Abstract: Carbon commutator parts used as races for brushes in electric motors are typically soldered to copper carriers. The solder does not bond well unless a metallic coating is first placed on the carbon part. To improve adhesion between the metallic coating and the carbon part, the surface must first be roughened. An improved method of roughening the surface involves immersing the carbon part in an aqueous solution of sodium hydroxide or potassium hydroxide, connecting the carbon part as an anode, and applying an electric current for two or three minutes. This produces oxidation on the surface of the pressed body, thereby roughening its surface, so that the solderable metallic coating will subsequently adhere much better.

Abstract: Printed circuit boards can be continuously electroplated by passing them through a pair of rollers (7) forming cathodic rollers, which are spring-pressed towards each other, the rollers being driven, for example at the circumferential speed of about 1/2 meter per minute. The rollers form a transport arrangement for the printed circuit board, while providing electrical connection to conductive tracks thereon. Closely downstream of the cathodic rollers are a pair of anodic rollers, made, for example, of titanium with a covering of platinum or iridium, over which a felt sleeve is placed, on which felt sleeve an electrolyte, including sulfuric acid and copper is sprayed. The anodic rollers, connected to a positive terminal, are spaced from the surface of the printed circuit board to leave a surface gap between the rollers and the printed circuit board of about 0.1 mm. Copper is electrolytically deposited, for example, at the current density of about 15 A/dm.sup.

Abstract: A method and apparatus for the regeneration of a copper-containing etching solution which contains copper (II) chloride as well as alkali chloride as a sequestering agent, wherein the cathode is operated at a current density of 40-400 A/dm.sup.2 and the anode is operated at a current density of 1-100 A/dm.sup.2. Copper forms at the cathode as a powdered slurry while chlorine forms at the anode which oxidizes copper (I) chloride to copper (II) chloride. With this method one can process etching solutions which contain not only copper but also base metals including zinc from etching brass or tombac, and obtain a powdered mixture of copper and base metal. The apparatus features a rotating disk-shaped cathode from whose outer face the metal powder is stripped by a scraper.