Based on permeation, which is one of the most important properties for membrane applications, Ba0.5Sr0.5(Co0.8Fe0.2)(0.97)Zr0.03O3-delta, appears to be promising as a membrane/substrate material. Since creep deformation is a critical mechanical aspect for this application, previous studies concentrated on the creep of dense material which revealed a very complex behavior due to the influence of secondary phases. The current study attempts to extend the current knowledge On the influence of secondary phases on creep characteristics for this material. The study also assesses the creep behavior of the necessary porous substrate material which is expected to have a larger impact on the deformation of the composite than the thin dense layer. The creep characterization concentrated on the temperature range from 775 to 950 degrees C for heating and cooling sequences. While the analysis on the creep behavior of the dense material is significantly extended compared to that reported for the Ba0.5Sr0.5(Co0.8Fe0.2)(0.97)Zr0.03O3-delta reference material and verified that it is strongly influenced by the secondary phase at lower temperatures, novel creep investigation of porous material revealed a progressively increasing creep rate with increasing temperature. (C) 2014 Elsevier B.V. All rights reserved