Patent US4451302A successfully refreshed from Google Patents.
US4451302A
Expired / Lapsed
US
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Aluminum nitriding by laser
Assignee: Alcoa Corp
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Filing: 1982-08-27
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Granted: 1984-05-29
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Expires: 2002-08-27
Abstract
Abstract Nitriding a workpiece of aluminum or aluminum alloy by laser treatment in an atmosphere rich in nitrogen is disclosed. Laser treatment is applied for a period of less than one second at a laser power density of at least 0.1x106 W/cm2 to form a hard workpiece surface layer comprising aluminum nitride. A workpiece surface pretreatment, prior to exposure to the laser beam, forms a smutty surface layer having a low content of impurities. A preferred embodiment includes utilizing an aluminum alloy containing an amount of at least 5 weight percent silicon and less than 2.1 weight percent magnesium.
Inventors
- 👤 Ernest Prescott
- 👤 William C. Cochran
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 21:41
CPC Classifications
C; C22; C22F; C22F3/00
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
82 words
A method for nitriding a metal workpiece, comprising: (a) providing a workpiece comprising compact aluminum or aluminum alloy containing less than about 2.1 weight percent magnesium; (b) maintaining an atmosphere rich in nitrogen in contact with said workpiece; and (c) exposing a portion of the surface layer of said workpiece to a laser beam at a power density of at least 0.1×10 6 W/cm 2 for less than one second to form on said workpiece a hardened surface layer comprising aluminum nitride.
Claim 2
Independent Claim
82 words
A method for nitriding a metal workpiece, comprising: (a) providing a workpiece comprising compact aluminum or aluminum alloy containing less than about 2.1 weight percent magnesium; (b) maintaining an atmosphere rich in nitrogen in contact with said workpiece; and (c) exposing a portion of the surface layer of said workpiece to a laser beam at a power density of at least 0.1×10 6 W/cm 2 for less than one second to form on said workpiece a hardened surface layer comprising aluminum nitride.
Claim 3
Dependent Claim
50 words
A hardened aluminum workpiece comprising a workpiece of aluminum or aluminum alloy containing less than about 2.1% magnesium by weight and a finely defined region of hardness containing nitride on the surface of said workpiece, wherein said finely defined region is formed by the nitriding method according to claim 1.
Claim 4
Dependent Claim
32 words
A method according to claim 1 further comprising surface treating said workpiece prior to said exposing to a laser beam to form a smutty surface layer having a low content of impurities.
Claim 5
Dependent Claim
24 words
Claim 3 or claim 2 wherein said workpiece consists of aluminum alloy containing silicon in an amount of at least about 5 weight percent.
Claim 6
Dependent Claim
12 words
Claim 4 wherein said alloy is essentially free of Mg 2 Si.
Claim 7
Dependent Claim
10 words
Claim 5 wherein said atmosphere comprises 75-100 volume percent nitrogen.
Claim 8
Dependent Claim
10 words
Claim 6 wherein said atmosphere comprises 95-100 volume percent nitrogen.
Claim 9
Dependent Claim
20 words
Claim 7 wherein said surface treating comprises contacting said workpiece surface with an aqueous solution of an alkali metal hydroxide.
Claim 10
Dependent Claim
14 words
Claim 8 wherein said laser interaction time is less than 0.01 of a second.
Claim 11
Dependent Claim
24 words
The workpiece according to claim 2 wherein said finely defined region has a bandwidth in the range of 1 mil to about 1.0 inch.
Claim 12
Dependent Claim
27 words
The workpiece according to claim 10 wherein said finely defined region has a depth of nitride in the range of about 1 mil to about 50 mils.
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) | 1987-05-29 | 1987-11-28 | 1988-05-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-05-29 | 1991-11-28 | 1992-05-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-05-29 | 1995-11-28 | 1996-05-29 | $7700.00 | Window Closed / Lapsed |