SnO₂-Zn₂SnO₄复合陶瓷的压敏特性研究

The Varistor Property of SnO₂-Zn₂SnO₄ Composite Ceramics

摘要: 采用传统陶瓷工艺制备了(1 − x) SnO₂ + x Zn₂SnO₄复合陶瓷，并测试了样品的电流-电压非线性关系。结果表明：随着Zn₂SnO₄含量的变化，当x = 0.13时，样品的半导化程度最高，压敏电压达到最低值3 V/mm。对样品的势垒高度测量表明，势垒高度随Zn₂SnO₄含量的增加变化不明显，但随着测试温度的升高而增大，室温下样品的势垒高度约为0.8 eV。进一步研究显示，电模量虚部频谱出现了峰值，随着温度的升高，峰向高频方向移动。通过Arrhenius关系拟合发现，峰值对应的激活能约为0.38 eV。以上结果说明，晶界处的肖特基势垒是SnO2-Zn2SnO4复合陶瓷电学非线性性质起源的重要原因之一，氧空位对于SnO₂-Zn₂SnO₄复合陶瓷晶粒的半导化和势垒的形成有重要作用。

Abstract: SnO₂-Zn₂SnO₄ composite ceramics have been prepared using the traditional ceramic process and the relations between the current density and applied voltage have been investigated. The results show that with the increase of Zn₂SnO₄ content, the breakdown voltage of the SnO₂-Zn₂SnO₄ com-posite ceramics reached a minimum and simultaneously, the semi-conductive degree achieved the maximum at x = 0.13. With the increase of Zn₂SnO₄ content, the barrier height changed slightly and the value for each sample was about 0.8 eV at room temperature, whereas, the barrier height increased obviously with increasing testing temperature. In the imaginary part of electric modulus spectrum, a peak was presented and with the increase of temperature, this peak shifted to high frequency. From the shifting of modulus peak, the activation energy about 0.38 eV was obtained according to the Arrhenius law. The results suggest that the Schottky barrier at the grain boundary plays a key role in the origin of the nonlinear property for SnO₂-Zn₂SnO₄ composite ceramics and the oxygen vacancies are important to the barrier formation.