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Microstructure and Densification of Pressureless‐Sintered Al 2 O 3 /Si 3 N 4 ‐Whisker Composites
Author(s) -
Tseng Wenjea J.,
Funkenbusch Paul D.
Publication year - 1992
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.1151-2916.1992.tb05555.x
Subject(s) - whisker , materials science , sintering , microstructure , composite material , composite number , volume fraction , slip (aerodynamics) , whiskers , homogenization (climate) , physics , thermodynamics , biodiversity , ecology , biology
Composite densification was studied by performing slip casting and sintering experiments on an Al 2 O 3 matrix and Si 3 N 4 whisker system. Even though all the slip‐cast powder compacts exhibited high green densities (up to 70% of the theoretical) and narrow pore‐size distribution (pore radius around 15 to 30 nm), significant differential densification on a microscopic scale was found due to the existence of local whisker agglomeration. The inhomogeneous whisker distribution resulted in a binary mixture of large and small pores in the sintered composites, in which whisker‐associated flaws remained stable even after prolonged sintering. The sintered microstructures showed that the spatial distribution as well as the volume fraction of the Si 3 N 4 affect composite densification. Inhomogeneous whisker distribution dominated the complete densification of the composites.