Studies of the deposition of cadmium on foreign substrates

Abstract

Cadmium deposition on nickel, lead, silver, gold and copper has been studied by the potential sweep and potentiostatic method with a simultaneous observation of the surface by optical microscopy. It was found that the substrates could be divided into two groups-those at which there is no significant underpotential deposition of cadmium and those at which the latter does take place. In the former case non-epitaxial growth predominates, once some nucleation overpotential (of about 16 mV) is overcome; the potential sweep diagrams are characterized by a loop exhibiting an inductive nature. Two maxima on the anodic branch of the voltammogram could be ascribed to the dissolution of non-epitaxial and epitaxial deposits. Microscopic observations confirmed those conclusions. Well developed granular deposits have been obtained with grains increasing size while remaining constant in number.