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Effect of High‐Temperature Aging on the Fracture Toughness of 40 mol% Ceria‐Stabilized Zirconia
Author(s) -
Jiang Kuo,
Liu Songbai,
Xi Wenjun
Publication year - 2015
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/jace.13308
Subject(s) - materials science , fracture toughness , tetragonal crystal system , monoclinic crystal system , cubic zirconia , composite material , ceramic , activation energy , grain size , crystal structure , crystallography , chemistry , organic chemistry
The 40 mol% CeO 2 ‐stabilized ZrO 2 ceramic was synthesized by the sol‐spray pyrolysis method and aged at 1400°C–1600°C. The effects of high‐temperature aging on its fracture toughness were investigated after heat treatments at 1500°C for 6–150 h in air. Characterization results indicated that the activation energy for grain growth of 40 mol% CeO 2 ‐stabilized ZrO 2 was 593 ± 47 kJ/mol. The average grain size of this ceramic varied from 1.4 to 5.6 μm within the aging condition of 1500°C for 6–150 h. The Ce ‐lean tetragonal phase has a constant tetragonality (ratio of the c ‐axis to a ‐axis of the crystal lattice) of 1.0178 during the aging process. It was found that the fracture toughness of 40 mol% CeO 2 ‐stabilized ZrO 2 was determined to be 2.0 ± 0.1 MPa·m 1/2 , which did not vary significantly with prolonging aging time. Since no monoclinic zirconia was detected in the regions around the indentation crack‐middle and crack‐tip, the high fracture toughness maintained after high‐temperature aging can be attributed to the remarkable stability of the tetragonal phase in 40 mol% CeO 2 ‐stabilized ZrO 2 composition.