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The Microstructure of National Bureau of Standards Reference Fly Ashes

Published online by Cambridge University Press:  21 February 2011

J. C. Qian ,
E. E. Lachowski  and
F. P. Glasser
J. C. Qian
Affiliation:
Department of Chemistry, University of Aberdeen, Meston Walk, Old Aberdeen, AB9 2UE, Scotland.
E. E. Lachowski
Affiliation:
Department of Chemistry, University of Aberdeen, Meston Walk, Old Aberdeen, AB9 2UE, Scotland.
F. P. Glasser
Affiliation:
Department of Chemistry, University of Aberdeen, Meston Walk, Old Aberdeen, AB9 2UE, Scotland.
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Abstract

A suite of three fly ashes, National Bureau of Standards* Standard Reference Materials (SRMs) 2689, 2690 and 2691, was studied by transmission electron microscopy and by analytical electron microscopy (aem): sample preparation techniques are described. The chemical compositions of the glassy phase, analyzed by aem, showed a wide dispersion of values although the mean composition of the glass remained close to that of the whole fly ash.

The microstructure of these materials is complex: besides crystalline inclusions, the aluminasilica glasses have undergone phase separation on a nanometer scale, and consist of two glassy phases. Since liquid-liquid phase separation has also been found in British fly ashes, it appears to be a characteristic feature of the glassy phase in Class F ashes and is also encountered in occasional Al-Si rich particles in Class C ashes. High iron content glass was found in fly ash SRM 2689, and its phase separation and crystallization were investigated.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 136: Symposium O – Fly Ash and Coal Conversion By-Products V , 1988 , 77
Copyright
Copyright © Materials Research Society 1989

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References

REFERENCES

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