Abstract: To avoid or minimize the occurrence of cross streaks or current streaks on a substrate that is transported through an electrolytic bath and roughened electrochemically in it, the current density is regulated in the electrolyte between a first alternating or three-phase current electrode and the substrate in such a way that at the beginning of a roughening zone, the current density has a lesser value than within the roughening zone, in the transport direction of the substrate. Downstream of the first alternating or three-phase current electrode, either a further alternating current electrode or a further three-phase current electrode acts on the substrate. In a preferred embodiment, the first alternating or three-phase current electrode has a rounded outline, which is composed of a curved portion and adjoining it a straight portion.

Abstract: A method and apparatus for electrochemically roughening a support is disclosed to minimize the occurrence of surface discharges or electrical discharges on the support. A DC voltage acts on the support at the start of the movement of the support through the electrolyte bath. Subsequently, a three-phase or single-phase current acts on the support in the roughening zone. Three-phase electrodes are arranged in the electrolyte bath and are connected to the secondary of a three-phase transformer. The primary of the three-phase transformer is connected, via control transformers to a three-phase power transformer. A DC electrode is located upstream of the three-phase electrodes in the direction in which the support is transported through the bath. The DC electrode may be connected to the positive pole of a DC source while the negative pole of this DC source makes contact with the support.