Electrochemical study of the silver-sodium substitution in a borosilicate glass

The study of the silver for sodium ions substitution kinetics is carried out using an electrochemical set-up. A silver metal anode, a reference and counter electrode are deposited as thin films on a 0.6 SiO₂-0.2 B₂O₃-0.2 Na₂O glassy electrolyte. The anode dissolution is studied by a chronoamperometric method. The generally proposed interdiffusion models assuming constant diffusion coefficients for both Ag⁺ and Na⁺ cations are not able to justify the experimental voltage time dependence. The deviation from theoretical predictions can be minimised by assuming a mixed cation effect in the glass, taking into account a concentration dependence of the Ag⁺ and Na⁺ diffusion coefficients.