Preparation of Ceramic Nanocomposite with Perovskite Dispersoid

1996 ◽  
Vol 457 ◽  
Author(s):  
T. Nagai ◽  
H. J. Hwang ◽  
M. Sando ◽  
K. Niihara
Keyword(s):  
Phase Stability ◽  
Ceramic Composites ◽  
Structural Ceramics ◽  
Conventional Sintering ◽  
Perovskite Type ◽  
Ceramic Nanocomposite

ABSTRACTIn order to introduce ferroelectricity into structural ceramics, we synthesized novel ceramic composites containing submicron sized perovskite-type ferroelectrics (ceramic / perovskite-type ferroelectrics nanocomposites). Although perovskite compounds easily react with other ceramics, MgO/BaTiO3 nanocomposites were successfully fabricated using conventional sintering technique. The microstructure of nanocomposites and the phase stability of the dispersed BaTiO3 particulate are discussed.

scholarly journals Temperature dependence of hardness prediction for high-temperature structural ceramics and their composites

2021 ◽  
Vol 10 (1) ◽  
pp. 586-595
Author(s):  
Ruzhuan Wang ◽  
Dingyu Li ◽  
Weiguo Li
Keyword(s):  
High Temperature ◽  
Temperature Dependence ◽  
Material Design ◽  
Theoretical Models ◽  
Ceramic Composites ◽  
Basic Material ◽  
Experimental Measurements ◽  
Control Mechanisms ◽  
Oxide Ceramics ◽  
Structural Ceramics

Abstract Hardness is one of the important mechanical properties of high-temperature structural ceramics and their composites. In spite of the extensive use of the materials in high-temperature applications, there are few theoretical models for analyzing their temperature-dependent hardness. To fill this gap in the available literature, this work is focused on developing novel theoretical models for the temperature dependence of the hardness of the ceramics and their composites. The proposed model is just expressed in terms of some basic material parameters including Young’s modulus, melting points, and critical damage size corresponding to plastic deformation, which has no fitting parameters, thereby being simple for materials scientists and engineers to use in the material design. The model predictions for the temperature dependence of hardness of some oxide ceramics, non-oxide ceramics, ceramic–ceramic composites, diamond–ceramic composites, and ceramic-based cermet are presented, and excellent agreements with the experimental measurements are shown. Compared with the experimental measurements, the developed model can effectively save the cost when applied in the material design, which could be used to predict at any targeted temperature. Furthermore, the models could be used to determine the underlying control mechanisms of the temperature dependence of the hardness of the materials.

scholarly journals Mechanical Investigation of a Novel Ceramic Composite Consisting of the YAG Matrix With Alumina Nanoparticles Fabricated by Slip Casting and the Conventional Sintering Process

2020 ◽  
Author(s):  
Mohammad Torki ◽  
behrooz movahedi ◽  
S S. ghazanfari ◽  
M. Milani
Keyword(s):  
Relative Density ◽  
Slip Casting ◽  
Ceramic Composites ◽  
Alumina Nanoparticles ◽  
Solid Loading ◽  
Sintering Process ◽  
The Matrix ◽  
Conventional Sintering ◽  
Mechanical Investigation ◽  
Composite Hardness

Abstract The aim of this study was to fabricate YAG/Al2O3 ceramic composites with different alumina nanoparticles using slip casting and the atmospheric sintering process. In addition, some mechanical properties such as hardness and elastic modules of this novel ceramics were evaluated using the nanoindention technique. The results showed that the rheological behavior of the slurry was optimized to the solid loading of 55 wt% and the relative density of the green body was enhanced up to 65%. Relative density was increased after sintering at 1700 °C for 12 h to 99.5% and the pore size (150 nm) was reduced to half of that of powder particles. It should be noted that the optimum amount of alumina nanoparticles as a reinforcing agent in the matrix was less than 5%wt and the composite hardness was increased to 7.3%, as compared to the pure YAG ceramic.

scholarly journals The structure and optical properties of lead-free transparent KNLTN-La0.01 ceramics prepared by conventional sintering technique

2014 ◽  
Vol 32 (4) ◽  
pp. 597-603
Author(s):  
W. Yang ◽  
H. Xiu ◽  
Y. Xiong ◽  
J. Wang ◽  
C. Yuan ◽  
...  
Keyword(s):  
Optical Properties ◽  
Dispersion Model ◽  
Point Group ◽  
Lead Free ◽  
Dense Microstructure ◽  
Abo3 Perovskite ◽  
Conventional Sintering ◽  
Significant Wavelength ◽  
Perovskite Type ◽  
Better Than

Abstract(Na0.52K0.44Li0.04)0.97La0.01Ta0.20Nb0.80O3 (KNLTN-La0.01) lead-free subtransparent ceramics was prepared by a conventional sintering technique. The structure and the optical properties of the ceramics were investigated. The room temperature crystallographic indexing revealed the ABO3 perovskite type, tetragonal phase and P4mm point group in the ceramics. The surface and fractured surface SEM micrographs showed a dense microstructure with few micropores in KNLTN-La0.01 ceramics, which was obviously better than for the pure KNLTN ceramics. The refractive indexes of the films were investigated by an ellipsometer and the results show that the KNLTN-La0.01 subtransparent ceramics reveals significant wavelength dependent dispersion. The refractive index ranges from 2.14 to 2.06 with the wavelength increase from 380 nm to 900 nm. The dispersive behavior was analyzed by three parameters of Cauchy dispersion model and the values of the parameters A, B and C are 2.0610±0.0005, 0.0054±0.0003 and 0.00069±0.00004, respectively.

Piezoelectric Composites Based on Hydroxyapatite / Barium Titanate

2008 ◽  
Vol 54 ◽  
pp. 1-6 ◽  
Author(s):  
Chris R. Bowen ◽  
K.V.S. Raman ◽  
Vitaly Yu. Topolov
Keyword(s):  
Volume Fraction ◽  
Active Material ◽  
Ferroelectric Ceramic ◽  
Ceramic Composites ◽  
Batio3 Ceramic ◽  
Physical Factors ◽  
Electromechanical Properties ◽  
Modified Model ◽  
Perovskite Type

This paper reports experimental and modelling results on the manufacture and properties of hydroxyapatite / BaTiO3 ceramic composites and studies their electromechanical properties with ferroelectric ceramic volume fractions, mFC ³ 0.7. In these composites the bio-active properties of hydroxyapatite are combined with the electromechanical properties of a perovskite-type ferroelectric BaTiO3 ceramic in an attempt to create a novel polarised bone-substitute material. Experimental results of the volume fraction dependences of the effective piezoelectric coefficients * 31 d (mFC), * 33 d (mFC) and dielectric permittivity e *s 33 (mFC) of stress free samples are analysed within the framework of a modified model of a porous piezo-active material that is described in terms of 1–3 (one-dimensional rods in a continuous matrix) and 2–2 connectivity (laminates). The role of several structural elements and physical factors in forming the electromechanical properties of the composites is discussed. It is shown that performance of these materials typical properties are 5 pC / N < | * 31 d |< 45 pC / N, 20 pC / N < * 33 d < 100 pC / N and 400 < e *s 33 / 0 e < 1300.

Phase Stability and Oxygen Nonstoichiometry of Highly Oxygen-Deficient Perovskite-Type Oxides: A Case Study of (Ba,Sr)(Co,Fe)O3−δ

2012 ◽  
Vol 24 (2) ◽  
pp. 269-274 ◽  
Author(s):  
David N. Mueller ◽  
Roger A. De Souza ◽  
Han-Ill Yoo ◽  
Manfred Martin
Keyword(s):  
Phase Stability ◽  
Oxygen Nonstoichiometry ◽  
Perovskite Type

scholarly journals Sintering of Hydroxyapatite/Yttria Stabilized Zirconia Nanocomposites under Nitrogen Gas for Dental Materials

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
C. H. Leong ◽  
A. Muchtar ◽  
C. Y. Tan ◽  
M. Razali ◽  
Noor Faeizah Amat
Keyword(s):  
Relative Density ◽  
Phase Stability ◽  
Dental Materials ◽  
Gas Pressure ◽  
Yttria Stabilized Zirconia ◽  
Stabilized Zirconia ◽  
Nitrogen Gas ◽  
Conventional Sintering ◽  
Gas Pressure Sintering ◽  
The Relationship

This study aims to determine the effect of adding 3 mol% yttria stabilized zirconia (3YSZ) in hydroxyapatite (HA) and sintering HA/3YSZ nanocomposites under nitrogen gas on HA decomposition. This paper presents the relationship between microstructure and mechanical properties of HA/3YSZ nanocomposites. Gas pressure and conventional sintering were performed on HA/3YSZ nanocomposites containing different amounts of 3YSZ (i.e., 0, 0.5, 1, and 7 wt%) at 1250°C. The phase stability, morphology, relative density, and microhardness of the HA/3YSZ nanocomposites were investigated. The phase stability of the HA/3YSZ nanocomposites was affected by adding different amounts of 3YSZ. Overall, gas pressure sintering leads to the formation of greater grain size compared with the conventional sintering method. The severe HA decomposition and the presence of the porosity in HA/7 wt% 3YSZ have led to deterioration in relative density and microhardness. In this study, HA/0.5 wt% 3YSZ with gas pressure sintering exhibited the optimum microstructure with the highest relative density (97%) and microhardness (3.93 GPa).

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