Large Alumina Parts from an Aqueous Suspension: Hydrolysis Assisted Solidification (HAS)

  1. Prof. Dr. G. Müller
  1. Saša Novak and
  2. Tomaž Kosmač

Published Online: 27 APR 2006

DOI: 10.1002/3527607293.ch25

Ceramics - Processing, Reliability, Tribology and Wear, Volume 12

Ceramics - Processing, Reliability, Tribology and Wear, Volume 12

How to Cite

Novak, S. and Kosmač, T. (2000) Large Alumina Parts from an Aqueous Suspension: Hydrolysis Assisted Solidification (HAS), in Ceramics - Processing, Reliability, Tribology and Wear, Volume 12 (ed G. Müller), Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim, FRG. doi: 10.1002/3527607293.ch25

Editor Information

  1. Fraunhofer-Institut für Silicatforschung, Neunerplatz 2, 97082 Würzburg, Germany

Author Information

  1. Jožef Stefan Institute, Ljubljana, Slovenia

Publication History

  1. Published Online: 27 APR 2006
  2. Published Print: 27 JUN 2000

Book Series:

  1. EUROMAT 99

ISBN Information

Print ISBN: 9783527301942

Online ISBN: 9783527607297

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Keywords:

  • hydrolysis-assisted solidification process;
  • forming large alumina ceramic parts

Summary

Hydrolysis assisted solidification (HAS) is a new method for net-shaping ceramic green parts from aqueous suspensions. The process exploits thermally activated and/or accelerated hydrolysis of aluminum nitride powder added to highly loaded ceramic suspensions. Several simultaneously occurring effects accompany the hydrolysis of AlN: an increase in the effective solids content of the suspension due to internal water consumption, a decreasing zeta potential due to ammonia formation, an increase in the surface area of the solid phase, etc. The overall result is a rapid increase of the suspension's viscosity and hence the setting of the low viscous suspension to form a rigid solid part. As a result, green parts can be prepared by slip-casting or injection molding within an impermeable mould.

The present paper presents the basic principle of the hydrolysis-assisted solidification process and in addition, the preparation technique for forming alumina ceramic parts is described and the properties of the green and sintered products presented. The green parts of different size, formed by slip-casting or injection molding, show homogeneous microstructures and high green strength. The sintered alumina parts have high density, homogeneous microstructure and good mechanical properties.