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991.
992.
K. Takagi T. Kobayashi H. Ohkita T. Mizushima N. Kakuta A. Abe K. Yoshida 《Catalysis Today》1998,45(1-4):123-127
Ag/Al2O3 catalysts prepared from boehmite needles (ca. 10 nm×100 nm), which were formed by a hydrolysis of aluminium tri-isopropoxide (AIP), showed good performances for selective catalytic reduction of NOx compared with the previously reported catalysts [N. Aoyama, K. Yoshida, A. Abe, T. Miyadera, Catal. Lett. 43 (1997) 249], especially when ethanol is employed as a reducing agent in the presence of water. Temperature programmed reduction (TPR) study revealed that the Ag species are attractively interacted with the alumina surface and the oxidized Ag species contribute positively for the improvement of the catalytic activity at the temperatures above 750 K. It is concluded that the boehmite needles as a precursor of alumina support are useful to create the catalytically active sites for NOx reduction. 相似文献
993.
994.
结构Al合金海洋环境腐蚀监测技术 总被引:2,自引:1,他引:1
根据结构Al合金在海洋环境中的腐蚀特点对现有的电化学和其它腐蚀测量技术进行了评价,着重介绍了利用荧光基化学传感材料进行结构Al合金的海洋环境腐蚀监测的方法,对荧光化合物传感材料的腐蚀监测原理与应用进行了论述. 相似文献
995.
Rods made of continuous carbon fibers are being extensively used as structural materials in light weight micro-air vehicles owing to their excellent specific modulus and strength. Further, they possess excellent tribological characteristics – low friction and wear coupled with high conductivity making them an ideal reinforcement in developing light weight, high strength aluminum based metal matrix composites. In the last three decades, researchers have focused mainly on the study of mechanical and tribological behavior of discontinuous carbon fiber reinforced metal matrix composites. However, no information is available regarding the tribological behavior of carbon fibers rod reinforced metal matrix composites, although it is interesting and will result in expanding the applications of metal matrix composites (MMC) where tribological failures are expected.In the light of the above, the present work focuses on development of innovative Al6061–carbon fiber rods composites by casting route and assessing their tribological characteristics. Carbon fiber rods of 4 mm and 6 mm diameters were surface sensitized to achieve electro less nickel coating. Copper plating on the electro less nickel coated carbon fiber rods were carried out. The copper plated carbon fiber rods were arranged in cylindrical array in the metallic mold to which molten Al6061 alloy after degassing was poured at a temperature of 700 °C. The developed innovative composites were subjected to density tests, microstructure studies, hardness, friction and wear tests. A pin on disk configuration was used with hardened steel as the counter face. Load was varied from 20 N to 60 N while the sliding velocity was varied between 0.12 m/s and 0.62 m/s. Scanning electron microscopy (SEM) studies on worn surfaces and wear debris have been carried out to validate the wear mechanism. The developed innovative composites (11 Vol.% & 25 Vol.%) have exhibited lower coefficient of friction and wear rates when compared with matrix alloy. 相似文献
996.
997.
John S. Wang Ping LiuElena Sherman Mark VerbruggeHarshad Tataria 《Journal of power sources》2011,196(20):8714-8718
Increasing the thickness of a battery electrode without comprising cell electrochemical performance, such as power density and cycling stability, is very challenging. In this work, we demonstrate the utility of 3D (three dimensional) Cu foam framework as a current collector for building carbon negative electrodes as thick as 1.2 mm. When tested in a bipolar configuration, electrodes of 1.2 and 0.6 mm thick delivered capacities of over 350 mAh g−1 (>95% of theoretical capacity) up to a C/5 rate. We have also assembled a full cell composed of a 1.2 mm thick negative electrode with Cu foam as the current collector and a 1.2 mm thick L333 (LiNi1/3Mn1/3Co1/3O2) positive electrode with Al foam as the current collector. The cell exhibited good capacity retention at low rates. These results underscore the promise of 3D foam structures in terms of enabling ultra-thick electrodes for high energy density battery applications. 相似文献
998.
Tayfun Soysal 《Science & Technology of Welding & Joining》2013,18(6):559-565
ABSTRACTThe susceptibility to solidification cracking was predicted for aluminium welds of 2024 Al made with filler metals 2319, 4043 and 4145 Al and of 6061 Al made with filler metals 4043 (traditional) and 4943 Al (new, higher strength). The maximum |dT/d(fS)1/2| (T: temperature; fS: fraction of solid) was used as the crack susceptibility index. In each case, the index was calculated using the weld metal composition based on the measured dilution level. The predicted crack susceptibility decreased in the order of 2319 Al, 4043 Al and 4145 Al for 2024 Al, and was similar between 4043 Al and 4943 Al for 6061 Al. These predictions agreed well with the experimental results of recent crack susceptibility tests of these welds. 相似文献
999.
The corrosion of aluminum alloy AlSi8Cu3Fe(Zn) in ethanol and ethanol solutions containing 10 vol.% water and 10 vol.% acetic acid, respectively, was investigated by means of electrochemical impedance spectroscopy (EIS), polarization curve, immersion, optical microscopy, scanning electron microscopy and element mapping. The Al alloy in the ethanol and its solutions exhibited a capacitive loop in the measured Nyquist EIS spectra at high frequencies, which can be attributed to the ethanol’s dielectric response. Addition of 10 vol.% acetic acid increased the ethanol corrosivity more significantly than the same amount of water addition. The Al–Si–Cu–Mg precipitated zones in the alloy were susceptible to corrosion attack due to the micro-galvanic effect by the Cu-containing precipitates. 相似文献
1000.
《Science & Technology of Welding & Joining》2013,18(6):561-566
AbstractThe isolation coupling device is designed based on the principle of high pass filter circuit, which can achieve isolation and coupling between ac welding power and ultrasonic frequency excitation source. In addition, ac arc ultrasonic vibration is obtained successfully. The plasma arc in situ welding of SiCp/6061Al was performed using two different processes. The first process is that the plasma gas is argon nitrogen mixture and the filler material is flux cored wire (Al–5Ti–5Si); the other process is that the plasma gas is argon and the filler material is flux cored wire (Al–15Ti–3Si). The two joints are respectively enhanced by nitride and Al3Ti, which were obtained in these processes. After arc ultrasonic vibrations were imposed on the two welding processes, it was revealed that arc ultrasonic improved the distribution of the new nitride phases and optimised the morphology of Al3Ti to improve the mechanical properties of joints that reached 246 and 263 MPa. Fracture analysis showed that the improvement of the mechanical properties resulting from Al3Ti is better than that from nitride under the effect of arc ultrasonic. 相似文献