ELECTROLYTE ADDITIVE FOR A DYE BATH FOR COLOURING ALUMINIUM AND A PROCESS FOR COLOURING ALUMINIUM

摘要

PCT No. PCT/EP91/01994 Sec. 371 Date Apr. 29, 1993 Sec. 102(e) Date Apr. 29, 1993 PCT Filed Oct. 21, 1991 PCT Pub. No. WO92/07976 PCT Pub. Date May 14, 1992.The invention describes a novel electrolyte additive for a sulfuric acid tin(II) containing colorant bath for the alternating current coloring of anodized aluminum surfaces, consisting of a synergistic mixture of at least one antioxidant of one of the general formulas (I to IV) and at least one throwing power improver of general formula (V), and to a process for the alternating current coloration of anodized aluminum surfaces using the electrolyte additive of the invention.