The temperature field of two types of porous graded ZrO2 subjected to thermal shock loading is analyzed in this paper using the finite‐element method. The numerical simulation results indicate that the structure of Z...
The temperature field of two types of porous graded ZrO2 subjected to thermal shock loading is analyzed in this paper using the finite‐element method. The numerical simulation results indicate that the structure of ZrO2 with an un‐symmetric porous microstructure is superior to symmetric one and that, ignoring the influence of temperature dependent properties, the effects of thermo‐mechanical coupling can be ignored if the imposed heat flux density is less than 4 WM/m2.
The air plasma spray (APS) technology was used to prepare WC/NiCrAl and WC/NiCrBSi ceramic/metal composite wear preventive coating on cast iron substrate. The microstructure, microhardness, bond strength and slurry we...
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The air plasma spray (APS) technology was used to prepare WC/NiCrAl and WC/NiCrBSi ceramic/metal composite wear preventive coating on cast iron substrate. The microstructure, microhardness, bond strength and slurry wear preventive performance of coating was measured. The results revealed that all of the coating prepared by APS has good qualities. The coating with NiCrBSi as its combining metal is better than that with NiCrAl on wear preventive performance, and coating containing more WC is supreme than that containing less WC Finally, wear mechanics and the principle of the coating's wear preventive property was concluded.
Transparent Fe-doped In2O3 thin film was prepared by sol-gel method on (general) glass substrate. The structure, morphologies, transmission and magnetic properties of the sample have been characterized by X-ray diffra...
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Transparent Fe-doped In2O3 thin film was prepared by sol-gel method on (general) glass substrate. The structure, morphologies, transmission and magnetic properties of the sample have been characterized by X-ray diffraction, field emission scanning electron microscopy, UV-Vis spectroscopy and vibrating sample magnetometer. XRD result indicated that the sample was single cubic In2O3 phase. FE-SEM clearly showed that the film was homogenous and composed of refining grain with an average size of 14 nm. UV-Vis spectrum indicated that the transmittance of the film was higher than 80% in the visible light, and the Fe-doped In2O3 film arose the optical absorption spectrum red shift. VSM demonstrated the sample was (room temperature ferromagnetic.
It is very difficult to prepare full-densified aluminum nitride-boron nitride （AIN/BN） composite ceramics with homogeneous microstructure and high thermal conductivity. Spark plasma sintering （SPS） was used to ful...
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It is very difficult to prepare full-densified aluminum nitride-boron nitride （AIN/BN） composite ceramics with homogeneous microstructure and high thermal conductivity. Spark plasma sintering （SPS） was used to fully densify the AIN/BN composites in this work. Microstructure, mechanical properties and thermal conductivity of the SPS sintered AIN/BN composites with 5-30 vol% BN were investigated. The results show that the microstructure of composites is fine and homogenous, and the AIN/BN composites exhibit high mechanical properties. To promote the growth of AIN grains and modify the distribution of grain boundary in AIN/BN composites, a heat treating methodology was introduced through gas pressure sintering （GPS）. This processing was significantly beneficial to enhancing the thermal conductivity of the specimen. The thermal conductivity of AIN/BN composites with 5-30 vol% BN reached 60 W/m K after the samples were treated by GPS.
Phase-based matching is a key technique for optical measurements using projected grating pattern analysis. The matching accuracy determines the final 3-D reconstruction accuracy. However, the reconstruction accuracy o...
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Phase-based matching is a key technique for optical measurements using projected grating pattern analysis. The matching accuracy determines the final 3-D reconstruction accuracy. However, the reconstruction accuracy of integer-pixel matching is relatively low. A sub-pixel matching algorithm was developed based on phase linear interpolation assuming a linear phase distribution between adjacent pixels. Simulation results indicate that the proposed sub-pixel matching algorithm improves the final 3-D reconstruction accuracy with high processing speed. Verification experiments show that the accuracy can reach 0.03 mm. A 3-D surface measurement system utilizing the sub-pixel matching algorithm can provide very high accuracy.
The precursor of M-type barium hexaferrite with iron excess, which the nominal composition was BaFe12.4O19.6, was prepared by a so-called co-dump coprecipitation method. The crystallization behavior of the precursor u...
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The precursor of M-type barium hexaferrite with iron excess, which the nominal composition was BaFe12.4O19.6, was prepared by a so-called co-dump coprecipitation method. The crystallization behavior of the precursor under the spark plasma sintering (SPS) conditions and the magnetic properties of the SPS samples were investigated. The results show that the samples obtained at 700-850°C were composed of single-phase M-type barium hexaferrite, and that the crystallization of intermediates such as BaFe2O4 and Y-Fe2O3 did not occur. The distribution of crystal grains obviously changed with the increase of temperature;the distribution was random at 700°C and became preferential orientation when the temperature was more than 700°C. The saturation magnetization significantly increased at 700°C and remained almost constant in the range of 750°C to 850°C. This accorded with the evolution characteristics of the phase composition of the SPS samples with the increase of temperature. The coercivity first increased and then decreased with the increase of the temperature, which was attributed to the corresponding increases in the content of M-type barium ferrite and the degree of preferential orientation of crystal grains.
Tin dioxide based ceramics doped with ZnO, Sb2O3 and ZnO-Sb2O3 were prepared by the pressureless sintering. The relative density (ρr) was measured by the Archimedes method, the resistivity (R) was measured by the van...
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Tin dioxide based ceramics doped with ZnO, Sb2O3 and ZnO-Sb2O3 were prepared by the pressureless sintering. The relative density (ρr) was measured by the Archimedes method, the resistivity (R) was measured by the van der Pauw method, and the mi-crostructure and crystal structure were measured by scanning electron microscope. Then the internal relationship between the material and structure were analyzed. The results indicate that ZnO can improve the sintering characteristics of the material;the ρr increases and then decreases with the increase of ZnO, and the optimal content of ZnO is 1.0% (mole fraction, the same below). However, the ρr decreases with the increase of Sb2O3;the R decreases at first, and then increases and decreases at last. The ρr and R of the material are good when Sb2O3 content is 0.5%. The SnO2 based ceramic doped with 1.0% ZnO-0.5% Sb2O3 and sintered at 1400°C has high performance;the ρr is 97% and the R is 0.1099 Ω·cm.
Ga dopping GaxPb1-xTe(x=0.01-0.05) compounds were prepared by melting reaction method, and the in-c fluence of Ga content on the thermoelectric properties were investigated. The results showed that temperature dopende...
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Ga dopping GaxPb1-xTe(x=0.01-0.05) compounds were prepared by melting reaction method, and the in-c fluence of Ga content on the thermoelectric properties were investigated. The results showed that temperature dopendent carrier concentration increased and the hall mobility decreased with increasing Ga content, which indicated that the carrier scattering mechanism gradually changed from an acoustical scattering to the interaction between an acoustical phone and an ionized impurity scattering as x increased. All samples show n-type conduct and the absolute Seebeck coefficient values and the electric conductivity increase significantly with increasing Ga content.
The layered perovskite-type organic-inorganic hybrids (CnH2n+1NH3)2 MnCl4 (n=2, 4, 6, 8, 10, 12) were synthesized in solution and their structures were characterized. The results showed that the structures of the prod...
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The layered perovskite-type organic-inorganic hybrids (CnH2n+1NH3)2 MnCl4 (n=2, 4, 6, 8, 10, 12) were synthesized in solution and their structures were characterized. The results showed that the structures of the products were independent on the reaction initial temperature. The X-ray diffraction (XRD) patterns and the scanning electron microscopy (SEM) images of the products demonstrated that the hybrids crystallize very well and had typical layered structures. The interlayer distance of each hybrid was obtained from the XRD patterns. It was linear dependent on the carbon atom number in the organic chain and the organic chains interdigitated between the two adjacent inorganic sheets.
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