Journal of the Korean Institute of Electrical and Electronic Material Engineers (한국전기전자재료학회논문지)

The Korean Institute of Electrical and Electronic Material Engineers (한국전기전자재료학회)
권호 표지
DOI QR코드

DOI QR Code

The Effect of SiO2 on the Microstructure and Electrical Properties of BaTiO3 PTC Thermistor

BaTiO3 PTC 써미스터의 미세구조 및 전기적 특성에 대한 SiO2 영향

  • Chun, Myoung-Pyo (Nano IT Materials Team, Korea Institute of Ceramic Engineering and Technology)
  • 전명표 (한국세라믹기술원 나노IT소재팀)
  • Received : 2012.11.05
  • Accepted : 2012.11.28
  • Published : 2013.01.01
Download PDF
⟨ Previous Next ⟩

Abstract

PTCR ceramics of $(Ba_{0.998}Sm_{0.002})TiO_3+0.001MnCO_3+xSiO_2$ (x=1, 2, 3, 4, 5, 6 mol%) were fabricated by solid state method. Disk samples of diameter 5 mm and thickness about 1mm were sintered at $1,290^{\circ}C$ for 2 h in reduced atmosphere of $5%H_2-95%N_2$ followed by re-oxidation at $600^{\circ}C$ for 30 min. in $20%O_2-80%N_2$.and their microstructures and electrical properties were investigated with SEM and Multimeter. The color of sintered samples was strongly dependent on $SiO_2$ content showing that the color of samples with $SiO_2$ of 1~2 mol% was gray but that of samples with $SiO_2$ of 4~6 mol% was changed from gray to blue, which seems to be related with the reduction of samples due to the oxygen vacancies created during the sintering in reduced atmosphere. $SiO_2$ content had a great influence on the microstructure and the electrical properties. With increasing $SiO_2$ content, the grain size of samples increased and the resistivity as well as the resistivity jump ($R_{285}/R_{min}$) decreased, which is considered to be attributed to the resistivity change at grain interior and grain boundary due to the fast mass transfer through $SiO_2$ liquide phase during the sintering. Samples with 2 mol% $SiO_2$ has the resistivity of $202{\Omega}cm$ and the resistivity jump of 3.28. It is expected that $SiO_2$ doped $BaTiO_3$ based PTC ceramics can be used for multilayered PTC thermistor due to the resistance to the sintering in reduced atmosphere.

Keywords

References

  1. H. Ihrig, J. Am. Ceram. Soc., 64, 617 (1981). https://doi.org/10.1111/j.1151-2916.1981.tb10228.x
  2. T. Matsuoka, Y. Matsuo, H. Sasaki, and S. Hayakawa, J. Am. Ceram. Soc., 55, 108 (1972). https://doi.org/10.1111/j.1151-2916.1972.tb11223.x
  3. A. Yamada and Y. M. Chiang, J. Am. Ceram. Soc., 78, 909 (1995). https://doi.org/10.1111/j.1151-2916.1995.tb08413.x
  4. M. H. Lin and H. Y. Lu, Mater. Sci. Eng., A335, 101 (2002).
  5. S. Tashiro, A. Kanda, and H. Igarashi, Jpn. J. Ceram. Soc., 102, 284 (1994). https://doi.org/10.2109/jcersj.102.284
  6. A. Kanda, S. Tashiro, and H. Igarashi, Jpn. J. Appl. Phys., 33, 5431 (1994). https://doi.org/10.1143/JJAP.33.5431
  7. Y. Matsuo, M. Fujimura, H. Sasaki, K. Nagase, and S. Hayakaw, Am. Ceram. Soc. Bull., 47, 292 (1968).
  8. D. E. Rase and R. Roy, J. Am. Ceram. Soc., 38, 389 (1955). https://doi.org/10.1111/j.1151-2916.1955.tb14562.x
  9. M. A. Zubair and C. Leach, J. Euro. Ceram. Soc., 28, 1845 (2008). https://doi.org/10.1016/j.jeurceramsoc.2007.12.034
  10. X. Wang, H. L. Chan, and C. Choy, J. Euro. Ceram. Soc., 24, P1227 (2004). https://doi.org/10.1016/S0955-2219(03)00379-0
  11. U. C. Chung, C. Elissalde, S. Mornet, M. Maglione, and C. Estounes, Appl. Phys. Lett., 94, 072903 (2009). https://doi.org/10.1063/1.3076125
  12. F. D. Morrison, D. C. Sinclair, and A. R. West, J. Am. Ceram. Soc., 84, 531 (2001). https://doi.org/10.1111/j.1151-2916.2001.tb00694.x
  13. T. Shimizu, H. Bando, Y. Aiura, Y. Haruyama, K. Oka, and Y. Nishihara, Jpn. J. Appl. Phys., Part2, 34, L1305 (1995). https://doi.org/10.1143/JJAP.34.L1305
  14. S. M. Mukhopadhyay and T. S. Chen, J. Mater. Res., 10, 1502 (1995). https://doi.org/10.1557/JMR.1995.1502
  15. M. A. Zubair and C. Leach, J. Euro. Ceram. Soc., 30, 107 (2010). https://doi.org/10.1016/j.jeurceramsoc.2009.07.026