CaO过剩型Ca_(1-x)ZrO_(3-δ)陶瓷的阻抗行为研究

Impedance Behavior of Excess CaO Type Ca_(1-x)ZrO_(3-δ) Ceramics

采用共沉淀法制备CaO过剩型的Ca_(1-x)ZrO_(3-δ),用交流阻抗法研究了阻抗行为。结果表明:C1.2Z试样前驱体在1000℃焙烧后生成较纯的斜方CaZrO_3相;试样的总电导率随着温度的升高而显著增大,其活化能为1.17 eV;随着温度的升高,试样的弛豫时间和电容均显著减小;在低温晶界的介电常数明显高于晶粒的,进而推测出氧离子缺陷分布不均和CaO对Ca_(l-x)ZrO_(3-δ)基体的非均匀;随着温度的升高介电常数显著减小,表明氧空位的分布逐渐趋于均匀化。

Excess CaO type non-stoichiometric calcium zirconate was prepared by a co-precipitation method, and the impedance properties was investigated by AC impedance determination. The results show that precursor powder can be synthesized into pure orthorhombic CaZrO3, the total electrical conductivity significantly increases with temperature increases, and the activation energy was calculated to be 1.17eV. Both relaxation time and capacitance decrease dramatically with the rising of temperature. The permittivity of grain boundary was found higher than that of grain at low temperature. In this way, the heterogeneous distribution of oxygen vacancies was indicated, and the doping mechanism of CaO in Ca1-xZrO3-δ matrix was deduced to be heterogeneous. However, permittivity decreases evidently with temperature rises, which suggests the oxygen vacancies distribute more homogeneously at higher temperature.