新型无铋ZnO压敏陶瓷组成设计及微观机理研究

ZnO varistors have been extensively used in protection devices against transient voltage surges in electrical and electronic systems owing to their excellent nonlinear current–voltage properties. The conventional ZnO-Bi2O3, ZnO-Pr6O11, ZnO-V2O5-based systems now meet a big challenge due to the high volatility, the reaction with Ag/Pd inner electrode, high costs, low amount in earth and toxicity, which greatly limit their promising applications. Based on the potential ability to form nonlinear I-V characteristic of Cr2O3, we now propose a new type ZnO-Cr2O3 varistor to solve the present problems of the conventional ZnO varistors. In this project, composition design, properties control and microstructure mechanism will be studied. Transition metal oxides will be introduced to optimize the varistor properties; the effect of dopants on the microstructure and properties will be discussed; the microstructure mechanism of the nonlinear I-V behavior will be deeply investigated by the combination of microstructure and local electrical performance analysis, which lay the foundation for improving the performance and design the new type ZnO-Cr2O3 varistor for applications.

ZnO压敏电阻具有优异的非线性伏安特性，可用来吸收浪涌电压，在电子、电力、交通、航天等领域发挥重要的关键器件保护作用。传统ZnO-Bi2O3、ZnO-Pr6O11、ZnO-V2O5系压敏陶瓷因存在易挥发、与电极反应、原料稀缺、有毒等问题，从而严重制约了其应用潜力。为此，研制新型高性能压敏材料是当前的发展前沿。本课题基于Cr2O3显示出的形成非线性伏安特性的潜在可能，拟开展新型ZnO-Cr2O3系压敏陶瓷的组成设计、制备、性能调控及微观机理研究。通过引入过渡族金属氧化物优化组成设计；研究添加剂对晶界势垒和压敏性能的调控规律；结合晶界结构、缺陷类型的精细表征和微区伏安特性的原位表征，获得高性能新型ZnO-Cr2O3系压敏陶瓷，并阐明其形成非线性伏安特性的微观物理机制和晶界势垒调控机制，为新型ZnO-Cr2O3系压敏陶瓷的创新研发和深度应用提供重要科学依据。

ZnO压敏电阻具有优异的非线性伏安特性，可用来吸收浪涌电压，在电子、电力、交通、航天等领域发挥重要的关键器件保护作用。传统ZnO-Bi2O3、ZnO-Pr6O11、ZnO-V2O5系压敏陶瓷因存在易挥发、与电极反应、原料稀缺、有毒等问题，从而严重制约了其应用潜力。为此，研制新型高性能压敏材料是当前的发展前沿。本课题开展了新型ZnO-Cr2O3系压敏陶瓷的组成设计、制备、性能调控及微观机理研究。研究表明以Cr为形成非线性的添加剂，Ca、Co、Sb为增加非线性的添加剂，获得了高性能新型ZnO-Cr2O3系压敏陶瓷，非线性系数高达219，漏电流低于0.2 μA/cm2，性能优于目前现有的压敏陶瓷。结合晶界结构、缺陷类型的精细表征和微区电势特性的原位表征，阐明Cr是形成非线性伏安特性的关键元素，容易在晶界聚集，形成受主缺陷，从而形成晶界势垒；Ca、Co、Sb有助于增加晶粒的费米能级高度从而增加晶界势垒，提高非线性系数，降低漏电流，本研究为新型ZnO-Cr2O3系压敏陶瓷的创新研发和深度应用提供重要科学依据。