Abrasive grains having unique features

1. An uncoated abrasive or superabrasive grain having at least one grain face comprising three or more features projecting from said grain face wherein the height (h) and the lateral length (l) of each feature is greater than about 0.1 micron, wherein the features comprise at least one of peaks, valleys, concave indentations and half-ellipsoids, in a pattern comprising at least one of blisters or fish scales.

2. The grain of claim 1 , wherein said grain has at least one face on the grain is concave having a depth greater than about 1.0 micron.

3. The grain of claim 2 , wherein the concave face is smooth.

4. The grain of claim 2 , wherein the concave face comprises a plurality of peaks and valleys in which the height between the peak and valley is greater than about 0.1 micron.

5. The grain of claim 1 , wherein said superabrasive grain is a cubic boron nitride grain.

6. The grain of claim 1 , wherein said grain further comprises a coating material selected from the group of metals, metal alloys, glass, metals oxides and carbide.

7. A plurality of superabrasive grains in which at least about 15% of the grains have at least one grain face comprising three or more features wherein the height (h) and the lateral length (l) of each feature is greater than about 0.1 micron wherein said grains are free of coating material, wherein said grains are free of coating material, wherein the features comprise at least one of peaks, valleys, concave indentations and half-ellipsoids, in a pattern comprising at least one of blisters or fish scales.

8. The grains of claim 7 , wherein at least about 20% of the grains have at least one face on the grain that is concave having a depth greater than about 1.0 micron.

9. The grains of claim 8 , wherein the concave face is smooth.

10. The grains of claim 7 , wherein said superabrasive grains are cubic boron nitride grains.

11. The grains of claim 8 , wherein the concave face comprises a plurality of peaks and valleys in which the height between the peak and valley is greater than about 0.1 micron.

12. The grains of claim 7 , wherein at least about 20% of the grains have at least one face that comprises a) concave with a depth greater than about one (1.0) micron, wherein the face is either smooth or irregularly fluctuant; and b) with more than three features on at least one face; wherein the height (h) and the lateral length (l) of each feature is greater than about 0.1 microns.

13. The grains of claim 7 , wherein at least about 20% of the grains have a combination of two or more of the following face types: smooth, irregularly fluctuant, concave, and faces with at least three features per face such that the height (h) and lateral length (l) of said features is greater than about 0.1 microns.

14. The grains of claim 7 , wherein the features are uniformly orientated on the face of the grain.

15. The grains of claim 7 , wherein the features are randomly distributed on the face of the grain.

16. The grains of claim 7 , wherein said features exist in grain mesh sizes ranging from about 30− to about 400+.

17. The grains of claim 7 , wherein said features exist in grain mesh sizes of 30+ and 400−.

18. The grains of claim 7 , wherein said features exist in grain sizes of about 10 microns or less.

19. A cutting tool which comprises abrasive grains according to claim 1 .

20. The tool of claim 19 , which is in the form of a grinding wheel.

21. The tool of claim 19 , which is in the form of a drill bit.

22. The tool of claim 19 , which is in the form of a saw blade.

23. A plurality of superabrasive grains in which at least about 15% of the grains have at least one grain face comprising three or more features wherein the height (h) and the lateral length (l) of each feature is greater than about 0.1 micron and wherein at least about 20% of the grains have at least one face on the grain that is concave having a depth greater than about 1.0 micron, wherein said grains are free of coating material, wherein the features comprise at least one of peaks, valleys, concave indentations and half-ellipsoids, in a pattern comprising at least one of blisters or fish scales.

24. The grains of claim 23 , wherein said superabrasive grains are cubic boron nitride grains.

25. A grain comprising at least one face having at least three features on said face wherein the height of said features is greater than about 1% of the diameter of the grain, wherein the features comprise at least one of peaks, valleys, concave indentations and half-ellipsoids, in a pattern comprising at least one of blisters or fish scales.

26. A grain comprising at least one concave face wherein the depth of said concave face is greater than about 3% of the diameter of the grain, wherein the features comprise at least one of peaks, valleys, concave indentations and half-ellipsoids, in a pattern comprising at least one of blisters or fish scales.

27. A method of making a plurality of cubic boron nitride (cBN) grains comprising the steps of: providing a plurality of hexagonal boron nitride (hBN) grains; providing a catalyst; subjecting said hBN grains and said catalyst to high pressure and high temperature for a time period sufficient to form a reaction mass containing cBN grains; and cleaning said cBN grains from said reaction mass using a combination of water and acidic solutions or caustic chemicals, wherein at least about 15% of said plurality of cBN grains have at least one grain face comprising three or more features wherein the height (h) and the lateral length (l) of each feature is greater than about 0.1 micron, wherein said grains are free of coating material, wherein the features comprise at least one of peaks, valleys, concave indentations and half-ellipsoids, in a pattern comprising at least one of blisters or fish scales.

28. A plurality of cBN grains made from the method of claim 27 wherein at least one grain face on each of said plurality of grains comprises three or more features projecting from said grain face wherein the height (h) and the lateral length (l) of each feature is greater than about 0.1 micron.

29. The method of claim 27 , wherein said cBN grains have an average weight loss of more than about 5% w/w of the weight loss compared to conventional cBN grains not subjected to said method.

30. A method of making a plurality of cubic boron nitride (cBN) grains comprising the steps of: providing a plurality of hexagonal boron nitride (hBN) grains; providing a catalyst; subjecting said hBN grains and said catalyst to high pressure and high temperature for a time period sufficient to form a reaction mass containing cBN grains; reducing the pressure below for a time exceeding about 30 seconds to allow for limited dissolution of said cBN grains; reducing the temperature and pressure to atmospheric level; and cleaning said cBN grains from said reaction mass using a combination of water and acidic solutions or caustic chemicals, at a temperature of about 290° C. to about 400° C. for about 5 to about 10 minutes, wherein at least about 15% of said plurality of cBN grains have at least one grain face comprising three or more features wherein the height (h) and the lateral length (l) of each feature is greater than about 0.1 micron, wherein said grains are free of coating material, wherein the features comprise at least one of peaks, valleys, concave indentations and half-ellipsoids, in a pattern comprising at least one of blisters or fish scales.

31. An uncoated abrasive or superabrasive grain having at least one grain face comprising three or more features projecting from said grain face wherein the height (h) and the lateral length (l) of each feature is greater than about 0.1 micron and wherein said grain has at least one face on the grain is concave having a depth greater than about 1.0 micron, wherein the features comprise at least one of peaks, valleys, concave indentations and half-ellipsoids, in a pattern comprising at least one of blisters or fish scales.