High pressure superabrasive particle synthesis

• US 7,585,366 B2
• Filed: 12/14/2006
• Issued: 09/08/2009
• Est. Priority Date: 04/04/1997
• Status: Expired due to Fees

• Current Assignee: Chien-Min Sung
• Original Assignee: Chien-Min Sung
• Inventors: Sung, Chien-Min
• Primary Examiner(s): Eley, Timothy V
• Application Number:
  US11/640,131
• Publication Number:
  US 20070157917A1
• Time in Patent Office: 999 Days
• Field of Search: 512/97, 512/98, 513/07, 513/08, 512/93, 423/446, 117/103, 117/79, 117/929, 117/4, 117/7, 125/12, 125/16.02, 125/21, 125/22, 451/527, 451/529, 451/533, 451/544
• US Class Current: 117/79
• 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 particulate crystal growth layer by mixing a raw material and a catalyst material 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 particulate crystal growth layer, including a substantially homogeneous mixture of raw material and catalyst material;

b) placing crystalline seeds in a predetermined pattern at least partially in the particulate crystal growth layer to form a growth precursor; and

c) heating and pressing the growth precursor to a temperature and pressure sufficient for growth of superabrasive particles to produce grown superabrasive particles;

wherein the step of placing crystalline seeds includes the steps of;

a) placing a template having a pattern of apertures upon a surface of the crystal growth layer, each of said apertures being configured to receive a single crystalline seed;

b) filling the apertures of said template with the crystalline seeds; and

c) pressing said crystalline seeds at least partially into the crystal growth layer;

or

wherein the step of placing crystalline seeds includes the steps of;

d) providing a transfer sheet having an adhesive layer thereon;

e) placing a template having a pattern of apertures upon the adhesive layer, each of said apertures being configured to receive a single crystalline seed;

f) filling the apertures of said template with the crystalline seeds;

g) placing the transfer sheet against a surface of the crystal growth layer; and

h) pressing said crystalline seeds at least partially into the crystal growth layer;

or

wherein the step of placing crystalline seeds includes the steps of;

i) providing a vacuum chuck configured with a pattern of apertures;

j) pulling a vacuum through the apertures and engaging a single crystalline seed in each aperture;

k) depositing the crystalline seeds on a surface of the crystal growth layer such that the crystalline seeds are arranged in a predetermined pattern corresponding to the pattern of apertures; and

l) pressing said crystalline seeds at least partially into the crystal growth layer.

2. The method of claim 1, wherein said particulate crystal growth layer consists essentially of raw material and 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 crystalline seeds are coated with a catalyst coating.

13. 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.

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

15. 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.

16. 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.