In the present study, we fabricated high purity and electrically machinable Ti3SiC2 ceramics by mechanical alloying and subsequent spark plasma sintering. The effect of a trace amount of Al on these synthesis processe...
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In the present study, we fabricated high purity and electrically machinable Ti3SiC2 ceramics by mechanical alloying and subsequent spark plasma sintering. The effect of a trace amount of Al on these synthesis processes was examined. Our results showed that Ti3SiC2 could be synthesized by high energy milling. Spark plasma sintering of mechanically alloyed powder at the temperatures of 1000-1200°C produced nearly single-phased Ti3SiC2 materials. The purity of the sintered Ti3SiC2 bulk was remarkably increased by addition of a small amount of Al. Ti3SiC2 with a purity of 99.3 wt% and a relative density of 98.9% was obtained by mechanical alloying and subsequent spark plasma sintering from a starting mixture composed of n(Ti) : n(Si) : n(Al) : n(c) = 3 : 1 : 0.2 : 2 at 1100°C.
Na0.5Bi0.5TiO3(NBT) is considered to be an excellent candidate for lead-free piezoelectric ceramics. In this study, we propose a hydrothermal method for the preparation of single phase NBT powder at relatively low tre...
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Na0.5Bi0.5TiO3(NBT) is considered to be an excellent candidate for lead-free piezoelectric ceramics. In this study, we propose a hydrothermal method for the preparation of single phase NBT powder at relatively low treatment-temperature. The particle size and morphology of the synthesized powders were examined by SEM. The powders were further pressed into disk and sintered at 1120°C/2h in air, and its properties and microstructure were compared with traditionally prepared samples.
AgxPbmSbTe2+m thermoelectric materials were fabricated using a combined process of mechanical alloying (MA) and spark plasma sintering (SPS). The compound powder was synthesized by mechanical alloying (MA) from elemen...
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AgxPbmSbTe2+m thermoelectric materials were fabricated using a combined process of mechanical alloying (MA) and spark plasma sintering (SPS). The compound powder was synthesized by mechanical alloying (MA) from elemental powders using a planetary mill after a short time, and high-density bulk samples were fabricated by spark plasma sintering (SPS) at low temperature within a short time (12 minutes). The P-type materials were obtained with electrical properties comparable to the newly reported data. The properties of P-type AgxPbmSbTe2+m-based materials could be improved by optimizing the composition and the process.
Si3N4-filled epoxy resin composite was fabricated employing liquid press molding method. Properties, such as thermal conductivity, dielectric constant of Si3N4-filled epoxy resin composite were evaluated, the effect o...
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Si3N4-filled epoxy resin composite was fabricated employing liquid press molding method. Properties, such as thermal conductivity, dielectric constant of Si3N4-filled epoxy resin composite were evaluated, the effect of the content of Si3N4 and surface treatment of the filler was also considered. A silane coupling agent, namely NH2-(CH2)3Si-(OC2H 5)3, was applied to functionalize the surface of Si 3N4 filler. Experimental results showed that the thermal conductivity of the composites is strongly dependent on the filler and is dominated by the interface of epoxy resin and Si3N4 particles. As the Si3N4 volume fraction increasing, thermal conductance of Si3N4-filled composite was improved obviously, especially for that of silane-treated Si3N4 powder filled composite. Dielectric constant of the composite increases linearly, however, it still remains at a relatively low level (
The surface coating processing technique was used to modify hydrothermally synthesized-Ba(Ti,Zr)O3 (BTZ) with an Nb-organic compound and Zn-organic compound in an organometallic precursor (Nb-EDTA and Zn-EDTA), which ...
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The surface coating processing technique was used to modify hydrothermally synthesized-Ba(Ti,Zr)O3 (BTZ) with an Nb-organic compound and Zn-organic compound in an organometallic precursor (Nb-EDTA and Zn-EDTA), which were coated on the powders uniformly. The sintering temperature was decreased and dense ceramics were obtained with well-developed grain growth at 1300 °C. Both increasing the amount of Nb-Zn and decreasing the Nb/Zn ratio greatly promoted grain growth. On increasing the Nb/Zn ratio, the Curie point temperature was markedly lowered, accompanied by a large decrease in the corresponding dielectric maximum and a simultaneous enhancement of the ferroelectric relaxor characteristic. At Nb/Zn - 2, the Curie temperature was monotonously lowered with increasing Nb-Zn content. The shift rate of the phase transition point of Nb-Zn co-doped BTZ was 6.5°C/mol %. The corresponding dielectric maximum was enhanced rapidly from 9020 for a 0.35 mol % Nb-Zn doped sample to more than 12000 for a 0.90 mol % Nb-Zn doped sample.
A series of BN-SiO2 composite ceramics with high relative densities have been fabricated by hot pressing of a mixture of hexagonal boron nitride powder and silica sol. X-ray diffraction (XRD) results show that silica ...
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A series of BN-SiO2 composite ceramics with high relative densities have been fabricated by hot pressing of a mixture of hexagonal boron nitride powder and silica sol. X-ray diffraction (XRD) results show that silica are distributed in the BN matrix as noncrystalline state. Microstructure of as-sintered composite ceramics is observed by scanning electron microscopy (SEM). The influence of the secondary phase on the mechanical properties is studied by varying the silica content from 10 wt% up to 40 wt%, Dielectric properties of composite ceramics are also measured from 1 MHz to 2.0 GHz.
The sintering kinetics model of initial stage by spark plasma sintering (SPS) is discussed in this paper. During SPS, there are discharges among the powder particles. And the particles surface will be melted and form ...
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The sintering kinetics model of initial stage by spark plasma sintering (SPS) is discussed in this paper. During SPS, there are discharges among the powder particles. And the particles surface will be melted and form viscose flow. These phenomena accelerate the particles rearrangement and reduce the sintering time. The relationship between the shrinkage ratio of particles and the sintering time during the initial stages of sintering by SPS has been obtained. The results show that ΔL/L0 is linear to the time.
Highly dense Na1-xKxNbO3 (x=0.2-0.8) ceramics were successfully prepared using spark plasma sintering (SPS) at temperature as low as 920°C. Solid solutions were formed during the composition range investigated. T...
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Highly dense Na1-xKxNbO3 (x=0.2-0.8) ceramics were successfully prepared using spark plasma sintering (SPS) at temperature as low as 920°C. Solid solutions were formed during the composition range investigated. The piezoelectric constant and planar mode electromechanical coupling coefficient are significantly dependent on the Na/K ratio, with the maximum value of 148 pC/N and 38.9% at the composition Na 0.5K0.5NbO3.
Nowadays, it is popular that the dealer makes profits by selling a kind of discount coupons, which can be used as money to purchase commodities with total cost less than or equal to the face value of the coupon. We ca...
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Nanoimprint lithography offers the possibility to pattern wafer-scale surfaces with nm-sized structures in polymers reaching the 10 nm lateral size. Printable polymers can be tailored to have a surface upon which mole...
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