The carbonyl iron/Al2O3 core-shell composite particles with different morphologies of nanoshells were prepared and the influences of the Al2O3 nanoshell morphologies on the properties of the carbonyl iron/Al2O3 core-s...
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The carbonyl iron/Al2O3 core-shell composite particles with different morphologies of nanoshells were prepared and the influences of the Al2O3 nanoshell morphologies on the properties of the carbonyl iron/Al2O3 core-shell composite particles were investigated. The results show that the shell morphologies of the carbonyl iron/Al2O3 core-shell composite particles strongly depend on the species of acid and pH value. Compared to the carbonyl iron particles, the anti-oxidation property, microwave electromagnetic parameters and mechanical properties of the composite particles are significantly improved, and the particles, uniform, compact and grain-like Al2O3 nanoshells are beneficial to improving the anti-oxidation property and decreasing permittivity with the retention of permeability, while fiber-like Al2O3 nanoshells are more advantageous to improving the interface compatibility between the particles and the matrix of the polymers, resulting in obvious increase of mechanical properties of their based absorbing coatings.
Tin dioxide based ceramics doped with ZnO, Sb2O3 and ZnO-Sb2O3 were prepared by the pressureless sintering. The relative density (ρr) was measured by the Archimedes method, the resistivity (R) was measured by the van...
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Tin dioxide based ceramics doped with ZnO, Sb2O3 and ZnO-Sb2O3 were prepared by the pressureless sintering. The relative density (ρr) was measured by the Archimedes method, the resistivity (R) was measured by the van der Pauw method, and the mi-crostructure and crystal structure were measured by scanning electron microscope. Then the internal relationship between the material and structure were analyzed. The results indicate that ZnO can improve the sintering characteristics of the material;the ρr increases and then decreases with the increase of ZnO, and the optimal content of ZnO is 1.0% (mole fraction, the same below). However, the ρr decreases with the increase of Sb2O3;the R decreases at first, and then increases and decreases at last. The ρr and R of the material are good when Sb2O3 content is 0.5%. The SnO2 based ceramic doped with 1.0% ZnO-0.5% Sb2O3 and sintered at 1400°C has high performance;the ρr is 97% and the R is 0.1099 Ω·cm.
Ga dopping GaxPb1-xTe(x=0.01-0.05) compounds were prepared by melting reaction method, and the in-c fluence of Ga content on the thermoelectric properties were investigated. The results showed that temperature dopende...
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Ga dopping GaxPb1-xTe(x=0.01-0.05) compounds were prepared by melting reaction method, and the in-c fluence of Ga content on the thermoelectric properties were investigated. The results showed that temperature dopendent carrier concentration increased and the hall mobility decreased with increasing Ga content, which indicated that the carrier scattering mechanism gradually changed from an acoustical scattering to the interaction between an acoustical phone and an ionized impurity scattering as x increased. All samples show n-type conduct and the absolute Seebeck coefficient values and the electric conductivity increase significantly with increasing Ga content.
The layered perovskite-type organic-inorganic hybrids (CnH2n+1NH3)2 MnCl4 (n=2, 4, 6, 8, 10, 12) were synthesized in solution and their structures were characterized. The results showed that the structures of the prod...
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The layered perovskite-type organic-inorganic hybrids (CnH2n+1NH3)2 MnCl4 (n=2, 4, 6, 8, 10, 12) were synthesized in solution and their structures were characterized. The results showed that the structures of the products were independent on the reaction initial temperature. The X-ray diffraction (XRD) patterns and the scanning electron microscopy (SEM) images of the products demonstrated that the hybrids crystallize very well and had typical layered structures. The interlayer distance of each hybrid was obtained from the XRD patterns. It was linear dependent on the carbon atom number in the organic chain and the organic chains interdigitated between the two adjacent inorganic sheets.
The solubility of layered perovskite-type organic-inorganic hybrids (CnH2n+1 NH3)2MCl4 (where M = Mn, Co, Cu, Zn;n = 2, 4, 6, 8, 10, 12) in seven kinds of solvent are obtained by atomic absorption spectrometry and tit...
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The solubility of layered perovskite-type organic-inorganic hybrids (CnH2n+1 NH3)2MCl4 (where M = Mn, Co, Cu, Zn;n = 2, 4, 6, 8, 10, 12) in seven kinds of solvent are obtained by atomic absorption spectrometry and titration method. The solvents are sherwood oil, cyclohexane, acetone, trichloromethane, DMF, methanol and water. The results show that the hybrids are prone to dissolve in polar solvent. This is attributed to the polarity of the hybrids. The hybrids disassembly dissolve when the interaction between the ammonium and the electron-donating group of the solvent is stronger than that between the organic and the inorganic parts in the hybrids. The series of M = Zn and Co have better solubility in the polar solvent than that of M = Mn and Cu and this is presumably because there are weaker interactions between the organic and inorganic parts in hybrids of M = Zn and Co.
In this study, K3Li2-xNb5+xO 15+2x (KLN) thin films were prepared by laser-ablated a sintered ceramic target. For an optimum deposition condition, in-situ post annealing method was employed on as-deposited films. XRD ...
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In this study, K3Li2-xNb5+xO 15+2x (KLN) thin films were prepared by laser-ablated a sintered ceramic target. For an optimum deposition condition, in-situ post annealing method was employed on as-deposited films. XRD measurements showed that KLN films with (310) preferred orientation were obtained on fused quartz substrate. Surface morphology studies indicated mat in-situ post annealing could improve the surface quality of KLN thin films. The average transmittance of as-deposited and annealed films in the visible range was nearly 80% to 90%.
In this paper, we presented a novel route for fabricating Ti 3SiC2-based and Ti3AlC2-based solid solutions with mixed powders of TiC/Ti/Si/Al in different molar ratios. The phase compositions of these solid solutions ...
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In this paper, we presented a novel route for fabricating Ti 3SiC2-based and Ti3AlC2-based solid solutions with mixed powders of TiC/Ti/Si/Al in different molar ratios. The phase compositions of these solid solutions were studied by XRD and the stoichiometrics of these compounds were determined to be Ti 2.63Si0.87Al0.13C2 and Ti 2.76Al0.78Si0.22C2 by EDS. We also investigated the electronic properties and mechanical properties of these two ceramics. The results showed that the dopants were not only beneficial to the fabrication of Ti3SiC2 and Ti3AlC2 but also improved the properties of these two ceramics.
Ca(Al1/2Nb1/2)O3 (CAN) and Ca(Fe 1/2Nb1/2)O3 (CFN) were prepared by solid reaction route. With the sintering temperature increased, the Q×f value of CAN changes from 7 200 to 17 500 GHz due to the changing of the...
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Ca(Al1/2Nb1/2)O3 (CAN) and Ca(Fe 1/2Nb1/2)O3 (CFN) were prepared by solid reaction route. With the sintering temperature increased, the Q×f value of CAN changes from 7 200 to 17 500 GHz due to the changing of the ordering degree, whereas, the dielectric constant and Q×f value of CFN decrease remarkably without structural changing. The reason of this phenomenon is that the difference in size of two B-site ions in CAN is larger than that in CFN. As a result, the ordering degree of CAN is more sensitive to the conditions of sample preparation, compared with CFN.
A modification analytical model is presented for the thermal elastoplastic stresses of functionally graded materials subjected to thermal loading. The presented model follows the analytical scheme presented by Y. L. S...
A modification analytical model is presented for the thermal elastoplastic stresses of functionally graded materials subjected to thermal loading. The presented model follows the analytical scheme presented by Y. L. Shen and S. Suresh [6]. In the present model, the functionally graded materials are considered as multilayered materials. Each layer consists of metal and ceramic with different volume fraction. The ceramic layer and the FGM interlayers are considered as elastic brittle materials. The metal layer is considered as elastic‐perfectly plastic ductile materials. Closed‐form solutions for different characteristic temperature for thermal loading are presented as a function of the structure geometries and the thermomechanical properties of the materials. A main advance of the present model is that the possibility of the initial and spread of plasticity from the two sides of the ductile layers taken into account. Comparing the analytical results with the results from the finite element analysis, the thermal stresses and deformation from the present model are in good agreement with the numerical ones.
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