Chapter 5. Color Degradation in a Terra Cotta Glaze

  1. William M. Carty
  1. Hyo Jin Lee,
  2. William Carty and
  3. John Gill

Published Online: 26 MAR 2008

DOI: 10.1002/9780470294611.ch5

Materials & Equipment/Whitewares: Ceramic Engineering and Science Proceedings, Volume 21, Issue 2

Materials & Equipment/Whitewares: Ceramic Engineering and Science Proceedings, Volume 21, Issue 2

How to Cite

Lee, H. J., Carty, W. and Gill, J. (2008) Color Degradation in a Terra Cotta Glaze, in Materials & Equipment/Whitewares: Ceramic Engineering and Science Proceedings, Volume 21, Issue 2 (ed W. M. Carty), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470294611.ch5

Author Information

  1. School of Ceramic Engineering and Materials Science, New York State College of Ceramics at Alfred University, Alfred, New York

Publication History

  1. Published Online: 26 MAR 2008
  2. Published Print: 1 JAN 2000

ISBN Information

Print ISBN: 9780470375679

Online ISBN: 9780470294611

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Keywords:

  • color degradation;
  • terra cotta;
  • glazed products;
  • roofing products;
  • OIT samples

Summary

Color degradation of terra cotta roof tile following a two-year installation period was investigated by comparison to tiles that had never been installed. Tile samples were examined via several methods including bulk property measurements, microstructure analysis, chemical analysis, and refiring testing. Proof of the color degradation was verified through a refiring test, in which a degraded tile was fractured and one-half was heated to 900°C; the heat-treated halfreturned to a deep blue. It is proposed that the color degradation was due to one of two reasons (or a combination of the two reasons): underfred original tiles or high boron levels in the glaze, both leading to environmental degradation.