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Characterization of the Spinel Phase from SiO 2 ‐Al 2 O 3 Xerogels and the Formation Process of Mullite
Author(s) -
OKADA KIYOSHI,
ŌTSUKA NOZOMU
Publication year - 1986
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.1151-2916.1986.tb07466.x
Subject(s) - mullite , spinel , hydrolysis , amorphous solid , materials science , chemical engineering , phase (matter) , aluminium nitrate , alkoxide , characterization (materials science) , sol gel , mineralogy , corundum , inorganic chemistry , aluminium , chemistry , catalysis , metallurgy , crystallography , ceramic , organic chemistry , nanotechnology , engineering
Two kinds of xerogels were prepared by the slow and rapid hydrolyses of tetraethoxysilane and aluminum nitrate nonahydrate dissolved in ethanol. Xerogels prepared by slow hydrolysis crystallized mullite directly from the amorphous state on firing whereas those formed by rapid hydrolysis crystallized a spinel phase before mullite formation. The composition of the spinel phase was characterized by various methods to be near SiO 2 ·6Al 2 O 3 . The process of mullite formation is discussed in relation to the structures of the starting materials.