The influence of a high temperature annealing (≈2200C) on the microstructure and the electrical properties of BaZr0.9Y0.1O3−δ was examined. The high temperature annealing was achieved using an optical float-zone furnace. The obtained sample was homogeneous with an average grain size of about 5μm. No additional phases were found in the X-ray diffraction pattern and the structure was identified to be cubic. After the high temperature annealing, the grain boundary conductivity was increased by approximately 2 orders of magnitude, while the bulk conductivity remains the same.

Electrical Conductivity of the Proton Conductor BaZr0.9Y0.1O3−δ Obtained by High Temperature Annealing. S.B.C.Duval, P.Holtappels, U.F.Vogt, E.Pomjakushina, K.Conder, U.Stimming, T.Graule: Solid State Ionics, 2007, 178[25-26], 1437-41