Issue |
Microsc. Microanal. Microstruct.
Volume 6, Number 5-6, October / December 1995
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Page(s) | 587 - 599 | |
DOI | https://doi.org/10.1051/mmm:1995102 |
DOI: 10.1051/mmm:1995102
Local Chemistry at Interfaces and Boundaries: Ceramic and Electronic Composite Materials
R.W. Carpenter1, J.S. Bow1, M.J. Kim1, K. Das Chowdhury1 et W. Braue21 Center for Solid State Science and the Science and Engineering of Materials Program, Arizona State University, Tempe AZ 85287-1704, U.S.A.
2 German Aerospace Research Establishment (DLR), Materials Research Institute, 51147 Cologne, Germany
Abstract
The spatial extent of chemical solute distributions that formed
in interfaces between platinum or silicon nitride and silicon
carbide or in silicon nitride grain boundaries during high
temperature processing of these composites has been investigated
by position resolved nanospectroscopy, Z-contrast imaging and
energy selected imaging. The solute distributions resulted from
intentional sintering aid additions or interfacial reaction.
The distribution widths normal to the nominal interface/boundary
planes, called chemical interface/boundary widths, were much
larger than the corresponding structural widths of the same
boundaries and interfaces, determined by HREM imaging.
Qualitative agreement between the three methods used to
determine chemical widths was excellent. Differences in count
rate resulting from beam current differences among the methods
resulted is some predictable quantitative disagreements in
absolute chemical widths. Energy selected imaging proved to be
a very fast, efficient method for examination of chemical
distributions over large specimen areas.
8265J - Heterogeneous catalysis at surfaces and other surface reactions.
6116D - Electron microscopy determinations of structures.
Key words
ceramics -- composite materials -- electron microscopy -- grain boundaries -- platinum -- silicon compounds -- sintering -- surface chemistry -- ceramics -- composite materials -- chemical solute distributions -- grain boundaries -- high temperature processing -- position resolved nanospectroscopy -- Z contrast imaging -- energy selected imaging -- sintering aid -- interfacial reaction -- boundary width -- HREM -- count rate -- beam current -- Pt SiC -- Si sub 3 N sub 4 SiC
© EDP Sciences 1995