Influence of Tetragonality on Tetragonal-to-Monoclinic Phase Transformation during Hydrothermal Aging in Plasma-Sprayed Yttria-Stabilized Zirconia Coatings

2001 ◽  
Vol 84 (5) ◽  
pp. 1037-1042 ◽  
Author(s):  
Kazuhiro Yasuda ◽  
Yasuhiro Goto ◽  
Hiromitsu Takeda
Keyword(s):  
Phase Transformation ◽  
Monoclinic Phase ◽  
Yttria Stabilized Zirconia ◽  
Stabilized Zirconia ◽  
Hydrothermal Aging ◽  
Plasma Sprayed

Environmental Effect on the Crack Behavior of Yttria-Stabilized Zirconia During Laser Drilling

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Hong Shen ◽  
Juan Jiang ◽  
Decai Feng ◽  
Chen Xing ◽  
Xiaofeng Zhao ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Phase Transformation ◽  
Environmental Effect ◽  
Monoclinic Phase ◽  
Oxygen Vacancies ◽  
High Stress ◽  
Laser Drilling ◽  
Yttria Stabilized Zirconia ◽  
Stabilized Zirconia ◽  
Crack Behavior

The crack behaviors of yttrium-stabilized zirconia during laser drilling in air, vacuum, and water environments were investigated. Due to the high stress and low fracture toughness induced by tetragonal-monoclinic phase transformation, tremendous cracks occur during drilling in air. Contrastly, cracks were reduced in vacuum drilling since the phase transformation was suppressed due to the generation of oxygen vacancies. By protection of water, no cracks were observed due to low stress and maintained fracture toughness. The crack mechanisms in different drilling media were discussed.

Thermal-Spray Yttria-Stabilized Zirconia Phase Changes During Annealing

2000 ◽  
Author(s):  
J. Ilavsky ◽  
J. Wallace ◽  
J.K. Stalick
Keyword(s):  
Tetragonal Phase ◽  
Monoclinic Phase ◽  
Tetragonal Zirconia ◽  
Rietveld Analysis ◽  
Phase Changes ◽  
Yttria Stabilized Zirconia ◽  
Stabilized Zirconia ◽  
Yttria Partially Stabilized Zirconia ◽  
Zirconia Phase ◽  
Plasma Sprayed

Abstract Phase stability of the thermal barrier deposits made from yttria-partially-stabilized zirconia (Y-PSZ) is a requirement for extended service lifetime. The response of Y-PSZ plasma-sprayed deposits to annealing at 1000 °C, 1200 °C, and 1400 °C with times from 1 to 1000 hours has been evaluated using Rietveld analysis of neutron diffraction data. Results show that yttria concentration of the as-sprayed tetragonal zirconia component generally decreased with increasing annealing temperature and time. As the yttria content in the tetragonal phase approached a limiting concentration, the tetragonal phase transformed into monoclinic phase on cooling. An increase in monoclinic phase content was clearly observable after annealing 24 hours at 1400 °C and was nearly 35 % after 100 hours at 1400 °C. A similar trend was observed at 1200 °C for longer annealing times, with monoclinic phase formation beginning after 400 hours. At 1000 °C experimental times were not sufficient for monoclinic phase to form although a decrease in the yttria concentration in the tetragonal phase was observed. Keywords: neutron scattering, yttria-stabilized zirconia, phase composition, Rietveld analysis

scholarly journals Influence of Preaging Temperature on the Indentation Strength of 3Y-TZP Aged in Ambient Atmosphere

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2767
Author(s):  
Ki-Won Jeong ◽  
Jung-Suk Han ◽  
Gi-Uk Yang ◽  
Dae-Joon Kim
Keyword(s):  
Residual Stress ◽  
Phase Transformation ◽  
Low Temperature ◽  
Compressive Residual Stress ◽  
Yttria Stabilized Zirconia ◽  
Ambient Atmosphere ◽  
Aged Specimen ◽  
Stabilized Zirconia ◽  
M Phase ◽  
The Relationship

Yttria-stabilized zirconia (3Y-TZP) containing 0.25% Al2O3, which is resistant to low temperature degradation (LTD), was aged for 10 h at 130–220 °C in air. The aged specimens were subsequently indented at loads ranging from 9.8 to 490 N using a Vickers indenter. The influence of preaging temperature on the biaxial strength of the specimens was investigated to elucidate the relationship between the extent of LTD and the strength of zirconia restorations that underwent LTD. The indented strength of the specimens increased as the preaging temperature was increased higher than 160 °C, which was accompanied by extensive t-ZrO2 (t) to m-ZrO2 (m) and c-ZrO2 (c) to r-ZrO2 (r) phase transformations. The influence of preaging temperature on the indented strength was rationalized by the residual stresses raised by the t→m transformation and the reversal of tensile residual stress on the aged specimen surface due to the indentation. The results suggested that the longevity of restorations would not be deteriorated if the aged restorations retain compressive residual stress on the surface, which corresponds to the extent of t→m phase transformation less than 52% in ambient environment.

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