Microscopic Mechanisms behind the Toughening Behavior of Ceria Stabilized Tetragonal Zirconia/Alumina Nanocomposite for Biomedical Applications

2007 ◽  
Vol 361-363 ◽  
pp. 813-816 ◽  
Author(s):  
Masahiro Nawa ◽  
Kiyotaka Yamada ◽  
Giuseppe Pezzotti
Keyword(s):  
Fracture Toughness ◽  
Biomedical Applications ◽  
Mechanical Performance ◽  
Human Life ◽  
Tetragonal Zirconia ◽  
Confocal Raman Spectroscopy ◽  
Reliability Characteristics ◽  
Monolithic Zirconia ◽  
Confocal Raman

With elongation of average human life, problem such as bone embrittlement and osteoporosis call for quick solution and the expectation for artificial biomaterials heightens. Many ceramics widely used as artificial biomaterials are limited by their poor reliability characteristics. A CeO2 stabilized tetragonal zirconia polycrystalline (Ce-TZP) matrix incorporating nanometer sized Al2O3 particles within the zirconia grains (Ce-TZP/Al2O3) was recently developed. This material experienced significant improvements in both fracture toughness and strength above the standard mechanical performance of monolithic zirconia. In this paper, we performed a macro/microscopic fracture mechanics assessment of this developed Ce-TZP/Al2O3 nanocomposite, in comparison with a 3 mol% Y-TZP according to advanced in situ confocal Raman spectroscopy techniques.

Confocal Raman Spectroscopic Analysis of Phase Transformation and Residual Stresses in Ce-TZP/Al2O3 Nanocomposite for Biomedical Applications

2007 ◽  
Vol 330-332 ◽  
pp. 373-376 ◽  
Author(s):  
Kiyotaka Yamada ◽  
Masahiro Nawa ◽  
Giuseppe Pezzotti
Keyword(s):  
Residual Stress ◽  
Raman Spectroscopy ◽  
Phase Transformation ◽  
Biomedical Applications ◽  
Mechanical Performance ◽  
Stress Fields ◽  
Confocal Raman Spectroscopy ◽  
Raman Spectroscopic ◽  
Bearing Materials ◽  
Confocal Raman

Zirconia ceramics have been widely used for new generation of bearing materials in biomedical applications. In this context, a zirconia-matrix, stabilized with cerium oxide and dispersed with fine alumina particles (Ce-TZP/Al2O3 nanocomposite) was recently developed and this material experienced significant improvements in both fracture toughness and strength above the standard mechanical performance of monolithic zirconia. In this paper, we used confocal Raman spectroscopy to provide quantitative assessments with high spatial resolution of phase structure and residual stress fields developed in the Ce-TZP/Al2O3 nanocomposite. According to confocal Raman spectroscopy, we have directly visualized patterns of phase transformation and residual stress fields stored on the very surface of the material around an indentation print. These spectroscopic assessments may open a perspective in understanding the micromechanical behavior of the Ce-TZP/Al2O3 nanocomposite when subjected to local surface impingement and shocks.

scholarly journals Improving the mechanical properties of commercial feldspathic dental porcelain by addition of Alumina-Zirconia

2019 ◽  
pp. 67-76
Author(s):  
Juliana Gómez ◽  
Astrid Rueda ◽  
Edgar Alexader Ossa Henao
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Contact Resistance ◽  
Mechanical Performance ◽  
Tetragonal Zirconia ◽  
Dental Ceramics ◽  
Aesthetic Response ◽  
Early Failure ◽  
Feldspathic Porcelain ◽  
Natural Tooth

Dental ceramics made from Yttria stabilized tetragonal Zirconia polycrystalline (Y-TZP) with feldspathic porcelain veneers have similar mechanical and aesthetic response to natural tooth. However, cases of early failure, such as chipping or fracture in the veneering have been reported after short periods of use. The present study evaluated the feldspathic porcelain (VITA-VM9) with addition of 0.5 and 2.5 wt% Alumina-Zirconia as reinforcing agents. Hardness, fracture toughness, contact resistance and color variations were evaluated finding better mechanical performance on the new formulations.

In situ analysis of water management in operating fuel cells by confocal Raman spectroscopy

2011 ◽  
Vol 13 (5) ◽  
pp. 418-422 ◽  
Author(s):  
P. Huguet ◽  
A. Morin ◽  
G. Gebel ◽  
S. Deabate ◽  
A.K. Sutor ◽  
...  
Keyword(s):  
Water Management ◽  
Raman Spectroscopy ◽  
Fuel Cells ◽  
In Situ Analysis ◽  
Confocal Raman Spectroscopy ◽  
Confocal Raman

scholarly journals In-Line and Off-Line Monitoring of Skin Penetration Profiles Using Confocal Raman Spectroscopy

Pharmaceutics ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 67
Author(s):  
Richard Krombholz ◽  
Yali Liu ◽  
Dominique Jasmin Lunter
Keyword(s):  
Raman Spectroscopy ◽  
Ex Vivo ◽  
Skin Penetration ◽  
Confocal Raman Spectroscopy ◽  
Line Measurement ◽  
Lauryl Ether ◽  
Confocal Raman ◽  
Ex Vivo Study

Ex-vivo and in-vivo skin analysis has been extensively evaluated by confocal Raman spectroscopy (CRS). The off-line measurement with a CRS-suited skin-mounted device after Franz-cell incubations is the most popular choice. However, real-time monitoring of in-line measurement has clear advantages for obtaining dynamic and more timely results. In our study, a custom-built setup suitable for in-line measurements was implemented, which ensures constant skin incubation and in-situ skin detections. We aim to compare the differences between using in-line and off-line devices for monitoring skin drug penetrations. A well-assessed formulation gel with procaine-HCl as the active ingredient was used as reference. The PEG-23 lauryl ether was added to the formulation as a penetration enhancer to evaluate the enhancement effects of procaine on skin. After incubation times of 14, 20, and 24 h, skin penetration profiles were assessed. Comparable results between off-line and in-line measurements were obtained. Remarkable improvements in penetrated procaine amount and depth were observed. Based on the significant differences of their enhanced penetration amounts, fairly similar estimations were achieved from both methods. A slight difference of 14 h incubation between these two setups can still be found, which may be due to the different detection conditions and affected skin properties. Overall, in-line measurements could provide a more time- and labor-saving alternative for off-line measurements in ex-vivo study.

Development of In Situ Techniques for Torsion and Tension Testing in Hydrogen Environment

2011 ◽  
Author(s):  
John Jy-An Wang ◽  
Fei Ren ◽  
Wei Zhang ◽  
Zhili Feng ◽  
Lawrence Anovitz ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Fracture Behavior ◽  
Structural Integrity ◽  
Mechanical Performance ◽  
High Strength Steels ◽  
Structural Materials ◽  
Fracture Testing ◽  
Hydrogen Environment ◽  
In Situ Techniques

Reliability of hydrogen pipelines and storage tanks is significantly influenced by the mechanical performance of the structural materials exposed to the hydrogen environment. Fracture behavior and fracture toughness are of specific interest since they are relevant to structural integrity. However, many conventional fracture testing techniques are difficult to be realized under the presence of hydrogen. Thus it is desired to develop novel in situ techniques to study the fracture behavior of structural materials in hydrogen environments. In this study, two special testing apparatus were designed to facilitate in situ fracture testing in H2. In addition to a multi-notch tensile fixture, a torsional fixture was developed to utilize an emerging fracture testing technique, Spiral Notch Torsion Test (SNTT). The design concepts will be discussed. Preliminary in situ testing results indicated that the exposure to H2 significantly reduces the fracture toughness of 4340 high strength steels by up to 50 percent. Furthermore, SNTT tests conducted in air demonstrated a significant fracture toughness reduction in samples subject to simulated welding heat treatment using a Gleeble machine, which illustrated the effect of welding on the fracture toughness of this material.

scholarly journals C0.3N0.7Ti-SiC Toughed Silicon Nitride Hybrids with Non-Oxide Additives Ti3SiC2

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1428
Author(s):  
Heng Luo ◽  
Chen Li ◽  
Lianwen Deng ◽  
Yang Li ◽  
Peng Xiao ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Silicon Nitride ◽  
Flexural Strength ◽  
Mechanical Performance ◽  
Sintering Temperature ◽  
Hot Press ◽  
Pull Out ◽  
Hot Press Sintering ◽  
Si3n4 Ceramics

In situ grown C0.3N0.7Ti and SiC, which derived from non-oxide additives Ti3SiC2, are proposed to densify silicon nitride (Si3N4) ceramics with enhanced mechanical performance via hot-press sintering. Remarkable increase of density from 79.20% to 95.48% could be achieved for Si3N4 ceramics with 5 vol.% Ti3SiC2 when sintered at 1600 °C. As expected, higher sintering temperature 1700 °C could further promote densification of Si3N4 ceramics filled with Ti3SiC2. The capillarity of decomposed Si from Ti3SiC2, and in situ reaction between nonstoichiometric TiCx and Si3N4 were believed to be responsible for densification of Si3N4 ceramics. An obvious enhancement of flexural strength and fracture toughness for Si3N4 with x vol.% Ti3SiC2 (x = 1~20) ceramics was observed. The maximum flexural strength of 795 MPa for Si3N4 composites with 5 vol.% Ti3SiC2 and maximum fracture toughness of 6.97 MPa·m1/2 for Si3N4 composites with 20 vol.% Ti3SiC2 are achieved via hot-press sintering at 1700 °C. Pull out of elongated Si3N4 grains, crack bridging, crack branching and crack deflection were demonstrated to dominate enhance fracture toughness of Si3N4 composites.

Sign in / Sign up

Export Citation Format

Share Document