Geometrical aspect of electrodeposition: The Hecker effect

Abstract

We have studied the growth of electrodeposits from solutions of copper sulfate in thin cells, and focused our attention on the spectacular morphological transitions that occur in almost every experimental condition. We give experimental evidence and numerical and theoretical results showing that these transitions are due to the propagation of charged impurities leaving the dissolving anode at the beginning of the growth and hitting the deposit at later times. The arrival of the impurity front against the growing deposit modifies the growing conditions, thus leaving on the deposit the trace of an almost homothetical ‘‘ghost’’ image of the anode.