SPATIALLY COUPLED BIPOLAR ELECTRODEPOSITION IN THIN_LAYER CELLS UNDER PERIODIC VOLTAGE CONTROL

. D'ANGELO, G. MARSHALL, J_C. BRADLEY, G. GONZÁLEZ, S. BABU, F. V. MOLINA, AND C. IEMMI

Washington

Congreso; 199th Meeting of The Electrochemical Society; 2001

The Electrochemical Society

ABSTRACT We study the ion transport in the interdisc region of thin_layer cells under square wave electric potential pulses by means of optical and particle velocimetry techniques. Experiments and measurements reveal that ion transport and deposit morphology, that constitute crucial factors in the characteristics of the connection, are substantially influenced by pulse frequency. Measurements show that the incubation time is roughly twice of that observed under DC conditions and does not increase with frequency. During this period, migration and diffusion are the dominant transport modes. After branching develops, convection plays a relevant role as well. It is found that the deposit morphology becomes less ramified as frequency increases, while the deposit growth speed is not significantly affected. A remarkable effect is found at low frequencies: the ion transport and the deposit growth pulsate in phase with the electric potential. At the scale of the observation (10x), no signs of inertial effects were discerned.