Chapter 52. Densification and Defect Chemistry Related to the Varistor Performance of ZnO-Based Ceramics

  1. John B. Wachtman Jr.
  1. M. C. S. Nobrega1,2 and
  2. J. K. West2

Published Online: 28 MAR 2008

DOI: 10.1002/9780470314555.ch52

Proceedings of the 18th Annual Conference on Composites and Advanced Ceramic Materials - B: Ceramic Engineering and Science Proceedings, Volume 15, Issue 5

Proceedings of the 18th Annual Conference on Composites and Advanced Ceramic Materials - B: Ceramic Engineering and Science Proceedings, Volume 15, Issue 5

How to Cite

Nobrega, M. C. S. and West, J. K. (1994) Densification and Defect Chemistry Related to the Varistor Performance of ZnO-Based Ceramics, in Proceedings of the 18th Annual Conference on Composites and Advanced Ceramic Materials - B: Ceramic Engineering and Science Proceedings, Volume 15, Issue 5 (ed J. B. Wachtman), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470314555.ch52

Author Information

  1. 1

    COPPE/UFRJ, C.P. 68501, Rio de Janeiro — BRAZIL

  2. 2

    AMRC, Advanced Materials Research Center — University of Florida, One Progress Blvd, Box 14, Alachua, FL — USA

Publication History

  1. Published Online: 28 MAR 2008
  2. Published Print: 1 JAN 1994

ISBN Information

Print ISBN: 9780470375334

Online ISBN: 9780470314555

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Keywords:

  • nonlinear voltage-current;
  • densification;
  • znO-based ceramics;
  • intrinsic defect concentrations;
  • znO grain-boundary

Summary

Studies dealing with nonlinear voltage-current characteristics versus densification and defect chemistry in ZnO-based ceramics may elucidate structure-properties related aspects still not clearly understood on the functionality of these materials. In this paper, evaluation of both densification and intrinsic defect concentrations at the ZnO grain-boundary are used to understand the nonlinearity performance of ZnO ceramics. On the basis of defect chemistry equations for ZnO, the intrinsic concentration of the defects, namely zinc and oxygen vacancies, related to sintering conditions was calculated. The nonlinearity was found to be enhanced when densification was maximized and when the oxygen-rich atmosphere also increased the acceptor concentration.