Alcan International Limited

Dewi G Evans

Pierre Henri Marois

Paul E Fortin

A process is described for producing a corrosion resistant aluminum composite sheet product for use in brazing. The process steps comprise:

Process for improving the corrosion resistance of brazing sheet

A corrosion resistant aluminum article is described. It includes a main body portion formed of an aluminum alloy containing no more than 0.4% iron, no more than 0.15% silicon, from about 0.1% to about 0.6% copper and from about 0.7% to about 1.5% manganese. The corrosion resistance is provided by a silicon-rich band of dense precipitate formed in the alloy adjacent at least one face thereof. This band has a thickness of about 20-50 .mu.m and there is substantially less manganese in solid solution in the band than in the alloy outside the band. To form the band, a silicon-containing layer is applied to a surface of the alloy body to be protected and the composite thus formed is heat treated at a temperature of at least 550.degree. C.

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Kingston, Canada

Dewi G Evans