TiO2, MgO, Me, Al2O3 and Bi2O3 up to a few percentages in quantity were intentionally added to BaZr0.9Y0.1O3-delta. The selected additives do not contribute to any improvement of the sintefing behaviour. The lattice BaZr0.9Y0.1O3-delta parameter of for the samples containing additives is smaller than for the pure material. The bulk conductivity also falls drastically with metal addition. For instance, the conductivity of the sample containing TiO2 is 2.5 orders of magnitude lower than the sample without additive. The grain boundary conductivity is also affected by the presence of metal ions. (c) 2007 Elsevier B.V. All rights reserved.