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XRD investigation of Si–SiC composites with fine SiC microstructure

Published online by Cambridge University Press:  05 March 2012

Matthias Wilhelm*
Affiliation:
Institute for Chemical Technology of Inorganic Materials, Vienna University of Technology, Austria
Frank Kubel
Affiliation:
Institute for Mineralogy, Crystallography and Structural Chemistry, Vienna University of Technology, Austria
Werner Wruss
Affiliation:
Institute for Chemical Technology of Inorganic Materials, Vienna University of Technology, Austria
*
a)Author to whom correspondence should be addressed.

Abstract

Si–SiC composite (reaction bonded SiC) with a submicron SiC microstructure (starting SiC particle size: 0.22 μm) was examined by XRD analysis to determine the amount and phase composition of the secondary SiC formed by the reaction between silicon and carbon during the sintering process. It was found that the secondary SiC has grown onto the original hexagonal α-SiC grains as well as into the porosity of the green body. An increase of 3C–SiC was found within the microstructure after infiltration (from 2.6 wt. % before infiltration to 8.8 wt. % after infiltration) whereas the 4H-ploytype content was reduced. This behavior may be explained by the very small original SiC grains which acted as seeds for disoriented SiC growth and were assumed to force the nonepitaxically deposition of secondary SiC. Solid state and fast transportation processes caused the observed transformation of the SiC. Examinations of the silicon source (infiltrant) after the infiltration procedure showed that most of the carbon was converted to SiC with cubic modification (3C stacking sequence)

Type
New Diffraction Data
Copyright
Copyright © Cambridge University Press 2001

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