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 small punch creep (SP-C) test technique is a new method which is applied to evaluate the high temperature creep properties of materials by using miniature specimen. In the present paper, the Finite Element Method ...
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Polypyrrole-coated V 2 O 5 nanotubes hybrid materials have been synthesized through an in situ polymerization of pyrrole monomers in the presence of prepared V 2 O 5 nanotubes. The hybrids were characterized by scan...
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ISBN:
(纸本)9781424435432;9781424435449
Polypyrrole-coated V 2 O 5 nanotubes hybrid materials have been synthesized through an in situ polymerization of pyrrole monomers in the presence of prepared V 2 O 5 nanotubes. The hybrids were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Experimental data showed that polypyrrole was uniformly coated on the surface of the V 2 O 5 nanotubes, and the polypyrrole coating is 30 nm thick. Gas sensing tests showed that the hybrids possessed very high sensitivity to ethanol gas at room temperature, implying its potential application for gas sensors.
The MoxV3−xO7/MWNTs nanocomposites were fabricated via a hydrothermal reaction followed by self-assembling process. The nanocomposites were characterized in terms of surface morphology and structure by FESEM, TEM, XRD...
The MoxV3−xO7/MWNTs nanocomposites were fabricated via a hydrothermal reaction followed by self-assembling process. The nanocomposites were characterized in terms of surface morphology and structure by FESEM, TEM, XRD and XPS analysis, respectively. The electrochemical behaviors of the nanocomposites were investigated by galvanostatic charge-discharge test and cyclic voltammetry. The results showed that MoxV3−xO7/MWNTs nanocomposites had great cycleability as well as capacity characteristics, which was 277.4 mAh/g in the first discharge process and remained 207.9 mAh/g after fiftieth discharge cycle. In the rapid charge-discharge test, the capacity rate still remained 88.6 % after twentieth cycles at 1.2 C discharge.
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.
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.
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 .
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