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.
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 controllab.e 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.
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.
To reuse roller waste as a raw material of high performance green ceramic balls, three kinds of white alumina ceramic balls whose wear resistance were 2-3 times of the best high alumina ceramic ball with 90% Al2O3 wer...
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To reuse roller waste as a raw material of high performance green ceramic balls, three kinds of white alumina ceramic balls whose wear resistance were 2-3 times of the best high alumina ceramic ball with 90% Al2O3 were prepared, and the Al2O3 content of the prepared balls was 75%. It is found that the effect of calcia and magnesia on the wear resistance of ceramic balls is contrast to the accepted one： the wear rate of the ceramic balls prepared in CaO-Al2O3-SiO2 system is the lowest and the wear rate of the ceramic balls prepared in MgO-Al2O3-SiO2 is the highest. The main crystal phase of the ceramic ball is mullite and corundum. The ceramic ball granular is uniform and fine with 4-5 μm average size. The pore diameter is about 2 μm. The wear way of the ceramic balls is mainly transcrystalline fracture.
Transparent Fe-doped In2O3 thin film was prepared by sol-gel method on (general) glass substrate. The structure, morphologies, transmission and magnetic properties of the sample have been characterized by X-ray diffra...
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Transparent Fe-doped In2O3 thin film was prepared by sol-gel method on (general) glass substrate. The structure, morphologies, transmission and magnetic properties of the sample have been characterized by X-ray diffraction, field emission scanning electron microscopy, UV-Vis spectroscopy and vibrating sample magnetometer. XRD result indicated that the sample was single cubic In2O3 phase. FE-SEM clearly showed that the film was homogenous and composed of refining grain with an average size of 14 nm. UV-Vis spectrum indicated that the transmittance of the film was higher than 80% in the visible light, and the Fe-doped In2O3 film arose the optical absorption spectrum red shift. VSM demonstrated the sample was (room temperature ferromagnetic.
KNbO 3 films were prepared on Si (100) substrates by pulsed laser deposition. The effect of experimental parameters on the films structure and composition was investigated. Well crystallized and single-phase KNbO 3 fi...
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KNbO 3 films were prepared on Si (100) substrates by pulsed laser deposition. The effect of experimental parameters on the films structure and composition was investigated. Well crystallized and single-phase KNbO 3 films were obtained at the substrate temperature of 650 °C, laser energy of 7.5 mJ/pulse and target-substrate distance of 40 mm, but a severe potassium-deficient was observed in the deposited films. The mechanism of K deficiency in films was explored and a method to control the composition was designed. The experimental results indicate that the composition of films can be well controlled by adjusting the oblique angle of substrates from the axial direction of plume. The stoichiometric KNbO 3 films with K/Nb molar ratio of 0.98 were obtained by locating the substrate at an oblique angle of 3–12° from the plume axis.
A numerical study of residual stresses and warpage was undertaken according to the characteristics of plastic injection molding process. A linear thermoviscoelastic model was adopted in simulating residual stresses, w...
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A numerical study of residual stresses and warpage was undertaken according to the characteristics of plastic injection molding process. A linear thermoviscoelastic model was adopted in simulating residual stresses, with multiple boundary conditions and assumptions during different stages. A Finite difference method in the time was employed in calculation with a layer discretization in the thickness direction. Warpage simulation was based on a modified flat model with surface mesh, which avoided the deficiencies of traditional flat models. Validation was carried out by comparing with application data. It was found that the residual stress and warpage could be predicted well by the proposed simulation.
Sintering behavior, microstructure and microwave dielectric properties of Ba1+x(Mg1/3Nb2/3)O3 (-0.01 [less-than or equal to] x [less-than or equal to] 0.01) were investigated. An improvement of the degree of 1:2 order...
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Sintering behavior, microstructure and microwave dielectric properties of Ba1+x(Mg1/3Nb2/3)O3 (-0.01 [less-than or equal to] x [less-than or equal to] 0.01) were investigated. An improvement of the degree of 1:2 ordering and sinterability was found in Ba-deficient Ba(Mg1/3 Nb2/3)O3 because there existed Ba vacancies. Excessive Ba inhibits the sintering and the degree of 1:2 ordering. It was proposed that excessive Ba exist in grain boundary and inhibit the movement of grain boundary. Therefore, the sintering was restrained. Ba-deficiency had little effect on dielectric constant of Ba(Mg1/3Nb2/3)O3 ceramics. With Ba-deficiency increasing, Qf value decreased drastically.
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