Barium titanyl oxalate (BTO) particles modified with trace polyaniline (PAn) are fabricated via an in-situ polymerization of aniline in the BTO suspensions. The modification of PAn improves the wettability of the BTO ...
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Barium titanyl oxalate (BTO) particles modified with trace polyaniline (PAn) are fabricated via an in-situ polymerization of aniline in the BTO suspensions. The modification of PAn improves the wettability of the BTO particles and the static shear stress of the BTO-based ER fluids. The ER fluids based on the modified-particles with the dosage of PAn 1.7% show the best ER properties, its static shear stress is up to 54.5 kPa, which is 3.3 times than that of pure BTO particles. The improvement of the interfacial polarization and wettability is the main reason for the huge enhancement of ER effect.
Si3N4 ceramics were prepared by aligning the α-Si3N4 whisker in the substrate via tape casting and hot-press sintering. The phases and microstructure of the ceramics were studied by X-ray diffraction and scanning ele...
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Si3N4 ceramics were prepared by aligning the α-Si3N4 whisker in the substrate via tape casting and hot-press sintering. The phases and microstructure of the ceramics were studied by X-ray diffraction and scanning electron microscopy. The effects of tape casting on the distribution of α-Si3N4 whiskers in the substrate and the sintering conditions on the microstructure of the sintered samples were discussed. The results show that the tape casting and hot-press sintering can make the whiskers align in the substrate;the densities of the sintered samples increase with the increase of temperature. The Si3N4 ceramics with added α-Si3N4 of 10.6% (in mass) and sintered at 1500°C have higher fracture toughness of 9.24 MPa·m1/2 and Vickers hardness (Hv) of 15.74 GPa. The ceramic with rod-like grains of β-Si3N4 phase transformed by α-Si3N4 phase sintered at 1600°C has better the mechanical properties, and the fracture toughness and Hv are 10.26 MPa·m1/2 and 16.56 GPa, respectively.
Temperature distribution in the sample and the die during the process of Spark Plasma Sintering (SPS) were studied both theoretically and experimentally. The temperature difference is inevitable in the samples in SPS....
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Temperature distribution in the sample and the die during the process of Spark Plasma Sintering (SPS) were studied both theoretically and experimentally. The temperature difference is inevitable in the samples in SPS. Under certain conditions, the difference may reach a few hundreds of degrees of centigrade. Controlling of processing parameters can decrease the temperature difference. The atom diffusion at the interfaces and necks of specimen under SPS was also investigated and compared with Hot Pressing (HP). It was found that the atom diffusion in SPS is faster than that in HP, which indicates that SPS is more efficient.
Titanium diboride (TiB2) was hot-pressed with 5% aluminum nitride (AlN) as a sintering at different sintering temperatures (1700-1900°C). The effects of sintering temperatures on microstructure and mechanical pro...
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Titanium diboride (TiB2) was hot-pressed with 5% aluminum nitride (AlN) as a sintering at different sintering temperatures (1700-1900°C). The effects of sintering temperatures on microstructure and mechanical properties were investigated. The results showed that the composites achieved the better properties when sintered at 1800°C.
Mg-W composites with 0-92% W were prepared by spark plasma sintering (SPS) technique at 600°C-30 MPa-5 min. The mechanism of densification was researched and the relation between the mechanical property and the c...
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Mg-W composites with 0-92% W were prepared by spark plasma sintering (SPS) technique at 600°C-30 MPa-5 min. The mechanism of densification was researched and the relation between the mechanical property and the content of W was discussed. The results indicated that W and Mg exit in the composites through mechanical mixtures. The samples with low content of W were spread by partly molten Mg connecting the particles of Mg, the ones with high content of W through molten Mg joining the particles of W together. Increasing the content of W, elasticity modulus and bending strength increase, the Poisson's ratio decreases.
Spark plasma sintering(SPS) prepared transparent AlN ceramics by using different-content CaF2 as sintering aids, preparing porous materials and welding of alloys were researched. SPS shows its merits which could prepa...
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Spark plasma sintering(SPS) prepared transparent AlN ceramics by using different-content CaF2 as sintering aids, preparing porous materials and welding of alloys were researched. SPS shows its merits which could prepare transparent ceramics with high transparency in short time, prepare porous materials with homogeneous and controllable hole under low temperature in short time, obtain quite strong welding junction under low welding temperature and in short soaking time, owing to its special characters.
A kind of Li2O-Al2O3-SiO2 system glass-ceramics, which had a low coefficient of thermal expansion, was prepared by melting method and used as the ramp-wave generator material. On one-stage light-gas gun, the experimen...
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A kind of Li2O-Al2O3-SiO2 system glass-ceramics, which had a low coefficient of thermal expansion, was prepared by melting method and used as the ramp-wave generator material. On one-stage light-gas gun, the experimental technique for quasi-isentropic compression via the ramp-wave generator was explored. By impacting the ramp-wave generator, quasi-isentropic compression waves with an extended wave's front were produced. The quasi-isentropic loadings to LY12-A1 samples were further realized via the ramp-wave generator. The results showed that the more the thickness of the ramp-wave generator, the longer the front of the generated waves and the lower the rate of the compression. The present research offered a feasible loading means for the quasi-isentropic compression under low pressures.
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.
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.
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