摘要 |
<p>In processes for electrolytically dyeing anodic oxide layers on aluminum or aluminum alloys with direct or alternating current in electrolytes containing metal salts, high requirements are imposed on the uniformity of the dyeing and on the dyeing rate. The improvement of the uniformity of the dyeing and an increased dyeing rate can be achieved by pretreating the oxide layer by means of asymmetric alternating current before it is dyed. Such a process is preferably used in combination with an Sn-containing electrolyte.</p> |