DEVICE AND METHOD FOR GROWING DIAMOND IN A LIQUID PHASE

• US 20090257942A1
• Filed: 04/14/2009
• Published: 10/15/2009
• Est. Priority Date: 04/14/2008
• Status: Active Grant

• Current Assignee: Chien-Min Sung
• Original Assignee: Chien-Min Sung
• Inventors: Sung, Chien-Min
• Granted Patent: US 8,252,263 B2
• Time in Patent Office: Days
• US Class Current: 423/446
• CPC Class Codes: B01J 2203/061 Graphite
• CPC Class Codes: B01J 2203/062 Diamond
• CPC Class Codes: B01J 2203/0625 Carbon
• CPC Class Codes: B01J 2203/0655 Diamond
• CPC Class Codes: B01J 2203/068 Crystal growth
• CPC Class Codes: B01J 23/83 with rare earths or actinides
• CPC Class Codes: B01J 3/062 characterised by the composition of the materials to be processed
• CPC Class Codes: B01J 3/065 Presses for the formation of diamonds or boronitrides
• CPC Class Codes: C01B 32/26 Preparation by using ultra-high pressure B01J3/06; by crystal growth C30B29/04
• CPC Class Codes: C30B 9/00 Single-crystal growth from melt solutions using molten solvents by normal or gradient freezing C30B11/00; by zone-melting C30B13/00; by crystal pulling C30B15/00; on immersed seed crystal C30B17/00; by liquid phase epitaxial growth C30B19/00; under a protective fluid C30B27/00
• CPC Class Codes: Y10T 117/1024 for crystallization from liquid or supercritical state

Abstract

A method of growing a diamond mass in a liquid growth medium. The liquid growth medium can include a carbon source, a diamond growth catalyst such as a diamond catalyst metal-rare earth element alloy or nanocatalyst, and a dissociated hydrogen of a hydrogen source. The carbon source provides carbon atoms for growing diamond and can include a diamond seed material for diamond growth. The molten liquid phase provides a diamond growth catalyst which allows the carbon to form diamond at the temperature and low pressure conditions discussed. Furthermore, the dissociated hydrogen acts as a concentrator for assembling carbon atoms at a relatively high concentration which mimicks, in some respects, diamond growth under more conventional high pressure processes without the high pressure.

Claims

1. A method of growing diamond, comprising:

a) growing at least one diamond mass from a diamond seed material in a liquid growth medium of a carbon source, a diamond growth catalyst, and a dissociated hydrogen of a hydrogen source, said growing occurring within a temperature profile for a time sufficient to allow three dimensional growth of the diamond mass from the carbon source, said liquid growth medium including a molten liquid phase which is a continuous phase having the hydrogen source dispersed therein under a low pressure; and

b) removing the diamond mass either from the molten liquid phase or from a solidified mass formed from cooling the molten liquid phase.

2. The method of claim 1, wherein the diamond growth catalyst is a diamond growth catalyst alloy which forms at least a portion of the molten liquid phase.

3. The method of claim 2, wherein the diamond growth catalyst alloy is an alloy of a diamond catalyst and a rare earth element.

4. The method of claim 3, wherein the diamond growth catalyst has a melting point from about 400°

C. to about 800°

C.

5. The method of claim 1, wherein the carbon source is a particulate carbon source, a gas carbon source, or a liquid carbon source.

6. The method of claim 1, wherein the diamond seed material is a plurality of diamond seeds which are dispersed in the liquid growth medium and from which a plurality of diamond particles grow with carbon from the carbon source to form the diamond mass.

7. The method of claim 1, wherein the diamond seed material is a crystalline wafer.

8. The method of claim 1, wherein the hydrogen source is hydrogen gas.

9. The method of claim 1, wherein the low pressure is from vacuum to 10 atm.

10. The method of claim 1, wherein the molten liquid phase comprises from 20 vol % to about 99 vol % of the liquid growth medium.

11. The method of claim 1, wherein the liquid growth medium further includes a second molten liquid phase having a density less than the first molten liquid phase.

12. The method of claim 1, wherein the liquid growth medium further includes a hydrogen catalyst.

13. The method of claim 1, wherein the molten liquid phase further comprises an additive in an amount less than 1 wt %.

14. The method of claim 1, wherein the heating is accomplished using an electrically heated and substantially enclosed furnace including a hydrogen source inlet and a gas purge outlet.

15. The method of claim 1, wherein the temperature profile is substantially constant during growth.

16. The method of claim 1, wherein the diamond mass grows at a growth rate from about 10 μ

m/hr to about 100 μ

m/hr per diamond surface.

17. The method of claim 1, wherein the diamond mass is substantially free of crystal and impurity defects.

18. The method of claim 1, further comprising cooling the molten liquid phase prior to removing the diamond mass therefrom.

19. The method of claim 1, wherein the hydrogen source is injected into the liquid growth medium during heating so as to create an upward mixing flow within the liquid growth medium sufficient to keep the particulate carbon source and other dispersed solids suspended.

20. A diamond growth apparatus, comprising:

a) a substantially enclosed furnace including an inlet and an outlet;

b) a heating mechanism thermally associated with the furnace;

c) a porous ceramic oriented in the inlet to allow hydrogen gas into the furnace and prevent egress of molten liquid from the furnace; and

d) a hydrogen source fluidly connected to the inlet.