阴极材料用Pr_(0.6–x)Nd_xCa_0.4FeO_(3–δ)陶瓷的特性

CHARACTERISTICS OF Pr_(0.6–x)Nd_xCa_0.4FeO_(3–δ) CERAMICS FOR CATHODE MATERIALS

以Pechini法合成了ABO3型钙钛矿结构的Pr0.6-xNdxCa0.4FeO3-δ(x=0.1,0.3,0.5)系列稀土复合氧化物粉体。用Fourier变换红外光谱和激光共焦Raman光谱对粉体烧结后样品的化学键及物相进行了表征。用热膨胀仪测定烧结样品的热膨胀系数。通过扫描电镜观察样品用作阴极材料时的微结构及阴极/电解质[钐掺杂氧化铈(samarium-doped ceria,SDC)]复合层的断口形貌。结果表明:1200℃煅烧2h的样品的主晶相为正交钙钛矿,x=0.3的样品是正交与立方相的混合晶。在室温～1000℃范围内,烧结样品的平均热膨胀系数为12.76×10-6/K,与SDC及La0.8Sr0.2Ga0.85Mg0.15O3-δ(LSGM)电解质的热膨胀系数一致。烧结样品内部孔隙分布均匀,孔隙率约35%,阴极/电解质复合层界面清晰。将复合氧化物粉体和SDC在1200℃煅烧10h没有检测出第三相。

Perovskite structure ABO3-type of series rare-earth composite oxide powders Pr0.6-xNdxCa0.4FeO3-δ （x=0.1, 0.3, 0.5） were synthesized using the Pechini method. The samples were characterized with a Fourier transform infrared spectroscope and laser micro Raman spectroscope. The thermal expansion coefficient （TEC） of sintered ceramic sample was determined by dilatometcr. The microstructure of the sintered sample during use as cathode material and the cross-section morphology of the composite layer between the cathode and intermediate-temperature electrolytes such as samarium-doped ceria （SDC） were observed using a scanning electron microscope. The results show that the main crystalline phase of samples that sintered at 1 200 ℃ for 2 h is orthorhombic perovskite, whereas the sample for x=0.3 is a mixed crystal with orthorhombic and cubic symmetry. The mean TEC value of sintered sample is about 12.76× 10^-6/K in the range from room temperature to 1 000 ℃, which corresponded with that of the SDC and/or La0.8Sr0.2Ga0.85Mg0.15O3-δ（LSGM）. The pores in the sintered sample are dispersed homogeneously, with a porosity of 35%. The composite interface of cathode/ electrolyte is clear, and there are no visible diffusion particles. After sintering the mixed powder of oxides and SDC at 1 200℃ for 10h, there is no new phase detected.