US4187344A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Protective silicon nitride or silicon oxynitride coating for porous refractories
Assignee: Saint Gobain Abrasives Inc
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Filing: 1978-09-27
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Granted: 1980-02-05
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Expires: 1998-09-27
Abstract
Abstract Porous refractory articles resistant to degradation at high temperatures for example by oxygen, chlorine and the like, are composed of a main body of a porous sintered carbide, nitride, boride or silicide which is coated with silicon nitride or silicon oxynitride. The coating is not only on the surface of the main body of the porous refractory article, but also penetrates the article to a depth at least greater than the depth of the surface pores.
Inventors
- 👤 John I. Fredriksson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 21:14
CPC Classifications
C; C04; C04B; C04B41/00; C04B41/009; C04B41/45; C04B41/50; C04B41/5053; C04B41/5062; C04B41/80; C04B41/81; C04B41/85; C04B41/87; Y; Y10; Y10T; Y10T428/00; Y10T428/249921; Y10T428/249953; Y10T428/249955; Y10T428/249956; Y10T428/249957; Y10T428/249967; Y10T428/24997; Y10T428/25; Y10T428/259; Y10T428/29; Y10T428/2982; Y10T428/2991; Y10T428/2993
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
49 words
A porous refractory article including a protective coating thereon, said coating being a material selected from the group consisting of silicon nitride, silicon oxynitride, and mixtures thereof, and wherein said coating has penetrated the porous refractory article to a depth greater than the depth of the surface pores therein.
Claim 2
Dependent Claim
49 words
A porous refractory article including a protective coating thereon, said coating being a material selected from the group consisting of silicon nitride, silicon oxynitride, and mixtures thereof, and wherein said coating has penetrated the porous refractory article to a depth greater than the depth of the surface pores therein.
Claim 3
Dependent Claim
18 words
The refractory article of claim 1 wherein the main body of said article is comprised of a nitride.
Claim 4
Dependent Claim
18 words
The refractory article of claim 1 wherein the main body of said article is comprised of a boride.
Claim 5
Dependent Claim
18 words
The refractory article of claim 1 wherein the main body of said article is comprised of a silicide.
Claim 6
Dependent Claim
18 words
The refractory article of claim 1 wherein the main body of said article is comprised of a carbide.
Claim 7
Dependent Claim
19 words
The refractory article of claim 5 wherein said carbide is silicon carbide and said article is a heating element.
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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) | 1983-02-04 | 1983-08-06 | 1984-02-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-02-04 | 1987-08-06 | 1988-02-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-02-04 | 1991-08-06 | 1992-02-05 | $7700.00 | Window Closed / Lapsed |