Method for electrolytic coloring of aluminum material

摘要

This invention relates to an improvement of a process for electrolytically coloring an aluminum material comprising immersing an aluminum material consisting of anodized aluminum or an anodized aluminum alloy in an electrolytic coloring bath containing a soluble metal salt, performing a pretreatment prior to coloring by passing a direct current waveform with said aluminum material serving as the anode, and performing alternating current electrolytic coloring in the same electrolytic coloring bath and the improved process comprises performing said pretreatment prior to coloring until the voltage and current respectively reach the preset ultimate values. It is possible to prevent as much as possible an occurrence of irregular coloring not only in one energizing lot but also in different energizing lots and produce an aluminum material colored in a uniform tone stably and readily on a commercial scale.