The Role of Niobium in (Ca, Si, Ce, Nb)-Doped TiO₂ Varistors

Abstract

The present work attempted to investigate the effect of Nb addition on the electrical properties of the (Ca,Si,Ce,Nb)-doped TiO2 ceramics. The content of added niobium is in the range 0.1-1.0mol %, while that of the other additives keeps constant. The results showed that an optimal composition doped with 0.8mol% Nb2O5, followed by sintering at 1350°C, was obtained with low V1 mA of 7.22V, high nonlinear coefficient of 5.76, ultrahigh dielectric constant (er = 86000) as well as relatively low loss (tgd = 0.52) in room temperature at 1 kHz. SEM studies show that change of niobium had significant influence on grain growth and micro structural characteristics of the sintered samples.

Nonlinear electrical properties of MnO2-doped TiO2 capacitor varistor ceramics

“…There are several types of practical varistor ceramic systems studied such as ZnO [1], SnO 2 [2], WO 3 [3], SrTiO 3 [4], TiO 2 [5]. ZnO-based varistors with high nonlinear coefficients are the most widely used in electronic circuits and devices [6].…”

PREPARATION AND CHARACTERIZATION OF TiO₂-Ta₂O5-CaCO₃ VARISTOR CERAMICS BY HOT ISOSTATIC PRESSING (HIP) AND POST-ANNEALING

“…Since TiO2 ceramics was found to exhibit varistor characteristics in the Bell Labs in 1982 [4], researchers tried to improve its α value. Many works studied the effects of donor single doping, acceptor single doping and co-doping on the varistor properties [14][15][16][17].…”

Effect of La₂O₃ on the Microstructure and Electrical Properties of (Ti,Sn)O₂ Varistor Ceramics

“…Zinc oxide varistors exhibit highly nonlinear current-voltage (I-V) characteristics and are widely used as voltage suppressors in a large variety of power systems and electric circuits [3,4] . The recent trend in electrical appliance design, however, requires varistors that contain multifunction and have relatively low breakdown voltage [5][6][7][8] . TiO 2 based varistors are attracting a great deal of attention for better characteristics of noise absorption and multifunction properties.…”