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Near‐Net Shape β‐Si 4 Al 2 O 2 N 6 Parts by Hydrolysis Induced Aqueous Gelcasting Process
Author(s) -
Ganesh Ibram
Publication year - 2009
Publication title -
international journal of applied ceramic technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.4
H-Index - 57
eISSN - 1744-7402
pISSN - 1546-542X
DOI - 10.1111/j.1744-7402.2008.02258.x
Subject(s) - materials science , aqueous solution , hydrolysis , slurry , ceramic , near net shape , chemical engineering , composite material , nuclear chemistry , organic chemistry , chemistry , engineering
In this paper, a new net‐shaping process, an hydrolysis‐induced aqueous gelcasting (GC) (GCHAS) has been reported for consolidation of β‐Si 4 Al 2 O 2 N 6 ceramics from aqueous slurries containing 48–50 vol%α‐Si 3 N 4 , α‐Al 2 O 3 , AlN, and Y 2 O 3 powders mixture. Dense ceramics of same composition were also consolidated by aqueous GC and hydrolysis assisted solidification routes. Among three techniques used, the GCHAS process was found to be superior for fabricating defect‐free thin wall β‐Si 4 Al 2 O 2 N 6 crucibles and tubes. Before use, the as purchased AlN powder was passivated against hydrolysis. The sintered β‐Si 4 Al 2 O 2 N 6 ceramics exhibited comparable properties with those reported for similar materials in the literature.