| 摘要 |
A process is provided for plating a composite structure which includes one surface composed of an aluminum base metal and another surface composed of a ferrous base metal with a thin adherent layer of tin or an alloy of tin. The process comprises contacting the composite structure with a mineral acid containing a source of ions selected from the group consisting of fluoride ions, fluoride containing ions or mixtures thereof to activate the surface of the aluminum base metal and then immersing the composite structure in an aqueous plating bath which contains a mineral acid, a source of ions selected from the group consisting of fluoride ions, fluoride containing ions or mixtures thereof and a source of stannous ions with the stannous ions being present in an amount ranging from about 1 to about 75 grams per liter, for a period of time sufficient to cause tin or tin alloy to be deposited concurrently on the aluminum base metal surface by the exchange of aluminum ions for tin ions and on the ferrous base surface by means of a galvanic couple formed between the aluminum base metal and the ferrous base metal. |
