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Direct comparison between hot pressing and electric field-assisted sintering of submicron alumina

Langer, Jochen and Hoffmann, Michael J. and Guillon, Olivier (2009):
Direct comparison between hot pressing and electric field-assisted sintering of submicron alumina.
In: Acta Materialia, pp. 5454-5465, 57, (18), ISSN 13596454, [Online-Edition: http://dx.doi.org/10.1016/j.actamat.2009.07.043],
[Article]

Abstract

This study compares hot pressing (HP) and the electric field-assisted sintering technique (FAST) of two different electrically insulating Al2O3 submicron powders with median particle sizes of 150 and 500 nm. Sample geometry, heating schedule, applied pressure and atmosphere were identical for both sintering methods. The densification behavior and characterization of the microstructure revealed that FAST sintered samples reached a higher density compared with HP, in particular for the finer powder. It was found that an increase in dwell time was required to reach the same final density by HP. However, analysis of the sintering curves showed that the densification mechanism for both sintering methods was grain boundary diffusion. Increasing the heating rate up to 150 K min−1 did not modify the densification mechanism. The sintering trajectory showed that the grain size was only dependent on density and was insensitive to the sintering method, in addition to showing a lack of preferential grain orientation.

Item Type: Article
Erschienen: 2009
Creators: Langer, Jochen and Hoffmann, Michael J. and Guillon, Olivier
Title: Direct comparison between hot pressing and electric field-assisted sintering of submicron alumina
Language: English
Abstract:

This study compares hot pressing (HP) and the electric field-assisted sintering technique (FAST) of two different electrically insulating Al2O3 submicron powders with median particle sizes of 150 and 500 nm. Sample geometry, heating schedule, applied pressure and atmosphere were identical for both sintering methods. The densification behavior and characterization of the microstructure revealed that FAST sintered samples reached a higher density compared with HP, in particular for the finer powder. It was found that an increase in dwell time was required to reach the same final density by HP. However, analysis of the sintering curves showed that the densification mechanism for both sintering methods was grain boundary diffusion. Increasing the heating rate up to 150 K min−1 did not modify the densification mechanism. The sintering trajectory showed that the grain size was only dependent on density and was insensitive to the sintering method, in addition to showing a lack of preferential grain orientation.

Journal or Publication Title: Acta Materialia
Volume: 57
Number: 18
Uncontrolled Keywords: Alumina; Electric field-assisted sintering (FAST); Hot pressing (HP); Densification
Divisions: 11 Department of Materials and Earth Sciences > Material Science > Nonmetallic-Inorganic Materials
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences
Date Deposited: 20 Jun 2011 10:47
Official URL: http://dx.doi.org/10.1016/j.actamat.2009.07.043
Identification Number: doi:10.1016/j.actamat.2009.07.043
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