US4278449A
Expired / Lapsed
US
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Method for improving the quality of abrasive grains
Assignee: Tyrolit-Schleifmittelwerke Swarovski KG
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Filing: 1979-12-06
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Granted: 1981-07-14
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Expires: 1999-12-06
Abstract
Abstract Abrasive grain, corundum (Al 2 O 3 ) comprising titanium oxide, preferably Ti 2 O 3 , is provided with a ceramic coating. The abrasive grain is subjected to a heat treatment whereby the Ti-oxides change from the trivalent into the quadrivalent degree of oxidation. The coating and the change of the degree of oxidation are effected simultaneously.
Inventors
- 👤 Harald Helletsberger
- 👤 Anton Aichhorn
- 👤 Erich Bogusch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 05:59
CPC Classifications
C; C09; C09K; C09K3/00; C09K3/14; C09K3/1436
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
106 words
A method of improving abrasive grains of a grinding disc, the abrasive grains made predominantly of Al 2 O 3 with impurities including titanium oxide, comprising: coating the abrasive grains with a ceramic material mixed with metallic oxides capable of giving up nascent oxygen when heated, coating the abrasive grain by fusing the coating onto the abrasive grain at a temperature of between 1,250° and 1,350° C. over a period of between 15 minutes to 2 hours, the ceramic coating being at least partially melted onto the abrasive grain simultaneously with a change of the titanium oxide from the trivalent into the quadrivalent degree of oxidation.
Claim 2
Independent Claim
106 words
A method of improving abrasive grains of a grinding disc, the abrasive grains made predominantly of Al 2 O 3 with impurities including titanium oxide, comprising: coating the abrasive grains with a ceramic material mixed with metallic oxides capable of giving up nascent oxygen when heated, coating the abrasive grain by fusing the coating onto the abrasive grain at a temperature of between 1,250° and 1,350° C. over a period of between 15 minutes to 2 hours, the ceramic coating being at least partially melted onto the abrasive grain simultaneously with a change of the titanium oxide from the trivalent into the quadrivalent degree of oxidation.
Claim 3
Dependent Claim
23 words
A method according to claim 1 wherein said heat treatment is carried out over a period of between 20 minutes and 45 minutes.
Claim 4
Dependent Claim
24 words
A method according to claim 1 wherein metallic oxides, preferably ferric oxides and/or manganese oxides and/or chromium oxides are admixed to the coating material.
Claim 5
Dependent Claim
20 words
A method according to claim 1 wherein substances of a high coefficient of expansion, are admixed to the coating material.
Claim 6
Dependent Claim
14 words
A method according to claim 1 wherein kaolin is used as the coating material.
Claim 7
Dependent Claim
25 words
A method according to claim 1 wherein said abrasive grain is moistened by means of an aqueous solution of borates prior to the coating process.
Claim 8
Dependent Claim
27 words
A method according to claim 1 wherein said abrasive grain is moistened prior to the coating process by means of phosphoric acid, boric acid or silicic acid.
Claim 9
Dependent Claim
23 words
A method according to claim 1 wherein said abrasive grain is moistened prior to the coating process by means of an organic Si-compound.
Claim 10
Dependent Claim
25 words
A method according to claim 1 wherein 0.5-1.5 weight percent of SiC, referred to the amount of abrasive grain, are admixed to the coating material.
Claim 11
Dependent Claim
32 words
A method according to claim 1, wherein said ceramic and metallic oxides mixture is chosen from the group consisting of: inorganic silicates, clay, high melting glass frits, inorganic borates, and inorganic phosphates.
Claim 12
Dependent Claim
28 words
A method according to claim 1, wherein said ceramic and metallic oxides mixture comprises a clay containing at least one of ferric oxides, manganese oxides and chromium oxides.
Claim 13
Dependent Claim
14 words
A method according to claim 4, wherein said substances consist of ZrO 2 .
Claim 14
Dependent Claim
33 words
A method according to claim 1, wherein said metallic oxides include in addition a material having high coefficient of expansion with respect to said ceramic material whereby cracks are formed in the coating.
Claim 15
Dependent Claim
55 words
A method according to claim 1, including in addition the steps of: mixing a bonding material with the coated abrasive grains, and a filler, placing the thus-formed mixture into a form and submitting the form and thus-formed mixture to a temperature of above 195° C. to cure the binding material and form the grinding disc.
Claim 16
Dependent Claim
19 words
A method according to claim 14, wherein the binding material comprises a phenolic resin, the filler material comprises cryolite.
Claim 17
Dependent Claim
42 words
A method according to claim 1, wherein the titanium oxide forming impurities in the abrasive grain before the abrasive grain is heated comprises Ti 2 O 3 which changes to the titanium oxide of TiO 4 after the abrasive grain is heated.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-07-13 | 1985-01-12 | 1985-07-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-07-13 | 1989-01-12 | 1989-07-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-07-13 | 1993-01-12 | 1993-07-14 | $7700.00 | Window Closed / Lapsed |