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...
详细信息
The paper presents results on the mechanism of spark plasma sintering (SPS). First, the temperature distribution in the sample and the die in SPS were studied. Under certain conditions, the difference may reach a few ...
详细信息
ISBN:
(纸本)0470081562
The paper presents results on the mechanism of spark plasma sintering (SPS). First, the temperature distribution in the sample and the die in SPS were studied. Under certain conditions, the difference may reach a few hundreds of degrees of centigrade. Controlling of processing parameters can decrease the temperature difference. Second, the process of atomic diffusion due to the effect of the current was also studied. It was found that the atomic diffusion is enhanced at the interface between specimens in the SPS relative to hot pressing (HP). Third, we have utilized the SPS process to form transparent ceramics, porous metals and ceramics, and to effect welding of alloys.
In situ reaction method was undertaken to fabricate A1N-BN composites in this paper. Factors including temperature, heat preservation time, and the ratio of Al to BN were investigated in this system. DTA and XRD were ...
详细信息
In situ reaction method was undertaken to fabricate A1N-BN composites in this paper. Factors including temperature, heat preservation time, and the ratio of Al to BN were investigated in this system. DTA and XRD were employed to character the phases of production. SEM was conducted to observe the microstructure of the samples. The results showed that the grains tended to perfect with the increasing of the sintering temperature and soaking time. Optimum parameters were temperature of 1000°C and 1.5 h for soaking time.
AlN was synthesized by in situ reaction with Al and BN in this paper. AlN-BN composites were fabricated by hot-pressed sintering without additives. The relationship between the ratio of Al to BN and microstructure and...
详细信息
AlN was synthesized by in situ reaction with Al and BN in this paper. AlN-BN composites were fabricated by hot-pressed sintering without additives. The relationship between the ratio of Al to BN and microstructure and properties were studied. The results show that the content of AlN increases with the ratio of Al to BN increasing, and the density, hardness, bending strength, thermal conductivity and dielectric constant also increase with the ratio of Al to BN increasing. The results show that the samples with thermal conductivity 63.5 W/m·K and dielectric constant 8.76 are acquired by hot-pressed sintering under nitrogen atmosphere and two hours soaking time.
Aluminum borate whisker with TiB2 as borate source was prepared in this paper. The phase transformation process and whisker growth mechanism were analyzed. The results indicate that TiB2 is oxidized by active [O] rele...
详细信息
Aluminum borate whisker with TiB2 as borate source was prepared in this paper. The phase transformation process and whisker growth mechanism were analyzed. The results indicate that TiB2 is oxidized by active [O] released from the decomposition of (NH4)2SO4. B2O3 released from TiB2 oxidation provide borate source for whisker growing. Al/B ratio has influence on whisker morphology. Surplus B2O3 is needed during aluminum borate whisker growth because liquid B2O3 is a medium to transport Al2O3 to the tiny whisker nearby.
High-energy ball mill method was used to treat the stainless steel powder;the effects of treat parameters (ball-raw materials rate, treatment time) on the microstructure and phase composite were studied. X- ray diffra...
详细信息
High-energy ball mill method was used to treat the stainless steel powder;the effects of treat parameters (ball-raw materials rate, treatment time) on the microstructure and phase composite were studied. X- ray diffraction, SEM and the BET method were used to evaluate the microstructure of treated samples. The results showed that with increasing in ball mill time, the particle size of stainless steel powder decreases obviously;surface features of powder were changed significantly. X-ray diffraction calculation results showed that the particle size of stainless steel powder have been 28 nm after 120 h ball mill treatment, the BET analysis results agree with the X-ray diffraction calculation results.
Cobalt-rich filled skutterudite compounds CeyFexCo4-xSb12 (y=0-0.42) are synthesized using the melting-diffusion method. The structure and thermoelectric properties of the compounds are investigated. Results indicate ...
详细信息
Cobalt-rich filled skutterudite compounds CeyFexCo4-xSb12 (y=0-0.42) are synthesized using the melting-diffusion method. The structure and thermoelectric properties of the compounds are investigated. Results indicate that the lattice constants increase linearly with the Ce filling fraction. Hall coefficient is positive. Hole concentration and electrical conductivity decreased as the Ce filling fraction increases. Seebeck coefficient increase with the Ce filling fraction. The lattice thermal conductivity reached the minimum value when the Ce filling fraction was about 0.29, indicating that the effect of Ce rattling on phonon scattering is the strongest as Sb-dodecahedron partial voids are filled by Ce. A maximum ZT value of 0.65 is obtained for Ce0.29Fe1.41Co2.59Sb12.32 at 725 K.
The nanostructure of the ball milled FeNi particles were characterized as functions of the ball milling time (t) using quantitative X-ray diffraction (XRD), high resolution transmission electronic microscopy (HRTEM) a...
详细信息
The nanostructure of the ball milled FeNi particles were characterized as functions of the ball milling time (t) using quantitative X-ray diffraction (XRD), high resolution transmission electronic microscopy (HRTEM) analysis techniques. The results showed that the nanocrystalline bcc FeNi particles were availab.e using carbonyl iron and nickel powders as the raw materials during the high-energy ball milling. After 10 h ball milling, the alloy of carbonyl iron and carbonyl nickel began to form, and the sample kept its original bcc and fcc structure;after 100 h ball milling, the sample became a solid solution with bcc structure;after 200 h ball milling, the diffraction peak of Ni almost disappeared and the isotropic grains with Dmin achieved, which was mainly attributed to the dislocations of the nanocrystalline bcc FeNi suffering from severe plastic deformation by ball milling.
The α-Fe fibers were prepared successfully by the method of electrodepositing in porous alumina template. The results indicated that the diameter of the fibers was 300 nm and the length of them increased along with t...
详细信息
The α-Fe fibers were prepared successfully by the method of electrodepositing in porous alumina template. The results indicated that the diameter of the fibers was 300 nm and the length of them increased along with the electrodepositing time increasing. The saturation magnetization per m2 of the iron fibers increased with the increasing of the length/diameter ratio, but the coercive field decreased.
This research is that cellulose/poly-silicate hybrid material was prepared with viscose and poly-silicate by sol-gel method. The influence of aluminum salt and poly-silicate on hybrid material thermal property was stu...
详细信息
This research is that cellulose/poly-silicate hybrid material was prepared with viscose and poly-silicate by sol-gel method. The influence of aluminum salt and poly-silicate on hybrid material thermal property was studied. Based on the analysis of the DSC and TG curve of hybrid material, we have found that the hybrid material has splendid heat-resistance and fire retardancy.
暂无评论