Method for providing environmentally stable aluminum surfaces for adhesive bonding and product produced

摘要

Environmentally stable bond joints of aluminum metal and aluminum alloys in adhesively joined structures are formed by utilizing a prebonding anodization of the aluminum surfaces in a phosphoric acid electrolyte containing from about 1.5 to about 50% H3PO4 at 1 to 50 volts for a period of 5 to 60 minutes using a bath temperature of 50 DEG to 100 DEG F. The anodized surface is then washed free of electrolyte, dried and coated with an adhesive resin. The aluminum metal segments are then arranged in a composite arrangement and bonded together under pressure and heat to cure the adhesive resin. The resulting structure is resistant to failure of the bond joints on exposure to moist atmospheric conditions. The surface preparation provides a hydration resistant aluminum oxide surface which minimizes adhesive-aluminum separation under aqueous exposure. Alloys containing copper and other alloying constituents may be successfully anodized and bonded by this process.