Process for electrochemically graining and anodically oxidising aluminium, and its use as a base material for offset printing plates

摘要

The two-stage process for electrochemically graining and anodically oxidising sheet, foil or strip material made of aluminium or its alloys is carried out in at least two treatment chambers using at least one electrode. In the first treatment chamber is an aqueous electrolyte containing hydrochloric and/or nitric acid and in the second an aqueous electrolyte containing sulphuric and/or phosphoric acid. In both treatment chambers an alternating current derived from the same current source is applied via at least one electrode in each case to the material, which is connected as central conductor. Material produced in this way is used, in particular, as a base material for offset printing plates with a radiation-sensitive layer.