Nanocomposite WC-10Co powder produced by spray pyrolysis-continuous reduction & carbonization technology and cubic boron nitride (CBN) plated with titanium by vacuum vapor deposit were used, and this paper adopted...
详细信息
Nanocomposite WC-10Co powder produced by spray pyrolysis-continuous reduction & carbonization technology and cubic boron nitride (CBN) plated with titanium by vacuum vapor deposit were used, and this paper adopted spark plasma sintering (SPS) process to prepare CBN enhanced ultrafine WC-10Co cemented carbide cermets composite material. The microstructure and mechanical properties of CBN-WC-10Co composites were investigated. The results show that CBN-WC-10Co composites consolidated by spark plasma sintering can reach 95.0 % relative density, and transverse rupture strength (TRS) is 1050 MPa, the average grain size of cermets matrix is less than 420 nm, and CBN-WC-10Co composites with excellent properties are achieved. The CBN still remains very good crystal shape after 1240°C spark plasma sintering, and there is not obvious clearance between CBN plated with titanium and the cermets matrix, the coated titanium layer can not only improve the thermal stability of CBN, but also increase the properties of CBN-WC-10Co composites.
Three-dimension reconstruction from serial sections has been used in the last decade to obtain information concerning three-dimensional microstructural ge-ometry. One of the crucial steps of three-dimension reconstruc...
详细信息
Three-dimension reconstruction from serial sections has been used in the last decade to obtain information concerning three-dimensional microstructural ge-ometry. One of the crucial steps of three-dimension reconstruction is getting compact and fairing grain contours. Based on the achievement of closed raw con-tours of ceramic composite grains by using wavelet and level set, an adaptive method is adopted for the polygonal approximation of the digitized raw contours. Instead of setting a fixed length of support region in advance, the novel method computes the suitable length of support region for each point to find the best es-timated curvature. The dominant points are identified as the points with local maximum estimated curvatures. Periodic closed B-spline approximation is used to find the most compact B-spline grain boundary contours within the given tolerance. A flexible distance selection approach is adopted to obtain the common knot vector of serial contours consisting of less knots that contain enough degrees of freedom to guarantee the existence of a B-spline curve interpolating each contour. Finally, a B-spline surface interpolating the serial contours is generated via B-spline surface skinning.
A novel method was used to fabricate AlN coating on graphite substrate. This approach included two steps： firstly, the emulsion composed of BN and anhydrous ethanol was sprayed on the surface of the graphite substrat...
详细信息
A novel method was used to fabricate AlN coating on graphite substrate. This approach included two steps： firstly, the emulsion composed of BN and anhydrous ethanol was sprayed on the surface of the graphite substrate; secondly, AlN coating was formed through the in-situ reaction of Al with the sprayed BN. The reaction was investigated by thermogravimetric-differential thermal analysis （TG-DTA）, and the phase composition in the synthetic process was characterized by X-ray diffraction （XRD）. Scanning electronic microscopy （SEM） was used to observe the morphology, and electron probe microanalysis （EPMA） was used to observe the distribution of the elements. The experimental results show that the AlN coating is dense and bonded with graphite tightly.
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...
详细信息
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.
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.
As one of the advanced functional inorganic power materials, nanometer ZnO has extensive application fields. The specific surface area is considered to be a big factors for its application. In this paper, the gas adso...
详细信息
As one of the advanced functional inorganic power materials, nanometer ZnO has extensive application fields. The specific surface area is considered to be a big factors for its application. In this paper, the gas adsorption method was adopted to measure ZnO specific surface area, and the influences of different testing conditions on the results were studied. It was found that optimal testing condition is that sample weight, degas temperature and degas time are 0.3-0.5g, 250°C, 2h respectively.
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.
In this paper nano-crystalline binary Skutterudite compound CoSb3 was synthesized by ethanol sol-gel process for the first time. The starting reagents were CoCl2·6H2O, SbCl3, solvent of ethanol and complexin...
详细信息
In this paper nano-crystalline binary Skutterudite compound CoSb3 was synthesized by ethanol sol-gel process for the first time. The starting reagents were CoCl2·6H2O, SbCl3, solvent of ethanol and complexing agent of citric acid. After obtaining sol-gel, the dry gel was grinded and reduced at tube furnace. The results indicate that CoSb3 compound powder with about 30 nm was obtained through reduction processing under 300 to 600°C while flowing pure hydrogen and with proper moral ratios of Sb/Co and C6H8O7/Co.
(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.
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.
暂无评论