C/BN laminated composites were obtained by hot-pressing, and the micro-structure and property of the sintered bodies were investigated. The results indicated that the relative density of the samples was 99%. SEM indic...
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C/BN laminated composites were obtained by hot-pressing, and the micro-structure and property of the sintered bodies were investigated. The results indicated that the relative density of the samples was 99%. SEM indicated that the combined interface between graphite and BN was good, and the transition of graphite and BN was gradual. The sintered bodies between the graphite and BN were destroyed at 1200°C after thermal shocks for 30 times. The tensile strength of materials reached 8.9 MPa.
C/BN laminated composites were obtained by spark plasma sintering. The relationship between sintering conditions, microstructure and properties were studied. The analysis of micro structure indicated that with increas...
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C/BN laminated composites were obtained by spark plasma sintering. The relationship between sintering conditions, microstructure and properties were studied. The analysis of micro structure indicated that with increasing the temperature and time of heat preservation the coalescent between graphite and BN was increased gradually. The bonding strength transformed from molecular gravitation to the union of molecular gravitation and mechanical strength. The circulation times of materials reached 40 times at sintering temperature of 1750°C for 5 min. The test of mechanical properties of the materials indicated that the largest tensile strength reached 18.2 MPa.
A single flat-plate Solid Oxide Fuel Cell (SOFC) with Ni-YSZ|YSZ|LSM configuration was developed, the test system and the fuel control system was established. The electrical properties were examined with H2 as the fue...
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A single flat-plate Solid Oxide Fuel Cell (SOFC) with Ni-YSZ|YSZ|LSM configuration was developed, the test system and the fuel control system was established. The electrical properties were examined with H2 as the fuel and the air as the oxidant in a temperature range of 800 to 1000°C. Results showed that the open-circuit voltage (OCV) was over 1.01 V, the maximum power density at 1000°C reached to 7.73 mW/cm2. It was found that the large ohmic losses of the electrolyte were the main factor responsible for the relative low output power density. The relations of OCV vs. operating temperature and OCV vs. fuel flow rates were also investigated.
By using of high temperature XRD data, the high temperature structure behavior of corundum (α-Al2O3) with different crystal morphologies was studied by comparative crystal chemistry. It was revealed that cell paramet...
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By using of high temperature XRD data, the high temperature structure behavior of corundum (α-Al2O3) with different crystal morphologies was studied by comparative crystal chemistry. It was revealed that cell parameter (a, c) and Al-O bond length (LAl-O) of grain corundum were logarithmically increased because of thermal expansion, but that of the whisker corundum was linearly increased. The crystal lattice coefficient of thermal expansion (M) of the grain corundum was logarithmically increased almost in uniformity tendency, which was isotropy. On the contrary, that of the whisker corundum was linearly increased in whole tendency, the value M of cell parameter (a) is greater than cell parameter (c), which was anisotropy.
The effect of particle morphology of α-Al2O3 on sintering property of its compact is investigated in this paper. The morphology of α-Al2O3 particles and its compact were studied by SEM and TEM, and line-shrinkage ra...
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The effect of particle morphology of α-Al2O3 on sintering property of its compact is investigated in this paper. The morphology of α-Al2O3 particles and its compact were studied by SEM and TEM, and line-shrinkage rate, density and water absorption rate were measured respectively. The results showed that the expansion of compact at elevated temperature brought harm to densification and formation of homogenous structure of the compact and the sintering property of compact was influenced by the morphology of α-Al2O3 particles in different degrees.
BaCO3 whiskers exhibiting different morphologies were fabricated by a simple precipitation reaction of barium chloride with sodium carbonate in the absence and presence of poly-（styrene-alt-maleic acid） （PSMA） as ...
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BaCO3 whiskers exhibiting different morphologies were fabricated by a simple precipitation reaction of barium chloride 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?nm,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.
SiCp/Al composites containing high volume fraction of SiC particles were fabricated by spark plasma sintering (SPS), and their thermophysical properties, such as thermal conductivity (TC) and coefficient of thermal ex...
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SiCp/Al composites containing high volume fraction of SiC particles were fabricated by spark plasma sintering (SPS), and their thermophysical properties, such as thermal conductivity (TC) and coefficient of thermal expansion (CTE), were characterized. High relative density (R-D) of composites was successfully achieved through the optimization of sintering parameters, such as sintering temperature, sintering pressure and heating rate. The measured TCs of SiCp/Al composites fabricated by SPS are higher than 195 W/m k, no matter the volume fraction of SiC particles is high or low as long as the R-D is higher than 95%. The measured CTEs of SiCp/Al composites are in good agreement with the estimated values based on Kerners model. The high volume fraction of SiCp/Al composites are a good candidate material to substitute for conventional thermal management materials in advanced electronic packages due to its tailorable thermophysical properties.
After combining the PVDF and BST powders with different particle sizes, the anti-voltage strengths of composites was tested. Although the concentrates of ceramic were all the same, their anti-voltage strengths were di...
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Permittivity and dielectric strength determine the energy storage density of a material. Although a composite can be molded easier, its lower energy storage density prevents the material from applications since the po...
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In the present study, the processing-properties relationships of the ZrO2/(Ni+Al2O) 3) composites are examined. Dense composites were prepared either by pulse electrical current sintering (PECS) at 1350C for 5 minutes...
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In the present study, the processing-properties relationships of the ZrO2/(Ni+Al2O) 3) composites are examined. Dense composites were prepared either by pulse electrical current sintering (PECS) at 1350C for 5 minutes or by pressureless sintering (PLS) at 1600C for 1 h. The size of Ni particles is as small as 30 nm to 50 nm. Though the size of ZrO2 grains in the matrix increases as alumina and nickel particles are added, the strength of the ZrO2/(Ni+Al2O3) composites is significantly higher than that of monolithic ZrO2.
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