Ceramics-Silikáty 60, (1) 58 - 62 (2016) |
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INFLUENCE OF REOXIDATION ON SILICA-CONTAINING BARIUM TITANATE CERAMICS FOR PTCR THERMISTORS PREPARED BY TAPE CASTING
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Liu Jianqiao 1,2, Gong Shuping 2, Jin Guohua 1, Zhai Zhaoxia 1, Zhao Yuqing 1 , Luo Chuyao 1, Jiang Qiuxuan 1
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1 College of Information Science and Technology, Dalian Maritime University, Linghai Road 1, Ganjingzi District, Dalian 116026, Liaoning, China P.R.
2 Department of Electronic Science and Technology, Huazhong University of Science and Technology, Luoyu Road 1037, Hongshan District, Wuhan 430074, Hubei, China P.R.
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Keywords: Barium titanate, PTCR thermistor, Tape casting, Reoxidation, Ferroelectricity
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Silica-containing barium-rich BaTiO₃ ceramics for thermistors with a positive temperature coefficient of resistance are prepared by a tape-casting technique. The ceramics are sintered in a reducing atmosphere at low temperatures of 1175-1225°C. The influences of reoxidation are investigated after the reduced ceramics are reoxidized in air at 700-900°C. An anomalous correlation is illustrated between room temperature resistivity and reoxidation temperature. The anomaly results from the ferroelectricity rebuilding mechanism, which includes the spontaneous polarization theory and the ferroelectricity degradation caused by oxygen vacancies. The acceptor-state densities are estimated from the temperature-dependent resistivity. A critical temperature of 750-800°C is concluded for the grain boundary reoxidation. |
Record in: Scopus | Web of Science |
 PDF (1.3 MB) |
doi: 10.13168/cs.2016.0008
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