Patent US3629859A successfully refreshed from Google Patents.
US4746376A
Expired / Lapsed
US
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Method of preventing diffusion of N2, O2 or C in selected metal surfaces
Assignee: Kolene Corp
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Filing: 1986-10-22
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Granted: 1988-05-24
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Expires: 2006-10-22
Abstract
Abstract A method and composition for stopping-off nitrogen and/or carbon diffusion into metal surfaces. The composition, which is a mixture of a refractory material selected from the group of zirconium and aluminosilicate, sodium silicofluoride and sodium silicate, is coated onto the metal surface where diffusion is to be prevented. The mixture is cured and the metal part is subjected to elevated temperatures for carburizing, nitriding, or carbonitriding. The coating prevents nitrogen and/or carbon diffusion at the coated area. After treatment the coating is removed.
Inventors
- 👤 Charles M. Bessey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:50
CPC Classifications
C; C23; C23C; C23C8/00; C23C8/04; C21; C21D; C21D1/00; C21D1/68; C21D1/72
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
91 words
A method for preventing the diffusion of nitrogen, oxygen or carbon into a selected surface of a metal at elevated heat treating temperatures comprising, providing an aqueous mixture of a refractory material selected from the group of zircon and aluminosilicate, sodium silicofluoride and a sodium silicate binder, coating the selected surface with said mixture, allowing said mixture to cure, subjecting the work piece to an elevated temperature in the presence of nitrogen or oxygen or carbon or combinations thereof, cooling the work piece, and thereafter removing said coating from work piece.
Claim 2
Independent Claim
91 words
A method for preventing the diffusion of nitrogen, oxygen or carbon into a selected surface of a metal at elevated heat treating temperatures comprising, providing an aqueous mixture of a refractory material selected from the group of zircon and aluminosilicate, sodium silicofluoride and a sodium silicate binder, coating the selected surface with said mixture, allowing said mixture to cure, subjecting the work piece to an elevated temperature in the presence of nitrogen or oxygen or carbon or combinations thereof, cooling the work piece, and thereafter removing said coating from work piece.
Claim 3
Dependent Claim
30 words
The invention as defined in claim 1 wherein there is from about 50% to 80% refractory material, from 10 to 48% sodium silicate, and about 2 to 40% sodium silicofluoride.
Claim 4
Dependent Claim
13 words
The invention as defined in claim 2 wherein the refractory material is zircon.
Claim 5
Dependent Claim
25 words
The invention as defined claim 3 wherein the zircon is about 66% the sodium silicate is about 22% and the sodium silicofluoride is about 12%.
Claim 6
Dependent Claim
13 words
The invention as defined in claim 2 wherein the refractory material is aluminosilicate.
Claim 7
Dependent Claim
26 words
The invention as defined in claim 5 wherein the aluminosilicate is about 53%, the sodium silicate is about 22% and the sodium silicofluoride is about 25%.
Claim 8
Dependent Claim
27 words
The invention as defined in claims 2, 3, 4, 5 or 6 wherein the ratio of SiO2:Na2O in the sodium silicate is between about 2.0:1 and 3.25:1.
References Cited (Backward Citations)
US2641556A
Cited
US3945862A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-05-24 | 1991-11-23 | 1992-05-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-05-24 | 1995-11-23 | 1996-05-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-05-24 | 1999-11-23 | 2000-05-24 | $7700.00 | Window Closed / Lapsed |