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The effect of SiO 2 on electrical properties of low‐temperature‐sintered ZnO–Bi 2 O 3 –TiO 2 –Co 2 O 3 –MnO 2 ‐based ceramics
Author(s) -
Bai Hairui,
Zhang Minghui,
Xu Zhijun,
Chu Ruiqing,
Hao Jigong,
Li Huaiyong,
Gong Yunyun,
Li Guorong
Publication year - 2017
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.14575
Subject(s) - materials science , varistor , sintering , grain boundary , microstructure , grain size , analytical chemistry (journal) , electrical resistivity and conductivity , temperature coefficient , mineralogy , composite material , voltage , electrical engineering , chemistry , chromatography , engineering
ZnO–Bi 2 O 3 –TiO 2 –Co 2 O 3 –MnO 2 ‐based ( ZBTCM ) varistors were fabricated via the conventional solid‐state method, and the effect of SiO 2 content on the phase transformation, microstructure, and electrical properties of the ZBTCM had been investigated. Results showed that this varistor can be sintered at a low temperature of 880°C with a high sintering density above 0.95 of the ZnO theoretical density. In these components, SiO 2 acts as a controller in ZnO grain growth, decreasing the grain size of ZnO from 3.67 to 1.92 μm, which in turn results in an increase in breakdown voltage E 1mA from 358.11 to 1080 V/mm. On the other hand, SiO 2 has a significant influence on the defect structure and component distribution at grain‐boundary regions. When SiO 2 content increases from 0 to 4 wt%, the value of the interface state density ( N s ) increases sharply. At the same time, the electrical properties are improved gradually, and reach an optimized value with the nonlinear coefficient (α) up to 54.18, the barrier height (ϕ b ) up to 2.90 eV, and the leakage current ( I L ) down to 0.193 μA/cm 2 .