scholarly journals Effect of 3 mol% Yttria Stabilized Zirconia Addition on Structural and Mechanical Properties of Alumina-Zirconia Composites

2017 ◽  
Vol 08 (07) ◽  
pp. 584-602
Author(s):  
M. A. Gafur ◽  
Md. Saifur Rahman Sarker ◽  
Md. Zahangir Alam ◽  
M. R. Qadir
Keyword(s):  
Mechanical Properties ◽  
Yttria Stabilized Zirconia ◽  
Stabilized Zirconia ◽  
Zirconia Composites ◽  
Zirconia Addition

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.

scholarly journals The Effect of Yttria-Stabilized Zirconia on the Properties of the Fluorine-Substituted Hydroxyapatite Ceramics Prepared by Pressureless Sintering

2008 ◽  
Vol 1 ◽  
pp. 57-68 ◽  
Author(s):  
Y. Chen ◽  
Z. Dong ◽  
X. Miao
Keyword(s):  
Mechanical Properties ◽  
Thermal Decomposition ◽  
Sol Gel ◽  
Yttria Stabilized Zirconia ◽  
Pressureless Sintering ◽  
Stabilized Zirconia ◽  
Gel Method ◽  
Zirconia Composites ◽  
Zirconia Phase ◽  
Hydroxyapatite Phase

Hydroxyapatite-zirconia composites have received much attention during the last decade due to their combination of the desirable mechanical properties of zirconia and the excellent bioactivity of hydroxyapatite (HA). However, thermal decomposition of the hydroxyapatite phase and reaction between the zirconia phase and the hydroxyapatite phase remain a major problem in the hydroxyapatite-zirconia composites. In this study, thermally stable and fluorine-substituted hydroxyapatite (Ca10(PO4)6(OH)0.8F1.2; coded as HA06F) was prepared by a sol-gel method to replace the hydroxyapatite. Yttria-stabilized zirconia (YTZP) was also prepared by a sol-gel method in order to produce HA06F-YTZP composites with 5, 10, 15, 20, 40, and 60 wt% YTZP by simple and cost-effective pressureless sintering. Thermogravimetric analysis (TGA) and x-ray diffraction (XRD) of the HA06F-YTZP composites showed that the thermal stability of the HA06F matrices could be maintained when the YTZP content did not exceed 20 wt% and for sintering temperatures less than 1400 oC. Dilatometric analysis and microstructural observation revealed that the YTZP phase in the HA06F-YTZP composites retarded the densification of the composites if the zirconia content was over 20 wt%. Electron scanning microscopy (SEM) and high resolution transmission electron microscopy (HR-TEM) of the HA06F-YTZP composites showed that the YTZP second phase had a size in the nanometer scale and the reaction between the HA06F phase and the zirconia phase was suppressed. Mechanical properties including the Knoop hardness, the Young’s modulus, and the fracture toughness of the HA06F-YTZP composites increased with the YTZP content until the optimal content of 20 wt%; higher YTZP contents led to low mechanical properties due to poor densification of the composites and the severe thermal decomposition of the HA06F phase. The optimal HA06F-20YTZP composite also showed desirable attachment and proliferation of osteoblast cells. Nevertheless, the study of the composite system indicated the limitations of the pressureless sintering technique. To achieve the full potential of the composites for medium or low load bearing applications, a pressure-assisted sintering technique would still be necessary.

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).

Effect of Coupled Conditions of Thermal Cycle and Dump Environment on Conductivity of 5mol% Yttria Stabilized Zirconia

2013 ◽  
Vol 591 ◽  
pp. 245-248 ◽  
Author(s):  
Jin Feng Xia ◽  
Hong Qiang Nian ◽  
Tao Feng ◽  
Hai Fang Xu ◽  
Dan Yu Jiang
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
High Temperature ◽  
Thermal Cycle ◽  
Oxygen Sensor ◽  
Yttria Stabilized Zirconia ◽  
Cyclic Change ◽  
Stabilized Zirconia ◽  
Transmission Electron

In some applications such as automotive oxygen sensor, 5mol% Y2O3stabilized zirconia (5YSZ) is generally used because it has both excellent ionic conductivity and mechanical properties. The automotive oxygen sensor would experience a cyclic change from high temperature (engine running) environment to the low temperature damp environment (in the tail pipe when vehicle stops). The conductivity change with coupled conditions of thermal cycle and dump environment in the 5mol%Y2O3ZrO2(5YSZ) system was examined by XRD,Impedance spectroscopy and transmission electron microscopy (SEM) in this paper.

scholarly journals Dense lanthanum silicate oxyapatite ceramics obtained by uniaxial pressing and slip casting

2018 ◽  
Vol 50 (4) ◽  
pp. 433-443
Author(s):  
Ramiro Toja ◽  
Nicolás Rendtorffa ◽  
Esteban Agliettia ◽  
Tetsuo Uchikoshi ◽  
Yoshio Sakka ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Vickers Hardness ◽  
Growth Process ◽  
Slip Casting ◽  
Yttria Stabilized Zirconia ◽  
Stabilized Zirconia ◽  
Oxygen Ion Conductivity ◽  
Oxygen Ion ◽  
Slip Cast ◽  
Lanthanum Silicate

Lanthanum silicate oxyapatite (LSO) is a promising ion conductive ceramic material, which has higher oxygen ion conductivity at intermediate temperatures (600-800?C) compared to yttria-stabilized zirconia. Its mechanical properties, though important for any of its applications, have been scarcely reported. In this study, we compare apparent densification, open porosity and Vickers hardness of samples conformed by uniaxial pressing and slip casting and fired up to 1600?C. Colloidal processing was optimized for slip casting in order to get high green densities. At sintering temperatures higher than 1400?C, both processing routes yielded comparable densities, although uniaxially pressed samples show slightly better mechanical properties, evidencing that slip cast ones already underwent a grain growth process.

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