The method of single detector, direct contact and longitudinal wave were used in this research. Ultrasonic wave attenuation coefficient of nine WC-10 Co hardmetals samples were tested, while fracture toughness values ...
详细信息
The method of single detector, direct contact and longitudinal wave were used in this research. Ultrasonic wave attenuation coefficient of nine WC-10 Co hardmetals samples were tested, while fracture toughness values were obtained by indentation method. SEM was performed to observe the sections of the samples. Distributions of the WC grains were analyzed. Density, Vickers hardness and transverse rupture strength were also tested. The relationships among ultrasonic wave attenuation coefficient, mean grain size, fracture toughness, density, Vickers hardness and transverse rupture strength were studied. Results showed that with the decrease of the mean WC grain size, the ultrasonic wave attenuation coefficient and the fracture toughness value increased. However, ultrasonic wave attenuation coefficient had no direct relation with density, Vickers hardness and transverse rupture strength. It was concluded that ultrasonic wave attenuation coefficient could be used to evaluate the fracture toughness of WC-10 Co hardmetals, instead of destructive mechanical method.
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...
详细信息
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.
(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...
详细信息
(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.
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...
详细信息
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...
详细信息
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.
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...
详细信息
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.
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...
详细信息
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.
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...
详细信息
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.
Sr-filled skutterudite compounds SryCo4Sb 12 (y=0-0.20) were synthesized by melting method. XRD and EPMA results revealed that the obtained samples are single skutterudite phase with homogeneous chemical composition. ...
详细信息
Sr-filled skutterudite compounds SryCo4Sb 12 (y=0-0.20) were synthesized by melting method. XRD and EPMA results revealed that the obtained samples are single skutterudite phase with homogeneous chemical composition. The lattice parameters increase linearly with increasing Sr content in the range of y=0-0.20. The thermal conductivity, electrical conductivity and Seebeck coefficient were measured in the temperature range of 300-850K. The measurement of Hall effect was performed by Van de Pauw method at room temperature. The obtained Sr-filled skutterudite exhibits n-type conduction. The absolute value of the Seebeck coefficient of Sr yCo4Sb12 decreases with the increase of Sr content. The electrical conductivity increases with the increase of Sr content. The lattice thermal conductivity of SryCo4Sb12 is significantly depressed as compared with unfilled CoSb3. The maximum dimensionless thermoelectric figure of merit is 0.7 for Sr 0.20Co4Sb12 at 850K. Further optimization of chemical composition would improve the thermoelectric performance.
Cubic Boron Nitride powder was heat treated in N2 or in vacuum at different temperatures and dwell time. Its phase composition and morphology were investigated by means of X-ray diffraction (XRD) and scanning electron...
详细信息
Cubic Boron Nitride powder was heat treated in N2 or in vacuum at different temperatures and dwell time. Its phase composition and morphology were investigated by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis. Results showed that the cubic Boron Nitride was transformed into hexagonal phase after heat treatment in N2 at 1350°C for 10 h, or in vacuum (pressure = 1-5 Pa) at 1550°C for 5 h, while no changes occurred in particle size and morphology.
暂无评论