Chapter 20. A Study of the Driving Force Behind AZS Glass Phase Exudation
- John B. Wachtman Jr
Published Online: 26 MAR 2008
Copyright © 1989 The American Ceramic Society, Inc.
Proceedings of the 49th Conference on Glass Problems: Ceramic Engineering and Science Proceedings, Volume 10, Issue 3/4
How to Cite
Walrod, D. (1989) A Study of the Driving Force Behind AZS Glass Phase Exudation, in Proceedings of the 49th Conference on Glass Problems: Ceramic Engineering and Science Proceedings, Volume 10, Issue 3/4 (ed J. B. Wachtman), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470310533.ch20
- Published Online: 26 MAR 2008
- Published Print: 1 JAN 1989
Print ISBN: 9780470374849
Online ISBN: 9780470310533
- fusion-cast materials;
Glassmakers are keenly aware that fusion-cast AZS refractories sometimes exude a siliceous glass in service. This exudate can be a source of quality problems in the ware, and is seen also as a potentially weak link in the corrosion resistance of AZS. Recent studies of exudation involving image analyses of tested microstructures indicate that the mechanisms involved are more complex than earlier believed. This paper outlines the influence on exudation of cyclical versus sustained heating as a function of micropore formation. A case is also presented for the dissolution of gases dissolved in AZS as being a major driving force behind exudation.
- 1Cyclical heating (from room temperature) produced approximately three times as much exudation as resulted from heating at a sustained temperature.
- 2The volume of microstructural porosity of the tested samples increased in near-direct proportion to the volume of exudation, indicating a displacement.
- 3Analyses by mass spectroscopy of the gas contained within the internal porosity indicated that air (as N2, O2, Ar) comprised the major species. Some analyses also indicated lesser levels of CO2 and SO2.