(AgSbTe2)x(PbTe)1-x (x = 0.04-0.20) samples were prepared by slow-cool-from-melts and the influences of AgSbTes content on the microstructure and thermoelectric properties were investigated. Results indicated that pha...
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(AgSbTe2)x(PbTe)1-x (x = 0.04-0.20) samples were prepared by slow-cool-from-melts and the influences of AgSbTes content on the microstructure and thermoelectric properties were investigated. Results indicated that phase segregation occurs as x increases and the samples are characterized by a bi-phased material containing one main Pb-rich phase and another Ag-Sb-rich phase. As AgSbTe2 content increases, the thermal conductivity is depressed and the electrical properties decrease to some extent. The dimensionless of figure of merits (ZT) is greater for sample with a lower AgSbTe2 content.
Ce0.8Sm0.2O1.9(SDC) was synthesized by calcination of mixed solution method. XRD patterns showed that SDC powders calcined at 800°C had a cubic fluorite structure and the average grain size was between 1-3 μm. A...
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Ce0.8Sm0.2O1.9(SDC) was synthesized by calcination of mixed solution method. XRD patterns showed that SDC powders calcined at 800°C had a cubic fluorite structure and the average grain size was between 1-3 μm. After sintered for 4 h at 1450°C, the relative density was 91.9%. The conductivity of SDC solid electrolyte was 0.087 S·cm-1 at 800°C.
CaCu3Ti4O12 ceramics with high dielectric constant were prepared by solid-state reaction followed by densification at high temperatures. The synthesis and sintering as well as the dielectric properties of the ceramics...
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CaCu3Ti4O12 ceramics with high dielectric constant were prepared by solid-state reaction followed by densification at high temperatures. The synthesis and sintering as well as the dielectric properties of the ceramics were investigated by means of XRD, SEM, and LCR. It was found that single phase CaCu3Ti4O12 was synthesized from CaCO3, CuO and TiO2 powders at temperatures higher than 1000°C, but it would decompose at 1150°C. The optimum temperature for sintering CaCu3Ti4O12 was 1100°C, where dense and well crystallized CaCu3Ti4O12 ceramics with a high dielectric constant above 1.5 × 104 and a loss tangent about 0.27 were successfully obtained.
The single-phase SmyFexCo4-xSb12 compounds were synthesized by using the solid-state reaction method and melting reaction method, and the thermoelectric properties of SmyFexCo4-xSb12 were investigated. Research result...
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The single-phase SmyFexCo4-xSb12 compounds were synthesized by using the solid-state reaction method and melting reaction method, and the thermoelectric properties of SmyFexCo4-xSb12 were investigated. Research results indicated that the electrical conductivity of SmyFexCo4-xSb12 decreased with increasing Sm filling fraction, which the carrier concentration dramatically depends on. Seebeck coefficient increased with increasing temperature and Sm filling fraction. The lattice thermal conductivity decreased evidently with increasing Sm filling fraction, and reached the minimum value at a certain Sm filling fraction. The maximum figure of merit ZTmax of Sm0.19Fe1.47Co2.53Sb12 is 0.55 at 750 K.
Potassium lithium niobate (KLN: K3Li2Nb5O15) films have been deposited on quartz glass by Pulsed laser deposition (PLD) technique using a stoichiometric KLN target as starting materials. By investigating the effects o...
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Potassium lithium niobate (KLN: K3Li2Nb5O15) films have been deposited on quartz glass by Pulsed laser deposition (PLD) technique using a stoichiometric KLN target as starting materials. By investigating the effects of both the oxygen pressure and the substrate temperature on the structure of KLN films, optimum parameters have been identified for the growth of high-quality KLN films. At 10Pa oxygen ambient pressure, tetragonal tungsten-bronze-type structure of KLN films with (310) preferred orientation can be achieved at substrate temperatures in the range of 700-800°C Optical studies indicate that the films are highly transparent in the visible-near-infrared wavelength range.
Nano-sized turbostritic-BN (t-BN) was fabricated through chemical process using boric acid and urea in this work. By the same method, the AlN powders coated with nano-BN were prepared too. The results of X-ray diffrac...
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Nano-sized turbostritic-BN (t-BN) was fabricated through chemical process using boric acid and urea in this work. By the same method, the AlN powders coated with nano-BN were prepared too. The results of X-ray diffraction (XRD) and transmission electron microscope (TEM) revealed that nano-sized t-BN was synthesized at about 600°C in nitrogen gas and it surrounded the surface of AlN particles. High-density AlN/BN nano-composites were fabricated spark plasma sintering (SPS). Microstructure and properties of AlN/BN nano-composites (5∼30vol% BN) were investigated. The h-BN flake particles were homogenously dispersed at AlN grain boundaries and within grains in the AlN/BN composites. A little nano-BN additions significantly improved the bending strength of the nano-composites. However, the bending strength was decreased with the BN content increasing. The thermal conductivity of AlN/BN nano-composites was investigated too.
Using the microwave sintering technology, the effects of VC/Cr3C2 additions on the microstructure and properties of the ultrafine WC-10Co alloys were investigated. Experimental results showed that ultrafine WC-10Co al...
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Using the microwave sintering technology, the effects of VC/Cr3C2 additions on the microstructure and properties of the ultrafine WC-10Co alloys were investigated. Experimental results showed that ultrafine WC-10Co alloys with 0.6% additions had the best properties while the excessive grain growth inhibitors would decrease the properties of alloys. Moreover, with or without additions, WC-10Co alloys with finely uniform grained WC by microwave sintering could be obtained.
AlN ceramics doped with yttrium o5xide (Y2O3) as the sintering additive were prepared via the spark plasma sintering (SPS) technique. The sintering behaviors and densification mechanism were mainly investigated. The r...
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AlN ceramics doped with yttrium o5xide (Y2O3) as the sintering additive were prepared via the spark plasma sintering (SPS) technique. The sintering behaviors and densification mechanism were mainly investigated. The results showed that Y2O3 addition could promote the AlN densification. Y2O3-doped AlN samples could be densified at low temperatures of 1600-1700°C in 20-25 minutes. The AlN samples were characterized with homogeneous microstructure. The Y-Al-O compounds were created on the grain boundaries due to the reactions between Y 2O3 and Al2O3 on AlN particle surface. With increasing the sintering temperature, AlN grains grew up, and the location of grain boundaries as well as the phase compositions changed. The Y/Al ratio in the aluminates increased, from Y3Al5O 12 to Y4lO3 and to Y4Al 2O9. High-density, the growth of AlN grains and the homogenous dispersion of boundary phase were helpful to improve the thermal conductivity of AlN ceramics. The thermal conductivity of 122Wm -1K-1 for the 4.0 mass%Y203-doped AlN sample was reached.
In the study Li4/3Ti5/3O4 thin films were deposited on Pt substrates by sol-gel method using a spin coator. The coated films are dried at 310-360 °C, and then annealed at 500-800 °C for 30min. The prepared f...
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In the study Li4/3Ti5/3O4 thin films were deposited on Pt substrates by sol-gel method using a spin coator. The coated films are dried at 310-360 °C, and then annealed at 500-800 °C for 30min. The prepared films were characterized by X-ray diffraction, atomic force microscope and scanning electron microscope. The results indicated that the prepared film belonged to a spinel structure and had a uniform morphology. Electrochemical properties of the prepared electrode films were evaluated by using a discharge and charge test. From these results, it can be showed that the thin film electrode annealed at 700 °C exhibited good crystallinity, smooth surface morphology, high capacity, and good rechargeability. Therefore, This film was therefore suitable for use as an anode for thin-film microbatteries.
Al2(1-x)MgxTi1+xO5(x=0.05-0.3) composite powder was prepared by the method of chemical coprecipitation and subsequent sintering using TiCl5, MgCl2 and AlCl 3 solution as the raw materials, and ammonia and ammonium car...
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Al2(1-x)MgxTi1+xO5(x=0.05-0.3) composite powder was prepared by the method of chemical coprecipitation and subsequent sintering using TiCl5, MgCl2 and AlCl 3 solution as the raw materials, and ammonia and ammonium carbonate as the solvent. Thermal dynamics and kinetic dynamics analysis of the precursor during the heat treatment were explored in detail, and the reaction process of Al2(1-x)MgxTi1+xO5(x=0.3) composite powder was confirmed. Results show that, as the temperature increases MgO reacts with TiO2 of anatase phase to form MgTi2O5. At about 650°C, anatase transfers into rutile. Then MgTi2Os reacts with Al2O3 to produce MgAl2O4 at 900°C. When the temperature is above 1100°C, the desired Al 2(1-x)MgxTi1+xO5(x=0.3) composite powder is synthesized by the reaction of MgAl2O24, Al 2O3 and TiO2 of rutile phase.
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