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High Nonlinearity and High Voltage Gradient ZnO Varistor Ceramics Tailored by Combining Ga 2 O 3 , Al 2 O 3 , and Y 2 O 3 Dopants
Author(s) -
Zhao Hongfeng,
Hu Jun,
Chen Shuiming,
Xie Qingyun,
He Jinliang
Publication year - 2016
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.14110
Subject(s) - varistor , materials science , dopant , ceramic , doping , grain boundary , leakage (economics) , mineralogy , optoelectronics , voltage , metallurgy , microstructure , electronic engineering , analytical chemistry (journal) , electrical engineering , chemistry , chromatography , economics , macroeconomics , engineering
This paper deals with the electrical characteristics of rare‐earth‐doped ZnO varistor ceramics. Multiple donor dopants (Al 3+ , Ga 3+ , and Y 3+ ) were employed to improve the comprehensive performance of ZnO varistor ceramics. The leakage current of rare‐earth‐doped ZnO varistor ceramics decreased noticeably with Ga 2 O 3 dopants. The Ga 3+ dopant occupies the defect sites of grain boundaries and increases the barrier potential of ZnO varistor ceramics, so the leakage current is effectively inhibited. Y 2 O 3 is primarily located around the grains, which restrains ZnO grain growth, increasing the voltage gradient. The Al 3+ goes into the lattices of ZnO grains, decreasing the grain resistance; thus, the residual voltage ratio can be controlled at low levels under a high impulse current. With the combined incorporation of Al 3+ , Ga 3+ , and Y 3 , excellent electrical properties of ZnO varistor ceramics can be acquired with a nonlinearity coefficient of 87, voltage gradient of 517 V/mm, leakage current of 0.96 μA/cm 2 , and residual voltage ratio of 1.60. These rare multiple donor dopants can aid in engineering high‐quality ZnO varistors.