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Acicular Mullite Crystals in Vitrified Kaolin
Author(s) -
Lu HongYang,
Wang WeiLin,
Tuan WeiHsing,
Lin MingHong
Publication year - 2004
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.1151-2916.2004.tb06328.x
Subject(s) - acicular , mullite , materials science , microstructure , aluminosilicate , scanning electron microscope , crystal (programming language) , transmission electron microscopy , crystallography , stoichiometry , mineralogy , phase (matter) , ceramic , composite material , chemistry , nanotechnology , biochemistry , organic chemistry , computer science , programming language , catalysis
The microstructure of vitrified kaolin ceramic tapes has been studied via scanning and transmission electron microscopy (SEM and TEM). The sintered samples contained crystalline phase of predominantly stoichiometric mullite (3Al 2 O 3 ·2SiO 2 ), which consisted of high aspect ratio, acicular crystals that are often referred to as secondary mullite. These crystals were interlocked and embedded in an aluminosilicate glass matrix of inhomogeneous composition. The glass matrix contained an average of ∼3.63 wt% K as determined by energy‐dispersive X‐ray analysis (EDS), whose composition could be approximated to 5Al 2 O 3 ·16SiO 2 ·0.1MgO·0.3K 2 O·0.15TiO 2 ·0.12Fe 2 O 3 . The acicular crystals have approximately the stoichiometric composition of Al 2 O 3 :SiO 2 = 3:2. They have grown along a specific crystallographic orientation along the [001] axis. The crystal growth front exhibited facetting on the {110) planes with microfacetting on both the {100) and {010) planes.