Polarization of the contact between fluorine-conducting solid electrolyte and metal alloys

Resumo

The kinetics of low-sized phase formation on polarization of the interface between LaF₃:Eu²⁺ and Pb–Sn, Sn–Bi, and Sb–Bi alloys is studied by the potentiostatic and linear voltammetry methods. The analysis of anodic transients shows that the new phase formation involving fluoride ions from the solid electrolyte proceeds by the mechanism of instantaneous two-dimensional or three-dimensional nucleation. Comparison of calculated and experimental transients describing the instantaneous nucleation with either two-dimensional growth on the I/I_m vs. t/t_m coordinates or three-dimensional growth on the I²/I_m² vs. t/t_m coordinates shows adequate agreement between the model and the initial regions of experimental curves. The properties of phases formed depend on the alloy composition and the polarization conditions as well as on the energy of interaction between components in the alloy and in the new phase.