Fabrication and characterization of ZrB2–SiC ceramic electrodes coated with a proton conducting, SiO2-rich glass layer

3.5 μm thin layers of dense, crack-free, proton conducting, SiO2-rich glass have been developed on ZrB2–SiC ceramic composites, by thermal oxidation at 1400 °C for 30 min in air. A conductivity of 2 mS cm−1 at 25 °C was found, as measured by AC impedance and steady-state voltammetry, and was estimated at ca. 2 × 10−2 S cm−1 at 80 °C. A striking behaviour of the oxidized ZrB2–SiC composites is also pointed out: underneath the glass layer, there is a porous layer rich in electronic conductive ZrB2, without well-defined interface between them, i.e., exhibiting a composition gradient in oxygen. In other words, protonic half-fuel cells could be fabricated under such conditions, for future use in hydrogen or direct alcohol fuel cells.