METHOD OF COLOUR ANODISING ALUMINIUM AND ALUMINIUM ALLOYS

摘要

This invention relates to the coloring of the surface of aluminum workpieces by anodization process wherein the anolyte consists principally of maleic acid with a small proportion of sulfuric acid for conductivity, and the catholyte consists of an organic acid of good conductivity or a mixture of organic acid to which a small quantity of sulfuric acid is added to conductivity. The anolyte and the catholyte are separated by a porous, ion-permeable diaphragm.