Pulsating potential electrolysis in the deposition of copper

A very low impedance circuit was constructed in order to provide a pulsating cathodic potential for a copper electrode immersed in a copper sulphate solution of the type used in copper refining. The increase in surface roughness during a fixed period of plating was investigated as a function of the frequency of pulsation. It was established that the relative increase in surface roughness depended linearly on the square root of the reciprocal frequency. This is in accordance with the theory based on the model of amplification of surface roughness being a transport controlled phenomenon.