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Preparation and Properties of Zirconia‐Toughened Mullite Ceramics
Author(s) -
YUAN QIMING,
TAN JIAQI,
JIN ZHENGGUO
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.tb07422.x
Subject(s) - mullite , materials science , thermal shock , composite material , ceramic , flexural strength , cubic zirconia , quenching (fluorescence) , tetragonal crystal system , nucleation , cristobalite , thermal expansion , phase (matter) , chemistry , physics , quartz , organic chemistry , quantum mechanics , fluorescence
Compacts formed from high‐purity fused submicrometer mullite powders, both pure and with the additions of 5 to 25 vol% ZrO 2 of particle size 1, 2, or 4 μm (average), were sintered in air at 1610°C for 6 h to form dense ceramic bodies. Mechanical properties (flexural strength, K ic , and Young's modulus) were measured both before and after thermal shock. The strength after thermal shock increased considerably in systems containing additions of 10 to 20 vol% ZrO 2 ; K ic also increased, but not so markedly. The low fraction of tetragonal ZrO 2 (0.1 to 0.2) in the as‐fired samples and the increase in Young's modulus after thermal shock for some strengthened samples supported the view that the interaction of residual internal stresses induced by quenching and the accompanying martensitic transformation of ZrO 2 result in potential nucleation sites for microcracking. Thus, microcracking may be the predominant energy‐absorbing mechanism responsible for strengthening and toughening the quenched ceramic bodies.