Study of the radiation disordering mechanisms of AlN ceramic structure as a result of helium swelling

2021 ◽  
Author(s):  
A. L. Kozlovskiy ◽  
M. V. Zdorovets
Keyword(s):  
Ceramic Structure

scholarly journals The (1-x)BiFeO3-xBaTiO3-Bi(Zn0.5Ti0.5)O3 high temperature lead-free piezoelectric ceramics with strong piezoelectric properties

2021 ◽  
Author(s):  
Yuanyuan Sun ◽  
Huabin Yang ◽  
Jiwen Xu ◽  
Weiran Huang ◽  
Minhong Jiang ◽  
...  
Keyword(s):  
High Temperature ◽  
Curie Temperature ◽  
Piezoelectric Properties ◽  
Ferroelectric Properties ◽  
Temperature Fields ◽  
Depolarization Temperature ◽  
Ceramic Structure ◽  
Low Dielectric ◽  
Tan Δ ◽  
Piezoelectric Performance

Abstract The structure, microstructure, piezoelectric properties, ferroelectric properties and Curie temperature of (1- x )BiFeO 3 - x BaTiO 3 -Bi(Zn 0.5 Ti 0.5 )O 3 +MnO 2 +Li 2 CO 3 ceramics were investigated experimentally by improved solid-state reaction approach. The crystalline structures were examined by X-ray diffractometry. When x = 0.3, the rhombohedral and pseudocubic phases coexist in the ceramic structure. It is considered that the morphotropic phase boundary was formed here. At the same time, the piezoelectric performance d 33 , Curie temperature T C , and depolarization temperature are as high as 184 pC/N, 550°C, 530°C at x = 0.3, respectively. It is worth noting that when x = 0.24, the ceramics have a high T C = 580°C and low dielectric loss tan δ = 1.9%. These results show that the BFBT-BZT system ceramics are applicable ceramics with high piezoelectric properties in high temperature fields.

Nanocrystalline ZrO2 Porous Ceramics Fabricated by SPS

2011 ◽  
Vol 306-307 ◽  
pp. 1398-1401 ◽  
Author(s):  
Di Zhang ◽  
Ming Gang Wang ◽  
Zhan Kui Zhao
Keyword(s):  
Cell Wall ◽  
Spark Plasma Sintering ◽  
Porous Ceramics ◽  
Porous Sample ◽  
Ceramic Structure ◽  
Sem Image ◽  
Nano Powder ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Cellular Ceramic

The porous ZrO2 ceramics was prepared by spark plasma sintering (SPS) at 520 °C. A dense closed micro-cellular ceramic structure was fabricated with micron Al90Mn9Ce1 alloy powders clading by 10 wt% ZrO2 nano-powder. SEM image showed that the thickness of ceramic cell wall was 1.0 - 2.0 μm. After deep corrosion with 10% HCl, an integrity nanocrystalline ZrO2 porous sample was obtained. Based on the experimental results, the transient spark plasma sintering mechanism of micron-nano mixing powder was also studied.

Fractal Geometry and Properties of Doped BaTiO3 Ceramics

2010 ◽  
Vol 67 ◽  
pp. 42-48 ◽  
Author(s):  
V.V. Mitic ◽  
V.B. Pavlovic ◽  
L. Kocic ◽  
V. Paunovic ◽  
L. Zivkovic
Keyword(s):  
Fractal Dimension ◽  
Solid State ◽  
Fractal Geometry ◽  
Grain Shape ◽  
Grain Structure ◽  
Fractal Method ◽  
Ceramic Structure ◽  
New Approach ◽  
Fractal Modeling ◽  
Dielectrical Properties

Taking into account that the complex grain structure is difficult to describe by using traditional analytical methods, in this study, in order to establish ceramic grain shapes of sintered BaTiO3, new approach on correlation between microstructure and properties of doped BaTiO3 ceramics based on fractal geometry has been developed. BaTiO3 ceramics doped with various dopants (MnCO3, Er2O3, Yb2O3) were prepared using conventional solid state procedure, and were sintered at 1350oC for four hours. The microstructure of sintered specimens was investigated by SEM-5300. Using method of fractal modeling a reconstruction of microstructure configurations, like grains shapes, or intergranular contacts has been successfully done. Furthermore, the area of grains surface was calculated using fractal correction that expresses the irregularity of grains surface through fractal dimension. The presented results, indicate that fractal method for ceramics structure analysis provides a new approach for describing, predicting and modeling the grain shape and relations between the BaTiO3-ceramic structure and dielectrical properties.

scholarly journals Effect of Fe2O3 on the Immobilization of High-Level Waste with Magnesium Potassium Phosphate Ceramic

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Hailin Yang ◽  
Mingjiao Fu ◽  
Bobo Wu ◽  
Ying Zhang ◽  
Ruhua Ma ◽  
...  
Keyword(s):  
Sintering Temperature ◽  
Potassium Phosphate ◽  
High Level Waste ◽  
Radioactive Nuclide ◽  
Hydration Reaction ◽  
Sintering Process ◽  
Positive Role ◽  
Ceramic Structure ◽  
High Level

For the proposed novel procedure of immobilizing HLW with magnesium potassium phosphate cement (MKPC), Fe2O3 was added as a modifying agent to verify its effect on the solidification form and the immobilization of the radioactive nuclide. The results show that Fe2O3 is inert during the hydration reaction. It slows down the hydration reaction and lowers the heat release rate of the MKPC system, leading to a 3°C-5°C drop in the mixture temperature during hydration. Early comprehensive strength of Fe2O3 containing samples decreased slightly while the long-term strength remained unchanged. For the sintering process, Fe2O3 played a positive role, lowering the melting point and aiding the formation of ceramic structure. CsFe(PO4)2, or CsFePO4, was generated by sintering at 900°C. These products together with the ceramic structure and absorption benefit the immobilization of Cs+. The optimal sintering temperature for heat treatment is 900°C; it makes the solidification form a fired ceramic-like structure.

scholarly journals Relationship between Rheological Behaviour and Final Structure ofAl2O3and YSZ Foams Produced by Replica

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
S. Y. Gómez ◽  
O. A. Alvarez ◽  
J. A. Escobar ◽  
J. B. Rodrigues Neto ◽  
C. R. Rambo ◽  
...  
Keyword(s):  
Mechanical Performance ◽  
Raw Materials ◽  
Rheological Behaviour ◽  
Rheological Parameters ◽  
Ceramic Structure ◽  
Ceramic Foams ◽  
Different Types ◽  
Binder Type ◽  
Ceramic Suspensions ◽  
Ceramic Thickness

Using rheological parameters of ceramic suspensions, it is possible to taylor the structure of the ceramic foams produced by replica. This method consists in the impregnation of a polymeric flexible template (polyurethane foam) with a ceramic suspension (slurry) containing the appropriate additives, followed by burning out organic compounds and additives and sintering the ceramic structure. In this work, ceramic foams were produced by the replica method from Al2O3and 3% Y2O3-ZrO2. Rheological parameters of the ceramic suspensions were investigated to improve the mechanical performance of final structures. Different types and quantities of raw materials were combined in order to select the formulations for ceramic foams. The parameters that have a significant influence on the process are the binder type and the amount of solids. Significant changes on the hysteresis area of the suspensions resulted in a lower density of macrodefects in the material. Likewise, when the shear rate viscosity is enhanced, the thickness of the struts increased proportionally. Lastly, when the hysteresis area magnitude and the ceramic thickness increased, the material with higher uniformity was internally densified, and the stress concentration of the internal defects was smoothed

scholarly journals Investigation of La3+ Doping Effect on Piezoelectric Coefficients of BLT Ceramics

2017 ◽  
Vol 62 (2) ◽  
pp. 691-696
Author(s):  
B. Wodecka-Dus ◽  
L. Kozielski ◽  
J. Erhart ◽  
M. Pawełczyk ◽  
D. Radoszewska ◽  
...  
Keyword(s):  
Atmospheric Pressure Plasma ◽  
Ferroelectric Materials ◽  
Charge Accumulation ◽  
Electromechanical Properties ◽  
Healthcare Applications ◽  
Dielectric Parameters ◽  
Ceramic Structure ◽  
Plasma Generation ◽  
Lanthanum Titanate ◽  
Cold Atmospheric Pressure Plasma

AbstractEffects of La3+admixture in barium lanthanum titanate (BLT) ceramics system with colossal permittivity on performance of prospective piezoelectric cold plasma application were studied. Usage of cold atmospheric pressure plasma appears promising in terms of industrial and healthcare applications. Performed investigation provide consistent evaluation of doping lanthanum amount on piezoelectric coefficients values with simultaneous capability of charge accumulation for effective plasma generation. Modification of ferroelectric materials with heterovalent ions, however with the lower radii than the original atoms, significantly affects their domain mobility and consequently electromechanical properties. To determine the piezoelectric coefficients, the resonance-antiresonance method was implemented, and values of piezoelectric and dielectric parameters were recorded. Finally the results indicated that addition of 0.4 mol.% of La3+ions to the ceramic structure maximally increased the values of piezoelectric coefficient tod33= 20 pC/N and to huge dielectric constant toε33T= 29277.

Design Methodology for Ceramic Structures

1977 ◽  
Vol 99 (4) ◽  
pp. 559-566 ◽  
Author(s):  
G. G. Trantina ◽  
H. G. deLorenzi
Keyword(s):  
Design Methodology ◽  
Subcritical Crack Growth ◽  
Structural Strength ◽  
Ceramic Materials ◽  
Strength Degradation ◽  
Critical Material ◽  
Ceramic Structure ◽  
Single Piece ◽  
Turbine Vane ◽  
Critical Regions

Unique design techniques are required to successfully take advantage of the superior high temperature structural strength of ceramic materials. The design methodology described here combines the results of a finite element stress analysis with a statistical analysis in order to predict the probability of failure of a ceramic structure. The strength degradation of a ceramic material as a result of subcritical crack growth under constant and cyclic loading conditions is incorporated into the methodology. Critical material properties such as strength, Weibull modulus, and the strength degradation exponent are discussed. A tapered disk and a wedge specimen are analyzed. When subjected to thermal shock, these specimens simulate the stresses in critical regions of structures such as the trailing edge of a gas turbine vane. Finally, applications of the design methodology to ceramic transition pieces are discussed where similar probabilities of failure are obtained for single-piece and four-piece designs.

Fabrication of Micro Patterned Ceramic Structure by Imprinting Process

2011 ◽  
Vol 58 (11) ◽  
pp. 673-678 ◽  
Author(s):  
Yang Xu ◽  
Fujio Tsumori ◽  
Hyungoo Kang ◽  
Hideshi Miura
Keyword(s):  
Ceramic Structure
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