Patent ID: 7578921

Claim:
A method of forming a protective coating on a surface of an aluminum, aluminum alloy, titanium or titanium alloy article, said method comprising: A) providing an anodizing solution comprised of water, a phosphorus containing acid and/or salt, and one or more additional components selected from the group consisting of: a) water-soluble complex fluorides, b) water-soluble complex oxyfluorides, c) water-dispersible complex fluorides, and d) water-dispersible complex oxyfluorides of elements selected from the group consisting of Ti, Zr, Hf, Sn, Al, Ge and B and mixtures thereof; B) providing a cathode in contact with said anodizing solution; C) placing an aluminum, aluminum alloy, titanium or titanium alloy article as an anode in said anodizing solution; and D) passing a pulsed direct current between the anode and cathode through said anodizing solution for a time effective to form a protective coating on at least one surface of the article.