BEHAVIOR OF TUNGSTEN CARBIDE HYDROGEN-DIFFUSION ELECTRODES IN CHLORIDE ETCHING SOLUTIONS

Studies were performed of tungsten carbide hydrogen-diffusion electrod es operating as anodes in electrolytic baths for regeneration of etchi ng solutions of CuCl2 and FeCl3. Under conditions of electrolytic rege neration of copper chloride solutions (i = 40 mA cm-2 40-degrees-C) af ter 1500 h operation the electrode polarization increased by about 200 mV. Maximum current efficiency of 60-65% was obtained at I(k) = 80 mA cm-2. It is demonstrated that the replacement of the standard carbon anodes with tungsten carbide hydrogen-diffusion electrodes and the eli mination of the ion exchange membrane separating the anodic from the c athodic space leads to a 2-4 V decrease of the electrolytic bath volta ge. The regenerated solutions of CuCl2 and FeCl3 can be reused as etch ing agents after adding 7-10 ml 30% solution of hydrogen peroxide per litre.