Mass Transfer and Current‐Potential Relation in Pulse Electrolysis

A generalized theory is presented for pulse electrolysis with rectangular current pulses, periodical pulse reverse, and double rectangular pulses with relaxations. It is shown that very high instantaneous mass transfer ates corresponding toa current density of 100-1000 A/cm 2 can be attained by short current pulses at high pulse frequencies. Numerical results for the concentration fluctuations and potential responses have also been calculated for the deposition/dissolution of copper on a rotating disk electrode in acid copper sulfate solution. The results indicate that the current pulses can profoundly change the current-potential re ationships and thus the current distribution and the morphology of electrodeposits onthe electrode surface. E lec t ro lys i s with a pulsating current (PC) has been extensively used in pulse plating, electrodissolution, anodizing, and a-c corrosion processes (1). In par-ticular, the pulse current can cause a profound change in the morphology of electrodeposits (2-5); it gives a softer, more uniform, and compact deposit with better adherence to the substrate. This can be attr ibuted to