Spark plasma sintering (SPS) and Self-propagating High-temperature synthesis/ quick pressing (SHS/QP) methods were used to fabricate nanotubes reinforced alumina. The difference in microstructure was discussed. In the...
Spark plasma sintering (SPS) and Self-propagating High-temperature synthesis/ quick pressing (SHS/QP) methods were used to fabricate nanotubes reinforced alumina. The difference in microstructure was discussed. In the SHS/QP process, the maximum densification temperature is 1660°C and the heating rate is about 1600°C /min. The whole densification process in SHS/QP is very short, which is much beneficial to protect the nanotubes and restrain the growing of grains. The fracture toughness of the sample prepared by SHS/QP is up to 4.9MPam½ for 1mass% CNTs/Al2O3 composites, which shows excellent toughening effects of nanotubes.
Novel CoCrFeNiTiAlx(x:molar ratio, other elements are equimolar) high-entropy alloys were prepared by vacuum arc melting and these alloys were subsequently annealed at 1000 °C for 2 h. The annealing effects on st...
Novel CoCrFeNiTiAlx(x:molar ratio, other elements are equimolar) high-entropy alloys were prepared by vacuum arc melting and these alloys were subsequently annealed at 1000 °C for 2 h. The annealing effects on structure and mechanical properties were investigated. Compared with the as-cast alloys, there are many complex intermetallic phases precipitated from the solid solution matrix in the as-annealed alloys with Al content lower than Al1.0. Only simple BCC solid solution structure appears in the as-annealed Al1.5 and Al2.0 alloys. This kind of alloys exhibit high resistance to anneal softening. Most as-annealed alloys possess even higher Visker hardness than the as-cast ones. The as-annealed Al0.5 alloys shows the highest compressive strength while the Al0 alloy exhibits the best ductility, which is about 2.6 GPa and 13%, respectively. The CoCrFeNiTiAlx high-entropy alloys possess integrated high temperature mechanical property as well.
The lyophilization method was used to enhance platinum (Pt) nanoparticle distribution on single-walled cabon nanotube (SWCNT). The results indicate that this method is very available to uniformly disperse nanotubes an...
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ISBN:
(纸本)9781424435432
The lyophilization method was used to enhance platinum (Pt) nanoparticle distribution on single-walled cabon nanotube (SWCNT). The results indicate that this method is very available to uniformly disperse nanotubes and effectively prevent Pt metal particles from agglomeration. The Platinum nanoparticle size ranging from 2 to 5 nm in diameter and uniformly deposited on SWCNT characterized by both transmission electron microscopy (TEM) and X-ray diffraction (XRD), instead, Pt/ SWCNT catalysts fabricated by drying method present a lower dispersion degree compared with that by lyophilization method. The as-prepared catalysts have higher electrochemical active surface area and higher ORR activity as compared to that by drying method characterized by cyclic voltammetry (CV) and oxygen reduction reaction (ORR).
We prepared a novel hybrid membrane by doping recast Nafion @ membrane with SiO 2 -CNTs composites where carbon nanotubes (CNTs) were decorated with SiO 2 nano-particles. SiO 2 -CNTs were prepared via sol-gel method...
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ISBN:
(纸本)9781424435432;9781424435449
We prepared a novel hybrid membrane by doping recast Nafion @ membrane with SiO 2 -CNTs composites where carbon nanotubes (CNTs) were decorated with SiO 2 nano-particles. SiO 2 -CNTs were prepared via sol-gel method, and then mixed with nafion resin through sonication. Hydrophilic SiO 2 nano-particles were chosed to increase the water uptake of hybrid membrane, and the CNTs were chosed to improve the mechanical property of hybrid membrane. A series of tests show that water uptake and thermal performance¿two key performance of proton exchange membrane (PEM) are improved.
In this paper, the effect of particle size on the dynamic behaviour and deformed microstructure in pure Al matrix composites reinforced with 30% ansd 40% volume fraction of 6, 13.5 and 50 μm SiC particles was investi...
In this paper, the effect of particle size on the dynamic behaviour and deformed microstructure in pure Al matrix composites reinforced with 30% ansd 40% volume fraction of 6, 13.5 and 50 μm SiC particles was investigated by using split Hopkinson pressure bar (SHPB). Firstly, the dynamic compressive stress-strain curves of SiCp/Al composites with 3 different particle sizes were obtained and the effect of the particle size on the stress-strain relationship was studied by a comparison analysis. Furthermore, the microstructure characteristics after the impact were observed by the scanning electron microscopy(SEM). The microstructure of SiCp/Al composites with 3 different particle sizes after the impact was compared. The results have demonstrated that the dynamic mechanical behaviour and the microstructure after the impact strongly depends on the particle size. The cracked particles and debonding are more readily observed in the composites reinforced with large particles than those in the composites with small particles.
Highly ordered TiO 2 nanotube arrays prepared by electrochemical anodization gets considerable interest as a practical air purifier, since the nanotube arrays can form a TiO 2 film with a porous surface and straight...
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ISBN:
(纸本)9781424435432;9781424435449
Highly ordered TiO 2 nanotube arrays prepared by electrochemical anodization gets considerable interest as a practical air purifier, since the nanotube arrays can form a TiO 2 film with a porous surface and straight gas diffusion channel. Here, we investigate photocatalytic decompositions of HCHO over TiO 2 and Ag/TiO 2 nanotube arrays. Compared with the pure TiO 2 nanotube arrays with similar thickness and geometric area, the results showed that Ag loading TiO 2 nanotube arrays within a certain range could significantly improve the degradation rate of HCHO, the main product of HCHO degradation was detected to be CO 2 .
Bulk heterojunction polymer solar cells, based on thin films of polymer/fullerene blends, have progressed rapidly during the past few years. Efficiencies over 6% have been achieved in research labs. In this chapter, a...
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Silver nanoparticles were prepared by pulsed wire discharge (PWD) using silver wire in deionized water at various relative energy (K) from 10 to 98, which is ratio of the charged energy of the capacitor in the electri...
Silver nanoparticles were prepared by pulsed wire discharge (PWD) using silver wire in deionized water at various relative energy (K) from 10 to 98, which is ratio of the charged energy of the capacitor in the electrical circuit to the vaporization energy of the wire. From energy deposition calculated by the measured voltage and current waveforms, deposited energy of the wire was increased with increasing K. From X-ray diffraction (XRD) analysis, prepared nanoparticles were phase identified as silver. From transmission electron microscopy observations, the shape of prepared silver nanoparticles were spherical and the median particle diameter (D50) and the geometric standard deviation (σg) were calculated from the particle distribution. D50 was decreased from 34 to 19 nm with increasing K. The particle size in prepared by PWD in liquid media can be controlled by K.
A novel method based on radio frequency magnetron sputtering tailored to the deposition of low residual stress and adherent c-BN thin films on silicon substrates was developed. In this study, the effect of noble gas (...
A novel method based on radio frequency magnetron sputtering tailored to the deposition of low residual stress and adherent c-BN thin films on silicon substrates was developed. In this study, the effect of noble gas (Kr, Ar, Ne and He) added in Ar gas during sputtering on the residual stress and the c-BN content has been investigated. As a result, it was found that the residual stress of c-BN thin film decreased with increasing the helium gas flow rate within argon gas.
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