Claims
- 1. A plurality of abrasive grain having a specified nominal grade, said plurality of abrasive grain having a particle size distribution, by volume, ranging from fine to coarse and a median particle size of up to 40 micrometers, wherein at least a portion of said abrasive grain is a plurality of sintered, crystalline ceramic, alpha alumina-based abrasive grain having an outer surface, an outer region, and an inner region, wherein said outer region is adjacent to said outer surface, wherein said sintered, crystalline ceramic, alpha alumina-based abrasive grain comprises:
- (a) alpha alumina crystallites; and
- (b) aluminate platelets comprising aluminate having a magnetoplumbite crystal structure, said aluminate platelets being distributed between said alpha alumina crystallites, and said aluminate platelets being present in said inner region and said outer region, and
- wherein said aluminate platelets in said outer region are on average larger in size than said aluminate platelets in said inner region.
- 2. The plurality of abrasive grain according to claim 1 wherein said aluminate is represented by the formula:
- LnMAl.sub.11 O.sub.19,
- wherein:
- Ln is a lanthanide rare earth selected from the group consisting of La.sup.3+, Nd.sup.3+, Ce.sup.3+, Pr.sup.3+, Sm.sup.3+, Gd.sup.3+, and Eu.sup.3+ ; and
- M is a divalent metal cation selected from the group consisting of Mg.sup.2+, Mn.sup.2+, Mn.sup.2+, Zn.sup.2+, Ni.sup.2+, and Co.sup.2+.
- 3. The plurality of abrasive grain according to claim 2, wherein at least 30 percent by volume of said abrasive grain is within 10 micrometers of said median particle size.
- 4. The plurality of abrasive grain according to claim 2 wherein at least 50 percent by volume of said abrasive grain is within 5 micrometers of said median particle size.
- 5. The plurality of abrasive grain according to claim 2 wherein said abrasive grain have particle sizes of less than 30 micrometers.
- 6. The plurality of abrasive grain according to claim 2 wherein said abrasive grain have particle sizes in the range from about 1 to about 25 micrometers.
- 7. The plurality of abrasive grain according to claim 2 wherein said abrasive grain have particle sizes of less than 25 micrometers.
- 8. The plurality of abrasive grain according to claim 2 wherein said abrasive grain have particle sizes of less than 20 micrometers.
- 9. The plurality of abrasive grain according to claim 2 wherein said abrasive grain have particle sizes of less than 15 micrometers.
- 10. The plurality of abrasive grain according to claim 2 wherein said sintered, polycrystalline ceramic, alpha alumina-based abrasive grain includes, on a theoretical oxide basis, up to 15 percent by weight oxide selected from the group consisting of iron oxide, magnesium oxide, manganese oxide, zinc oxide, cerium oxide, cobalt oxide, titanium oxide, nickel oxide, yttrium oxide, praseodymium oxide, samarium oxide, ytterbium oxide, neodymium oxide, lanthanum oxide, gadolinium oxide, dysprosium oxide, erbium oxide, europium oxide, silicon dioxide, chromium oxide, calcium oxide, strontium oxide, zirconium oxide, hafnium oxide, and combinations thereof, calculated as Fe.sub.2 O.sub.3, MgO, MnO, ZnO, Ce.sub.2 O.sub.3, CoO, Ti.sub.2 O.sub.3, NiO, Y.sub.2 O.sub.3, Pr.sub.2 O.sub.3, Sm.sub.2 O.sub.3, Yb.sub.2 O.sub.3, Nd.sub.2 O.sub.3, La.sub.2 O.sub.3, Gd.sub.2 O.sub.3, Dy.sub.2 O.sub.3, Er.sub.2 O.sub.3, Eu.sub.2 O.sub.3, SiO.sub.2, Cr.sub.2 O.sub.3, CaO, SrO, Zr.sub.2 O.sub.3, and HfO.sub.2.
- 11. An abrasive article including
- (a) a binder; and
- (b) said plurality of abrasive grain according to claim 2 secured within said article by said binder.
- 12. An abrasive article according to claim 11 wherein said abrasive article is a grinding wheel.
- 13. An abrasive article according to claim 11 wherein said abrasive article is a nonwoven abrasive.
- 14. A coated abrasive article comprising:
- (a) a backing having a major surface; and
- (b) an abrasive layer comprising said plurality of abrasive grain according to claim 2 secured to said major surface of said backing by a binder.
- 15. The plurality of abrasive grain according to claim 2 wherein at least 15 percent by weight of said abrasive grain is said alpha alumina-based abrasive grain.
- 16. The plurality of abrasive grain according to claim 2 wherein at least 30 percent by weight of said abrasive grain is said alpha alumina-based abrasive grain.
- 17. The plurality of abrasive grain according to claim 2 wherein at least 50 percent by weight of said abrasive grain is said alpha alumina-based abrasive grain.
- 18. The plurality of abrasive grain according to claim 2 wherein at least 75 percent by weight of said abrasive grain is said alpha alumina-based abrasive grain.
- 19. The plurality of abrasive grain according to claim 2 consisting essentially of said sintered, polycrystalline ceramic, alpha alumina-based abrasive grain.
- 20. The plurality of abrasive grain according to claim 2 further comprising abrasive grain other than said alpha alumina-based abrasive grain, said other abrasive grain having an average particle size less than the average particle size of said alpha alumina-based abrasive grain.
- 21. The plurality of abrasive grain according to claim 2 wherein said median particle size is less than 30 micrometers.
- 22. An abrasive article including:
- (a) a binder; and
- (b) said plurality of abrasive grain according to claim 21 secured within said article by said binder.
- 23. The plurality of abrasive grain according to claim 1 wherein median particle size is less than 30 micrometers.
- 24. An abrasive article including:
- (a) a binder; and
- (b) said plurality of abrasive grain according to claim 23 secured within said article by said binder.
- 25. A plurality of abrasive grain having a specified nominal grade, said abrasive grain having a particle size distribution, by volume, ranging from fine to coarse and a median particle size of up to 40 micrometers, wherein at least a portion of said abrasive grain is a plurality of sintered, crystalline ceramic, alpha alumina-based abrasive grain having an outer surface, an outer region, an inner region, and a particle size less than 30 micrometers, wherein said outer region is adjacent to said outer surface, wherein said sintered, crystalline ceramic, alpha alumina-based abrasive grain comprises:
- (a) alpha alumina crystallites; and
- (b) aluminate platelets comprising aluminate having a magnetoplumbite crystal structure, said aluminate platelets being distributed between said alpha alumina crystallites, and said aluminate platelets being present in said inner region and said outer region, and
- wherein said aluminate platelets in said outer region are on average larger in size than said aluminate platelets in said inner region.
- 26. The plurality of abrasive grain according to claim 25 wherein said aluminate is represented by the formula:
- LnMAl.sub.11 O.sub.19,
- wherein:
- Ln is a lanthanide rare earth selected from the group consisting of La.sup.3+, Nd.sup.3+, Ce.sup.3+, Pr.sup.3+, Sm.sup.3+, Ge.sup.3+, and Eu.sup.3+ ; and
- M is a divalent metal cation selected from the group consisting of Mg.sup.2+, Mn.sup.2+, Zn.sup.2+, Ni.sup.2+, and Co.sup.2+.
- 27. The plurality of abrasive grain according to claim 26 wherein said median particle size is less than 30 micrometers.
- 28. An abrasive article including:
- (a) a binder; and
- (b) said plurality of abrasive grain according to claim 26 secured within said article by said binder.
- 29. The plurality abrasive grain according to claim 1 wherein said median particle size is less than 20 micrometers.
Parent Case Info
This is a continuation of application Ser. No. 08/174,675 filed Dec. 28, 1993, now abandoned.
US Referenced Citations (23)
Foreign Referenced Citations (1)
Number |
Date |
Country |
0291029 |
Nov 1988 |
EPX |
Continuations (1)
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Number |
Date |
Country |
Parent |
174675 |
Dec 1993 |
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