Bibliographic Citation

 
7377419
Brazing open cell reticulated copper foam to stainless steel tubing with vacuum furnace brazed gold/indium alloy plating
View USPTO link (Link will open in a new window)
05/27/2008
US patent application 11/017,544
Howard, Stanley R. (Windsor, SC); Korinko, Paul S. (Aiken, SC)
Westinghouse Electric Company
United States Department of Energy
AC09-96SR18500
The United States of America as represented by the United States Department of Energy (Washington, DC)
A method of fabricating a heat exchanger includes brush electroplating plated layers for a brazing alloy onto a stainless steel tube in thin layers, over a nickel strike having a 1.3 .mu.m thickness. The resultant Au-18 In composition may be applied as a first layer of indium, 1.47 .mu.m thick, and a second layer of gold, 2.54 .mu.m thick. The order of plating helps control brazing erosion. Excessive amounts of brazing material are avoided by controlling the electroplating process. The reticulated copper foam rings are interference fit to the stainless steel tube, and in contact with the plated layers. The copper foam rings, the plated layers for brazing alloy, and the stainless steel tube are heated and cooled in a vacuum furnace at controlled rates, forming a bond of the copper foam rings to the stainless steel tube that improves heat transfer between the tube and the copper foam.

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