Atomistic Aspects of Electrochemical Alloy Formation: A Review of Nucleation and Growth of Nano-clusters and Thin Films

Atomistic aspects of electrochemical alloy formation are reviewed and discussed on the basis of theoretical considerations and experimental results obtained in selected model systems. The role of interactions between co-deposited metal atoms, as well as metal-substrate interactions during the initial stages of electrochemical co-deposition has been discussed. Nucleation kinetics in binary alloy systems is considered theoretically, applying the atomistic approach. Experimental data on the nucleation rate, the size and the composition of Ag-Hg alloy nuclei. electrodeposited on a platinum electrode are presented and discussed in detail. The formation of surface alloys is discussed in terms of models including place exchange between metal adatoms and substrate atoms, solid state diffusion and nucleation and growth phenomena. The correlation between the deposition conditions and the composition and properties of alloy coatings obtained in the advanced stages of electrochemical alloy formation is demonstrated on the basis of experimental data for the growth of Ag-Au alloy