Method of fluxless brazing and diffusion bonding of aluminum containing components
OwnerJames C. Administrator of the National Aeronautics and Space Administration, with respect to an invention of Fletcher, Aleck B. Featherston +1inventors
InventorsJames C. Administrator of the National Aeronautics and Space Administration, with respect to an invention of Fletcher, Aleck B. Featherston, Kent P. O'Kelly
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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.
Claims18
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.
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.
Dependencies are inferred from the claim text.