Analyses of Ternary Alloy Plating Systems by a New Kinetic Model

Abstract

A new model for the electrochemical alloy deposition is applied for several ternary plating systems. This model is treating the interaction of the electrode surface sites and the electrolyte metal ions. The discussed concept is based on the finite Markov chain theory and gives the first analytical relationship between a binary alloy composition and the metal ion concentrations of the electrolyte. The elementary parameters gAB-1 and gBA-1, also called selectivity constants, are determined from experimental data of binary alloy depositions. The selectivity constants give a quantified description of the competitive adsorption kinetic of metal ions at different kink site positions of an alloy electrode. Thus this basic information from different binary couples can be applied to give a valid prediction for a resulting ternary alloy composition. Beside the calculations of the expected alloy contents also additive and temperature influences are discussed in terms of changed selectivity constants.