Engineering grain size and electrical properties of donor-doped barium titanate ceramics

Krisztian Niesz, Teyeb Ould-Ely, Hisashi Tsukamoto, Daniel E. Morse

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)

Abstract

A semiconducting lanthanum-doped barium titanate ceramic has been fabricated for battery safety applications by simple means from nanoparticles prepared at room temperature by kinetically controlled vapor diffusion catalysis. The material, characterized by electron microscopy, X-ray diffraction and electrical measurements, exhibits a difficult to achieve combination of submicron grain size (∼500 nm) and attractive electrical properties of room temperature resistivity below 100 Ω cm and a 12-fold increase in resistivity through the Curie temperature (positive thermal coefficient of resistivity, PTCR). Systematic investigation of sintering conditions revealed that a short period of heating at 1350 °C under air is necessary to suppress abnormal grain growth, while precise control of the cooling rate is needed to achieve the targeted electrical properties. Cooling must be sufficiently fast to avoid complete back-oxidation, yet slow enough to facilitate oxygen adsorption at the grain boundaries to produce the thin oxide layer apparently responsible for the observed PTCR.

Original languageEnglish
Pages (from-to)303-311
Number of pages9
JournalCeramics International
Volume37
Issue number1
DOIs
Publication statusPublished - Jan 1 2011

Keywords

  • C. Electrical properties
  • Ceramics
  • Chemical synthesis
  • Crystal growth

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Process Chemistry and Technology
  • Surfaces, Coatings and Films
  • Materials Chemistry

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