Polycrystalline alumina was prepared at high temperature and high pressure from combustion reaction plus mechanical pressure. The defect structure in the sintered alumina was investigated by transmission electron micr...
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Polycrystalline alumina was prepared at high temperature and high pressure from combustion reaction plus mechanical pressure. The defect structure in the sintered alumina was investigated by transmission electron microscopy and a regular hexagonal dislocation network was found. Diffraction contrast technique revealed that the regular hexagonal network on the (0001) plane was composed of three dislocations with Burgers vectors: 1/3[12¯10], 1/3[2¯110] and 1/3[112¯0]. The formation process of dislocation network was discussed.
Composite magnetic particles (CMPs) with carbonyl iron (CI) core and N-glucose ethylenediamine triacetic acid (GED3A) shell were prepared by an in-situ chelating reaction, where the CI surface was coated with GED3A. A...
Composite magnetic particles (CMPs) with carbonyl iron (CI) core and N-glucose ethylenediamine triacetic acid (GED3A) shell were prepared by an in-situ chelating reaction, where the CI surface was coated with GED3A. And novel kind of aqueous magnetorheological (MR) fluids were prepared with thus obtained CMPs. The properties of CMPs, including morphology, structure, and magnetic behaviours were characterized, and the magnetorheological properties of the MR fluids were analyzed via a strain-controlled rheometer. It was found that the MR fluids exhibited high shear stress and quick response rate to magnetic field. Furthermore, the dispersion stability and the anti-oxidation property were substantially improved as revealed by stability test.
Solvothermal synthesis has been explored to prepare Sb2Te3 material in the solvent of DMF. The effect of reaction temperature and time on the phase composition and micro-structure have also been studied. The structure...
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Solvothermal synthesis has been explored to prepare Sb2Te3 material in the solvent of DMF. The effect of reaction temperature and time on the phase composition and micro-structure have also been studied. The structure and morphologies of nano-powders were investigated by XRD, SEM, TEM, and EDS observations. The growth mechanism of Sb2Te3 crystal has been researched. The results indicate that the particle size of the powders significantly increase with the escales temperature and the increasing time. At the temperature of 180 degree and maintaining for 24 hours, Sb2Te3 powder of hexagonal crystal was yielded.
ZnO whiskers were grown by a simple vapor-phase approach by using microwave energy without any catalyst in a very short time. The result of the XRD indicates that the production structure was wurtzite. The SEM shows s...
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ZnO whiskers were grown by a simple vapor-phase approach by using microwave energy without any catalyst in a very short time. The result of the XRD indicates that the production structure was wurtzite. The SEM shows some are rod crystals, the other are tubes with 50 μm diameter and 500 μm length. The photoluminescence (PL) exhibits strong ultraviolet emission (wavelength is 360 nm) and blue emission (wavelength is 470 nm) at room temperature. Experiments indicate that the temperature gradient is very important for the ZnO whiskers growth by using vapor phase. The temperature gradient between conventional and microwave heating is different.
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.
In this study, the sedimentation stability and rheology of a new magnetorheological fluid formulation were experimentally investigated before and after being stored for 24 months, as well as after being milled. The re...
In this study, the sedimentation stability and rheology of a new magnetorheological fluid formulation were experimentally investigated before and after being stored for 24 months, as well as after being milled. The results reveal that, after undergoing 24 months of steady storage, the off-state viscosity and field-induced yield stress of the MR fluid remained constant, and that its flowability and redispersibility were maintained. After being subjected to ball milling for 2 hours at 200 rpm and 300 rpm, the field-induced yield stress was also maintained.
In the present study, steel-bonded cemented carbide GT35 has been fabricated from natural ilmenite by in-situ carbothermic reduction and vacuum pressureless sintering. The effect of different carbon source on the mech...
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In the present study, steel-bonded cemented carbide GT35 has been fabricated from natural ilmenite by in-situ carbothermic reduction and vacuum pressureless sintering. The effect of different carbon source on the mechanical properties and microstructure of GT35 composite was studied. The quality of the composite synthesized from natural graphite is higher than those from other carbon source. Some good results were obtained from experiments: the density is about 6.2g/cm3, and the bending strength is 1390MPa, which higher than that of other samples. The structures and ingredient of different carbon source were analyzed to elucidate their different performance in the reactions.
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