Process for producing anodic films exhibiting colored patterns and

Abstract

A process for producing a structure including an anodic film exhibiting a colored pattern, and the resulting structures. The process involves anodizing a surface of a metal substrate or article made of or coated with aluminum or an anodizable aluminum alloy to produce an anodic film, preferably having pores extending from the film surface inwardly towards the underlying metal. A semi-reflective layer of a non-noble metal is then deposited within the pores of the film in order to generate a color by effects including light interference. Limited areas of the resulting film are then contacted with a solution of an acid or other leaching material, preferably by a maskless procedure, in order to leach the non-noble metal from the film, at least partially. The film is then contacted by a solution of a more noble metal compound (e.g. Pd, Au or Pt). The more noble metal from the solution at least partially replaces the non-noble metal remaining in or on the film and stabilizes the deposits against further leaching. A further anodization step creates different colors in the leached and unleached areas. The result is a patterned anodized article in which the colors are highly resistant to fading or lack of uniformity.