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Preparation of beta-silicon nitride seeds for self-reinforced silicon nitride ceramics

Ramesh, P. D.; Oberacker, R.; Hoffmann, M. J.

Abstract:
This paper describes a method for the preparation of silicon nitride
(Si3N4) seeds that have an average aspect ratio of similar to 4, The
seeds are prepared via heat treatment of a powder mixture that contains
oc-phase-rich Si3N4 and 0.5 wt% Y2O3 at a temperature of 1800 degrees C
and a nitrogen pressure of 35 kPa. A Y-Si-O-N liquid forms during heat
treatment; this liquid acts as a flux for seed precipitation. During
cooling, the Y-Si-O-N liquid transforms to a thin intergranular
grain-boundary phase and causes strong agglomeration of the seeds. The
seeds can be isolated by dissolving the grain-boundary phase in hot
phosphoric acid, followed by an ultrasonic treatment (for 30 min). The
method can be used to produce large quantities of seeds.


Zugehörige Institution(en) am KIT Institut für Keramik im Maschinenbau (IKM)
Publikationstyp Zeitschriftenaufsatz
Jahr 1999
Sprache Englisch
Identifikator ISSN: 0002-7820
KITopen ID: 1000007703
Erschienen in Journal of the American Ceramic Society
Band 82
Heft 6
Seiten 1608-1610
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