摘要
采用传统的固相烧结法制备了Yn（Ba0.8Bi0.2）1–nFe0.9Sn0.1O3负温度系数热敏陶瓷。借助X射线衍射分析仪、扫描电镜、阻温测试仪和交流阻抗分析仪对这类热敏陶瓷的物相、显微结构、阻温特性和阻抗特征进行了表征分析。所得Yn（Ba0.8Bi0.2）1–nFe0.9Sn0.1O3热敏陶瓷为伪立方钙钛矿结构, 粒度约1.0 μm, 随Y含量增加晶格常数a变小; 其室温电阻率、热敏常数和活化能分别介于2.17~9.17 MΩ·cm、6757~7171 K和0.583~0.618 eV范围内, 且均随Y含量增加趋于增大。阻抗分析表明, 在n=0.02、0.04时, 陶瓷体电阻由晶界、晶壳和晶粒电阻构成, 其中晶粒电阻贡献最大; 而在n=0.06、0.08时, 陶瓷体电阻由晶界、畴壁和电畴三个部分构成, 其中电畴区域电阻贡献最大; 在限定的测量温度范围内, 晶界、晶壳、晶粒、畴壁和畴电阻均表现出负温度系数热敏行为。
Negative temperature coefficient thermistor ceramics based on Yn（Ba0.8Bi0.2）1–nFe0.9Sn0.1O3 were fabricated by conventional solid-state reaction techniques. Phases, microstructures, resistance-temperature curves and impedance characteristics of thermistor ceramics were characterized by X-ray diffraction, scanning electron microscope, resistance-temperature tester and ac impedance analyzer, respectively. Yn（Ba0.8Bi0.2）1–nFe0.9Sn0.1O3 thermistor ceramics with pseudo-cubic perovskite structure show average grain size of ~1.0 μm and the decreasing lattice parameter a with increase of Y content. Room-temperature resistivity, thermistor constant and activation energy of thermistor ceramics are in the range of 2.17–9.17 MΩ·cm, 6757–7171 K and 0.583–0.618 eV, respectively. When n = 0.02 and 0.04, the ceramic resistance is mainly attributed to the contribution of grain boundaries, grains and grain shells. Among them, the resistance value of grain is the highest one. However, for the ceramics with n = 0.06 and 0.08, the total resistance of thermistor ceramics is ascribed to the contribution of grain boundaries, domain walls and domains, and the domain regions show the larger resistance value than that of the other two elements. In the limited measured temperature range, all of grain boundaries, grain shells, grains, domain walls and domains show negative temperature coefficient thermistor behavior.
出处
《无机材料学报》
SCIE
EI
CAS
CSCD
北大核心
2014年第1期91-97,共7页
Journal of Inorganic Materials
基金
国家自然科学基金青年基金(51102055)~~
