5. Pyroplastic Deformation Revisited

  1. William M. Carty
  1. Aubree M. Buchtel1,
  2. William M. Carty1 and
  3. Mark D. Noirot2

Published Online: 26 MAR 2008

DOI: 10.1002/9780470291177.ch5

Whitewares and Materials: Ceramic Engineering and Science Proceedings, Volume 25, Issue 2

Whitewares and Materials: Ceramic Engineering and Science Proceedings, Volume 25, Issue 2

How to Cite

Buchtel, A. M., Carty, W. M. and Noirot, M. D. (2004) Pyroplastic Deformation Revisited, in Whitewares and Materials: Ceramic Engineering and Science Proceedings, Volume 25, Issue 2 (ed W. M. Carty), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470291177.ch5

Author Information

  1. 1

    Whiteware Research Center, New York State College of Ceramics at Alfred University, Alfred, New York

  2. 2

    US. Borax Inc., Valencia, California

Publication History

  1. Published Online: 26 MAR 2008
  2. Published Print: 1 JAN 2004

ISBN Information

Print ISBN: 9780470051474

Online ISBN: 9780470291177

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Keywords:

  • robust test method;
  • quartz dissolution ceases;
  • steady state creep;
  • microstructural evolution;
  • theory of elasticity

Summary

A simple, robust test method was developed for measuring pyroplastic deformation of a whiteware body based upon the calculated stress on a body during firing. Stress is determined from sample geometry, size, and span. A pyroplastic index is generated based on sample stress and deformation, which successfully demonstrates the ability to charaderize the deformation tendency. Two deformation events are apparent in deformation versus firing temperature data, both due to viscous flow. A significant portion of deformation occurs in a non-steady-state region of firing, far below the dwell temperature, proposed to be due to heterogeneities caused by microstructural evolution of the body. A secondary deformation event, proposed to be steady-state creep, occurs at the dwell temperature. Quartz dissolution ceases between 1 and 2 h of dwell time at the peak temperature, and the amount of mullite remains constant, therefore the microstructure is proposed to be steady-state. Through the measurement of bending sample deformation, strain and strain rate can be calculated. The steady-state creep equation can then be used to calculate the system viscosity.