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Journal of Materials Science

, Volume 29, Issue 23, pp 6061–6068 | Cite as

Effect of atmosphere on the PTCR properties of BaTiO3 ceramics

  • D. C. Sinclair
  • A. R. West
Article

Abstract

The influence of low-temperature annealing, at < 360 °C, in various reducing and oxidizing atmospheres for a series of BaTiO3 ceramics with a positive temperature coefficient of resistance (PTCR) is discussed. Combined impedance and modulus spectroscopy is used to analyse a.c. impedance data and shows that the total resistance of the sample can be composed of up to three components, dependent on the cooling rate from the sintering temperature. For quickly cooled samples the PTCR response is dominated by an outer shell on individuals grains, whereas for slowly cooled samples the grain boundary resistance dominates. Annealing in reducing atmospheres destroys the grain boundary PTCR effect whereas the outer-shell grain PTCR effect is relatively insensitive to the reducing atmosphere. It is proposed that the acceptor states responsible for the outer-grain and grain-boundary PTCR effects are predominantly intrinsic metal vacancies, i.e. Ba and/or Ti, and adsorbed oxygen, respectively.

Keywords

Atmosphere Cool Rate BaTiO3 Sinter Temperature Temperature Coefficient 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Chapman & Hall 1994

Authors and Affiliations

  • D. C. Sinclair
    • 1
  • A. R. West
    • 1
  1. 1.Chemistry DepartmentUniversity of AberdeenAberdeenUK

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