Patent ID: 6379523
Filing Date: 2002-04-30
Classification: C25D

Abstract:
A surface treatment method for aluminum-based materials comprising the steps of:anodizing an aluminum-based material consisting of aluminum or aluminum alloy in an anodizing bath comprising an amount of nitrate ion together with at least one ion selected from among an organic acid ion or an inorganic acid ion able to form a porous anodic oxide coating, thereby forming a porous anodic oxide coating on the surface of said aluminum-based material, controlling the amount of the nitrate ion in the anodizing bath to form a desired thickness of a barrier layer portion defining a bottom of each pore of the porous anodic oxide coating; and then, electroplating said aluminum-based material in an electroplating bath comprising metal ion so that metal is electroplated from said electroplating bath into the pores in said porous anodic oxide coating, thereby giving said anodic oxide coating conductivity; wherein said anodizing bath comprises 100-300 g/l of sulfuric acid and 60-140 g/l of nitric acid, and 10-100 g/l of a nitrate.