ANALYSIS OF CONVECTIVE MASS-TRANSFER BY POTENTIAL RELAXATION .2. TRANSIENT NATURAL-CONVECTION COPPER DEPOSITION

A transient potential relaxation technique was used to determine mass transfer boundary-layer thicknesses during steady-state and pre-steady-state natural convection copper deposition at a vertical flat plate cathode. Boundary-layer thicknesses for constant currents below the limiting current and pulsed currents at 6 Hz were found by matching experimentally measured concentration overpotentials after current interruption to a theoretical surface concentration decay model. The initial growth of constant and pulsed current boundary-layers with the time of current passage was found to be diffusion controlled. Steady-state pulsed current boundary-layer thicknesses were approximately 33% smaller than those obtained from constant current experiments. © 1990, The Electrochemical Society, Inc. All rights reserved.