Sol-Gel法制备ZnO压敏陶瓷及其电性

采用溶胶-凝胶(sol-gel)工艺制备ZnO电压敏陶瓷粉体.探讨其制备的最佳工艺条件以Zn(NO3)2与NaOH为反应前驱物制取胶体,Zn2+浓度控制在0.5mol*L-1以上，pH值7.5左右，预烧温度300°C，陶瓷烧结温度1200°C；制得的压敏电阻的非线性系数α=28；研究了稀土La2O3掺杂对该陶瓷电性的影响低浓度掺杂时，可提高压敏电压，高浓度掺杂时，不呈现压敏特性；对粉体进行了X射线衍射和透射电镜分析，预烧后得到五元掺杂的ZnO粉体粒形呈球状，属六方晶系，粒径分布窄，约为40～80nm.

Preparation of Rare Earth Oxide Doped ZnO Varistor and its Electrical Properties

A new process of preparing non-linear ZnO varistor ceramics was reported. The optimum processing conditions were determined as follows: Zn(NO3)2 and NaOH as the raw material, the concentration of Zn2+ to be above 0.5mol*L-1, pH value of 7.5, calcining temperature of 300C, sintering temperature of 1200C; the varistors with non-linear coefficient of 28 were obtained. The effect of rare earth element La2O3 on the electrical properties of the ceramics was discussed to be: doping at low concentration is helpful to enhance its breakdown voltage; at high concentration its voltage sensitive properties will disappear. The powder was characterized by XRD and TEM, showing the five-additive powder to be spherical and with a diameter about 40～80 nm.