Impregnation of grinding wheels using supercritical fluids

• US 20050101237A1
• Filed: 11/06/2003
• Published: 05/12/2005
• Est. Priority Date: 11/06/2003
• Status: Active Grant

• Current Assignee: Saint-Gobain Abrasives Incorporated (Compagnie De Saint-Gobain)
• Original Assignee: Saint-Gobain Abrasives Incorporated (Compagnie De Saint-Gobain)
• Inventors: Vecchiarelli, Jodi Ann, Kinisky, Thomas G., Sheldon, David A.
• Granted Patent: US 7,344,573 B2
• Time in Patent Office: Days
• US Class Current: 451/548
• CPC Class Codes: B24D 18/0027 by impregnation
• CPC Class Codes: B24D 3/348 utilised as impregnating agent for porous abrasive bodies
• CPC Class Codes: C09K 3/1409 Abrasive particles per se preparation of diamond C01B32/25
• CPC Class Codes: Y02P 20/54 using solvents, e.g. supercritical solvents or ionic liquids

Abstract

An additive impregnated abrasive article and method for fabricating the same is provided. The method includes providing an abrasive article having a pore structure, dissolving an additive in a supercritical fluid, and exposing the abrasive article to the additive-laden supercritical fluid, so that the fluid disperses through the pore structure. The supercritical fluid is then brought to below its critical point for a period of time sufficient to dissociate the additive from the fluid, so that the additive is deposited within the pore structure of the abrasive article.

Claims

1. A method for fabricating an additive impregnated abrasive article, said method comprising:

a) providing an abrasive article having a pore structure;

b) dissolving an additive in a supercritical fluid;

c) exposing the abrasive article to the additive-laden supercritical fluid in a reaction vessel at a pressure in excess of atmospheric pressure, whereby the additive is carried into the pore structure; and

d) depressurizing the reaction vessel to dispose the supercritical fluid below its critical point for a period of time sufficient to dissociate the additive from the fluid, whereby the additive is deposited within the pore structure.

2. The method of claim 1, wherein the abrasive article is substantially insoluble in the supercritical fluid.

3. The method of claim 2, wherein the abrasive article comprises abrasive grain and bond material.

4. The method of claim 3, wherein the bond is selected from the group consisting of inorganic, organic, and metallic bonds.

5. The method of claim 4, wherein the bond comprises vitrified bond material.

6. The method of claim 4, wherein the abrasive article comprises resinous bond material.

7. The method of claim 6 wherein the resinous bond material comprises a resin selected from the group consisting of phenolic resins, epoxy resins, unsaturated polyester resins, bismaleimide resins, polyimide resins, cyanate resins, melamine polymers, and mixtures thereof.

8. The method of claim 3 wherein said abrasive grain comprises an abrasive grain selected from the group consisting of diamond, cubic boron nitride, fused alumina, sintered alumina, sintered sol gel alumina, alumina-zirconia, alumina-oxynitrides, silicon carbide, fused or sintered alloys of alumina with at least one ceramic oxide selected from the group consisting of M_gO, C_OO, TiO₂, V₂O₃ Cr₂O₃, tungsten carbide and combinations thereof.

9. The method of claim 3 wherein said abrasive grain comprises an average particle size ranging from:

greater than or equal to about 0.5 microns; and

less than or equal to about 5000 microns.

10. The method of claim 3, wherein the abrasive article comprises superabrasive grain.

11. The method of claim 1, wherein said dissolving b) and said exposing c) further comprise heating the vessel.

12. The method of claim 1, wherein said disposing d) comprises depressurizing the vessel.

13. The method of claim 12, wherein said disposing d) further comprises lowering the temperature of the vessel.

14. The method of claim 1 wherein said additive comprises a non-polar organic material.

15. The method of claim 1 wherein said additive is selected from the group consisting of:

alkanes;

C16-C40 alkanes and their non-polar derivatives;

C10 or greater cycloalkanes and their non-polar derivatives, C10 or greater alkenes and their non-polar derivatives, C10 or greater arenes and their non-polar derivatives, lipids, hydrocarbons, waxes, fluoropolymer resins, and mixtures thereof.

16. The method of claim 15 wherein said additive comprises tetracosane.

17. The method of claim 15 wherein said additive comprises wax.

18. The method of claim 1 wherein the supercritical fluid is selected from the group consisting of CO₂, ethane, propane, butane, H₂O, and combinations thereof.

19. The method of claim 1 wherein said supercritical fluid comprises carbon dioxide.

20. An abrasive article fabricated by the method of claim 1.

21. The abrasive article of claim 20, wherein the abrasive article is selected from the group consisting of bonded abrasive wheels, discs, blades, stones, hones, coated abrasive articles, abrasive grain agglomerates, and combinations thereof.

22. The method of claim 21, wherein the abrasive article has a porosity ranging from:

greater than or equal to about 1 volume percent; and

less than or equal to about 85 volume percent.

23. The method of claim 22, wherein the abrasive article has a porosity ranging from:

greater than or equal to about 40 volume percent; and

less than or equal to about 60 volume percent.

24. The method of claim 23, wherein the abrasive article has pore sizes ranging from:

greater than or equal to about 2 microns; and

less than or equal to about 2000 microns.

25. A method for fabricating an additive impregnated abrasive article, said method comprising:

a) providing an abrasive article having a pore structure;

b) placing a supercritical fluid-soluble additive into a vessel;

c) suspending the abrasive article in superposed orientation with the additive, within the vessel;

d) supplying fluid under pressure to the vessel;

e) sealing the vessel;

f) heating the vessel;

g) supplying sufficient heat and pressure to bring the fluid beyond its critical point to form a supercritical fluid, wherein the additive is dissolved in the supercritical fluid and is dispersed into the pore structure; and

h) depressurizing and cooling the vessel to bring the supercritical fluid below its critical point, wherein the additive is dissociated from the fluid and deposited within the pore structure.

26. An abrasive article fabricated by the method of claim 25.