Electrical properties of BaCe_(0.8)Zr_(0.1)Y _(0.1)O_(3-α) ceramics and thin films designed by reactive magnetron sputtering: Effect of the electrochemical cell configuration

摘要

BaCe_(0.8)Zr_(0.1)Y_(0.1)O_(3-α) (BCZY10) protonic conductor coatings were co-sputter deposited from Ba, Zr and Ce_(0.9)Y_(0.1) metallic targets in argon-oxygen reactive gas mixtures. The targeted composition of the coatings was obtained using suitable discharge currents applied on Zr and Ce_(0.9)Y_(0.1) targets and discharge current applied on Ba target. The as-deposited coatings were amorphous and presented a good chemical stability against carbonation in air up to 573 K. The films crystallised in BaCO_3 and CeO_2 mixture after annealing treatment around 873 K for 2 h in air. Nevertheless, the crystallization in the expected perovskite structure was obtained after annealing treatment under vacuum (5 × 10~(-3) Pa) at 873 K during 2 h to prevent the carbonation of the coating. The crystallized films kept their initial morphological properties. The strong influence of the electrochemical cell configuration (substrate, electrodes nature?) on the electrical conductivity of the samples was demonstrated and discussed. The best electrical properties were obtained for a cermet-supported film, and were found close to that of a reference bulk sample of the same composition in the same conditions, whereas platinum based collectors gave very poor conductivity due to interfacial blocking effect.