US4948662A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Boron nitride coated ceramic fibers and coating method
Assignee: Boeing Co
•
Filing: 1986-04-07
•
Granted: 1990-08-14
•
Expires: 2006-04-07
Abstract
Abstract Oxide-based ceramic fibers are treated in a novel process to create a substantially uniform boron nitride barrier coating at their surface. The process involves heating the fibers in a nitriding atmosphere at between about 2200-2600° F. to create a BN coating at the surface of the fiber from boron initially within the fiber.
Inventors
- 👤 Frederick H. Simpson
- 👤 Juris Verzemnieks
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 19:35
CPC Classifications
C; C23; C23C; C23C8/00; C23C8/06; C23C8/28; C04; C04B; C04B35/00; C04B35/622; C04B35/62227; C04B35/62231; C04B35/6224; C04B35/62245; C04B35/626; C04B35/628; C04B35/62844; C04B35/62857; C04B35/62865; C04B35/62868; C04B41/00; C04B41/45; C04B41/4584; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2913; Y10T428/2916; Y10T428/2933; Y10T428/294; Y10T428/2956; Y10T442/00; Y10T442/20; Y10T442/2926; Y10T442/2975
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
77 words
A method for coating a ceramic fiber that contains boron with boron nitride, comprising the step of diffusing boron in the fiber to the fiber surface and reacting the diffusing boron at the surface with a suitable source of nitrogen in a nitriding atmosphere, to form a surface coating the reaction occurring at a temperature of between about 2200° F.-2600° F., wherein all the boron in the boron nitride coating comes from boron originally in the fiber.
Claim 2
Independent Claim
77 words
A method for coating a ceramic fiber that contains boron with boron nitride, comprising the step of diffusing boron in the fiber to the fiber surface and reacting the diffusing boron at the surface with a suitable source of nitrogen in a nitriding atmosphere, to form a surface coating the reaction occurring at a temperature of between about 2200° F.-2600° F., wherein all the boron in the boron nitride coating comes from boron originally in the fiber.
Claim 3
Dependent Claim
13 words
The method of claim 1 wherein the atmosphere includes 5-100% vol. % ammonia.
Claim 4
Dependent Claim
21 words
The method of claim 1 wherein the atmosphere includes 5-10 vol. % ammonia, 0-12 vol. % hydrogen, and the remainder nitrogen.
Claim 5
Dependent Claim
13 words
The method of claim 1 wherein the temperature is between about 2400-2500° F.
Claim 6
Dependent Claim
21 words
The method of claim 1 wherein the atmosphere is a continuously flowing gas having a flowrate between about 0.25-3.2 standard liters/min.
Claim 7
Dependent Claim
11 words
The method of claim 1 wherein the ceramic fiber is oxide-based.
Claim 8
Dependent Claim
10 words
The method of claim 6 wherein the fiber includes boria.
Claim 9
Dependent Claim
11 words
The method of claim 7 wherein the fiber further includes aluminosilicate.
Claim 10
Dependent Claim
29 words
The method of claim 1 further comprising the step of crystallizing the remaining portion of the fiber during the reaction of boron with the atmosphere to form the coating.
Claim 11
Independent Claim
111 words
A method for coating a ceramic fiber, comprising a major portion of aluminosilicate and a minor portion of boria, to produce a crystalline aluminosilicate fiber having a thin, uniform, and continuous boron nitride coating formed with boron initially within the fiber, the method comprising the steps of: (a) heating an uncoated aluminoborosilicate fiber rapidly from about ambient to at least about 2200° F. in a nitriding atmosphere containing ammonia; (b) diffusing boron from within the fiber to the surface of the fiber where the boron reacts with the atmosphere to form a boron nitride coating, the diffusing step occurring for between about 5-90 minutes at a temperature of about 2200-2600° F.
Claim 12
Independent Claim
111 words
A method for coating a ceramic fiber, comprising a major portion of aluminosilicate and a minor portion of boria, to produce a crystalline aluminosilicate fiber having a thin, uniform, and continuous boron nitride coating formed with boron initially within the fiber, the method comprising the steps of: (a) heating an uncoated aluminoborosilicate fiber rapidly from about ambient to at least about 2200° F. in a nitriding atmosphere containing ammonia; (b) diffusing boron from within the fiber to the surface of the fiber where the boron reacts with the atmosphere to form a boron nitride coating, the diffusing step occurring for between about 5-90 minutes at a temperature of about 2200-2600° F.
Claim 13
Dependent Claim
16 words
The method of claim 10 wherein the temperature during the diffusing step is about 2400-2500° F.
Claim 14
Dependent Claim
17 words
The method of claim 10 wherein the heating step lasts for no more than about two hours.
Claim 15
Dependent Claim
22 words
The method of claim 10 wherein the atmosphere includes about 5-10 vol. % ammonia, 0-12 vol. % hydrogen and the remainder nitrogen.
Claim 16
Independent Claim
165 words
A method for coating an uncoated oxide-based ceramic fibers in a fiber cloth, the fiber comprising a major portion of aluminosilicate and a minor portion of boria, the product being a coated aluminosilicate fiber having a thin, continuous, uniform boron nitride coating on all surfaces of the fibers, including fractures and fiber ends, the boron in the coating coming wholly from boron within the fibers, the method comprising the steps of: (a) placing a fiber cloth in a furnace; (b) flowing a nitriding atmosphere past the fiber cloth in the furnace, the atmosphere containing at least 5 vol. % ammonia; (c) heating the furnace from ambient to at least about 2200° F. in no more than about two hours; and (d) maintaining the temperature between about 2200-2600° F. for between about 5-90 additional minutes to allow boron within the fibers to diffuse to the surface of the fibers and to react with the nitriding atmosphere at the fiber surface to form the boron nitride coating.
Claim 17
Independent Claim
165 words
A method for coating an uncoated oxide-based ceramic fibers in a fiber cloth, the fiber comprising a major portion of aluminosilicate and a minor portion of boria, the product being a coated aluminosilicate fiber having a thin, continuous, uniform boron nitride coating on all surfaces of the fibers, including fractures and fiber ends, the boron in the coating coming wholly from boron within the fibers, the method comprising the steps of: (a) placing a fiber cloth in a furnace; (b) flowing a nitriding atmosphere past the fiber cloth in the furnace, the atmosphere containing at least 5 vol. % ammonia; (c) heating the furnace from ambient to at least about 2200° F. in no more than about two hours; and (d) maintaining the temperature between about 2200-2600° F. for between about 5-90 additional minutes to allow boron within the fibers to diffuse to the surface of the fibers and to react with the nitriding atmosphere at the fiber surface to form the boron nitride coating.
Claim 18
Dependent Claim
25 words
A boron nitride coated aluminosilicate ceramic fiber comprising an aluminosilicate fiber and a thin, uniform, continuous boron nitride coating at the surface of the fiber.
Claim 19
Dependent Claim
25 words
A boron nitride coated aluminosilicate ceramic fiber comprising an aluminosilicate fiber and a thin, uniform, continuous boron nitride coating at the surface of the fiber.
Claim 20
Dependent Claim
10 words
The fiber of claim 15 wherein the aluminosilicate is crystalline.
Claim 21
Dependent Claim
42 words
The fiber of claim 16 wherein the boron in the coating is initially within the fiber and is incorporated into the coating by diffusing the boron to the surface and reacting the boron there with a nitriding atmosphere to form boron nitride.
Claim 22
Dependent Claim
14 words
The fiber of claim 17 wherein the fiber includes about 12 wt % boria.
Claim 23
Dependent Claim
21 words
A boron nitride coated NEXTEL aluminoborosilicate fiber formed by coating a NEXTEL 312 fiber according to the method of claim 1.
Claim 24
Dependent Claim
10 words
The fiber cloth formed by the process of claim 14.
Claim 25
Dependent Claim
46 words
A ceramic fiber composite, comprising: a plurality of ceramic fibers, wherein each crystalline NEXTEL 312 fiber; a fiber coating of boron nitride disposed over each fiber made in accordance with the method of claim 1; and a glass ceramic matrix encapsulating said plurality of coated fibers.
References Cited (Backward Citations)
US2745763A
Cited
US2958610A
Cited
US3058809A
Cited
US3212926A
Cited
US3351484A
Cited
US3451840A
Cited
US3386918A
Cited
US3422321A
Cited
US3520722A
Cited
US3576610A
Cited
US3573969A
Cited
US3634132A
Cited
US3720536A
Cited
US3811928A
Cited
US3668059A
Cited
US3837997A
Cited
US4009305A
Cited
US3955038A
Cited
US4196233A
Cited
US4163074A
Cited
US4284610A
Cited
US4346147A
Cited
US4331772A
Cited
US4309203A
Cited
US4335190A
Cited
US4642271A
Cited
US4605588A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-08-13 | 1994-02-12 | 1994-08-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-08-13 | 1998-02-12 | 1998-08-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-08-13 | 2002-02-12 | 2002-08-14 | $7700.00 | Window Closed / Lapsed |