J. Korean Ceram. Soc. > Volume 51(6); 2014 > Article
 Journal of the Korean Ceramic Society 2014;51(6): 612. doi: https://doi.org/10.4191/kcers.2014.51.6.612
 Effect of Er2O3 Content on Nonlinear Properties and Impulse Clamping Characteristics of Pr/Co/Cr/Al Co-doped Zinc Oxide Ceramics Choon-Woo Nahm Semiconductor Ceramics Laboratory, Department of Electrical Engineering, Dongeui University ABSTRACT The microstructure, nonlinear properties, and impulse clamping characteristics of Pr/Co/Cr/Al co-doped zinc oxide ceramics were investigated with various contents of $Er_2O_3$. Increasing $Er_2O_3$ content increased the density of the sintered pellets from 5.69 to $5.83g/cm^3$, and decreased the average grain size from 10.6 to $6.5{mu}m$. With increased $Er_2O_3$ content, the breakdown field increased from 2318 to 4205 V/cm, and the nonlinear coefficient increased from 19.4 to 40.2. The clamp characteristics were improved with the increase of the content of $Er_2O_3$. The varistors doped with 2.0 mol% exhibited the best clamp characteristics, in which the clamp voltage ratio was 1.40-1.73 at 1-50 A in an impulse current. Key words: Microstructure, Erbium, Electrical properties, Electroceramics, Varistors
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