| 摘要 |
PURPOSE:To subject an aluminum surface to uniform and beautiful coloring with good efficiency by impressing a positive voltage of a specific intermittent waveform to the aluminum to make the pretreatment thereof prior to electrolytic coloring of the aluminum subjected to an anodic oxidation treatment. CONSTITUTION:The voltage of the waveform in which the substantially continuous two positive voltage waveforms of the same shape are repeated via a substantial quiescent part is impressed to the aluminum or aluminum alloy subjected to the anodic oxidation treatment by the conventional method to pretreat the anodic oxidation treatment prior to electrolytic coloring of the aluminum or aluminum alloy in an electrolytic coloring liquid contg. a metallic salt. The ratio of the impression time T1 and quiescent time T2 of the two continuous positive waveforms is made about T1:T2=1:0.1-10, the max. value of the impressed voltage is made about 30-100V, the electricity conduction time is made about 5sec-5min and the voltage increase speed is made about 0.1-10V/sec. Since the barrier layer is effectively reformed, the throwing power and coloring speed are remarkably improved when the electrolytic coloring is executed in the electrolytic coloring liquid thereafter. The uniform electrolytic coloring film is thus formed in a short period.
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