Protective YSZ-based thin films deposited by RF magnetron sputtering

Protective Zr(Y)O2−δ-based films sputter-deposited onto apatite-type lanthanum silicate ceramics were appraised for potential applications in solid oxide fuel cells with silicate-based solid electrolytes, where the performance may suffer from surface decomposition processes in reducing atmospheres. Dense and crystalline coatings were deposited using radio-frequency magnetron sputtering from an yttria-stabilized zirconia target. On the basis of microstructural analysis and profile measurements, a sputtering power of 300 W was selected in order to achieve deposition rates in the range 0.50–0.75 μm/h. The surface morphology studies using an atomic force microscope revealed typical film structures with small (<50 nm) grains. The polarization of model electrochemical cells with cermet anodes comprising Ni, yttria-stabilized zirconia and Ce0.8Gd0.2O2−δ (50:30:20 wt.%), deposited onto the protective zirconia films, was found quite similar to that of copper–zirconia cermets without interlayers, suggesting that the electrochemical reaction is essentially governed by the oxygen anion transfer from zirconia phase and/or hydrogen oxidation in the vicinity of zirconia film surface.