Patent US4500644A successfully refreshed from Google Patents.
US4500644A
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Preparation and composition of sialon grain and powder
Assignee: Indresco Inc
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Filing: 1983-12-19
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Granted: 1985-02-19
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Expires: 2003-12-19
Abstract
Abstract Dense sialon grain is produced by briquetting mixtures of micronized silicon and reactive alumina. Sialon powder is produced by ball milling the briquettes after nitriding. The starting mixtures can contain from 10 to 38% reactive alumina with the balance of the mixture micronized silicon. Mixtures made within this range when pressed into dense briquettes and nitrided produce useful sialon grain having minimal free alumina contamination.
Inventors
- 👤 Howard M. Winkelbauer
- 👤 Kenneth W. Hill
- 👤 Ke-Chin Wang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 14:25
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/597; C01; C01B; C01B21/00; C01B21/082; C01B21/0821; C01B21/0826
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
70 words
A method for producing nitride bonded ceramic grain comprising the steps of: mixing, a composition consisting essentially of, by weight, 62-90% micronized silicon powder and about 10 to 38% fine grain alumina powder; ball milling the composition to thoroughly disperse the silicon and alumina powders; compacting the composition to increase the density thereof; and burning the composition at an elevated temperature in a nitriding atmosphere to form the nitride bond.
Claim 2
Independent Claim
70 words
A method for producing nitride bonded ceramic grain comprising the steps of: mixing, a composition consisting essentially of, by weight, 62-90% micronized silicon powder and about 10 to 38% fine grain alumina powder; ball milling the composition to thoroughly disperse the silicon and alumina powders; compacting the composition to increase the density thereof; and burning the composition at an elevated temperature in a nitriding atmosphere to form the nitride bond.
Claim 3
Dependent Claim
33 words
A method in accordance with claim 1 further including the step of adding to the composition about 1/2 weight percent of an additive from the group consisting of calcium fluoride and aluminum fluoride.
Claim 4
Dependent Claim
24 words
A method in accordance with claim 1 wherein the fine grain alumina powder is generally sized between less than one micron and five microns.
Claim 5
Dependent Claim
31 words
a method in accordance with claim 1 wherein the silicon powder consists essentially, by weight, about 70 to 75% and the alumina powder consists essentially, by weight, about 25 to 30%.
Claim 6
Dependent Claim
29 words
A nitride bonded ceramic grain made from a batch consisting essentially of, by weight, 62 to 90% micronized silicon powder and about 10 to 38% fine grain alumina powder.
Claim 7
Dependent Claim
29 words
A nitride bonded ceramic grain made from a batch consisting essentially of, by weight, 62 to 90% micronized silicon powder and about 10 to 38% fine grain alumina powder.
Claim 8
Dependent Claim
30 words
A nitride bonded ceramic grain in accordance with claim 5 wherein the batch includes an additive of, by weight, 1/2% from the group consisting of calcium fluoride and aluminum fluoride.
Claim 9
Dependent Claim
27 words
A nitride bonded ceramic grain in accordance with claim 5 wherein the fine grain alumina powder is generally sized between less than one micron and five microns.
Claim 10
Dependent Claim
34 words
A nitride bonded ceramic grain in accordance with claim 5 wherein the silicon powder consists essentially, by weight, about 70 to 75% and the alumina powder consists essentially, by weight, about 25 to 30%.
References Cited (Backward Citations)
US4243621A
Cited
US4184884A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-02-19 | 1988-08-20 | 1989-02-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-02-19 | 1992-08-20 | 1993-02-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-02-19 | 1996-08-20 | 1997-02-19 | $7700.00 | Window Closed / Lapsed |