Improvement of thermal stability of Yttria-doped tetragonal zirconia polycrystals by alloying with various oxides

doi:10.1016/0267-3762(86)90048-2

International Journal of High Technology Ceramics

Volume 2, Issue 3, 1986, Pages 167-177

https://doi.org/10.1016/0267-3762(86)90048-2 Get rights and content

Abstract

Yttria-doped tetragonal zirconia polycrystals doped with 0–12 mol% of CaO, MgO, CeO₂ and TiO₂ were sintered at 1400–1600°C for 3 h, and the mechanical properties and thermal stability of the sintered bodies were evaluated. The degree of the tetragonal-to-monoclinic phase transformation by annealing in humid air or hot water decreased with both increasing amounts of CeO₂ or TiO₂ and decreasing grain size of ZrO₂. Alloying with TiO₂ accelerated the grain growth and depressed densification, but alloying with less than 6 mol% of CeO₂ caused no significant changes in grain size and mechanical properties.

References (11)

T. Sato et al.
Transformation of ceria-doped tetragonal zirconia polycrystals by annealing in water
Am. Ceram. Soc. Bull.
(1985)
R.C. Garvie et al.
Ceramic steel?
Nature (London)
(1975)
D.L. Porter et al.
Mechanism of toughening partially stabilized zirconia ceramics (PSZ)
J. Am. Ceram. Soc.
(1977)
F.F. Lange
Transformation toughening
J. Mater. Sci.
(1982)
F.F. Lange
Transformation toughening
J. Mater. Sci.
(1982)
F.F. Lange
Transformation toughening
J. Mater. Sci.
(1982)
F.F. Lange
Transformation toughening
J. Mater. Sci.
(1982)
F.F. Lange
Transformation toughening
J. Mater. Sci.
(1982)
K. Kobayashi et al.
Thermal and mechanical properties of ZrO₂Y₂O₃ solid electrolyte after aging
Solid State Ionics
(1981)

There are more references available in the full text version of this article.

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When the TiO2 content was increased to 7.7 mol%, the amount of monoclinic phase reached 80% after ageing for 120 h [133,134]. Sato et al. [125] found that ageing-induced t to m phase transformation (in air at 200 °C for 50 h) could be suppressed with the addition of higher TiO2 content of 10 mol%. Miyazaki [135] doped higher concentration of TiO2, up to 20 mol%, in zirconia and found that the addition of 8 mol% TiO2 could improve the thermal stability of zirconia matrix with no significant cracks or volume change during heating and cooling of the samples.
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Effect of calcia co-doping on ceria-stabilized zirconia
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Improvement of thermal stability of Yttria-doped tetragonal zirconia polycrystals by alloying with various oxides

Abstract

Am. Ceram. Soc. Bull.

Ceramic steel?

Nature (London)

Mechanism of toughening partially stabilized zirconia ceramics (PSZ)

J. Am. Ceram. Soc.

Transformation toughening

J. Mater. Sci.

Transformation toughening

J. Mater. Sci.

Transformation toughening

J. Mater. Sci.

Transformation toughening

J. Mater. Sci.

Transformation toughening

J. Mater. Sci.

Thermal and mechanical properties of ZrO2Y2O3 solid electrolyte after aging

Solid State Ionics

Thermal and mechanical properties of ZrO₂Y₂O₃ solid electrolyte after aging