Journal of Inorganic Materials

• Research Paper • Previous Articles     Next Articles

Influence of Grain Boundaries on the Properties of Sr0.4Pb0.6TiO3 Thermistors

ZHAO Jing-Chang; LI Long-Tu; GUI Zhi-Lun   

  1. State Key Laboratory of New Ceramics and Fine Processing; Dept. of Materials Science and Engineering; Tsinghua University; Beijing 100084; China
  • Received:2001-04-02 Revised:2001-05-28 Published:2002-03-20 Online:2002-03-20

Abstract: A kind of V-shaped thermistor based on Sr0.4Pb0.6TiO3 materials was fabricated by solid
state reaction methods. The samples exhibit novel NTCR effect below the Curie temperature (Tc) and typical PTCR effect above Tc, the room-
temperature resistivities and the values of log(ρ25℃min) increase with elevating soaking temperature. The phase structure, microstructure
and compositional distribution of samples were investigated by using XRD, SEM and EDS respectively. The results show that Sr, Ti
concentrations near the grian boundaries are higher than that in the grains. It is estimated that the NTCR effects of (Sr,Pb)TiO3
ceramics are closely related to the Pb2+ ionic vacancies near the grain boundaries. The semiconductive mechanism of Y3+-doped
(Sr,Pb)TiO3 ceramics was also discussed.

Key words: (Sr, Pb)TiO3, PTCR, NTCR

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