Quantitative XRD analysis of zirconia-toughened alumina ceramics

1987 ◽  
Vol 22 (10) ◽  
pp. 3566-3570 ◽  
Author(s):  
R. Fillit ◽  
R. P. Homerin ◽  
R. J. Schafer ◽  
R. H. Bruyas ◽  
R. F. Thevenot
Keyword(s):  
Xrd Analysis ◽  
Alumina Ceramics ◽  
Zirconia Toughened Alumina

scholarly journals Sintering of alumina ceramics reinforced with a bioactive glass of 3CaO.P2O5-SiO2-MgO system

Cerâmica ◽  
2015 ◽  
Vol 61 (358) ◽  
pp. 160-167 ◽  
Author(s):  
A. W. Huang ◽  
C. Santos ◽  
R. O. Magnago ◽  
R. F. F. Silva ◽  
K. Strecker ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Relative Density ◽  
Transient Liquid Phase ◽  
Xrd Analysis ◽  
Alumina Ceramics ◽  
Crystalline Phases ◽  
Powder Mixtures ◽  
Solid State Sintering ◽  
Sintering Condition

<p>Alumina-based ceramics, Al<sub>2</sub>O<sub>3</sub>, exhibit a combination of properties which favor its use as biomaterial, specifically as structural dental prosthesis. Its most important properties as biomaterial are its elevated hardness, chemical stability and biocompatibility. Usually, Al<sub>2</sub>O<sub>3</sub> is processed by solid-state sintering at a temperature of about 1600 <sup>o</sup>C, but it is very difficult to eliminate the porosity due to its diffusional characteristics. The objective of this work was the development and characterization of sintered Al<sub>2</sub>O<sub>3</sub> ceramics, densified with a transient liquid phase formed by a bioactive 3CaO.P<sub>2</sub>O<sub>5</sub>-SiO<sub>2</sub>-MgO glass. Powder mixtures of 90 wt.% Al<sub>2</sub>O<sub>3</sub> and 10 wt.% bioglass were milled, compacted and sintered at 1200 <sup>o</sup>C to 1450 <sup>o</sup>C. Comparatively, monolithic Al<sub>2</sub>O<sub>3</sub> samples were sintered at 1600 <sup>o</sup>C/120 min. The sintered specimens were characterized by relative density, crystalline phases, microstructure and mechanical properties. The results indicate that the specimen sintered at 1450 <sup>o</sup>C/120 min present the best properties. Under this sintering condition, a relative density of 95% was reached, besides hardness higher than 9 GPa and fracture toughness of 6.2 MPa.m<sup>1/2</sup>. XRD analysis indicate alumina (αAl<sub>2</sub>O<sub>3</sub>), whitlockite (3CaO.P<sub>2</sub>O<sub>5</sub>) and diopsite [3(Ca,Mg)O.P<sub>2</sub>O<sub>5</sub>], as crystalline phases. Comparatively, monolithic sintered Al<sub>2</sub>O<sub>3</sub> samples presented 92% of relative density with 17.4 GPa and 3.8 MPa.m<sup>1/2</sup> of hardness and fracture toughness respectively.</p>

Controlling Grain Size in Oxide Ceramics for Optimization of Strength and Wear Resistance

2012 ◽  
Vol 715-716 ◽  
pp. 703-710
Author(s):  
W.M. Rainforth ◽  
P. Zeng ◽  
L. Ma
Keyword(s):  
Grain Size ◽  
Sliding Wear ◽  
Second Phase ◽  
Alumina Ceramics ◽  
Size Dependent ◽  
Mild Wear ◽  
Accumulation Mechanism ◽  
Wear Transition ◽  
Magnitude Increase ◽  
Zirconia Toughened Alumina

t is well known that alumina ceramics undergo a time dependent wear transition during sliding wear. The transition, which is associated with 1-2 orders of magnitude increase in specific wear rate, involves a change from mild wear to intergranular fracture. The transition is strongly grain size dependent, with the time to the transition decreasing with grain size. However, there is a minimum grain size that can be achieved in fully dense alumina using commercially viable processing. Alternative strategies for reducing grain size and increasing toughness are through the addition of a fine second phase, with SiC and ZrO2being the most promising. The resultant composite not only has finer grain size, but also exhibits additional toughening mechanisms. This paper reports on the microstructural control in alumina, zirconia toughened alumina and alumina-silicon carbide composites. The grain size and residual stress distribution are related to the damage accumulation mechanism that occur during frictional contact, in particular the surface specific dislocation activity.

Structural Characteristic and Dielectric Properties of Zirconia Toughened Alumina

2020 ◽  
Vol 1010 ◽  
pp. 250-255
Author(s):  
Nik Akmar Rejab ◽  
Nurul Khairunnisa Su ◽  
Wan Fahmin Faiz Wan Ali ◽  
Mohd Fadzil Ain ◽  
Zainal Arifin Ahmad ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Dielectric Resonator ◽  
Cutting Tool ◽  
High Hardness ◽  
Xrd Analysis ◽  
Dielectric Resonator Antenna ◽  
Frequency Range ◽  
Band Frequency ◽  
X Band ◽  
Zirconia Toughened Alumina

Zirconia toughened alumina (ZTA) has shown a great effect in the cutting tool application due to its high hardness and comparable fracture toughness. However, the capability of the materials to be applied in as the dielectric resonator antenna (DRA) is not being discussed in detail. In this study, an attempt is made to further explore the potential of ZTA to be applied in DRA. Various related characterization techniques were applied that is subjected to DRA properties. The addition of CeO2 (0 wt.% to 15 wt.%) on ZTA has been pressed into pellets shape and sintered at 1600 °C for 2 hours under pressureless conditions. Based on the XRD analysis, only corundum and yttria doped zirconia phases were present. Shift in position of the zirconia peaks was observed due to an existence of Ce2Zr3O10 phase. For the DRA measurement, ZTA with 10 wt.% CeO2 addition have resonated at 6.76 GHz which is suitable for X-band applications. Meanwhile the radiation pattern indicated the omnidirectional characteristic, which suggested that the signal could be received by this dielectric antenna in various positions. Therefore, ZTA- 10 wt.% CeO2 have high potential to be used as DRA that operates X-band frequency range applications.

scholarly journals Processing and properties of zirconia-toughened alumina ceramics

1994 ◽  
Vol 17 (7) ◽  
pp. 1435-1439 ◽  
Author(s):  
D S Patil ◽  
B C Mutsuddy
Keyword(s):  
Alumina Ceramics ◽  
Zirconia Toughened Alumina

Influence of Zircon Addition on Thermal Shock Resistance of ZTA for Plasma Reactors

2007 ◽  
Vol 544-545 ◽  
pp. 379-382
Author(s):  
Kyung Hun Jang ◽  
Bum Rae Cho
Keyword(s):  
Thermal Expansion ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Sintering Temperature ◽  
Plasma Reactors ◽  
Alumina Ceramics ◽  
Low Thermal Expansion ◽  
Resultant Data ◽  
Shock Resistance ◽  
Zirconia Toughened Alumina

The effect of CaO, MgO and SiO2 as a flux on the sinterability of zirconia toughened alumina(ZTA) used for plasma reactors was investigated and the effect of zircon addition on thermal shock resistance of ZTA with 15wt.% of ZrO2 was also investigated. The resultant data revealed that ZTA shows the best sinterability at the composition of 2wt.% of CaO, 4wt.% of MgO and 2wt.% of SiO2 and at the sintering temperature of 1350°C. Thermal shock resistance of ZTA containing zircon was improved significantly. It is shown that ZTA containing 10wt.% of zircon shows better thermal shock resistance than others. This fact can be explained due to the low thermal expansion coefficient of zircon. It was concluded that zircon is an effective material to improve thermal shock resistance of alumina ceramics.

scholarly journals The Effect of the Addition of Y2O3 on the Microstructure of Polycrystalline Alumina Ceramics

Proceedings ◽  
2018 ◽  
Vol 2 (23) ◽  
pp. 1407
Author(s):  
Serkan Abalı ◽  
Cem Uğur Karaçam
Keyword(s):  
Bending Strength ◽  
Xrd Analysis ◽  
Milling Process ◽  
Alumina Ceramics ◽  
Mechanical Behaviors ◽  
Cold Isostatic Press ◽  
Powder Mixtures ◽  
Polycrystalline Alumina ◽  
Microscope Images ◽  
Pure Al2o3

In the scope of this study, a powder mixture was prepared that contained 3 Al2O3-Y2O3 consisting of 99.99% pure Al2O3 and aluminum oxide of 65–67% and 70% by weight of 99.999% pure Y2O3 powders. After the powders were weighed on a precision scale, the milling process was carried out in a vibratory disc mill. For the granulation, 3 powder mixtures that were subject to sintering were sieved to a size of less than 106 µm in a powder sieve shaker. The powders were shaped with a cold isostatic press after this step and the 3 acquired samples were sintered for 12 h under a temperature of 1923 K. Selected physical and mechanical behaviors were taken by evaluating microhardness measurements, bending strength XRD analysis and electron microscope images of the 3 sintered samples. The changes in the Y2O3 additive and phase composition, microstructure, and mechanic properties were examined.

Fabrication of dense zirconia-toughened alumina ceramics through a stereolithography-based additive manufacturing

2017 ◽  
Vol 43 (1) ◽  
pp. 968-972 ◽  
Author(s):  
Haidong Wu ◽  
Wei Liu ◽  
Rongxuan He ◽  
Ziwei Wu ◽  
Qiangguo Jiang ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Alumina Ceramics ◽  
Zirconia Toughened Alumina

Surface Phase Transformation Analysis of Nanozirconia Toughened Alumina Ceramics under Two-Dimentional Ultrasonic Vibration Grinding

2010 ◽  
Vol 42 ◽  
pp. 259-262
Author(s):  
Yan Yan Yan ◽  
Pei Lin Xu ◽  
Bo Zhao
Keyword(s):  
Phase Transformation ◽  
Ultrasonic Vibration ◽  
Xrd Analysis ◽  
Processing Method ◽  
Surface Phase ◽  
Alumina Ceramics ◽  
Processing Property ◽  
Transformation Ratio ◽  
Surface Phase Transformation ◽  
Ultrasonic Vibration Assisted Grinding

Based on good processing property of two-dimentional ultrasonic vibration assisted grinding (TUVAG), phase transformation in the grinding surface of nanozirconia toughened alumina ceramics (ZTA ceramics) is studied by XRD analysis. Experimental results show different processing method and grinding depth may lead to surface phase transformation of ZTA ceramics. Under the same grinding parameters, phase transformation ratio of grinding surface under TUVAG is higher than that under diamond grinding (DG), and its phase transformation ratio increases with the increasing of grinding depth. Phase transformation ratio can effectively inhibit generation and expansion of microcracks of grinding surface.

Research on the Fracture Phenomenon of Zirconia-Toughened Alumina Ceramics under Ultrasonic Vibration

2010 ◽  
Vol 455 ◽  
pp. 156-160
Author(s):  
Yan Yan Yan ◽  
Bo Zhao ◽  
Jun Li Liu
Keyword(s):  
Ultrasonic Vibration ◽  
Surface Integrity ◽  
Normal Load ◽  
Alumina Ceramics ◽  
Ceramic Specimen ◽  
Ceramic Fracture ◽  
Propagation Behavior ◽  
Ultrasonic Vibration Assisted Grinding ◽  
Zirconia Toughened Alumina ◽  
Working Efficiency

A study of the fracture phenomenon of zirconia-toughened alumina (ZTA) ceramics was carried. It analyzes the mechanisms of crack propagation of ZTA ceramics, and constructs fracture experiments of ZTA ceramics, so the propagation behavior on fracture in ZTA ceramics was investigated according to the experiment. By contrast, intercrystalline fracture happed in V-shaped groove of ceramic specimen under normal load without ultrasonic vibration during ceramic fracture, and transcrystalline fracture happed in V-shaped groove of ceramic specimen under normal load with ultrasonic vibration during ceramic fracture. Furthermore, the loading force of ceramic specimen under normal load with ultrasonic vibration is smaller than that under normal load without ultrasonic vibration all other conditions being equal. The results of fracture experiment prove that ultrasonic vibration assisted is good for the fracture of ceramic specimen, and it also proves that ultrasonic vibration assisted grinding may raise the working efficiency and improve surface integrity of ceramics from the standpoint of the fracture.

scholarly journals Effect of micron aluminium powder on mechanical properties and microstructural in zirconia toughened alumina ceramics

2020 ◽  
Vol 15 (10) ◽  
pp. 684-687
Author(s):  
Ruihao Zhang ◽  
Bao Qi ◽  
Jie Wang ◽  
Xinwei She ◽  
Zhende Ran ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Alumina Ceramics ◽  
Aluminium Powder ◽  
Zirconia Toughened Alumina
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