Ceramics-Silikáty 59, (3) 227 - 232 (2015) |
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DOPING EFFECT OF ZrO₂ ON MICROSTRUCTURAL AND ELECTRICAL PROPERTIES OF ZnO.Pr₆O₁₁-BASED CERAMIC VARISTORS
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Fu Xiuli 1, Feng Hai 1,2, Gao Ruichao 2,1, Peng Zhi Jian 2
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1 State Key Laboratory of Information Photonics and Optical Communications, and School of Science, Beijing University of Posts and Telecommunications, Beijing 100876, P. R. China
2 School of Engineering and Technology, China University of Geosciences, Beijing 100083, China
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Keywords: ZnO varistor, Pr₆O₁₁, ZrO₂ doping, Electrical properties
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ZnO-Pr₆O₁₁-CoO-Cr₂O₃-based ceramic varistors doped with 0 - 2.0 mol.% ZrO₂ were fabricated via conventional ceramic processing by sintering at 1300°C for 2 h. X-ray diffraction results indicate that the doped ZrO2 reacted with praseodymium oxides during sintering, resulting in Pr₂Zr₂O₇ phase. Scanning electron microscopy analysis revealed that after the addition of ZrO2, the growth of ZnO grains was inhibited due to the formation of Pr₂Zr₂O₇. When the amount was less than 0.5 mol.%, ZrO₂ doping was beneficial for increasing the varistor nonlinear exponent. The varistor voltage increased with increasing ZrO₂contents in the ceramics, but the leakage current also increased with it. In this work, the sample doped with 0.5 mol.% ZrO₂ presented the highest nonlinear exponent (17), and its varistor voltage was 623 V mm⁻¹. The sample with 2.0 mol.% ZrO₂ presented the highest varistor voltage (1490 V mm⁻¹), and its nonlinear exponent was 10. The obtained varistor would be very promising in super-high-voltage power transmission systems. |
Record in: Scopus | Web of Science |
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