| In the first part of the thesis, perovskite La0.8Sr0.2Co0.5Fe0.5O3 (LSCF) powder materials for SOFC cathode were fabricated via the so called citric acid method and polyvinyl alcohol (PVA) method with citric acid and PVA as the carrier of the metal ions, respectively. The results showed that the molar ratio of citric acid and metal ion C/Mn+, the pH value of the precursor solution and the gelation temperature T were the main factors controlling the quality of the gel in the process of the citric acid method. The optimized processing parameters are C/Mn+=1.4:1, pH=6.0 and T=60℃. In the PVA process, gelation occurred at temperatures between 6080℃when the molar ratio of the charge number of the metal ions and the active group of the additive PVA Ax- was in the range between 8:110:1, and the pH value did not play an important role. In comparison with the citric acid method, the PVA process has the advantages of low cost, independence of pH value, high gelation temperature and fast gelation rate.Thermogravimetry (TG) analysis and Fourier transformation infrared radiation (FT-IR) were employed to determine the calcination temperature of the dried gels for forming perovskite structured LSCF, the optimized calcination temperature 750℃was selected. X-Ray diffraction (XRD) analysis was used to identify the crystal structure of the calcined powder, LSCF perovskite structure was established. The powder morphology of the LSCF was examined by scanning electronic microscope (SEM), nano-sized particles in clusters were observed, which was confirmed by laser particle analyzer. It was also found that LSCF powder prepared by the PVA method was chemically compatible with YSZ up to 1000℃, and demonstrated excellent mixed conductivity at SOFC operating temperatures as a cathode material, revealed by I-V measurement and AC impedance.In the second part of the thesis, effects of the main factors those control the slurry rheological behavior and green tape quality of the tape cast SOFC anode support, including ball-milling time, organic solvent type, dispersant addition, plasticizer/binder ratio (R), and deforming process as well, were systematically investigated. It has been found the mixed solvent of ethanol and xylene (1:1 volume ratio) had the optimized wetting capability on the used ceramic powders, improving the suspensibility of powders and the rheology of slurry; the viscosity of slurry decreased with the addition of the dispersant and reached the minimum at 1.8wt% of the dispersant concentration; ball-milling reduced the slurry viscosity that approached its lower limit after 24 hours of milling; the slurry viscosity decreased sharply with the increase of the R value, and a minimum was obtained at R = 1, the rheological behavior of the slurry was significantly improved; deforming agent and vacuum with agitation were effective on air bubble elimination.
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