High pressure superabrasive particle synthesis

• US 20070295267A1
• Filed: 06/14/2007
• Published: 12/27/2007
• Est. Priority Date: 04/04/1997
• Status: Abandoned Application

• Current Assignee: Chien-Min Sung
• Original Assignee: Chien-Min Sung
• Inventors: Sung, Chien-Min
• Application Number:
  US11/818,894
• Publication Number:
  US 20070295267A1
• Time in Patent Office: Days
• US Class Current: 117/64
• CPC Class Codes: B01J 2203/061 Graphite
• CPC Class Codes: B01J 2203/062 Diamond
• CPC Class Codes: B01J 2203/0635 Silicon carbide
• CPC Class Codes: B01J 2203/0645 Boronitrides
• CPC Class Codes: B01J 2203/0655 Diamond
• CPC Class Codes: B01J 2203/066 Boronitrides
• CPC Class Codes: B01J 2203/068 Crystal growth
• CPC Class Codes: B01J 2203/0685 Crystal sintering
• CPC Class Codes: B01J 3/062 characterised by the composition of the materials to be processed
• CPC Class Codes: B22F 1/05 Metallic powder characterised by the size or surface area of the particles
• CPC Class Codes: B22F 2003/1046 with separating means for articles to be sintered
• CPC Class Codes: B22F 2005/001 Cutting tools, earth boring or grinding tool other than table ware
• CPC Class Codes: B22F 2207/03 of the metallic binder phase in cermets
• CPC Class Codes: B22F 2999/00 Aspects linked to processes or compositions used in powder metallurgy
• CPC Class Codes: B22F 3/004 Filling molds with powder feeding material to presses in general B30B15/302
• CPC Class Codes: B23D 61/18 Sawing tools of special type, e.g. wire saw strands, saw blades or saw wire equipped with diamonds or other abrasive particles in selected individual positions cut-off wheels of bonded abrasive or with inserted abrasive blocks B24D5/12
• CPC Class Codes: B23D 65/00 Making tools for sawing machines or sawing devices for use in cutting any kind of material
• CPC Class Codes: B23P 15/28 cutting tools sawing tools B23D63/00, B23D65/00; files or rasps B23D73/00
• CPC Class Codes: B24D 18/00 Manufacture of grinding tools or other grinding devices, e.g. wheels, not otherwise provided for
• CPC Class Codes: B24D 2203/00 Tool surfaces formed with a pattern
• CPC Class Codes: B24D 3/08 : for close-grained structure, e.g. using metal with low melting point
• CPC Class Codes: B24D 7/066 : Grinding blocks; their mountings or supports
• CPC Class Codes: B24D 99/005 : Segments of abrasive wheels
• CPC Class Codes: C22C 1/051 : Making hard metals based on borides, carbides, nitrides, oxides or silicides; Preparation of the powder mixture used as the starting material therefor
• CPC Class Codes: C22C 2204/00 : End product comprising different layers, coatings or parts of cermet
• CPC Class Codes: C22C 26/00 : Alloys containing diamond or cubic or wurtzitic boron nitride, fullerenes or carbon nanotubes
• CPC Class Codes: E21B 10/5676 : having a cutting face with different segments, e.g. mosaic-type inserts

Abstract

An improved method for controlling nucleation sites during superabrasive particle synthesis can provide high quality industrial superabrasive particles with high yield and a narrow size distribution. The synthesis method can include forming a raw material layer, forming a particulate catalyst layer adjacent the raw material layer, and placing crystalline seeds in a predetermined pattern at least partially in the catalyst layer or raw material layer to form a growth precursor. Alternatively, the raw material and catalyst material can be mixed to form a particulate crystal growth layer and then placing the crystalline seeds in a predetermined pattern in the growth layer. Preferably, seeds can be substantially surrounded by catalyst material. The growth precursor can be maintained at a temperature and pressure at which the superabrasive crystal is thermodynamically stable for a time sufficient for a desired degree of growth. The crystalline seeds can be placed in a predetermined pattern using a template, a transfer sheet, vacuum chuck or similar techniques. The superabrasive particles grown using the described methods typically have a high yield of high quality industrial particles and a narrow distribution of particle sizes.

Claims

1. A method for controlling nucleation sites during superabrasive particle synthesis, comprising the steps of:

a) forming a raw material layer including a raw material;

b) forming a particulate catalyst layer adjacent the raw material layer to form a crystal growth layer, said particulate catalyst layer including a catalyst material; and

c) placing crystalline seeds in a predetermined pattern at least partially in at least one of the catalyst layer and the raw material layer to form a growth precursor.

2. The method of claim 1, wherein said catalyst layer consists essentially of catalyst material.

3. The method of claim 1, wherein the superabrasive particle is diamond and the raw material is a carbon source.

4. The method of claim 3, wherein said catalyst material is a member selected from the group consisting of Fe, Ni, Co, Mn, Cr, and alloys thereof.

5. The method of claim 4, wherein said catalyst material is an Fe—

Ni alloy having about 65 wt % Fe and about 35 wt % Ni.

6. The method of claim 3, wherein said carbon source is graphite.

7. The method of claim 6, wherein said graphite has a degree of graphitization of greater than 0.50.

8. The method of claim 7, wherein said graphite has a degree of graphitization of from about 0.75 to about 1.

9. The method of claim 1, wherein the superabrasive particle is cubic boron nitride and the raw material is a hexagonal boron nitride source.

10. The method of claim 9, wherein the catalyst material is a member selected from the group consisting of alkali, alkali earth metal, and compounds thereof.

11. The method of claim 1, wherein the crystalline seed is a member selected from the group consisting of diamond seed, cBN seed, SiC seed, and combinations thereof.

12. The method of claim 1, wherein the step of placing crystalline seeds includes placing the crystalline seeds in the raw material layer and the crystalline seeds are coated with a catalyst coating.

13. The method of claim 12, wherein said raw material layer is a particulate source layer.

14. The method of claim 12, wherein said catalyst coating is a catalyst metal selected from the group consisting of iron, nickel, cobalt, and alloys thereof.

15. The method of claim 1, wherein the step of placing crystalline seeds include placing the crystalline seeds in the catalyst layer.

16. The method of claim 1, wherein the step of placing crystalline seeds substantially surrounds each crystalline seed with catalyst material.

17. The method of claim 16, wherein the step of placing crystalline seeds further comprises pressing the crystalline seeds partially into the catalyst layer and then forming a second catalyst layer on the catalyst layer such that each crystalline seed is substantially surrounded by catalyst material.

18. The method of claim 16, wherein the step of placing crystalline seeds further comprises pressing the crystalline seeds completely into the catalyst layer such that each crystalline seed is substantially surrounded by catalyst material.

19. The method of claim 1, further comprising the steps of repeating the steps of forming layers and placing crystalline seeds at least one additional time to form a multi-layered growth precursor.

20. The method of claim 1, further comprising the step of heating and pressing the growth precursor to a temperature and pressure sufficient for growth of superabrasive particles to produce grown superabrasive particles.

21. The method of claim 20, wherein the temperature is from about 1000°

C. to about 1300°

C. and the pressure is from about 4 to about 7 GPa.

22. The method of claim 20, wherein the temperature is from about 10°

C. to about 200°

C. above a melting point of the catalyst.

23. The method of claim 20, wherein said crystalline seeds have an average diameter from about 0.05 to about 0.2 times an average diameter of the grown superabrasive particles.

24. The method of claim 1, wherein said crystalline seeds are from about 30 μ

m to about 500 μ

m in diameter.

25. The method of claim 1, wherein the predetermined pattern places crystalline seeds a distance of from about 400 μ

m to about 900 μ

m apart.

26. The method of claim 25, wherein the superabrasive particles have a particle size from about 100 μ

m to about 2 mm.

27. The method of claim 26, wherein the superabrasive particles have a particle size from about 210 μ

m to about 1 mm.

28. A growth precursor, comprising at least one crystal growth layer having a raw material layer and a particulate catalyst layer, said catalyst layer having a plurality of crystalline seeds placed in a predetermined pattern.

29. The precursor of claim 28, comprising from 3 to 10 crystal growth layers.

30. The precursor of claim 28, wherein said raw material is a carbon source.

31. The precursor of claim 30, wherein said catalyst material is a member selected from the group consisting of Fe, Ni, Co, Mn, Cr, and alloys thereof.

32. The precursor of claim 30, wherein said carbon source comprises graphite having a degree of graphitization of greater than 0.50.

33. The precursor of claim 28, wherein said raw material is a hexagonal boron nitride source.

34. The precursor of claim 33, wherein said catalyst material is a member selected from the group consisting of alkali, alkali earth metal, and compounds thereof.

35. The precursor of claim 28, wherein the crystalline seed is a member selected from the group consisting of diamond seed, cBN seed, SiC seed, and combinations thereof.