Síntese e sinterização em micro-ondas, e caracterização da perovskita Ba0,5Sr0,5Co0,8Fe0,2O3-δ
Nuernberg, Rafael Bianchini
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Ba0,5Sr0,5Co0,8Fe0,2O3-δ (BSCF) perovskite-type oxide is currently one of the most promising materials for applications in oxygen separation membranes. BSCF powder synthesis has received considerable attention because the powder characteristics are extremely important in shaping and sintering process of these membranes. On the other hand, the sintering stage is crucial in consolidation and microstructure development. In this study, BSCF perovskite has been synthesized and sintered using microwave heating. BSCF powders were synthesized by combustion method using conventional and microwave heating. The resulting BSCF powders were characterized by DSC/TG, BET, XRD and SEM. The sintering stage of pellets obtained by uniaxial pressing was conducted in different time and temperature conditions, as well as, in conventional and microwave heating. Microstructural characterization of BSCF samples was performed by OM and SEM. Mechanical characterization was made by diametral compression and Vickers hardness test and electrical characterization was carried out in impedance spectroscopy equipment. The BSCF powder that was synthesized in microwave, presented phase homogeneity, high specific surface area (9.93 g/m2) and submicrometric particle size. The microstructural characterization of sintered samples showed that the microwave sintering can achieve a relative density as high as conventional sintering with only 10% of dwell time (continue...).