US5215551A
Expired / Lapsed
US
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Alumina-based ceramics materials, abrasive materials and method for the manufacture of the same
Assignee: Resonac Holdings Corp
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Filing: 1990-02-01
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Granted: 1993-06-01
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Expires: 2010-02-01
Abstract
Abstract An α-alumina-based ceramics material comprising crystals of a particle diameter of no greater than 0.2 μm on an average or a particle diameter of substantially no greater than 0.2 μm, and having a density of no lower than 95% of the theoretical density and a hardness of no lower than 2,000 kg/mm 2 , and a method for the production thereof.
Inventors
- 👤 Tetsuo Hatanaka
- 👤 Tadashi Hiraiwa
- 👤 Minoru Matsukura
- 👤 Norimichi Aoki
- 👤 Shoichi Imai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 12:02
CPC Classifications
C; C09; C09K; C09K3/00; C09K3/14; C09K3/1409; C09K3/1418; C04; C04B; C04B35/00; C04B35/01; C04B35/10; C04B35/111; C04B35/1115
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
54 words
An α-alumina-based ceramic comprising crystals of a particle diameter in a range from 0.03 to 0.30 μm inclusively and an average particle diameter of no greater than 0.2 μm, and having a density of no lower than 95% of a theoretical density and a Vickers hardness of no lower than 2,000 kg/mm 2 .
Claim 2
Dependent Claim
54 words
An α-alumina-based ceramic comprising crystals of a particle diameter in a range from 0.03 to 0.30 μm inclusively and an average particle diameter of no greater than 0.2 μm, and having a density of no lower than 95% of a theoretical density and a Vickers hardness of no lower than 2,000 kg/mm 2 .
Claim 3
Dependent Claim
13 words
An alumina-based abrasive grain comprising said α-alumina-based ceramic as claimed in claim 1.
Claim 4
Dependent Claim
13 words
An abrasive material comprising said alumina-based abrasive grain as claimed in claim 2.
Claim 5
Dependent Claim
54 words
An α-alumina-based ceramic as claimed in claim 1, wherein said α-alumina-based ceramic contains at least one oxide of at least one of Fe, Cu, Ni, Ba, Be, Mg, Cr, Si, Mn, Zr, Ti, Ca, V, Ga, and Rh, the amount of said oxide being no more than 20 wt % of said α-alumina-based ceramic.
Claim 6
Dependent Claim
13 words
An aluminum-based abrasive grain comprising said α-alumina-based ceramic as claimed in claim 4.
Claim 7
Dependent Claim
13 words
An abrasive material comprising said alumina-based abrasive grain as claimed in claim 5.
Claim 8
Independent Claim
169 words
A method for the production of an α-alumina-based ceramic having a use as an abrasive grain, said α-alumina-based ceramic comprising crystals of a particle diameter in a range from 0.03 to 0.30 μm inclusively and an average particle diameter of no greater than 0.2 μm, by gelling an alumina sol containing fine α-alumina crystal grains, heating the gelled product to 900° C., subsequently increasing the temperature of the product from 900° C. to 1,100° C. in less than 90 seconds, and subsequently retaining the product at a temperature between 1,000° C. and 1,300° C. wherein the retention time is from 30 seconds to 10 minutes in the case where the retention temperature is in the range of from 1,200° to 1,300° C., from 10 minutes to 10 hours in the case where the retention temperature is in a range of from 1,100° to 1,200° C., and from 10 hours to 100 hours in the case where the retention temperature is in a range of from 1,000° to 1,100° C.
Claim 9
Independent Claim
169 words
A method for the production of an α-alumina-based ceramic having a use as an abrasive grain, said α-alumina-based ceramic comprising crystals of a particle diameter in a range from 0.03 to 0.30 μm inclusively and an average particle diameter of no greater than 0.2 μm, by gelling an alumina sol containing fine α-alumina crystal grains, heating the gelled product to 900° C., subsequently increasing the temperature of the product from 900° C. to 1,100° C. in less than 90 seconds, and subsequently retaining the product at a temperature between 1,000° C. and 1,300° C. wherein the retention time is from 30 seconds to 10 minutes in the case where the retention temperature is in the range of from 1,200° to 1,300° C., from 10 minutes to 10 hours in the case where the retention temperature is in a range of from 1,100° to 1,200° C., and from 10 hours to 100 hours in the case where the retention temperature is in a range of from 1,000° to 1,100° C.
Claim 10
Dependent Claim
67 words
A method as claimed in claim 7, wherein said gelled product further contains at least one oxide or precursor thereof of at least one of Fe, Cu, Ni, Ba, Be, Mg, Cr, Si, Mn, Zr, Ti, Ca, V, Ga, and Rh, so that the amount of said at least one oxide and oxide of said precursor in said α-alumina-based ceramic is no more than 20 wt %.
Claim 11
Independent Claim
133 words
A method for the production of an α-alumina-based ceramic having a use as an abrasive grain, said α-alumina-based ceramic comprising crystals of a particle diameter in a range from 0.03 to 0.30 μm inclusively and an average particle diameter of no greater than 0.2 μm, by a two-step sintering method comprising gelling an alumina sol containing fine α-alumina crystal grains, heating the gelled product from a temperature substantially near room temperature to 900° C., subsequently increasing the temperature of the product from 900° C to 1,100° C. in less than 90 seconds, and subsequently retaining the product at a temperature between 1,100° C. and 1,300° C., for from 30 seconds to 10 minutes, and further retaining the product at a temperature between 1,100° C. and 1,200° C. for from 1 to 100 hours.
Claim 12
Independent Claim
133 words
A method for the production of an α-alumina-based ceramic having a use as an abrasive grain, said α-alumina-based ceramic comprising crystals of a particle diameter in a range from 0.03 to 0.30 μm inclusively and an average particle diameter of no greater than 0.2 μm, by a two-step sintering method comprising gelling an alumina sol containing fine α-alumina crystal grains, heating the gelled product from a temperature substantially near room temperature to 900° C., subsequently increasing the temperature of the product from 900° C to 1,100° C. in less than 90 seconds, and subsequently retaining the product at a temperature between 1,100° C. and 1,300° C., for from 30 seconds to 10 minutes, and further retaining the product at a temperature between 1,100° C. and 1,200° C. for from 1 to 100 hours.
Claim 13
Dependent Claim
67 words
A method as claimed in claim 9, wherein said gelled product further contains at least one oxide or precursor thereof of at least one of Fe, Cu, Ni, Ba, Be, Mg, Cr, Si, Mn, Zr, Ti, Ca, V, Ga, and Rh, so that the amount of said at least one oxide and oxide of said precursor in said α-alumina-based ceramic is no more than 20 wt %.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-05-31 | 1996-11-30 | 1997-06-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-05-31 | 2000-11-30 | 2001-06-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-05-31 | 2004-11-30 | 2005-06-01 | $7700.00 | Window Closed / Lapsed |