Abrasive grain with an abrasive coating
A flowable, granular abrasive material and method of manufacture thereof. The material is comprised of at least one abrasive grain selected from aluminum oxide, silicon carbide, cubic boron nitride and/or diamond and has a organic or inorganic coating comprised of a binder and an abrasive filling material in the amounts of 0.5 to 8% and 1 to 15% by weight, respectively. The filling material may include sulfides, phosphates, carbonates, halogenides, and/or sulfide-, carbonate- and/or halogenide-containing complex compounds. The binder may include a low-viscosity phenol resin, epoxy resin and/or polyurethane resin.
1. An abrasive material comprising at least one abrasive grain selected from the group consisting of aluminum oxide, silicon carbide, cubic boron nitride and diamond, said abrasive grain having a coating of an inorganic or organic binder and an abrasive filling material comprising a mixture of lithium carbonate and manganese sulfate.
2. The abrasive material of claim 1 , wherein the abrasive filling material further comprises at least one material selected from the group consisting of sulfides, phosphates, carbonates, halogenides, and sulfide- carbonate- and halogenide-containing complex compounds including at least one material selected from the group of elements consisting of Na, Li, K, Mg, Al, Mn, Cu, Sn, Fe, Ti, Sb and Zn.
3. The abrasive material of claim 1 , wherein the abrasive filling material is present in an amount of 1 to 5% by weight relative to the at least one abrasive grain.
4. The abrasive material of claim 1 , wherein the abrasive filling material further comprises a mixture of calcium fluoride and calcium tri-phosphate.
5. The abrasive material of claim 4 , wherein the calcium fluoride and calcium tri-phosphate are mixed at a molar ratio of 1:1.
6. The abrasive material of claim 1 , wherein the lithium carbonate and manganese sulfate are mixed at a molar ratio of 1:1.
7. The abrasive material of claim 1 , wherein the binder comprises at least one low-viscosity resin selected from the group consisting of phenol resins, epoxy resins and polyurethane resins.
8. The abrasive material of claim 7 , wherein the viscosity of the resin is less than 1,000 mPa·s.
9. The abrasive material of claim 7 , wherein the viscosity of the resin is less than 700 mPa·s.
10. The abrasive material of claim 1 , wherein the binder comprises at least one inorganic polymer from the group consisting of silicates and phosphates.
11. The abrasive material of claim 1 , wherein the binder is an inorganic binder and comprises aluminum phosphate.
12. The abrasive material of claim 1 , wherein the binder is present in an amount of 1 to 5% by weight relative to the at least one abrasive grain.
13. The abrasive material of claim 1 , wherein the abrasive filler is present in an amount of 3 to 10% by weight relative to the at least one abrasive grain.
14. Method of producing a granular abrasive material, comprising the steps of:
a) mixing at least one abrasive grain with an organic or inorganic binder until the at least one abrasive grain is evenly coated with the binder, wherein the at least one abrasive grain is selected from the group consisting of aluminum oxide, silicon carbide, cubic boron nitride and diamond;
b) adding and admixing an abrasive filling material with the coated abrasive grains until an even distribution of the abrasive filling material on the surface of the grain has been achieved, wherein the abrasive filling material comprises a mixture of lithium carbonate and manganese sulfate; and
c) hardening the coating.
15. The method of claim 14 , wherein the binder is an organic binder and the hardening is effected by at least one of (a) the addition of a curing agent or (b) through thermal post-treatment.
16. The method of claim 15 , wherein the thermal post-treatment is conducted at a temperature of between 80 and 130° C.
17. The method of claim 14 , wherein the binder is an inorganic binder and hardening is carried out by thermally treating the binder in a furnace.
18. The method of claim 17 , wherein the thermal post-treatment is conducted at a temperature greater than or equal to 400° C.
19. The abrasive material of claim 1 , wherein the abrasive grain comprises aluminum oxide and the abrasive filler is present from 25 parts to 75 parts by weight relative to 1000 parts by weight of the abrasive grain, and the binder is an organic resin.
20. The abrasive material of claim 1 , wherein the abrasive grain comprises aluminium oxide and the abrasive filler is present from 15 parts to 30 parts by weight relative to 1000 parts by weight of the abrasive grain, and the binder is an inorganic binder.