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Microstructure and Short‐Term Oxidation of Hot‐Pressed Si 3 N 4 /ZrO 2 (+Y 2 O 3 ) Ceramics
Author(s) -
Falk Lena K. L.,
Rundgren Kent
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.tb05437.x
Subject(s) - materials science , microstructure , sintering , ceramic , hot pressing , atmospheric temperature range , solid solution , aluminium oxides , decomposition , composite material , chemical engineering , mineralogy , metallurgy , chemistry , catalysis , biochemistry , physics , organic chemistry , meteorology , engineering
Composite ceramic materials based on Si 3 N 4 and ZrO 2 stabilized by 3 mol% Y 2 O 3 have been formed using aluminum isopropoxide as a precursor for the Al 2 O 3 sintering aid. Densification was carred out by hot‐pressing at temperatures in the range 1650° to 1800°C, and the resulting micro‐structures were related to mechanical properties as well as to oxidation behavior at 1200°C. Densification at the higher temperatures resulted in a fibrous morphology of the Si 3 N 4 matrix with consequent high room‐temperature toughness and strength. Decomposition of the ZrO 2 grains below the oxidized surface during oxidation introduced radial stresses in the subscalar region, and from the oxidation experiments it is suggested that the ZrO 2 incorporated some N during densification.