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Microstructural Characterization of Reactively Sintered Mullites
Author(s) -
Kara Ferhat,
Turan Servet,
Little John A.,
Knowles Kevin M.
Publication year - 2000
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.2000.tb01199.x
Subject(s) - mullite , materials science , sintering , ceramic , transmission electron microscopy , characterization (materials science) , mineralogy , microstructure , wetting , aluminium silicate , composite material , colloidal silica , grain boundary , chemical engineering , metallurgy , nanotechnology , chemistry , engineering , coating
Mullite ceramics have been produced by reaction sintering of powders prepared using pseudoboehmite–colloidal silica and aluminum sulfate–colloidal silica mixtures. The microstructural development of these mullites was studied by a number of transmission electron microscopy based techniques including diffuse dark field, Fresnel fringe defocus imaging, and high‐resolution transmission electron microscopy. This characterization procedure showed that mullite ceramics free from glassy phases at triple junctions and grain boundaries could be produced from both mixtures using suitable sintering temperatures and alumina/silica ratios. The wetting of grain boundaries by glass, occurring in the mullite ceramics from either incomplete reaction between alumina and silica components or release of silica from the mullite structure with increasing temperature, was found to depend on the prior thermal history of the ceramics.