Patent US4557884A successfully refreshed from Google Patents.
US4557884A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Refractory
Assignee: Dresser Industries Inc
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Filing: 1984-06-29
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Granted: 1985-12-10
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Expires: 2004-06-29
Abstract
Abstract A means for producing nitride bonded refractory shapes, in situ, by mixing an aluminum metal powder, relatively pure silica and a refractory aggregate. The mixes are pressed into shapes and burned at elevated temperatures in a nitriding atmosphere to form the bond.
Inventors
- 👤 Daniel R. Petrak
- 👤 Howard M. Winkelbauer
- 👤 Thomas R. Kleeb
- 👤 Ke-Chin Wang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 07:10
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/622; C04B35/64; C04B35/65
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
138 words
A method for producing nitride bonded refractory bricks, in situ, comprising mixing, by weight, from about 1 to 25% aluminum, about 1 to 25% substantially pure silica and the balance a refractory brickmaking size graded refractory aggregate, selected from the group consisting of silicon carbide, fused mullite and deadburned magnesite, pressing said mixes into refractory bricks, burning the bricks at a first temperature in a nitriding atmosphere for a time sufficient to form silicon and reactive alumina, said temperature being less than the temperature level at which a sialon intergranular bond will form; further burning the bricks at a temperature exceeding the first temperature in a nitriding atmosphere to form silicon nitride from the previously formed silicon; and forming a sialon intergranular bond for the refractory brick by reacting the previously formed reactive alumina with the silicon nitride.
Claim 2
Independent Claim
138 words
A method for producing nitride bonded refractory bricks, in situ, comprising mixing, by weight, from about 1 to 25% aluminum, about 1 to 25% substantially pure silica and the balance a refractory brickmaking size graded refractory aggregate, selected from the group consisting of silicon carbide, fused mullite and deadburned magnesite, pressing said mixes into refractory bricks, burning the bricks at a first temperature in a nitriding atmosphere for a time sufficient to form silicon and reactive alumina, said temperature being less than the temperature level at which a sialon intergranular bond will form; further burning the bricks at a temperature exceeding the first temperature in a nitriding atmosphere to form silicon nitride from the previously formed silicon; and forming a sialon intergranular bond for the refractory brick by reacting the previously formed reactive alumina with the silicon nitride.
Claim 3
Dependent Claim
30 words
Method of claim 1 in which the aluminum comprises, by weight, about 1 to 16% and the substantially pure silica comprises, by weight, about 1.5 to 20% of the mix.
Claim 4
Dependent Claim
28 words
Method of claim 1 in which the first temperature at which the bricks are burned is approximately 800° C. and the second temperature is at least 1250° C.
Claim 5
Dependent Claim
24 words
Method of claim 1 in which the nitriding atmosphere is selected from the group consisting of gaseous nitrogen, industrial annealing gas and ammonia gas.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-12-09 | 1989-06-10 | 1989-12-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-12-09 | 1993-06-10 | 1993-12-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-12-09 | 1997-06-10 | 1997-12-10 | $7700.00 | Window Closed / Lapsed |