摘要:
本文通过传统的固相烧结法制备了一系列(Al+NB)共掺杂锐钛矿TiO2陶瓷，浓度分别为0.5%, 1%, 2% 和5%，摸索出了拥有优异介电性能的掺杂TiO2陶瓷最佳制备条件：掺杂量x = 0.02时，在1500℃温度下空气气氛中烧结10 h。通过对样品的微观结构、元素以及价态分析、介电温度谱等方面的研究，实验发现Ti1-2xAlxNbxO2陶瓷由锐钛矿型结构转变为金红石相结构；具有很高的致密性；陶瓷的介电性能有很好的频率稳定性以及温度稳定性；表面势垒层电容效应与晶界效应引起的界面极化效应均不是引起巨介电的主要原因，优异介电性能的主要因素来自于电子钉扎缺陷偶极子效应。
Abstract:
In this work, the (Al + Nb) co-doped anatase TiO2 ceramics were prepared by conventional solid phase sintering, and the concentrations were 0.5%, 1%, 2% and 5%, respectively. The optimized annealing conditions for (Al + Nb) co-doped TiO2 ceramics were 1500˚C for 10 h under air atmosphere and the concentration was 2%. According to the sample’s analysis of the microstructure, element, valence, different temperature of dielectric properties, we find that the structure of ceramics transforms from anatase phase structure into rutile phase structure, and all the ceramics have very high density. Their dielectric properties have a very good frequency and temperature stability. The primary origin of the observed colossal dielectric permittivities apparent in our ceramics is not fundamentally related to surface barrier layer capacitor (SBLC) effect and grain boundary effect. Electron-pinned defect-dipoles effect is responsible for the excellent CP properties observed in (Al + Nb) co-doped TiO2.