The reaction mechanism of silicon and iron composite powders was clarified during the fabrication of high silicon iron sheet with the Si-content of 6.5wt% by Direct Powder Rolling (DPR) technique. The changes of phase...
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The reaction mechanism of silicon and iron composite powders was clarified during the fabrication of high silicon iron sheet with the Si-content of 6.5wt% by Direct Powder Rolling (DPR) technique. The changes of phase composition and structure evolvement were mainly studied, It is found that a local graded structure, Fe-Fe(Si)-Fe3Si(Si)-Si, forms when sintering at 950-10007deg;C, which plays an important role in the DPR process. Fe 3Si(Si) phase keeps higher content of Si, and Fe(Si) phase remains the state with much lower Si-content, thus provides good mechanical proprieties of rolling and cutting. Then, the subsequent sintering at about 1200C improves the density and makes the distribution of Si homogeneous in the final high silicon iron sheets.
Translucent AlN ceramics were fabricated using spark plasma sintering (SPS) technique with 3wt% CaF2 as sintering additive. The samples achieved 52.4% maximum transmittance in medium IR region after 10 min holding tim...
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Translucent AlN ceramics were fabricated using spark plasma sintering (SPS) technique with 3wt% CaF2 as sintering additive. The samples achieved 52.4% maximum transmittance in medium IR region after 10 min holding time by spark plasma sintering at 1800°C and 30 MPa pressure in N2. The results from XRD, SEM, TEM and EDX showed that the sintered bodies were densely compacted and highly pure with fine grain size and uniform microstructures. No secondary phases were observed at the grain boundaries and triple grain junctions, which guaranteed good optical property of the sintered bodies.
A novel water-based magnetorheological (MR) suspension is based on the poly(ethy1ene glycol)-coated carbonyl iron particles, which is prepared by the co-sol-gel reaction using carbonyl iron particles as raw materials,...
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ISBN:
(纸本)9812771190
A novel water-based magnetorheological (MR) suspension is based on the poly(ethy1ene glycol)-coated carbonyl iron particles, which is prepared by the co-sol-gel reaction using carbonyl iron particles as raw materials, and water without any other additive. The microshucture, anti-oxidation properties, magnetic and magnetorheological properties of the core-shell particles are characterized by scanning electronic microscopy, transmission electronic microscopy, Fourier transform infrared spectroscopy, thermogravimetric- differential thermal analysis, vibrating sample magnetometer, and ARES2000 rheometer, respectively. The results show that the as prepared particles have core-shell structure with a polymer shell of less than 100 nm and its anti-oxidation property is enhanced due to the compound coating. Both the core-shell particles and its based MR suspension exhibit excellent soft magnetic performance. The based MR suspension shows low zero viscosity and high MR effects, especially greatly improved anti-settlement and redispersibility. The phenomena are attributed to the hydrophilic thin shell of the core-shell particles.
In the present study, α-Si3N4 is prepared by using MgO and Al2O3 as the sintering additives and spark plasma sintering (SPS) technique. The SPS sintering mechanism is discussed. The relationship between the content o...
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In the present study, α-Si3N4 is prepared by using MgO and Al2O3 as the sintering additives and spark plasma sintering (SPS) technique. The SPS sintering mechanism is discussed. The relationship between the content of sintering additives, sintering temperature and relative densities of the samples is analyzed. The results suggest that when the sintering temperature is 1300-1500°C, the content of sintering additives is 6wt.%-10wt.%, the relative density of sintered samples is 64%-96%. When the sintering temperature reaches 1400°C, the content of sintering additives is 10%, the samples can be fully dense sintered and the relative density can be up to 95%. The sintering mechanism is liquid phase sintering. The bending strength of the sintered samples is 50-403MPa and has a close correlation with the relative density.
Novel mesoporous ZnO-SiO2 (MZS) composites with rod-like morphology were synthesized from coprecipitation method, which was the first time to apply this method in the successful synthesis of ordered mesoporous composi...
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Novel mesoporous ZnO-SiO2 (MZS) composites with rod-like morphology were synthesized from coprecipitation method, which was the first time to apply this method in the successful synthesis of ordered mesoporous composites to our knowledge. This direct-synthesis method was more simple, convenient and efficient, compared with the post-synthesis ones. Structural characterization and spectroscopic study were discussed.
This article introduces a process for the growth of one-dimensional oxide nanomaterials that combines rheological phase reaction and hydrothermal self-assembling process. Fundamentals and practical approaches of hydro...
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This article introduces a process for the growth of one-dimensional oxide nanomaterials that combines rheological phase reaction and hydrothermal self-assembling process. Fundamentals and practical approaches of hydrothermal self-assembling process and rheological phase reaction are briefly described. Particular attention is devoted to the rheological self-assembling for the growth of low dimensional oxide nanomaterials. Many examples are shown that the rheological self-assembling is an effective method to prepare one-dimensional nanomaterials, organic-inorganic hybrids and 1-D nanomaterial array for optical-electronic and electrochemical devices and catalysis. Morphologies, microstructures, properties, and application of one-dimensional oxide nanomaterials are reviewed.
Nearly single-phase and polycrystalline charge-density-wave compound K0.3MoO3 have been prepared by using a simple method. In this work, K2CO3 and MoOs were used as starting materials and reacted by hot isostatic pres...
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Nearly single-phase and polycrystalline charge-density-wave compound K0.3MoO3 have been prepared by using a simple method. In this work, K2CO3 and MoOs were used as starting materials and reacted by hot isostatic pressing （HIP） sintering. The product is nearly single phase K0.3MoO3 determined by X-ray powder diffraction （XRD） and energy dispersive spectroscopy （EDS）. Measurement of temperature dependence of resistivity reveals that the transport property of polycrystalline K0.3MoO3 obviously differs from that of single crystal due to the grain boundaries and the anisotropic structure in this kind of compound.
This paper was the experimental research of photographic progress on BN-303 photo-resist, in which the ultraviolet light was used in exposure. The surface morphology was observed with SEM. It was discussed that the ef...
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This paper was the experimental research of photographic progress on BN-303 photo-resist, in which the ultraviolet light was used in exposure. The surface morphology was observed with SEM. It was discussed that the effect of soft-baking on 3D structure of MEMS, qualitatively. Finally, the optimized technical parameters obtained through experiments were as follows: soft-baking time was 80°C and soaking time was 30 min, under the condition of cleaning oxidized silicon mask with standard methods, activating sample surface for 30 min at drying temperature 200°C, coating photo-resist at 6000 r/min of rotating speed for 15 s with 17 s of exposure time. The above research results might provide some reliable technical parameters for fabricating micro-device.
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.
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.
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