US3607025A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Silica-deficient mullite fiber and a process for its production
Assignee: EIDP Inc
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Filing: 1968-04-25
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Granted: 1971-09-21
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Expires: 1988-04-25
Abstract
Abstract Silica-deficient mullite fibers of 82% to 99.9% A12O3 and 0.1% to 18% SiO2 are produced by intimately contacting an alkali metal halide and aluminum trichloride with a silica source in the presence of a moist oxidizing gas at a temperature of from about 1,000* C. to 1,350* C. for at least 10 minutes. The silicadeficient mullite fibers are single crystals exhibiting the X-ray pattern of mullite.
Inventors
- 👤 Howard W Jacobson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 23:13
CPC Classifications
C; C01; C01B; C01B33/00; C01B33/20; C01B33/36; C01B33/38; C01B33/42; C01B33/26; C01B33/40; C01B33/46; C30; C30B; C30B25/00; C30B25/005; C30B29/00; C30B29/10; C30B29/34
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
59 words
The process of claim 1 wherein said alkali metal salt, aluminum trichloride and silica form an intimately contacted charge to a reaction vessel and said aluminum trichloride constitutes from about 5 % to about 30 % by weight based on the total charge, and said silica is not in excess of 50 % by weight based on total charge.
Claim 2
Dependent Claim
62 words
The process of claim 2 wherein said salt melt includes (1) from about 1% to about 15% based on total charge, of a fluoride compound selected from the group consisting of MF, M3AlF6, and AlF3 where M is an alkali metal selected from the group consisting of potassium and sodium, and (2) a compound of the zeolite series as said silica source.
Claim 3
Dependent Claim
69 words
The process of cLaim 3 wherein said alkali metal salt is NaCl and KCl in eutectic proportions, said compounds of the zeolite series is an alkali metal silicate of the formula MAlSi3O8 where M is selected from the group consisting of sodium and potassium, said aluminum trichloride present for reaction is from about 18% to about 23% by weight, based on total charge, and said oxidizing gas is NO2.
Claim 4
Dependent Claim
75 words
A silica-deficient mullite fiber in single crystal form, exhibiting an X-ray pattern of mullite, consisting essentially of from about 0.1% to about 18% by weight silica and at least 82% alumina by weight and having a cross-sectional diameter of about 0.05 to about 30 microns and a length to diameter ratio of about 20:1 to 500:1, the percentage of silica in the fiber being essentially unchanged when the fiber is leached in concentrated hydrofluoric acid.
References Cited (Backward Citations)
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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) | 1974-09-20 | 1975-03-22 | 1975-09-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-09-20 | 1979-03-22 | 1979-09-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-09-20 | 1983-03-22 | 1983-09-21 | $7700.00 | Window Closed / Lapsed |