scholarly journals A Revised Relationship Between Fracture Toughness and Y2O3 Content in Modern Dental Zirconias

2021 ◽  
Author(s):  
Renan Belli ◽  
Katrin Hurle ◽  
Jana Schürrlein ◽  
Anselm Petschelt ◽  
Katharina Werbach ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Biomedical Applications ◽  
Cubic Phase ◽  
Zirconia Ceramics ◽  
Inverse Power Law ◽  
Phase Quantification ◽  
Implant Dentistry ◽  
The Relationship ◽  
Relevant Range ◽  
Sintered Materials

<p>The relationship between fracture toughness and Yttria content in modern zirconia ceramics was revised. For that purpose, we evaluated here 10 modern Y<sub>2</sub>O<sub>3</sub>-stabilized zirconia (YSZ) materials currently used in biomedical applications, namely prosthetic and implant dentistry. The most relevant range between 2-5 mol% Y<sub>2</sub>O<sub>3</sub> was addressed by selecting from conventional opaque 3 mol% YSZ up to more translucent compositions (4-5 mol% YSZs). A technical 2YSZ was used to extend the range of our evaluation. The bulk mol% Y<sub>2</sub>O<sub>3</sub> concentration was measured by X-Ray Fluorescence Spectroscopy. Phase quantification by Rietveld refinement are supplied by considering only two tetragonal phases or an additional improbable cubic phase. A first-account of the fracture toughness (<i>K</i><sub>Ic</sub>) of the partly-sintered materials is given, which amounted to 0.4 – 0.7 MPaÖm. In the fully-densified state, an inverse power-law behavior was obtained between <i>K</i><sub>Ic</sub> and bulk mol% Y<sub>2</sub>O<sub>3</sub> content, whether using only our measurements or including literature data, challenging some established relationships.</p>

scholarly journals A Revised Relationship Between Fracture Toughness and Y2O3 Content in Modern Dental Zirconias

2021 ◽  
Author(s):  
Renan Belli ◽  
Katrin Hurle ◽  
Jana Schürrlein ◽  
Anselm Petschelt ◽  
Katharina Werbach ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Biomedical Applications ◽  
Cubic Phase ◽  
Zirconia Ceramics ◽  
Inverse Power Law ◽  
Phase Quantification ◽  
Implant Dentistry ◽  
The Relationship ◽  
Relevant Range ◽  
Sintered Materials

<p>The relationship between fracture toughness and Yttria content in modern zirconia ceramics was revised. For that purpose, we evaluated here 10 modern Y<sub>2</sub>O<sub>3</sub>-stabilized zirconia (YSZ) materials currently used in biomedical applications, namely prosthetic and implant dentistry. The most relevant range between 2-5 mol% Y<sub>2</sub>O<sub>3</sub> was addressed by selecting from conventional opaque 3 mol% YSZ up to more translucent compositions (4-5 mol% YSZs). A technical 2YSZ was used to extend the range of our evaluation. The bulk mol% Y<sub>2</sub>O<sub>3</sub> concentration was measured by X-Ray Fluorescence Spectroscopy. Phase quantification by Rietveld refinement are supplied by considering only two tetragonal phases or an additional improbable cubic phase. A first-account of the fracture toughness (<i>K</i><sub>Ic</sub>) of the partly-sintered materials is given, which amounted to 0.4 – 0.7 MPaÖm. In the fully-densified state, an inverse power-law behavior was obtained between <i>K</i><sub>Ic</sub> and bulk mol% Y<sub>2</sub>O<sub>3</sub> content, whether using only our measurements or including literature data, challenging some established relationships.</p>

Novel Baddeleyite-Based Zirconia Ceramics for Biomedical Applications

2017 ◽  
Vol 13 ◽  
pp. 9-14
Author(s):  
Alexander I. Tyurin ◽  
Andrey O. Zhigachev ◽  
Alexey V. Umrikhin ◽  
Vyacheslav V. Rodaev ◽  
Tatyana S. Pirozhkova
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Tetragonal Phase ◽  
Biomedical Applications ◽  
Zirconia Ceramics ◽  
Engineering Ceramics ◽  
Synthesis Conditions ◽  
Microstructure And Mechanical Properties ◽  
First Time

For the first time nanostructured engineering ceramics were prepared from natural zirconia mineral (baddeleyite) with CaO as a tetragonal phase stabilizer. The effect of synthesis conditions on microstructure and mechanical properties of the baddeleyite-based ceramics is reported, furthermore, the effect of calcia content on hardness and fracture toughness is studied. Optimal calcia concentration and synthesis conditions are found, corresponding hardness and fracture toughness values are 10,8 GPa and 13,3 MPa×m1/2. The reported mechanical properties are comparable to those typically reported for yttria-stabilized engineering zirconia ceramics, prepared from chemically synthesized zirconia.

Effect of α/β phase ratio on microstructure and mechanical properties of silicon nitride ceramics

2001 ◽  
Vol 16 (8) ◽  
pp. 2264-2270 ◽  
Author(s):  
Hirokazu Kawaoka ◽  
Tomohiko Adachi ◽  
Tohru Sekino ◽  
Yong-Ho Choa ◽  
Lian Gao ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Silicon Nitride ◽  
Phase Ratio ◽  
Phase Content ◽  
Sintering Process ◽  
Β Phase ◽  
Nitride Ceramics ◽  
Pulse Electric ◽  
Sintering Condition ◽  
Sintered Materials

Highly densed silicon nitride ceramics with various α/β phase ratios were produced by pulse electric current sintering process. The β-phase content of Si3N4 in sintered materials varied from 20 to 100 wt% depending on the sintering condition. The microstructure was observed by scanning electron microscopy and investigated by image analysis. Young's modulus, hardness, fracture toughness, and strength were strongly dependent on the α/β phase ratio. The fracture toughness increased from 4.6 MPa m1/2 for 20-wt% b-phase content to 8.2 MPa m1/2 for 95-wt% β-phase content, and the fracture strength showed a maximum value of about 1.6 GPa at 60-to-80-wt% β-phase content.

Preparation and Electrical Property of Calcia Stabilized Zirconia Ceramics

2014 ◽  
Vol 616 ◽  
pp. 157-165 ◽  
Author(s):  
Chang Lian Chen ◽  
Hong Quan Wang ◽  
Jia You Ji ◽  
Ma Ya Luo ◽  
Bo Wu ◽  
...  
Keyword(s):  
Grain Size ◽  
Electrical Property ◽  
Arrhenius Equation ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Cubic Phase ◽  
Pressureless Sintering ◽  
Stabilized Zirconia ◽  
Zirconia Ceramics ◽  
Sintering Method

In this paper, using ZrO2 and Ca (NO3)•4H2O as raw materials, we prepared a series of calica stabilized zirconia (CSZ) ceramics by pressureless sintering method. The results show that the relative densities of all sintered samples are above 90%, and the sintered samples are composed of cubic, tetragonal and monoclinic ZrO2, and the main phase is cubic ZrO2 and tetragonal ZrO2. The content of cubic phase increases with the increase of sintering temperature and adding CaO content. The grain size of the sintered samples is relatively uniform and some pores exist. Increasing the additive amount of CaO, the conductivity first rises and then decreases, and the conductivity value of the sample containing 5wt% CaO is the maximum. When the sintering temperature is up to 1600 oC, the conductivity of the sample containing 5wt% CaO is up to 0.016S•cm-1 at 800 oC. Furthermore, the conductivity of sintered samples is increasing with the increase of test temperature according to the Arrhenius equation.

Modified Equation to Predict Leak/Rupture Criteria for Axially Through-Wall Notched X80 and X100 Linepipes Having Higher Charpy Energy

2004 ◽  
Author(s):  
Shinobu Kawaguchi ◽  
Naoto Hagiwara ◽  
Mitsuru Ohata ◽  
Masao Toyoda
Keyword(s):  
Fracture Toughness ◽  
Flow Stress ◽  
Pipe Material ◽  
Test Results ◽  
Absorbed Energy ◽  
Bending Tests ◽  
Full Scale Tests ◽  
Hoop Stresses ◽  
The Relationship ◽  
Modified Equation

A method of predicting the leak/rupture criteria for API 5L X80 and X100 linepipes was evaluated, based on the results of hydrostatic full-scale tests for X60, X65, X80 and X100 linepipes with an axially through-wall (TW) notch. The TW notch test results clarified the leak/rupture criteria, that is, the relationship between the initial notch lengths and the maximum hoop stresses during the TW notch tests. The obtained leak/rupture criteria were then compared to the prediction of the Charpy V-notch (CVN) absorbed energy-based equation, which has been proposed by Kiefner et al. The comparison revealed that the CVN-based equation was not applicable to the pipes having a CVN energy (Cv) greater than 130 J and flow stress greater than X65. In order to predict the leak/rupture criteria for these linepipes, the static absorbed energy for ductile cracking, (Cvs)i, was introduced as representing the fracture toughness of a pipe material. The (Cvs)i value was determined from the microscopic observation of the cut and buffed Charpy V-notch specimens after static 3-point bending tests. The CVN energy in the original CVN-based equation was replaced by an equivalent CVN energy, (Cv)eq’ which was defined as follows: (Cv)eq = 4.5 (Cvs)i. The leak/rupture criteria for the X80 and X100 linepipes with higher CVN energies were reasonably predicted by the modified equation using the (Cvs)i value.

scholarly journals On The Parameters of Geometric Constraints for Cracked Plates under Tension – Three-Dimensional Problems

2017 ◽  
Vol 22 (4) ◽  
pp. 901-919 ◽  
Author(s):  
M. Graba
Keyword(s):  
Fracture Toughness ◽  
Comparative Analysis ◽  
Crack Front ◽  
External Load ◽  
Three Dimensional ◽  
Geometric Constraints ◽  
Numerical Calculations ◽  
Cracked Plates ◽  
The Relationship ◽  
Actual Fracture

Abstract This paper provides a comparative analysis of selected parameters of the geometric constraints for cracked plates subjected to tension. The results of three-dimensional numerical calculations were used to assess the distribution of these parameters around the crack front and their changes along the crack front. The study also involved considering the influence of the external load on the averaged values of the parameters of the geometric constraints as well as the relationship between the material constants and the level of the geometric constraints contributing to the actual fracture toughness for certain geometries.

Effect of small amount of alumina on structure, wear and mechanical properties of 3Y-TZP ceramics

2014 ◽  
Vol 11 (1) ◽  
pp. 9-16 ◽  
Author(s):  
Igor Danilenko ◽  
Serhii Prokhorenko ◽  
Tetyana Konstantinova ◽  
Leonid Ahkozov ◽  
Valerii Burkhovetski ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Composite Structures ◽  
Tribological Behavior ◽  
Ceramic Composites ◽  
Synthesis Methods ◽  
Zirconia Ceramics ◽  
Alumina Composites ◽  
Co Precipitation ◽  
Metallic Parts

The use of ceramic instead of metallic parts in devices that operate in aggressive conditions increases the service life of machines and equipment for chemical, metallurgical and other industries. The wear resistant zirconia/alumina composites were sintered from nanopowders obtained by co-precipitation technique. In the case of addition of 1wt% of alumina in zirconia ceramics the wear resistance increased by approximately 30%.The formation of complex multilevel composite structures, such as Al3+ ion segregation on zirconia grain boundaries and intracrystalline alumina inclusions in zirconia grains, increased the fracture toughness values of composites obtained from co-precipitated nanopowders and consequently decreased the volume loss of ceramic material.In this study, we investigated the effect of nanopowders synthesis methods and alumina concentration on composite structure, fracture toughness and tribological behavior of 3Y-TZP/alumina ceramic composites and searched correlation between structures and mechanical properties.

scholarly journals Stability of Engineered Micro or Nanobubbles for Biomedical Applications

Pharmaceutics ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 1089
Author(s):  
Beomjin Park ◽  
Semi Yoon ◽  
Yonghyun Choi ◽  
Jaehee Jang ◽  
Soomin Park ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Biomedical Applications ◽  
Ultrasonic Field ◽  
Nanometer Scale ◽  
Factors Affecting ◽  
The Core ◽  
Bubble Structure ◽  
The Stability ◽  
The Relationship

A micro/nanobubble (MNB) refers to a bubble structure sized in a micrometer or nanometer scale, in which the core is separated from the external environment and is normally made of gas. Recently, it has been confirmed that MNBs can be widely used in angiography, drug delivery, and treatment. Thus, MNBs are attracting attention as they are capable of constructing a new contrast agent or drug delivery system. Additionally, in order to effectively use an MNB, the method of securing its stability is also being studied. This review highlights the factors affecting the stability of an MNB and the stability of the MNB within the ultrasonic field. It also discusses the relationship between the stability of the bubble and its applicability in vivo.

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