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采用低温燃烧合成法制备了用作中低温固体氧化物燃料电池的阴极材料La0.7Sr0.3Co1-yFeyO3-δ(y=0.00,0.20,0.25,0.30,0.35,0.40).分别利用TG-DSC、XRD表征了La0.7Sr0.3Co1-yFeyO3-δ形成过程的晶型演化行为和物相组成,结果表明该粉体经900℃热处理后可形成钙钛矿结构,随着Fe含量增加,衍射峰向低角度方向偏移.利用直流四端子法测试了La0.7Sr0.3Co1-yFeyO3-δ的电导率,结果表明样品的电导率随Fe含量的增加而降低.在所测量的温度范围内,y=0样品的电导率随温度升高而减小,符合类金属导电行为;其余样品的电导率随温度的升高而增大,服从半导体导电机理.在测试温度范围内,材料的电导率均大于600 S·cm-1. 相似文献
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In this study,the dependences of yttria content,porosity and grain size on the thermal properties of Y2O3 stabilized ZrO2 (YSZ) ceramics were investigated.YSZ ceramics were synthesized by the solid state reaction method.The phase,microstructure and thermal properties of YSZ ceramics were characterized by X-ray diffraction (XRD),scanning electron microscopy (SEM),differential scanning calorimetry (DSC) and laser-flash apparatus (LFA),respectively.The results indicated that the specific heat capacity of YSZ increased with the increase of temperature and decreased with the increase of yttria content.As the temperature increased,the thermal diffusivity and conductivity of YSZ ceramics were decreased,whereas their variations for 16YSZ,18YSZ and 20YSZ were much less pronounced than those for 12YSZ and 14YSZ.At a given temperature,the thermal conductivity of YSZ was opposite to yttria content.The thermal conductivity of YSZ ceramics almost linearly decreased with the increase of porosity.In addition,the grain size also had a great influence on the thermal conductivity. 相似文献
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采用尿素燃烧法合成了中温固体氧化物燃料电池阴极材料La0.8Sr0.2FeyCo1-yO3-δ粉体.分别利用TG-DSC、XRD和SEM对产物的形成过程、晶体结构和显微形貌进行了研究.结果表明,La0.8Sr0.2FeyCo1-yO3-δ粉体的主晶相为钙钛矿结构,个别试样伴有少量杂峰.采用直流四端子法测试了烧结后试样在500℃~800℃范围内的电导率,实验结果表明,y=0时,样品的电导率最大,且随温度升高而单调下降呈金属型导电;其它样品(y=0.20,0.25,0.30,0.35,0.40)的电导率随温度升高而增大,符合小极化子导电机制;在测试温度范围内,材料的电导率均大于400S/cm. 相似文献