Method for Soldering Aluminum and Magnesium.
Falke-WL; Lee-AY; Neumeier-LA
U S Patent 1986 (4):
Aluminum, magnesium, or their alloys are soldered by means of a tin- lead system following initial application of a thin coating of nickel-copper alloy. Thus, 1100 aluminum alloy pieces were chemically etched to clean surfaces and then given a electroless zincate treatment to deposit a thin layer of zinc, using cotton swabs to apply the solution. A ni-cu coating then was applied to the surfaces to be soldered by an electrolytic brush-coating method. Five to ten milliliters of an electrolyte containing 125 g/l of nickel acetate, 10 g/l of copper acetate and 5 g/l of boric acid were applied to the metal pieces as cathodes, and the ni-cu coating deposited with the aid of an anode consisting of a 70 pct ni-30 pct cu rod wrapped with a layer of gauze over cotton batting. The process took about 2 min at a current density of 200 ma/cm2 (based on the contact area between the anode stylus and the ni-cu alloy coating). The deposited alloy layer was about 2 um thick and contained 50-60 pct ni. The alloy coated aluminum pieces then were soldered using conventional techniques with 60 pct pb-40 pct sn solder and a rosin-type flux. The strengths of the joints were similar to joints between copper-copper or brass-brass substrates. The ni-cu alloy layer can also be applied by a conventional electrolytic cell method using the same electrolyte composition as for the brush-plating technique.
U.S. Patent No. 4,613,069, Sept. 23, 1986; Chem. Abstr. Not Found