundary phases
• CPC Class Codes: C04B 2235/9607 Thermal properties, e.g. thermal expansion coefficient
• CPC Class Codes: C04B 35/5831 based on cubic boron nitrides or Wurtzitic boron nitrides, including crystal structure transformation of powder
• CPC Class Codes: C04B 35/645 Pressure sintering
• CPC Class Codes: Y10T 407/27 comprising tool of specific chemical composition

Abstract

The invention generally relates to a sintered CBN composite compact having a non-CBN portion. The compact includes about 86 to about 90% CBN and the non CBN portion contains borides and nitrides of Al. The compact is for use as a cutting tool insert in continuous machining of gray cast iron. The sintered compact has a thermal conductivity of 1.25-4 W/cm/° K. in the temperature range of about 200° C. to about 600° C. and sonic velocity of at least about 14.5 Km/sec at room temperature.

Claims

1. A sintered cubic boron nitride composite compact having a non-cBN portion, the compact comprising:

about 86 to about 90 wt. % cBN; and

the non cBN portion consisting essentially of about 10 to about 14 wt. % AlN, AlB₂ and other borides of Al.

2. The sintered cubic boron nitride composite compact according to claim 1, said compact having a thermal conductivity at room temperature of about 1.25 to about 4 W/cm °

K. in the temperature range of about 200°

C. to about 600°

C.

3. The sintered cubic boron nitride composite compact according to claim 1, said compact having a sonic velocity of at least about 14.5 km/s.

4. The sintered cubic boron nitride composite compact according to claim 1, said compact having a cBN grain size distribution that is at least bimodal.

5. The sintered cubic boron nitride composite compact according to claim 4, wherein said cBN grain size distribution that is at least bimodal comprises fine grain particles in an amount of about 10% to about 50% of the total cBN content.

6. The sintered cubic boron nitride composite compact according to claim 4, wherein said cBN grain size distribution that is at least bimodal comprises about 80% coarse particles and about 20% fine particles.

7. The sintered cubic boron nitride composite compact according to claim 1, wherein said compact comprises a cutting insert for continuous machining of gray cast iron with an aging time of less than about 100 hours.

8. A process for making a sintered compact, the steps comprising:

preparing a mixture consisting essentially of about 91 to about 94 weight % cBN and about 6 to about 10 weight % Al; and

producing a sintered compact by applying high pressure and high temperature conditions to the material,

wherein the mixture comprises at least a bimodal distribution of cBN particles.

9. The process of claim 8, wherein the content of said Al is about 6 wt % to about 8 wt %.

10. The process of claim 8, wherein said compact has a thermal conductivity at room temperature of about 1.25 to about 4 W/cm °

K. in the temperature range of about 200°

C. to about 600°

C.

11. The process of claim 8, wherein said compact has a sonic velocity of at least about 14.5 km/s.

12. The process of claim 8, wherein said compact has a cBN grain size distribution that is at least bimodal.

13. The process of claim 12, wherein said cBN grain size distribution that is at least bimodal comprises about 80% coarse particles and about 20% fine particles.

14. A process for making a sintered compact, the steps comprising:

preparing a mixture consisting essentially of about 91 to about 94 weight % cBN and about 7.5 weight % Al; and

producing a sintered compact by applying high pressure and high temperature conditions to the material,

wherein the mixture comprises at least a bimodal distribution of cBN particles.