scholarly journals Investigating the effect of yttria contents on the structure and mechanical properties of zirconia ceramics

2016 ◽  
Vol 19 (4) ◽  
pp. 232-240
Author(s):  
Linh Ba Ngoc Nguyen ◽  
Dung Van Hoang ◽  
Van Thi Thanh Tran
Keyword(s):  
Mechanical Properties ◽  
Low Temperature ◽  
Critical Concentration ◽  
Annealing Process ◽  
Yttria Stabilized Zirconia ◽  
Precipitation Method ◽  
Stabilized Zirconia ◽  
Zirconia Ceramics ◽  
Grain Sizes ◽  
Co Precipitation

In this study, the co- precipitation method and annealing process were used to prepare the yttria stabilized zirconia ceramics. Data of Raman and XRD showed that an increase of yttria doping leads to an decrease of the ratio between monoclinic and tetragonal phases. Howerver, it existed a critical concentration of yttrium at which the highest value of hardness was about 14.5 GPa and grain sizes of 0.2–0.5 m. An investigation of low temperature degradation indicated that theaging process only occurred in the first 5 hours and then virtually negligible changes.

Mechanical properties of ytterbia stabilized zirconia ceramics (Yb-TZP) fabricated from powders prepared by co-precipitation method

2000 ◽  
Vol 26 (2) ◽  
pp. 207-211 ◽  
Author(s):  
Susumu Nakayama ◽  
Sachihiko Maekawa ◽  
Tetsuji Sato ◽  
Yoshio Masuda ◽  
Shinji Imai ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Precipitation Method ◽  
Stabilized Zirconia ◽  
Zirconia Ceramics ◽  
Co Precipitation

Microstructure and Mechanical Properties of Multiscale Zirconia Ceramics Prepared by Field Assisted Sintering Technique

2016 ◽  
Vol 697 ◽  
pp. 354-359
Author(s):  
Khalid Eltayeb ◽  
Dong Qin Jin ◽  
Young Hwan Han ◽  
Fei Chen ◽  
Qiang Shen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Yttria Stabilized Zirconia ◽  
Milling Machine ◽  
Stabilized Zirconia ◽  
Zirconia Ceramics ◽  
Dense Structure ◽  
Zirconia Composites ◽  
20 Nm ◽  
Field Assisted Sintering

Two kinds of powders of 3 mol. % yttria stabilized zirconia (3Y–TZP) with different particles sizes; one was 20 nm denoted by N whereas the other was 0.5 µm denoted by M, were mechanically mixed via ball milling machine using different amounts of N wt. % to obtain multiscale zirconia composite powder. Then the mixed powders were sintered by field assisted sintering technique (FAST). The effect of N content on the microstructure as well as on mechanical properties of zirconia is investigated. Results show that the microstructure of M completely surrounded by N emerged in zirconia composites, and tetragonal phase is presented in all the sintered samples. The obtained zirconia ceramics with 15 wt. % N own a highly dense structure (~ 99.9 % relative density) and high flexural strength of 813.59 MPa wherein a 15 % increase in flexural strength compared to zirconia ceramics without adding N, but the fracture toughness of the composites just lightly decreases. The improved flexural strength of the composites is caused by the multiscale effect.

Influence of Alumina Addition on Low Temperature Degradation of Y2O3-Coated Powder Based Y-TZP Ceramics

2014 ◽  
Vol 87 ◽  
pp. 139-144
Author(s):  
Fei Zhang ◽  
Kim Vanmeensel ◽  
Masanao Inokoshi ◽  
Bart van Meerbeek ◽  
Ignace Naert ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Low Temperature ◽  
Solubility Limit ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Hydrothermal Degradation ◽  
Coating Method ◽  
Alumina Addition ◽  
Co Precipitation ◽  
Coated Powder

The influence of the addition of 0.25, 2 and 5 wt.% alumina on the mechanical properties and low temperature degradation (LTD) behaviour of 3 mol% yttria-coated ZrO2powder based Y-TZP ceramics was investigated, and compared to commercial powder based co-precipitated 3Y-TZPs with 0-0.25 wt.% Al2O3addition. The ceramics were subjected to accelerated hydrothermal degradation in an autoclave in H2O at 134°C up to 40 hrs. X-ray diffraction and Raman spectroscopy were used to assess the LTD behaviour. Incorporating the Y2O3stabilizer by means of a coating method resulted in a higher LTD resistance without compromising the higher fracture toughness, compared to the co-precipitation method. Alumina addition did not significantly influence the mechanical properties of all Y-TZPs but significantly increased the LTD resistance of the Y-TZP ceramics. The LTD resistance of 0.25 wt% Al2O3doped TZPs was substantially higher than that of ceramics containing 2 or 5 wt.% Al2O3, which had a comparable susceptibility. The highest LTD resistance for the 0.25 wt.% alumina doped ceramics could be correlated to the solubility limit of alumina in zirconia.

Sintering of Mechanically Alloyed YSZ Nanocrystalline Powders

2007 ◽  
Vol 534-536 ◽  
pp. 1417-1420
Author(s):  
Marco Antonio López de la Torre ◽  
Oscar Juan Durá ◽  
M. Hernández ◽  
M. García Cordobés ◽  
Gemma Herranz ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Sintering Temperature ◽  
Yttria Stabilized Zirconia ◽  
Nanocrystalline Powders ◽  
Body Centered Cubic ◽  
Stabilized Zirconia ◽  
Mechanically Alloyed ◽  
Grain Sizes ◽  
Maximum Value ◽  
Mechanical And Structural Properties

We report on the mechanical and structural properties of nanocrystalline 8% and 10% mol yttria stabilized zirconia (YSZ) obtained using mechanical alloying (MA). For milling times above 32 hours the complete alloying of the starting Y2O3 and ZrO2 powders is achieved. The asmilled powders show a body-centered cubic crystalline structure with grain sizes in the order of 10 nm. After uniaxial pressing and sintering the compacts exhibit densities of more than 93% of the theoretical value. The microhardness of the compacts increases with sintering temperature, reaching a maximum value of 913 HV0.5 after sintering at 1220º C for 6 hours. The correlation of these enhanced mechanical properties with the microstructural changes induced by heat treatment of the nanocrystalline MA powders is discussed.

scholarly journals Polarization-assisted surface engineering for low temperature degradation-proof in yttria-stabilized zirconia ceramics

2015 ◽  
Vol 3 (2) ◽  
pp. 156-159
Author(s):  
Naohiro Horiuchi ◽  
Yu Tsuchiya ◽  
Norio Wada ◽  
Kosuke Nozaki ◽  
Miho Nakamura ◽  
...  
Keyword(s):  
Low Temperature ◽  
Surface Engineering ◽  
Yttria Stabilized Zirconia ◽  
Stabilized Zirconia ◽  
Zirconia Ceramics

Microstructural examination of modified yttria stabilized zirconia by EM analytical techniques

1986 ◽  
Vol 44 ◽  
pp. 842-843
Author(s):  
W. W. Davison ◽  
R. C. Buchanan
Keyword(s):  
Mechanical Properties ◽  
Analytical Techniques ◽  
Yttria Stabilized Zirconia ◽  
Stabilized Zirconia ◽  
Transmission Microscopy ◽  
Sintering Aid ◽  
Densification Temperature ◽  
Chemical Inertness ◽  
Scanning Transmission ◽  
Microstructural Examination

Yttria stabilized zirconia (YSZ) has become a significant technological material due to its high ionic conductivity, chemical inertness, and good mechanical properties. Temperatures on the order of 1700°C are required, however, to densify YSZ to the degree necessary for good electrical and mechanical properties. A technique for lowering the densification temperature is the addition of small amounts of material which facilitate the formation of a liquid phase at comparatively low temperatures. In this study, sintered microstructures obtained from the use of Al2O3 as a sintering aid were examined with scanning, transmission, and scanning transmission microscopy (SEM, TEM, and STEM).

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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