掺钙铬酸镧陶瓷的导电性能  

ELECTRICAL PROPERTIES OF Ca-DOPED LANTHANUM CHROMITES

作　　者：朱新德[1] 李胜利[1] 孙良成 刘伟明[1] 

机构地区：[1]山东大学材料科学与工程学院,济南250061 [2]包头稀土研究所,内蒙古包头014010

出　　处：《硅酸盐学报》2006年第12期1532-1536,共5页Journal of The Chinese Ceramic Society

基　　金：高等学校博士学科点专项科研基金(20050422026);山东省自然科学基金(Y2005F20)

摘　　要：用固相法合成掺钙铬酸镧(La1–xCaxCrO3)粉末,经模压、烧结制成不同样品。用电极法测量样品的电阻率,同时分析钙含量及烧结气氛对不同温度下电阻率的影响。研究发现:La1–xCaxCrO3的常温和高温电阻率均随钙含量的增大而减小,室温至800℃范围内,不同掺钙量铬酸镧样品的电阻率与温度关系均可用两段直线表示,分别满足Arrhenius公式。两段直线转折点温度随钙含量增大而提高,转折点温度对应La1–xCaxCrO3的正交结构向菱形结构的转变温度。菱形相中电导活化能低于正交相的,电导活化能随钙含量增大而减小。La0.99Ca0.01CrO3样品在刚玉管中烧结后比空气中烧结后的室温及高温电阻率均略大,而La0.92Ca0.08CrO3样品的两者相差不大。The powders of La1-xCaxCrO3 prepared by the solid state reaction method were pressed into cylindrical shapes and sintered into different samples. The high-temperature resistivity of the samples was measured by electric pole; meanwhile the influence of Ca content and sintering atmospheres on resistivity was investigated. It is found that with Ca content increasing, the resistivity of La1-xCaxCrO3 rose at the selected temperature range from room temperature to 800 ℃. The resistivity-temperature relation for La1-xCaxCrO3 may be sectionally represented by two divided Arrhenius equations of semiconductors, and the temperature of the inflexion point increased with Ca content increasing and corresponded to that of the structural transition from orthorhombic to rhombic. The activation energy of conductivity in the orthorhombic phase was higher than that in the rhombic; moreover, the activation energy dropped with Ca content increasing. The room temperature and high-temperature resistivity of La0.99Ca0.01CrO3 after being sintered in an alundum tube was slightly higher than those sintered in the air, while the samples of La0.92Ca0.08CrO3 sintered in this two atmospheres showed little difference.

关 键 词：铬酸镧 电阻率 半导体 电导活化能 

分 类 号：TB32[一般工业技术—材料科学与工程]