Title :
Residual voltage properties of ZnO varistors doped with Y2O3 for high voltage gradient
Author :
Hu, Jun ; Liu, Jun ; He, Jinliang ; Long, Wangchen ; Luo, Fengchao
Author_Institution :
Dept. of Electr. Eng., Tsinghua Univ., Beijing, China
Abstract :
Rare-earth oxides can remarkably enhance the voltage gradient of ZnO varistors as growth inhibitor of ZnO grains. However, the effect of rare-earth oxides on the residual voltage properties of ZnO varistors has not been completely investigated. In this paper, ZnO varistor samples with various contents of Y2O3 dopant were prepared and tested under different currents of 8/20 mus impulse surge. When the doped Y2O3 content is no more than 0.75mol%, the residual voltage ratio of ZnO varistor sample decreases with the increment of Y2O3 content. When the doped Y2O3 content reaches 1 mol% or above, the residual voltage ratio of ZnO varistor sample increases remarkably. Such observed experimental results were explained based on the current localization phenomena inner ZnO varistor´s microstructure.
Keywords :
materials preparation; materials testing; varistors; yttrium compounds; zinc compounds; ZnO:Y2O3; current localization phenomena; high voltage gradient; residual voltage properties; varistor microstructure; Additives; Ceramics; Extraterrestrial measurements; Impulse testing; Inhibitors; Surge protection; Temperature; Varistors; Voltage; Zinc oxide; ZnO varistor; high voltage gradient; residual voltage;
Conference_Titel :
Properties and Applications of Dielectric Materials, 2009. ICPADM 2009. IEEE 9th International Conference on the
Conference_Location :
Harbin
Print_ISBN :
978-1-4244-4367-3
Electronic_ISBN :
978-1-4244-4368-0
DOI :
10.1109/ICPADM.2009.5252278