ELECTROLYTIC COLORING METHOD OF ANODIZED FILM OF ALUMINUM OR ITS ALLOY

摘要

PURPOSE:To prevent effectively uneven coloring by electrolyzing preliminarily an anodized film of Al in a way as to prevent deposition of metallic components then increasing dividedly an AC voltage in multiple stages and suppressing an increase in the current quantity in the cathode direction with time. CONSTITUTION:AC of a low voltage (about 4-1V) at which metallic components are desired to be deposited in an electrolytic bath is first impressed on the anodized film of Al or an Al alloy to electrolyze preliminarily the film for at least 20sec in the stage of coloring said film by a secondary electrolytic treatment. The AC voltage (about 5-15V) is increased dividedly in multiple stages of >=2 times for a total treating time of about 4-20min at a treating temp. of about 10-30 deg.C in the stage of electrolyzing secondarily the film by increasing the AC voltage up to the voltage at which metallic components deposit. The current in the cathode direction is measured and controlled at all times so as to prevent an increase with time of the current quantity in the direction where the anodized film during the secondary electrolytic treatment acts as the cathode while the same AC voltage is impressed.