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Processing and Characterization of Multiphase Ceramic Composites Part II: Triplex Composites with a Wide Sintering Temperature Range
Author(s) -
Kim DongKyu,
Kriven Waltraud M.
Publication year - 2008
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.1551-2916.2008.02262.x
Subject(s) - materials science , nial , sintering , composite material , ceramic , composite number , microstructure , cubic zirconia , atmospheric temperature range , yttrium , grain size , annealing (glass) , thermal stability , intermetallic , metallurgy , chemical engineering , oxide , alloy , meteorology , engineering , physics
Three‐phase (triplex) ceramic composites with improved thermal stabilities resulting from minimized grain growth due to extended grain separations are introduced. Al 2 O 3 , yttrium aluminum garnet (YAG, Y 3 Al 5 O 12 ), and ZrO 2 were chemically compatible to make a stable triplex composite. Another stable composite could be made due to chemical compatibility among Al 2 O 3 , NiAl 2 O 4 , and 3 mol% yttria‐tetragonal zirconia polycrystals (3Y‐TZP). The composites of 33 vol% Al 2 O 3 –33 vol% YAG–33 vol% ZrO 2 , 33 vol% Al 2 O 3 –33 vol% NiAl 2 O 4 –33 vol% 3Y‐TZP, and 50 vol% Al 2 O 3 –25 vol% NiAl 2 O 4 –25 vol% 3Y‐TZP were fabricated using either sintering or hot pressing procedures. The sintered 33 vol% Al 2 O 3 –33 vol% YAG–33 vol% ZrO 2 and 33 vol% Al 2 O 3 –33 vol% NiAl 2 O 4 –33 vol% 3Y‐TZP composites demonstrated a “self accommodating sintering effect” having a wide sintering range without any extensive change in properties. Annealing of the 33 vol% Al 2 O 3 –33 vol% NiAl 2 O 4 –33 vol% 3Y‐TZP composite at 1600°C for 50 h resulted in higher strength retention after heat treatment compared with that expected from the sum of the strengths of constituent phases. This was attributed to a mutual, grain growth retardation effect. Chemical compatibilities, mechanical properties, microstructures, and thermal stabilities of the composites were studied.