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Structural Organization of Early Gels and Precipitates of Chemically Bonded Ceramics

Published online by Cambridge University Press:  25 February 2011

William B. White ,
Dorothy J. Vesper  and
Julia Kraus
William B. White
Affiliation:
Materials Research Laboratory, The Pennsylvania State University, University Park, PA 16802
Dorothy J. Vesper
Affiliation:
Materials Research Laboratory, The Pennsylvania State University, University Park, PA 16802
Julia Kraus
Affiliation:
Materials Research Laboratory, The Pennsylvania State University, University Park, PA 16802
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Abstract

Ceramic precursor materials in the silica-alumina-phosphous pentoxide system can be retained as solutions under suitably high or low pH conditions. Molecular species in these solutions have been characterized by their sharp, well-defined Raman spectra. Changes in pH or reduced water activity by addition of miscible organic solvents takes the system across sharp precipitation boundaries. Precipitates can take the form of colloidal gels, polymerized gels, or crystallites depending on chemical composition and rate of precipitation. Raman spectra of precipitates immersed in their parent solutions have much less structure and broader bands. Information of the structural characteristics of the precipitates are deduced from band widths and the amount of fine structures related to the coherence length for Raman scattering. Phosphate-rich compositions tend to be more highly ordered with more detailed spectra than the silicate rich compositions.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 121: Symposium H – Better Ceramics Through Chemistry III , 1988 , 213
Copyright
Copyright © Materials Research Society 1988

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References

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