MULTIPHASE ELECTROCRYSTALLIZATION IN THE THALLIUM OXIDE SYSTEM - SIMULTANEOUS NUCLEATION ON SITES OF DIFFERENT NATURE

An ex situ STM study was carried out of the surface morphology of thal lium oxide films (from 10 to 10000 effective monolayers) electrodeposi ted on Pt, and a tunnel-spectroscopic characterization of these materi als is presented. Taking into account these results and data on the ph ase composition of products and the thermodynamic properties of the th allium oxide system, the deposition transients and corresponding chron ocoulograms are analyzed. The formal kinetic parameters of two nucleat ion processes that take place during the oxide deposition have been de termined. A model is proposed which makes it possible to describe the transient shape at the simultaneous crystallization of two phases on s ites of different nature. Within the framework of the assumption on th e additivity of partial transients, it is shown that such a model prov ides an adequate description of the overpotential and the surface pret reatment effects on the shape of transients of the thallium oxide depo sition on an inert substrate.