A geometric characterization and modelling of microstructure development for ceramics composites BaZr0,9Y0,1O3-? + BaCe0,9Y0,1O3-? ( BCY-BZY)

Reference Presenter Authors
06-220 Huyra Estevao Araujo Araujo, H.E.(Federal Institute of Sao Paulo); The growing global demand on energy and the environmental problems due to pollution emission has stimulated extensive research related to sustainable sources of energy with highlight to electrochemical conversion of energy and the use of biofuel. Solid oxide fuel cells (SOFCs) work through electrochemical conversion of energy and show high efficiency and wide application range with fuel flexibility. The most common material used to this application is YSZ, however the high temperatures of operation is a challenge for this technology. Currently, proton?conducting ceramics have attracted interest as alternative YSZ) and in this way Barium Cerates and Zirconates have drawn attention as a candidate to electrolyte. Several strategies have been adopted to improve the performance of these materials as solid electrolytes: co-doping with trivalent elements, metallic, rare-earth elements, composites and advanced techniques on processing to provide a control of microstructures. BaZr0,9Y0,1O3 and BaCe0,9Y0,1O3 based ceramics powders were prepared through solid state reactions aiming prepare composites, calcined and sintered through several schedules. The fracture and polished surfaces were analyzed with Scanning Electron Microscopy and geometric parameters were obtained using ImageJ freeware. Values of grain size, polygons characterization, edges lengths and their distribution were compared to ceramics with densification higher than 90% of theoretical density and sintered in distinct schedules. The results shows that microstructure geometric parameters and their distribution have strong dependence with heating rate, dwell time and sintering temperature even to similar values of density. Additionally, it was observed that the increasing amount of BCY in the composite also improve the sinterability of the composite, compared to BZY sinterability,  and this result can be related to the lower sintering temperatures observed to obtain dense ceramics based com Barium Cerate.
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