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AssigneeLockheed Corporation
InventorRobert N. Miller
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A non-toxic corrosion resistant conversion coating for aluminum is formed by a process which includes subjecting the aluminum to an acidic aqueous solution containing potassium permanganate and cerous chloride, alone or in combination with strontium chloride. The corrosion resistance is improved by a subsequent treatment in an alkaline solution containing molybdate, nitrite and metasilicate ions. The corrosion resistant is further improved by treating the coated surface with an alcoholic solution containing glycidoxy(epoxy)polyfunctionalmethoxysilane, alone or in combination with phenyltrimethoxysilane. The coating thus produced is a mixture of oxides and hydroxides of cerium strontium and aluminum. These oxides and hydroxides may also be intermixed with molybdate silicate and nitrite ions. In the most corrosion resistant form the mixture further includes a silane overcoat.
A process for producing a corrosion resistant chemical conversion coating on aluminum and aluminum alloys comprising subjecting a cleaned, degreased and deoxidized aluminum to an aqueous solution containing cerous chloride and potassium permanganate at ambient temperature whereby an acidic condition is created by the hydrolysis of the cerous chloride which reacts with said deoxidized aluminum.
Dependencies are inferred from the claim text.