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Optimization of heating schedules in pyrolytic binder removal from ceramic moldings

Published online by Cambridge University Press:  31 January 2011

J. H. Song ,
J. R. G. Evans ,
M. J. Edirisinghe  and
E. H. Twizell
J. H. Song
Affiliation:
Department of Materials Engineering, Brunel University, Uxbridge, Middlesex UB8 3PH, United Kingdom
J. R. G. Evans
Affiliation:
Department of Materials Engineering, Brunel University, Uxbridge, Middlesex UB8 3PH, United Kingdom
M. J. Edirisinghe
Affiliation:
Department of Materials Engineering, Brunel University, Uxbridge, Middlesex UB8 3PH, United Kingdom
E. H. Twizell
Affiliation:
Department of Mathematics and Statistics, Brunel University, Uxbridge, Middlesex UB8 3PH, United Kingdom
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Abstract

A model that finds the maximum permissible heating rate for pyrolysis of ceramic moldings is extended to produce multi-segment temperature–time profiles to minimize the binder removal time. The degradation of the polymer and the diffusion of degradation products in solution to the free surface in a cylinder containing 50 vol% alumina and polyalphamethylstyrene is considered. The theory has previously been validated experimentally for fixed heating rates for cylindrical and flat plate geometries and for overpressure debinding. The extended model, presented here, calculates the vapor pressure of monomer over solution and modifies the heating rate to keep this just below ambient pressure. In this way, the temperature follows the maximum allowable rate at each stage to prevent boiling and hence the incidence of defects.

Type
Articles
Information
Journal of Materials Research , Volume 15 , Issue 2 , February 2000 , pp. 449 - 457
Copyright
Copyright © Materials Research Society 2000

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References

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