中文摘要：

Ca位掺杂可以优化Ca3Co4O9复合氧化物的电输运性能.采用柠檬酸溶胶凝胶结合放电等离子烧结制备了Ca位微量掺杂Ag的Ca3-xAgxCo4O9（x=0—0.05）氧化物块体试样,通过X射线衍射、扫描电子显微镜、电参数测试仪分析了所得试样.试验结果表明：产物呈单一物相,Ca位微量掺杂Ag降低了Ca3Co4O9的晶粒取向度,x=0.03的试样在所有掺杂试样中取向度最高;试样呈层状结构.测试温度范围内掺杂试样各温度点的电阻率随着Ag掺杂量x的增加先提高后略有降低,所有试样导电机制未发生变化,但是所有试样电阻率均较高,这是因为Ca位Ag掺杂改变了Ca3Co4O9的电子结构.其中Ag掺杂量x=0.04的试样在测试温度范围内具有最高的电阻率,在973K时达14.6mΩcm.

英文摘要：

The electrical transport properties of Ca3Co4O9 could be modified by doping in the Ca site. The Ca site doped Ca3-xAgxCo4O9（x = 0—0. 05） bulk samples were fabricated by citric acid sol-gel and spark plasma sintering method. The resulting samples were analyzed by X-ray power diffraction,scanning electron microscopy and electrical constant measurement. The results showed that all samples were single phased,the prefered orientation was lowered by Ag doping for Ca. The x = 0. 03 sample exhibited highest grain orientation among doped samples,which exhibited layered microstructure. Its electrical resistivity was increased and then decreased slightly by Ag doping,but the transport mechanism was not changed. However,the doped samples exhibited high electrical resistivity caused by changed electronic structure by Ag doping for Ca. The x = 0. 04 sample exhibited highest electrical resistivity in the measuring temperature region with the highest value 14. 6 mΩ·cm at 973 K.