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Fabrication of mixed-oxide sequential deposited silicon nitride powders

Lookup NU author(s): Dr Zafer Tatli, Emeritus Professor Derek Thompson

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Abstract

Silicon nitride can easily be hot-pressed with small additions of metal oxide to give a product with high strength and zero porosity but the disadvantage of hot-pressing is that it is an expensive process limited to the formation of fairly simple shapes and small batches. The present work has therefore focused on preparing MgO-Al2O3 densified samples of silicon nitride by the much cheaper and more versatile technique of pressureless sintering. Coating studies using mixed solutions of Mg- and Al-alkoxides showed a tendency for mutual polymerisation, rather than co-depositing homogeneously on the silicon nitride powder. Improved coating was achieved by sequential deposition, and this also afforded better control of the total thickness of the deposited layer. A particular advantage at the coated powders was that they could be sintered to >99% density at temperature as low as 1450degreesC. It is concluded that the powder coating technique is an excellent method of homogeneously incorporating minor amounts of sintering additive into a powder.


Publication metadata

Author(s): Tatli Z, Thompson DP

Editor(s): Mandal, H., Overcoglu, L.

Publication type: Conference Proceedings (inc. Abstract)

Publication status: Published

Conference Name: Euro Ceramics VIII: Proceedings of the 8th Conference and Exhibition of the European Ceramic Society

Year of Conference: 2004

Pages: 273-276

ISSN: 1013-9826

Publisher: Trans Tech Publications Ltd.

Library holdings: Search Newcastle University Library for this item

Series Title: Key Engineering Materials

ISBN: 9780878499465


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