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Fabrication of Mullite and Mullite‐Matrix Composites by Transient Viscous Sintering of Composite Powders
Author(s) -
Sacks Michael D.,
Bozkurt Nazim,
Scheiffele Gary W.
Publication year - 1991
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.1151-2916.1991.tb06780.x
Subject(s) - mullite , materials science , sintering , composite material , silicon carbide , composite number , aluminium silicate , particle (ecology) , fabrication , amorphous solid , ceramic , medicine , oceanography , alternative medicine , chemistry , organic chemistry , pathology , geology
Mullite was fabricated by a process referred to as transient viscous sintering (TVS). Composite particles which consisted of inner cores of α‐alumina and outer coatings of amorphous silica were used. Powder compacts prepared with these particles were viscously sintered to almost full density at relatively low temperatures (∼1300°C). Compacts were subsequently converted to dense, fine‐grained mullite at higher temperatures (∼1500°C) by reaction between the alumina and silica. The TVS process was also used to fabricate mullite/zirconia/alumina, mullite/silicon carbide particle, and mullite/silicon carbide whisker composites. Densification was enhanced compared with other recent studies of sintering of mullite‐based composites. This was attributed to three factors: viscous flow of the amorphous silica coating on the particles, avoidance of mullite formation until higher temperatures, and increased threshold concentration for the development of percolation networks.