Patent ID: 6406562
Filing Date: 2002-06-18
Classification: C23C

Abstract:
A method of treating a surface of aluminum and alloys thereof to increase corrosion resistance by modification of the surface to inhibit cathodic processes, the method comprising;exposing a surface of the aluminum or aluminum alloy to an aqueous solution in a single aqueous solution treatment to thereby modify the surface to inhibit cathodic processes and to increase corrosion resistance and wherein the aqueous solution comprises a salt of at least one rare earth element selected from the group consisting of yttrium, gadolinium, cerium, europium, terbium, samarium, neodymium, praseodymium, lanthanum, holmium, ytterbium, dysprosium, erbium, and combinations thereof, but substantially exclusive of halides, and a pH-modifying agent present in an amount effective to adjust the pH to from about 4.5 to an upper solubility limit of said salt of at least one rare earth element in said aqueous solution as a function of pH, and wherein said exposing is for an effective period of time with the solution being at an effective temperature to modify said surface to inhibit cathodic processes but not to purposefully grow a thick protective oxide coating thereon.