Electrochemical behavior of tungsten-containing nanocomposite with siloxane matrix

Abstract

Electrochemical properties of a thin-film nanocomposite “silicon-carbon matrix-tungsten carbide” deposited onto pyroceramics (“sitall”) substrate are studied by potentiodynamic curves and electrochemical impedance spectroscopy. Transfer coefficients in model redox system [Fe(CN)6]3−/4− are measured. With the decreasing of the films’ electrical resistance, their experiment behavior gradually changed from that of “poor conductor” till nearly metal-like one. In particular, the electrode differential capacitance increases, which is explained by the increase in the number of conducting metal-containing clusters in the film bulk and at the film/electrolyte solution interface. Some specific features of the complex-plane plots of impedance spectra are tentatively explained by the adsorption at the nanocomposite surface elements.