铌掺杂对Ce-Nb-TiO_2系压敏陶瓷结构与电性能的影响

研究了铌对Ce,Nb掺杂的二氧化钛压敏陶瓷结构和电性能的影响。结果表明,在1 350℃烧结条件下,掺入0.8%Nb2O5的样品具有优良的综合电性能,显示出低的压敏电压(U1mA=7.22V/mm)、高的非线性系数(α=5.76),是一种很有潜力的新型电容-压敏陶瓷材料。铌掺杂主要是Nb5+对Ti4+的掺杂取代,该掺杂存在一饱和值。Nb2O5在不同的掺杂浓度下,存在的形式和位置不同,同时与一些低熔点化合物相如Ce2Ti2(Si2O7)O4等相互作用,使得样品的电性能发生变化。

Effect of Nb on Microstructure and Electric Properties of Nb and Ce doped TiO2 Based Varistor Ceramics

The microstructure and electrical properties of(Ce,Nb)-doped TiO2 ceramics with various Nb2O5 amount had been investigated by varistor and dielectric measurements,SEM,EDAX and XRD.It was found that the Nb2O5 dopant had significant effect on the varistor properties and dielectric properties of(Ce,Nb)-doped TiO2 based varistor ceramics sintering at 1 350 ℃.An optimal composition dopant with 0.8% Nb2O5 was obtained with low breakdown voltage of 7.22 V/mm,high nonlinear coefficient of 5.76.It is a potential new type material for capacitor and varistor.The Nb-dopping is attributed to substitution of Nb5+ to Ti4+.As the content of Nb2O5 increases,its form and position of existence are different.The characteristics of the ceramics can be explained by the effect and the maximum of the substitution of Ti4+ with Nb5+,and the interaction between Nb5+ and some low-melting compounds such as perrierite(Ce2Ti2(Si2O7)O4) produced on grain boundary and sample face.