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Modeling of transport properties of interfacially controlled electroceramics: Application to n-conducting barium titanate

Modeling of transport properties of interfacially controlled electroceramics: Application to... Grain boundary regions in n-conducting barium titanate (BaTiO3) are re-oxidized during the cooling process after sintering the ceramics in air. The kinetics of this re-oxidation process is determined by rapid transport of oxygen along the grain boundaries and slow (rate-determining) diffusion of cation vacancies from the grain boundaries into the grains until the diffusion process is frozen-in. Based on numerical calculations of frozen-in diffusion profiles of cation vacancies at grain boundary regions for various cooling rates, a modified Schottky-barrier model is introduced in order to calculate the grain boundary resistivity as a function of temperature from the Curie-point up to 900°C. A change of the activation energy at approximately 500°C is predicted owing to an enrichment of holes in the space charge layers at elevated temperatures. The modeling results are compared with experimental data for BaTiO3-based positive temperature coefficient resistors (PTCRs). http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Journal of Electroceramics Springer Journals

Modeling of transport properties of interfacially controlled electroceramics: Application to n-conducting barium titanate

Preis, W.; Sitte, W.
Journal of Electroceramics , Volume 27 (2) – May 21, 2009
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References (22)

Publisher
Springer Journals
Copyright
Copyright © 2009 by Springer Science+Business Media, LLC
Subject
Materials Science; Optical and Electronic Materials; Ceramics, Glass, Composites, Natural Materials; Characterization and Evaluation of Materials; Electrochemistry; Crystallography and Scattering Methods
ISSN
1385-3449
eISSN
1573-8663
DOI
10.1007/s10832-009-9577-8
Publisher site
See Article on Publisher Site

Abstract

Grain boundary regions in n-conducting barium titanate (BaTiO3) are re-oxidized during the cooling process after sintering the ceramics in air. The kinetics of this re-oxidation process is determined by rapid transport of oxygen along the grain boundaries and slow (rate-determining) diffusion of cation vacancies from the grain boundaries into the grains until the diffusion process is frozen-in. Based on numerical calculations of frozen-in diffusion profiles of cation vacancies at grain boundary regions for various cooling rates, a modified Schottky-barrier model is introduced in order to calculate the grain boundary resistivity as a function of temperature from the Curie-point up to 900°C. A change of the activation energy at approximately 500°C is predicted owing to an enrichment of holes in the space charge layers at elevated temperatures. The modeling results are compared with experimental data for BaTiO3-based positive temperature coefficient resistors (PTCRs).

Journal

Journal of Electroceramics – Springer Journals

Published: May 21, 2009

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