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Densification behavior and properties of Y2O3-containing alpha-SiAlON-based composites

Bandyopadhyay, S.; Hoffmann, M. J.; Petzow, G.

Abstract:
Different SiAlON composites based on alpha'-SiAlON are investigated,
with respect to the phase relationships, densification behavior, and
mechanical properties, The compositions are located on a phase-diagram
line parallel to the Si3N4-Y2O3 . 9AlN compound in the
Si3N4-SiO2-AlN-Al2O3-Y2O3-YN system, Analysis of the reaction sequences
shows that the formation of the composites is associated with the
transient appearance of Y4Al2O9 (YAM), yttrium-aluminum-garnet (YAG),
melilite, and a nitrogen-rich liquid phase, The small shift of
compositions on the Si3N4-Y2O3 . 9AlN compound phase-diagram line
toward the Al2O3-rich side offers the advantage of a higher
sinterability and the removal of the melilite phase from a wide range
of compositions containing alpha'-SiAlON and polytypes, The
alpha'/beta'-SiAlON composites show better mechanical properties in
comparison to pure alpha'-SiAlON and composites of alpha'-SiAlON and
polytypes, A post-heat-treatment causes the crystallization of YAG as a
grain-boundary phase and leads to excellent strength retention up to
temperatures of 1350 degrees C.


Zugehörige Institution(en) am KIT Institut für Keramik im Maschinenbau (IKM)
Publikationstyp Zeitschriftenaufsatz
Jahr 1996
Sprache Englisch
Identifikator ISSN: 0002-7820
KITopen ID: 1000007709
Erschienen in Journal of the American Ceramic Society
Band 79
Heft 6
Seiten 1537-1545
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