US4082575A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Production of liquid compatible metals
Assignee: Aavid Thermacore Inc
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Filing: 1976-04-21
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Granted: 1978-04-04
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Expires: 1996-04-21
Abstract
Abstract A process for producing liquid compatible metals and a heat pipe manufactured by that process. One example of the process comprises the formation of an aluminum oxide surface layer on an aluminum bearing steel alloy by heating the steel to a high temperature in an oxidizing environment.
Inventors
- 👤 George Y. Eastman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 15:15
CPC Classifications
F; F28; F28D; F28D15/00; F28D15/02; C; C23; C23C; C23C8/00; C23C8/02; C23C8/06; C23C8/08; C23C8/10; C23C8/12; C23C8/14; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/4935; Y10T29/49353; Y10T428/00; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
154 words
A method of making a water compatible steel heat pipe which comprises: selecting a steel with a thermal expansion rate sufficiently similar to that of aluminum oxide to prevent cracking and spalling of an aluminum oxide coating during thermal cycling and containing between one-half and five percent aluminum as an alloying metal; performing all required forming operations to shape said steel into the casing of a heat pipe; heating said casing within an environment of clean, dry air to a temperature of between 500° to 1000° Centigrade for between one and ten hours, diffusing the aluminum alloying metal to the surface of said casing and causing a chemical reaction to occur between the aluminum and the oxygen of the air to form a continuous adherent water compatible surface coating of aluminum oxide of approximately one micron depth; and using said surface coated casing as a component of a heat pipe assembled by conventional methods.
Claim 2
Independent Claim
154 words
A method of making a water compatible steel heat pipe which comprises: selecting a steel with a thermal expansion rate sufficiently similar to that of aluminum oxide to prevent cracking and spalling of an aluminum oxide coating during thermal cycling and containing between one-half and five percent aluminum as an alloying metal; performing all required forming operations to shape said steel into the casing of a heat pipe; heating said casing within an environment of clean, dry air to a temperature of between 500° to 1000° Centigrade for between one and ten hours, diffusing the aluminum alloying metal to the surface of said casing and causing a chemical reaction to occur between the aluminum and the oxygen of the air to form a continuous adherent water compatible surface coating of aluminum oxide of approximately one micron depth; and using said surface coated casing as a component of a heat pipe assembled by conventional methods.
Claim 3
Dependent Claim
34 words
A method of making a water compatible heat pipe from steel as in claim 1 which comprises the additional step of cleaning said casing of the heat pipe immediately prior to the heating step.
Claim 4
Dependent Claim
78 words
A water-compatible steel part for a heat pipe which has a surface coating of aluminum oxide produced by heating the part formed from steel containing between one half and five percent aluminum in a clean, dry air atmosphere to a temperature of between 500 and 1000 degrees Centigrade for a time sufficient to oxidize the aluminum into a continuous surface coating of approximately one micron depth which protects the steel from the effects of contact with the water.
Claim 5
Dependent Claim
78 words
A water-compatible steel part for a heat pipe which has a surface coating of aluminum oxide produced by heating the part formed from steel containing between one half and five percent aluminum in a clean, dry air atmosphere to a temperature of between 500 and 1000 degrees Centigrade for a time sufficient to oxidize the aluminum into a continuous surface coating of approximately one micron depth which protects the steel from the effects of contact with the water.
Claim 6
Dependent Claim
86 words
A water-compatible steel sealed casing which remains imperious and chemically inert despite repeated extreme thermal cycling which has a surface coating of aluminum oxide produced by heating the part formed from steel containing between one half and five percent aluminum in a clean, dry air atmosphere to a temperature of between 500 and 1000 degrees Centigrade for a time sufficient to oxidize the aluminum into a continuous surface coating of approximately one micron depth which protects the steel from the effects of contact with the water.
Claim 7
Dependent Claim
86 words
A water-compatible steel sealed casing which remains imperious and chemically inert despite repeated extreme thermal cycling which has a surface coating of aluminum oxide produced by heating the part formed from steel containing between one half and five percent aluminum in a clean, dry air atmosphere to a temperature of between 500 and 1000 degrees Centigrade for a time sufficient to oxidize the aluminum into a continuous surface coating of approximately one micron depth which protects the steel from the effects of contact with the water.
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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) | 1981-04-03 | 1981-10-03 | 1982-04-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-04-03 | 1985-10-03 | 1986-04-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-04-03 | 1989-10-03 | 1990-04-04 | $7700.00 | Window Closed / Lapsed |