Durability of adhesively bonded aluminum structures and method for inhibiting the conversion of aluminum oxide to aluminum hydroxide
AssigneeMartin Marietta Corporation
InventorsJohn D. Venables, Maher E. Tadros, Brian M. Ditchek
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Abstract
It has been found that hydration of aluminum oxide surface coatings to aluminum hydroxide may be curtailed by the presence of corrosion inhibiting amounts of amino phosphonate compounds. Effective inhibitors, such as nitrilotris (methylene) triphosphonic acid, may be applied to aluminum substrates having aluminum oxide surfaces thereupon in concentrations of less than 50% by weight in aqueous solution, and suitably from 1 to about 500 ppm.
Claims42
A method for improving the bond durability of an adhesively bonded aluminum substrate which comprises treating the surface of said aluminum substrate with an aqueous solution of an amino phosphonate compound having a plurality of phosphorous atoms.
A method for preparing aluminum surfaces for adhesive bonding, said method comprising providing a micro porous aluminum oxide surface, treating said aluminum oxide surface with an amino phosphonate compound having a plurality of phosphorous atoms, and drying.
A method for improving the corrosion resistance of aluminum by inhibiting the hydration of aluminum oxide by application of a corrosion inhibitor selected from the group consisting of NR.sub.3, NHR.sub.2, R'NR.sub.2, (CH.sub.2 NR.sub.2).sub.2, and R.sub.2 NCH.sub.2 CH.sub.2 NRCH.sub.2 CH.sub.2 NR.sub.2, wherein R is CH.sub.2 PO(OH).sub.2, and R is a straight chain alkyl group having from 1 to 5 carbon atoms.
A bonded aluminum structure comprising one or more aluminum surfaces treated with an amino phosphonate corrosion inhibitor having a plurality of phosphorous atoms.
An aluminum substrate having a monomolecular layer thereupon of a hydration inhibitor comprising an amino phosphonate compound having a plurality of phosphorous atoms.
Dependencies are inferred from the claim text.