Patent US3937387A successfully refreshed from Google Patents.
US3937387A
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Method of fluxless brazing and diffusion bonding of aluminum containing components
Assignee: National Aeronautics and Space Administration
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Filing: 1974-03-12
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Granted: 1976-02-10
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Expires: 1994-03-12
Abstract
Abstract A method of diffusion bonding and fluxless brazing of aluminum containing components, including a method of preparing aluminum containing surfaces for such welding techniques wherein the aluminum surfaces are freed of any aluminum oxide coating and are coated with a polymeric sealer which can be thermally removed leaving essentially no residue, the polymeric sealer being removed in a substantially oxygen-free environment and the aluminum components then being brazed or diffusion bonded without the use of a flux to remove oxide coating.
Inventors
- 👤 with respect to an invention of Fletcher James C. Administrator of the National Aeronautics and Space Administration
- 👤 Aleck B. Featherston
- 👤 Kent P. O'Kelly
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 22:08
CPC Classifications
B; B23; B23K; B23K35/00; B23K35/001; B23K35/002; B23K35/22; B23K35/36; B23K35/3612; B23K35/3613
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
170 words
A method for fluxless brazing of aluminum-containing parts wherein said method utilizes an aluminum alloy brazing material, comprising the steps of: a. removing the aluminum oxide coating from the surfaces of said brazing alloy and said parts to be brazed; b. coating said surfaces with a sealer containing a polymeric material, said polymeric material having the property of preventing significant permeation of oxygen to said surfaces and being thermally removable from said surfaces leaving essentially no residue; c. disposing said brazing alloy between the surfaces of said parts to be brazed; d. bringing said surfaces of said parts to be brazed into intimate contact with said brazing alloy; e. subjecting said surfaces, in a substantially oxygen free environment, to a temperature sufficient to thermally remove all of said polymeric material from said surfaces; f. heating said surfaces and said brazing alloy, in said substantially oxygen free environment, to a temperature sufficient to cause fusion of said brazing alloy and adherence of said surfaces; and g. cooling said thus brazed parts.
Claim 2
Independent Claim
170 words
A method for fluxless brazing of aluminum-containing parts wherein said method utilizes an aluminum alloy brazing material, comprising the steps of: a. removing the aluminum oxide coating from the surfaces of said brazing alloy and said parts to be brazed; b. coating said surfaces with a sealer containing a polymeric material, said polymeric material having the property of preventing significant permeation of oxygen to said surfaces and being thermally removable from said surfaces leaving essentially no residue; c. disposing said brazing alloy between the surfaces of said parts to be brazed; d. bringing said surfaces of said parts to be brazed into intimate contact with said brazing alloy; e. subjecting said surfaces, in a substantially oxygen free environment, to a temperature sufficient to thermally remove all of said polymeric material from said surfaces; f. heating said surfaces and said brazing alloy, in said substantially oxygen free environment, to a temperature sufficient to cause fusion of said brazing alloy and adherence of said surfaces; and g. cooling said thus brazed parts.
Claim 3
Dependent Claim
32 words
The method of claim 1 wherein said sealer comprises said polymeric material dissolved in a suitable solvent and said solvent is evaporated leaving a coating of said polymeric material on said surfaces.
Claim 4
Dependent Claim
16 words
The method of claim 2 wherein said polymeric material comprises polystyrene and said solvent comprises toluene.
Claim 5
Dependent Claim
22 words
The method of claim 3 wherein said polystyrene is present in an amount of from about 0.5 to about 5% by weight.
Claim 6
Dependent Claim
11 words
The method of claim 4 wherein said solvent further includes acetone.
Claim 7
Dependent Claim
78 words
The method of claim 2 wherein said polymeric material coated surfaces are further coated with an adhesive containing an adhesive polymeric material, said adhesive polymeric material having the property of being thermally removable form said surfaces leaving essentially no residue and being thermally removable at substantially the same temperature at which said polymeric material in said sealer is removed, said adhesive material serving to hold said respective parts and said brazing alloy in position prior to said brazing.
Claim 8
Dependent Claim
20 words
The method of claim 6 wherein said adhesive polymeric material is the same as said polymeric material in said sealer.
Claim 9
Dependent Claim
31 words
The method of claim 7 wherein said adhesive contains an adhesive solvent for said adhesive polymeric material and adhesive solvent is removed prior to thermal removal of said adhesive polymeric material.
Claim 10
Dependent Claim
31 words
The method of claim 8 wherein said adhesive solvent comprises toluene and said adhesive polymeric material comprises polystyrene present in an amount of from about 5 to about 10% by weight.
Claim 11
Independent Claim
207 words
A method of diffusion bonding aluminum-containing parts comprising the steps of a. removing the aluminum oxide coating from the surfaces of said parts to be diffusion bonded; b. coating said surfaces with a sealer containing a polymeric material, said polymeric material having the property of preventing significant permeation of oxygen to said surfaces and being thermally removable from said surfaces leaving essentially no residue; c. bringing said surfaces of said parts to be diffusion bonded into contact with one another; d. subjecting said surfaces, in a substantially oxygen-free environment, to a first temperature sufficient to thermally remove all of said polymeric material from said surfaces; e. heating said surfaces, under pressure and in a substantially oxygen-free environment, to a second temperature which is high enough to cause said surfaces to soften but low enough to prevent fusion thereof and causing said surfaces while heated to said second temperature to intimately contact each other; f. cooling said surfaces to a third temperature which is in a predetermined diffusion temperature range which is sufficient to cause diffusion bonding of said surfaces with each other; g. maintaining said third temperature for a period of time sufficient to effect said diffusion bonding; and h. further cooling said thus diffusion bonded parts.
Claim 12
Independent Claim
207 words
A method of diffusion bonding aluminum-containing parts comprising the steps of a. removing the aluminum oxide coating from the surfaces of said parts to be diffusion bonded; b. coating said surfaces with a sealer containing a polymeric material, said polymeric material having the property of preventing significant permeation of oxygen to said surfaces and being thermally removable from said surfaces leaving essentially no residue; c. bringing said surfaces of said parts to be diffusion bonded into contact with one another; d. subjecting said surfaces, in a substantially oxygen-free environment, to a first temperature sufficient to thermally remove all of said polymeric material from said surfaces; e. heating said surfaces, under pressure and in a substantially oxygen-free environment, to a second temperature which is high enough to cause said surfaces to soften but low enough to prevent fusion thereof and causing said surfaces while heated to said second temperature to intimately contact each other; f. cooling said surfaces to a third temperature which is in a predetermined diffusion temperature range which is sufficient to cause diffusion bonding of said surfaces with each other; g. maintaining said third temperature for a period of time sufficient to effect said diffusion bonding; and h. further cooling said thus diffusion bonded parts.
Claim 13
Dependent Claim
32 words
The method of claim 10 wherein said sealer comprises said polymeric material dissolved in a suitable solvent and said solvent is evaporated leaving a coating of said polymeric material on said surfaces.
Claim 14
Dependent Claim
16 words
The method of claim 11 wherein said polymeric material comprises polystyrene and said solvent comprises toluene.
Claim 15
Dependent Claim
22 words
The method of claim 12 wherein said polystyrene is present in an amount of from about 0.5 to about 5% by weight.
Claim 16
Dependent Claim
11 words
The method of claim 13 wherein said solvent further includes acetone.
Claim 17
Dependent Claim
79 words
The method of claim 11 wherein said polymeric material coated surfaces are further coated with an adhesive containing an adhesive polymeric material, said adhesive polymeric material having the property of being thermally removable from said surfaces leaving essentially no residue and being thermally removable at substantially the same temperature at which said polymeric material in said sealer is removed, said adhesive material serving to hold said respective parts and said brazing alloy in position prior to said diffusion bonding.
Claim 18
Dependent Claim
20 words
The method of claim 15 wherein said adhesive polymeric material is the same as said polymeric material in said sealer.
Claim 19
Dependent Claim
32 words
The method of claim 16 wherein said adhesive contains an adhesive solvent for said adhesive polymeric material and said adhesive solvent is removed prior to thermal removal of said adhesive polymeric material.
Claim 20
Dependent Claim
30 words
The method of claim 17 wherein said adhesive solvent comprises toluene and said adhesive polymeric material comprises polystyrene present in an amount from about 5 to about 10% by weight.
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) | 1979-02-09 | 1979-08-11 | 1980-02-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-02-09 | 1983-08-11 | 1984-02-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-02-09 | 1987-08-11 | 1988-02-10 | $7700.00 | Window Closed / Lapsed |