US4244751A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for melt nitriding of aluminum or its alloy
Assignee: Hitachi Ltd
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Filing: 1979-06-26
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Granted: 1981-01-13
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Expires: 1999-06-26
Abstract
Abstract Aluminum or its alloy is subjected to surface treatment wherein the surface is heated and melted by the heat of an electric arc in an atmosphere of a mixture of inert gas and nitrogen gas. By this treatment, a dense layer of aluminum nitride is formed on the surface of aluminum or its alloy so that material of increased wear resistance is obtained.
Inventors
- 👤 Susumu Hioki
- 👤 Toshihiro Yamada
- 👤 Kazuyoshi Hatano
- 👤 Mitsuaki Haneda
- 👤 Shoji Imanaga
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 08:11
CPC Classifications
C; C23; C23C; C23C8/00; C23C8/06; C23C8/08; C23C8/24
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
76 words
A method for melt nitriding of a surface layer of aluminum or its alloy comprising the steps of: maintaining a surface layer of the aluminum or its alloy in a molten state for a predetermined period of time by heating the layer in an atmosphere of a gas mixture of inert gas and nitrogen gas by the heat of an electric arc to effect nitriding of the surface layer; and gradually cooling the surface layer therafter.
Claim 2
Independent Claim
76 words
A method for melt nitriding of a surface layer of aluminum or its alloy comprising the steps of: maintaining a surface layer of the aluminum or its alloy in a molten state for a predetermined period of time by heating the layer in an atmosphere of a gas mixture of inert gas and nitrogen gas by the heat of an electric arc to effect nitriding of the surface layer; and gradually cooling the surface layer therafter.
Claim 3
Dependent Claim
34 words
A method as set forth in claim 1, wherein the proportion of nitrogen gas in the gas mixture of inert gas and nitrogen gas is in a range between 0.10 and 50.0% by weight.
Claim 4
Dependent Claim
14 words
A method as set forth in claim 1, wherein the inert gas is argon.
Claim 5
Dependent Claim
36 words
A method as set forth in claim 1, wherein said predetermined period of time for maintaining the surface layer in molten state is sufficient to nitride the surface layer to a thickness of about 0.2 mm.
Claim 6
Dependent Claim
17 words
A method as set forth in claim 1, wherein said predetermined period of time is several seconds.
Claim 7
Dependent Claim
21 words
A method as set forth in claim 1 or claim 5, wherein said predetermined period of time is about five seconds.
Claim 8
Dependent Claim
45 words
A method as set forth in claim 1, wherein maintaining the molten surface layer of the aluminum or aluminum alloy in an atmosphere of a gas mixture of inert gas and nitrogen gas diffuses nitrogen into the molten surface layer of aluminum or aluminum alloy.
Claim 9
Dependent Claim
16 words
A method as set forth in claim 1, wherein said aluminum alloy is an aluminum-magnesium alloy.
Claim 10
Dependent Claim
21 words
A method as set forth in claim 1, wherein a portion of the surface layer is maintained in a molten state.
Claim 11
Independent Claim
88 words
A method for melt nitriding of a surface layer of aluminum or aluminum alloy comprising; flowing a gas mixture of argon gas and nitrogen gas against the surface of the aluminum or aluminum alloy; generating an electric arc between an electrode and the surface layer of aluminum or aluminum alloy to form a molten pool of aluminum or aluminum alloy; nitriding a surface layer of aluminum or aluminum alloy by diffusing nitrogen into said molten pool of aluminum or aluminum alloy; and gradually cooling the molten surface layer.
Claim 12
Independent Claim
88 words
A method for melt nitriding of a surface layer of aluminum or aluminum alloy comprising; flowing a gas mixture of argon gas and nitrogen gas against the surface of the aluminum or aluminum alloy; generating an electric arc between an electrode and the surface layer of aluminum or aluminum alloy to form a molten pool of aluminum or aluminum alloy; nitriding a surface layer of aluminum or aluminum alloy by diffusing nitrogen into said molten pool of aluminum or aluminum alloy; and gradually cooling the molten surface layer.
References Cited (Backward Citations)
US3944443A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-01-13 | 1984-07-14 | 1985-01-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-01-13 | 1988-07-14 | 1989-01-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-01-13 | 1992-07-14 | 1993-01-13 | $7700.00 | Window Closed / Lapsed |