双掺杂BaxAgyCa3-x-yCo4O9氧化物的织构与电输运性能

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Ba_xAg_yCa_3-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973 K时达到最低值（73 mΩcm），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973 K时为63 mΩcm. 关键词： 3Co₄O₉')" href="#">Ca₃Co₄O₉ 双掺杂 织构 电输运性能

Texture and electrical transport properties of Ba and Ag double substituted BaxAgyCa3-x-yCo4O9 oxide

Double substituted Ba_xAg_yCa_3-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_yCa_2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_yCa_28Co₄O₉ （y>0） bulks is prominently lower than that of Ca₃Co₄O₉ and the orientation of Ba_02Ca_2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 Ba_01Ag_01Ca_28Co₄O₉ bulk exhibits simultaneously lowered orientation and moderately low resistivity and the resistivity reaches 73 mΩ·cm at 973 K. The Ag_02Ca_28Co₄O₉ bulk exhibits lowest orientation and lowest resistivity, reaching 63 mΩ·cm at 973 K.