【摘要】 采用柠檬酸溶胶凝胶和放电等离子烧结制备了Ca位双掺杂型的BaxAgyCa3-x-yCo4O9烧结体,利用X射线衍射仪、扫描电子显微镜、电阻率测试仪等研究了烧结体相组成、取向度、织构及电性能.结果表明:含Ag的掺杂试样中出现了偏离化学计量比分布的Ag单质,掺杂试样取向度随Ba与Ag掺杂量之比x/y的增大而提高,含Ag的掺杂试样取向度低于未掺杂试样,不含Ag的掺杂试样取向度高于未掺杂试样.x=y=0.1的试样导电机理发生变化.Ba,Ag掺杂量相等的试样保持较低取向度的同时具有较低的电阻率,在973K时达到最低值(7.3mΩcm),而取向度最低的Ag单掺杂试样电阻率在所有试样中最低,在973K时为6.3mΩcm.更多还原

【Abstract】 Double-substituted Ba_xAg_yCa₃-x-yCo₄O₉ bulks were fabricated by nitric acid sol-gel and spark plasma sintering,and the phase composition,orientation,texture and electrical transport properties of the bulks were investigated by means of X_ray diffraction,scanning electron microscope and electrical resisitivity measurement.The result shows that silver which does not belong to the stoichiometric compounds Ba_xAg_yCa₂.8Co₄O₉ is distributed in the matrix.The degree of orientation increases with increasing ratio of Ba to Ag for the double-substituted bulk.The orientation of Ba_xAg_yCa₂.8Co₄O₉（y>0）bulks is prominently lower than that of Ca₃Co₄O₉ and the orientation of Ba₀.2Ca₂.8Co₄O₉ bulk is higher than that of Ca₃Co₄O₉ bulk.The electrical transport mechanism of the bulk with x=y=0.1 is changed slightly.The Ba₀.1Ag₀.1Ca₂.8Co₄O₉ bulk exhibits simultaneously lowered orientation and moderately low resistivity and the resistivity reaches 7.3 mΩ·cm at 973 K.The Ag₀.2Ca₂.8Co₄O₉ bulk exhibits lowest orientation and lowest resistivity,reaching 6.3 mΩ·cm at 973 K.更多还原