Patent ID: 6916414

Claim:
A method of forming a protective coating on a surface of a light metal-containing article, said method comprising: A) providing an anodizing solution comprised of water and one or more additional components selected from the group consisting of: a) water-soluble and water-dispersible oxysalts containing at least one element selected from the group consisting of Mn, Zr, Ti, V and Hf; or b) water-soluble and water-dispersible complex fluorides of elements selected from the group consisting of Ti, Zr, Hf, Si, Sn, Al, Ge and B; B) providing a cathode in contact with said anodizing solution; C) placing said light metal-containing article as an anode in said anodizing solution; and D) passing a pulsed current having an average voltage of not more than 250 volts between the anode and cathode though said anodizing solution for a time effective to form said protective coating on said surface.