Polycrystalline Grits and Associated Methods

• US 20090120009A1
• Filed: 11/07/2008
• Published: 05/14/2009
• Est. Priority Date: 11/08/2007
• Status: Abandoned Application

• Current Assignee: Chien-Min Sung
• Original Assignee: Chien-Min Sung
• Inventors: Sung, Chien-Min
• Application Number:
  US12/267,189
• Publication Number:
  US 20090120009A1
• Time in Patent Office: Days
• US Class Current: 51/295
• CPC Class Codes: C01B 32/28 After-treatment, e.g. purification, irradiation, separation or recovery
• CPC Class Codes: C09K 3/1409 Abrasive particles per se preparation of diamond C01B32/25

Abstract

A method for forming polycrystalline grits can include forming an abrasive dough, including a plurality of abrasive particles, into a sheet. The sheet can be divided into a plurality of abrasive precursors. By placing the sheet on a stretchable surface, separations among the plurality of abrasive precursors can be revealed by stretching the stretchable surface. The stretchable surface can include a particulate separating agent, and additional particulate separating agent can be distributed in the separations. The abrasive precursors can be sintered to form polycrystalline grits.

Claims

1. A method of forming polycrystalline grits, comprising:

forming an abrasive dough into a sheet, said abrasive dough including a plurality of abrasive particles;

placing at least a portion of the sheet on a stretchable surface including particulate separating agent;

dividing the sheet into predetermined shapes to form a plurality of abrasive precursors;

stretching the stretchable surface sufficient to reveal separations among the plurality of abrasive precursors;

distributing particulate separating agent in the separations; and

sintering the abrasive precursors to form a plurality of polycrystalline grits.

2. The method of claim 1, wherein the abrasive particles are selected from the group consisting of diamond, nanodiamond, cubic boron nitride, silicon carbide, quartz, corundum, silicon nitride, boron nitride, tungsten carbide, titanium carbide, zirconium carbide, zinc oxide, zirconia, alumina, aluminum nitride, titanium nitride, zirconium nitride, and mixtures or composites thereof.

3. The method of claim 1, wherein the abrasive particles are superabrasive particles.

4. The method of claim 3, wherein the abrasive particles are diamond particles.

5. The method of claim 1, wherein the abrasive particles include a mixture of superabrasive and non-superabrasive particles.

6. The method of claim 1, wherein the abrasive dough further comprises a sintering aid.

7. The method of claim 1, further comprising a step of dewaxing prior to the step of sintering.

8. The method of claim 1, wherein the particulate separating agent comprises a member selected from the group consisting of NaCl, Co, Cu, hexagonal boron nitride, graphite, and combinations thereof.

9. The method of claim 8, wherein the particulate separating agent includes graphite.

10. The method of claim 1, wherein the particulate separating agent has a particle size from about 1 μ

m to about 40 μ

m.

11. The method of claim 1, wherein the step of dividing the sheet into predetermined shapes occurs while the sheet is placed on the stretchable surface.

12. The method of claim 1, wherein the step of distributing particulate separating agent in the separations includes removing excess separating agent.

13. The method of claim 12, wherein removing excess separating agent includes directing a stream of air or other gas at the excess separating agent.

14. The method of claim 1, wherein the stretchable surface includes an organic material.

15. The method of claim 1, wherein the step of dividing the sheet into predetermined shapes to form a plurality of abrasive precursors creates a plurality of abrasive precursors, each having a surface with an inverse profile of a surface of another abrasive precursor.

16. A method of forming polycrystalline grits, comprising the steps of:

forming a plurality of abrasive precursors, including a binder and a plurality of abrasive particles;

coating the plurality of abrasive precursors with a particulate separating agent; and

sintering the abrasive precursors to form polycrystalline grits.

17. The method of claim 16, wherein the abrasive particles are diamond particles.

18. The method of claim 16, wherein the particulate separating agent has a particle size from about 1 μ

m to about 40 μ

m.

19. An abrasive precursor assembly, comprising:

a plurality of abrasive precursors including a sintering aid, abrasive particles, and binder, arranged on a stretchable surface, said stretchable surface stretched sufficient to reveal separations between the abrasive precursors; and

a particulate separating agent in the separations and between the abrasive precursors and stretchable surface.

20. The abrasive precursor assembly of claim 19, wherein the abrasive particles are diamond particles.