Sintering of industrial mullites in the presence of magnesia as a sintering aid

Citation
L. Montanaro et al., Sintering of industrial mullites in the presence of magnesia as a sintering aid, J AM CERAM, 83(1), 2000, pp. 189-196
Citations number
23
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science","Material Science & Engineering
Journal title
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
ISSN journal
00027820 → ACNP
Volume
83
Issue
1
Year of publication
2000
Pages
189 - 196
Database
ISI
SICI code
0002-7820(200001)83:1<189:SOIMIT>2.0.ZU;2-1
Abstract
The sinterability of two industrial mullite powders, in the presence of MgO as a sintering aid, was investigated. A glassy phase, which was generated during preparation, was present in both powders; this glassy phase had a st rong influence on sintering, depending on its content, composition, and spa tial distribution. MgO promoted sintering in the presence of a liquid phase , both in the as-received materials and in samples washed with HF, in which most of the pre-existing glassy phase was eliminated. Investigations using transmission electron microscopy, coupled with energy-dispersive spectrosc opy, as well as dilatometric measurements and X-ray diffraction data, on wa shed and unwashed materials and on quenched and slow-cooled samples allowed a better understanding of the influence of MgO and the glassy phase on the sintering behavior and the formation of new phases. Most of the phases, in fact, can be explained by using the MgO-Al2O3-SiO2 phase diagram, even in such complex systems.