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

Studies were performed of tungsten carbide hydrogen-diffusion electrodes operating as anodes in electrolytic baths for regeneration of etching solutions of CuCl2 and FeCl3. Under conditions of electrolytic regeneration of copper chloride solutions (i = 40 mA cm-2 40-degrees-C) after 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 elimination of the ion exchange membrane separating the anodic from the cathodic space leads to a 2-4 V decrease of the electrolytic bath voltage. The regenerated solutions of CuCl2 and FeCl3 can be reused as etching agents after adding 7-10 ml 30% solution of hydrogen peroxide per litre.