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.
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.
Single-phase n-type (AgIn)xPb1-2xTe compounds were synthesized using the melting reaction method. Influences of (AgIn) substituting for Pb on the constituent phases and thermoelectric properties of the (AgIn)xPb1-2xTe...
详细信息
Single-phase n-type (AgIn)xPb1-2xTe compounds were synthesized using the melting reaction method. Influences of (AgIn) substituting for Pb on the constituent phases and thermoelectric properties of the (AgIn)xPb1-2xTe(x=0.01-0.05) were investigated. Results indicate that single phase compound is obtained when the (AgIn) substitution fraction x&le0.04. However, the second phase (AgInTe2) was observed in the sample with x=0.05. The Seebeck coefficient increases gradually with the increasing of the (Agin) substitution fraction x, and the electrical conductivity of the compounds decreases with the increasing of x. Thermal conductivity decreases with the increasing of x. In all of the n-type (AgIn)xPb1-2xTe compounds, (AgIn)0.01Pb0.98Te compound has the greatest ZT value, reaching 1.1 at 800K.
BaCO3 whiskers exhibiting different morphologies were fabricated by a simple precipitation reaction of barium ch/oride with sodium carbonate in the absence and presence of poly-（styrene-alt-maleic acid） （PSMA） as ...
详细信息
BaCO3 whiskers exhibiting different morphologies were fabricated by a simple precipitation reaction of barium ch/oride with sodium carbonate in the absence and presence of poly-（styrene-alt-maleic acid） （PSMA） as a crystal growth modifier at room temperature. The as-prepared products were characterized by scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, and X-ray diffraction （XRD）. The influences of experimental parameters on the size and morphology of BaCO3 whiskers were investigated and discussed. It was found that the as-prepared BaCO3 whiskers are single crystals with diameter ranging from 100 to 300 run, and grow along the crystallographic a-axis or [100] direction. BaCO3 whiskers with different morphologies, such as branching and dendritic structure, can be obtained depending on the experimental conditions. With increasing PSMA concentration, the diameter of BaCO3 whiskers decreases.
Thermogravimetry (TG-DTA) was used to study the heat resistance characteristics and curing heat decomposition kinetics of ATPU/epoxy resin system. Results showed that the decomposition temperature of the cured ATPU-2/...
详细信息
Thermogravimetry (TG-DTA) was used to study the heat resistance characteristics and curing heat decomposition kinetics of ATPU/epoxy resin system. Results showed that the decomposition temperature of the cured ATPU-2/E-44 was higher than that of ATPU-1.5/E-44. The calculation results of decomposition reaction showed that the cured system of ATPU-2/E-44 had better heat resistance, the reaction decomposition active energy of ATPU-2/E-44 system was higher than that of ATPU-1.5/E-44.
A one-dimensional multi-layer heat conduction model of CRAM is developed based on its memory principle. According to the read/write requirement of memory cell, and to the condition of its thermal compatibility with CM...
详细信息
A one-dimensional multi-layer heat conduction model of CRAM is developed based on its memory principle. According to the read/write requirement of memory cell, and to the condition of its thermal compatibility with CMOS circuits, the critical parameters are fixed on. The temperature profiles are portrayed by solving the heat conduction equation with the reasonable boundary conditions. Under the limitation of the critical parameters, we adjust the parameters of cell structure, use heating layer, and then develop the structural model of CRAM memory cell which not only meet the need of read/write function of memory cell but for the first time achieve the thermal compatibility of CRAM memory cell with CMOS circuits.
The thermal shock resistance and anti- aluminum erosion of TiB2 - BN multiphase ceramics composites were studied. The experimental results show that the TiB2-BN multiphase ceramic possesses a good thermal shock resist...
详细信息
The thermal shock resistance and anti- aluminum erosion of TiB2 - BN multiphase ceramics composites were studied. The experimental results show that the TiB2-BN multiphase ceramic possesses a good thermal shock resistance at high temperatures （ 1000, 1200, 1400, 1500 ℃ ）, with the increasing in thermal shocking temperature, the electro-conductivity of TiB2-BN ceramics increases. The metal aluminum has a great influence on the properties of TiB2 - BN ceramics and the main reason is that the aluminum reacts seriously with BN. It is suggested that the content of BN should be reduced to the greatest extent.
Nanocrystalline WC-Co composite powder and coated tungsten diamond by using vacuum vapor deposition were consolidated by the spark plasma sintering （SPS） process to prepare diamond-enhanced WC-Co cemented carbide co...
详细信息
Nanocrystalline WC-Co composite powder and coated tungsten diamond by using vacuum vapor deposition were consolidated by the spark plasma sintering （SPS） process to prepare diamond-enhanced WC-Co cemented carbide composite materials. The interface microstructures between coated tungsten diamond and WC-Co cemented carbide matrix were investigated by scanning electron microscopy （SEM） and energy dispersive X-ray spectroscopy （EDXS）. The results showed that there is a transitional layer between the diamond and the matrix, in which the carbon content is 62.97wt.%, and the content of cobalt in the transitional zone is 6.19wt.%; the content of cobalt in the WC-Co cemented carbide matrix is 6.07wt.%, in which the carbon content is 15.95wt.%, and the content of cobalt on the surface of diamond is 7.30wt.%, in which the carbon content is 80.38wt.%. The transitional zone prevents the carbon atom of the diamond from spreading to the matrix, in which the carbon content does coincide with the theoretical value of the raw nanocomposite powders, and the carbon content forms a graded distribution among the matrix, transitional zone, and the surface of diamond; after the 1280℃ SPS consolidated process the diamond still maintains a very good crystal shape, the coated tungsten on the surface of the diamond improves thermal stability of the diamond and increases the bonding strength of the interface between the diamond and the matrix.
暂无评论