In the present study, (1-x)(Sr_(0.88)Bi_(0.08))TiO_(3)-xBi(Mg_(0.5)Ti_(0.5))O_(3) (SBT-BMT) system was synthesized using conventional solid stateprocessing. X-ray diffraction (XRD) and SEM testings were employed to d...
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ISBN:
(纸本)9781457711626
In the present study, (1-x)(Sr_(0.88)Bi_(0.08))TiO_(3)-xBi(Mg_(0.5)Ti_(0.5))O_(3) (SBT-BMT) system was synthesized using conventional solid stateprocessing. X-ray diffraction (XRD) and SEM testings were employed to determine the phase constitution and microstructure of ceramics. SBT-BMT ceramics exhibited moderate dielectric permittivities ((epsilon)_(r)) (>1100 at RT) and low dielectric loss (0.07percent) over the temperature range from -20 to 200 deg C, with flat temperature coefficients of permittivity. In addition, SBT-BMT ceramics were observed to possess dielectric relaxation characteristics and energy densities, being on the order of 1.4 J/cm~(3) at 180 kV/cm was observed for the 0.8S_(0.88)B_(0.08)T-0.2BMT ceramics.
Density functional perturbation theory, combined with quasi-harmonic approximation theory and the Debye theory, has been used to calculate the thermal conductivity of the double-perovskite perovskite slab–rocksalt la...
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Density functional perturbation theory, combined with quasi-harmonic approximation theory and the Debye theory, has been used to calculate the thermal conductivity of the double-perovskite perovskite slab–rocksalt layer oxide compounds L2SrAl2O7 (L = La, Nd, Sm, Eu, Gd, and Dy), a promising class of high-temperature thermal insulators. The predicted properties are compared with experimental data and show excellent agreement from room temperature up to 1000 °C. This indicates that the methodology is an effective approach to calculating the thermal conductivity of complex, defect-free crystal structures.
In order to verify the effect of CRP(continuous rheoconversion process) in the preparation of magnesium alloy semisolid billets,AM60 alloy billets were fabricated with CRP,and effects of pouring temperature,slope angl...
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In order to verify the effect of CRP(continuous rheoconversion process) in the preparation of magnesium alloy semisolid billets,AM60 alloy billets were fabricated with CRP,and effects of pouring temperature,slope angle,and length of the reactor on the microstructure of AM60 alloy were *** results show that the grain size is reduced with the decrease of pouring temperature.A small block/rosette grain is obtained when the pouring temperature is less than 680 °***,the available temperature process interval/window has to be *** change slope angle of reactor(from 30° to 45°) is helpful for formation of the small and block/rosette ***,the reactor with a length of 500 mm is enough for copious nucleation of primary *** changes the solidification microstructure of billets by controlling the nucleation and growth of the primary phase in melt.
Effect of stacking layers on the structure and properties of Ca(Mg 1/3Nb2/3)O3/CaTiO3 (CMN/CT) microwave dielectric heterogeneous thin films prepared was investigated. Precursor solutions for CMN and CT synthesis were...
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Nanocrystalline titanium dioxide powder was synthesized by in-flight oxidation of titanium dihydride （TiH2） powder in a thermal plasma jet. TiH2 powder was injected into the thermal plasma jet and allowed to react w...
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Nanocrystalline titanium dioxide powder was synthesized by in-flight oxidation of titanium dihydride （TiH2） powder in a thermal plasma jet. TiH2 powder was injected into the thermal plasma jet and allowed to react with oxygen injected downstream the jet. Characteriza- tion of the powder by various analytical tools indicated that the powder consisted of nano-sized titanium dioxide particles consisting predominantly of the anatase phase. It is suggested that the thermo-chemistry of the oxidation process contributes significantly to the formation of nano-sized titania. The large energy released during the oxidation process dissociates the TiO2 particles into TiO（g） and titanium vapour, which recombine downstream with oxygen and form nano particles of TiO2.
In the present work, silicon nitride nanowires (SNNWs) have been synthesized via nitriding cryomilled nanocrystalline silicon powder. The silicon powder exhibits a fine polycrystalline structure after the cryomilling ...
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Heavy steel castings, a symbol of the level of heavy industries, are high-tech products assembling materials, metallurgy, casting, etc. The feasible schemes for economizing manufacturing heavy steel castings were anal...
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Heavy steel castings, a symbol of the level of heavy industries, are high-tech products assembling materials, metallurgy, casting, etc. The feasible schemes for economizing manufacturing heavy steel castings were analyzed. The effects of riser design, sand mold, oxidation and deformation of casting during heat treatment, machining allowance, etc., on the economizing manufacture heavy steel castings were reviewed. Realization of efficient and economical manufacture of heavy steel castings will improve the output ratio of metal, shorten manufacturing period, save energy and resource, reduce pollution, and improve the competitiveness of enterprises.
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