A process for the anodic oxidation of the surface of aluminum or aluminum alloys

摘要

1,174,563. Ornamenting. K. E. ROBERTS. 7 Feb., 1967 [26 Feb., 1966], No. 8575/66. Heading B6G. [Also in Divisions C5 and C7] A two-colour design is produced on an anodized aluminium surface by dyeing a water washed anodized surface, warm air drying at 80-120‹ F., coating it with a photosensitive resist resin, exposing to ultra-violet light through a positive or negative stencil and developing, decolorizing uncovered areas with a solution containing potassium permanganate, nitric acid and sodium bisulphite, and removing residual coating. For producing a multicolour design, areas which have been decolorized are dyed a different colour to the original dye and the steps repeated, prior to removing residual coating, using a different stencil.