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http://dx.doi.org/10.3740/MRSK.2010.20.11.575

Microstructure and Positive Temperature Coefficient of Resistivity Characteristics of Na2Ti6O13-Doped 0.94BaTiO33-0.06(Bi0.5Na0.5)TiO3 Ceramics  

Cha, Yu-Joung (Electronic Components Lab., Korea Institute of Ceramic Eng. & Tech.)
Jeong, Young-Hun (Electronic Components Lab., Korea Institute of Ceramic Eng. & Tech.)
Lee, Young-Jin (Electronic Components Lab., Korea Institute of Ceramic Eng. & Tech.)
Paik, Jong-Hoo (Electronic Components Lab., Korea Institute of Ceramic Eng. & Tech.)
Lee, Wu-Young (Hiel Corporation)
Kim, Dae-Joon (Hiel Corporation)
Publication Information
Korean Journal of Materials Research / v.20, no.11, 2010 , pp. 575-580 More about this Journal
Abstract
The microstructure and positive temperature coefficient of resistivity (PTCR) characteristics of 0.1 mol%$Na_2Ti_6O_{13}$ doped $0.94BaTiO_3-0.06(Bi_{0.5}Na_{0.5})TiO_3$ (BBNT-NT001) ceramics sintered at various temperatures from $1200^{\circ}C$ to $1350^{\circ}C$ were investigated in order to develop eco-friendly PTCR thermistors with a high Curie temperature ($T_C$). Resulting thermistors showed a perovskite structure with a tetragonal symmetry. When sintered at $1200^{\circ}C$, the specimen had a uniform microstructure with small grains. However, abnormally grown grains started to appear at $1250^{\circ}C$ and a homogeneous microstructure with large grains was exhibited when the sintering temperature reached $1325^{\circ}C$. When the temperature exceeded $1325^{\circ}C$, the grain growth was inhibited due to the numerous nucleation sites generated at the extremely high temperature. It is considered that $Na_2Ti_6O_{13}$ is responsible for the grain growth of the $0.94BaTiO_3-0.06(Bi_{0.5}Na_{0.5})TiO_3$) ceramics by forming a liquid phase during the sintering at around $1300^{\circ}C$. The grain growth of the BBNT-NT001 ceramics was significantly correlated with a decrease of resistivity. All the specimens were observed to have PTCR characteristics except for the sample sintered at $1200^{\circ}C$. The BBNT-NT001 ceramics had significantly decreased $\tilde{n}_{rt}$ and increased resistivity jump with increasing sintering temperature at from $1200^{\circ}C$ to $1325^{\circ}C$. Especially, the BBNT-NT001 ceramics sintered at $1325^{\circ}C$ exhibited superior PTCR characteristics of low resistivity at room temperature ($122\;{\Omega}{\cdot}cm$), high resistivity jump ($1.28{\times}10^4$), high resistivity temperature factor (20.4%/$^{\circ}C$), and a high Tc of $157.9^{\circ}C$.
Keywords
PTCR; $Na_2Ti_6O_{13}$; $(Bi_{0.5}Na_{0.5})TiO_3$; liquid phase; sintering temperature;
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1 J. H. Ahn, J. -H. Lee, S. -H. Hong, N. -M. Hwang and D. -Y. Kim, J. Am. Ceram. Soc., 86, 1421 (2003).   DOI   ScienceOn
2 H. Y. Park, C. W. Ahn, H. C. Song, J. H. Lee, S. Nahm, K. Uchino, H. G. Lee and H. J. Lee, Appl. Phys. Lett., 89, 062906 (2006).   DOI   ScienceOn
3 O. Saburi, J. Phys. Soc. Jpn., 14(9), 1157 (1959).
4 G. G. Harman, Phys. Rev., 106, 1358 (1957).   DOI
5 P. W. Haayman, R. W. Dam and H. A. Klassens, German Patent No. 929350 (1955).
6 J. -H. Lee and S. -H. Cho, Kor. J. Mater. Res., 3(5), 553 (1993) (in Korean).
7 Y. Y. Lin, C. T. Hu, H. Y. Chang and I. N. Lin, J. Appl. Phys., 83, 1321 (1998).   DOI   ScienceOn
8 H. Takeda, T. Shimada, Y. Katsuyama and T. Shiosaki, J. Electroceram., 22, 263 (2009).   DOI
9 T. Shimada, K. Touji, Y. Katsuyama, H. Takeda and T. Shiosaki, J. Eur. Ceram. Soc., 27, 3877 (2007).   DOI   ScienceOn
10 H. Takeda, W. Aoto and T. Shiosaki, Appl. Phys. Lett., 87, 102104 (2005).   DOI   ScienceOn
11 W. Huo and Y. Qu, Sensor. Actuator. Phys., 128, 265 (2006).   DOI   ScienceOn
12 J. Wei, W. Pu, Y. Mao and J. Wang, J. Am. Ceram. Soc., 93(6), 1527 (2010).
13 S. -H. Hong and D. -Y. Kim, J. Am. Ceram. Soc., 84, 1597 (2001).   DOI   ScienceOn
14 J. R. Salgado, E. Djurado and P. Fabry, J. Eur. Ceram. Soc., 24, 2477 (2004).   DOI   ScienceOn
15 K. Teshima, S. H. Lee, S. Murakoshi, S. Suzuki, K. Yubuta, T. Shishido, M. Endo and S. Oishi, Eur. J. Inorg, Chem., 2010, 2936 (2010).   DOI   ScienceOn