Electroplating aluminum articles

Abstract

In a process for electroplating aluminum articles, the article is first electrolytically treated, as anode, in a bath consisting essentially of a solution of caustic alkali, and thereafter electroplated. The electrolytic caustic cleaning step, preferably involving agitation, is found specially suitable in composition and indeed is effective in a relatively short time to afford an essentially bare aluminum surface, i.e., free of anodic oxide film and also free of pitting or smut, for advantage in plating, as with tin or other metal. Intermediate steps can be employed such as immersion tinning or zincating and brief electroplating such as a bronze strike; the electrolytic cleaning co-acts well with the intermediate stages, indeed requiring fewer steps over all. Although applicable batchwise, the process is particularly appropriate for continuous electroplating wherein the aluminum wire or strip may pass rapidly through the electrolytic cleaning, intermediate and plating baths in succession.