Papers by Keyword: Nickel

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Authors: Zhi Gang Wu
Abstract: Pure metallic nickel nanoparticles, spherical shape have been successfully synthesized by the chemical reduction of nickel chloride with hydrazine at room temperature without any protective agent and inert gas protection. X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) were employed to characterize the nickel nanoparticles and of course, the magnetic properties were also measured. This synthetic method is proven to be simple and very facile. And it’s very interesting that the obtained nickel nanoparticle can be isolated in solid states and stabilized for several months in atmosphere.
Authors: Zhao Han, Hong Min Zhu
Abstract: Nano-sized nickel powders were prepared through a wet chemical reduction, of NiCl2 by sodium in liquid ammonia at -45 °C, and a subsequent heat-treatment in vacuum at 300 °C. The prepared product was systematically characterized by X-ray diffraction (XRD), scan electron microscopy (SEM), transmission electron microscopy (TEM), and BET specific surface area measurement. The results show that the product was composed of nano-sized nickel particles, with average particle diameter of about 20 nm, and specific surface area of about 30 m2g-1. The possible formation mechanism of the nano-sized nickel powder was also discussed briefly.
Authors: S. Mehatab Nabi, N. Sagar Babu, Sujith Vijayan, Kuttan Prabhakaran
Abstract: A novel process for the preparation of a nickel foam from nickel oxide has been studied. The solid organic foam prepared by the thermo-foaming of a nickel oxide powder dispersion in molten sucrose is heat treated at the 1000 °C in an inert atmosphere to produce the nickel foam. The nickel foam produced has interconnected cellular structure with porosity ~ 94%.
Authors: O. Assowe, Olivier Politano, Vincent Vignal, Patrick Arnoux, B. Diawara
Abstract: The interaction of water molecules on a nickel surface was studied using ReaxFF (reactive force field) molecular dynamics. This approach was originally developed by van Duin et al. to study the hydrocarbon chemistry and the catalytic properties of organic compounds. To our knowledge, this method has not been used to study the corrosion processes of nickel exposed to water, which is what we set out to achieve in the present investigation. To do so, calculations were first performed using ReaxFF in order to reproduce certain well-known properties of pure nickel and nickel-water systems. This allowed us to study the adsorption of a single water molecule interacting with an optimized nickel surface. We also investigated the interaction of 405 molecules of water (ρ=0.99 on the (100), (110) and (111) surfaces of a single crystal of nickel at 300 K. The results show that a water bilayer is adsorbed on nickel surfaces: the first water layer is directly bonded to the surface, whereas the molecules in the first and second layers are held together by hydrogen bonds.
Authors: Supawan Vichaphund, Duangduen Atong
Abstract: This work aimed to investigate the effect of different sintering routes on properties of Ni-Al2O3 membrane. Alumina powder was mixed with 10 wt% nickel powder by dried ball-milling. Then, the mixture powder was uniaxially pressed to a bar shape and sintered via different sintering conditions. First route, the Ni-Al2O3 specimen was sintered at 1300°C for 2 h under air and then reduced at 900°C for 2 h under H2 atmosphere. Second route, the specimen was sintered at 1300°C for 2 h under argon. After sintering process, the physical and mechanical properties of membrane obtained from two routes were compared and discussed.
Authors: Zeng Wei Zhu, Dong Wang, Jian Hua Ren
Abstract: Spherical abrasives were employed to polish the growing deposited layer during nickel electroforming process. On a translational flat cathode, nickel deposits with distinct polishing mark were obtained. It was found that the abrasive polishing can help to improve the microstructure and increase the mechanical properties of the nickel deposits. Compared with the deposits prepared with traditional method, the microstructure became more homogeneous and the microhardness increased nearly two times. The increase of current density led to coarse structure and lower microhardness.
Authors: Dong Zhang
Abstract: The adsorption capability of porous nano-barium-strontium titanate by sorghum straw template method (SBST) for nickel in water was studied. The optimum experimental parameters for the adsorption and preconcentration of the nickel, such as pH, time, eluent and coexisting ion, have been investigated. The results showed that the nickel in water could be adsorbed on the SBST. The adsorbed quantitively was affected by the pH value of medium and time. In the medium of pH 5-8, the adsorption time was 20 min, and capacity of adsorption was 13.27 mg•g-1. The adsorbed nickel could be completely eluated using 2 mol•L-1 HNO3. The pre-concentration factor for nickel was more than 100. The method has been applied to the preconcentration and flame atomic absorption spectrometry determination of nickel in water samples. The recoveries were 92.0%-104.0%.
Authors: Farah Aimi Fuadi, Siti Nor Izuera Nor-Azemi, Syed Shatir A. Syed-Hassan
Abstract: Four types of biomass were characterized to investigate its metal adsorption capacity. The biomass were soaked in with nickel and cobalt solutions to examine the effect of biomass to amount of metal adsorbed. Oil palm mesocarp fibre (OPMF), empty fruit bunch (EFB), palm kernel shell (PKS) and sawdust were used in this study. Among all the biomass studied, oil palm mesocarp fibre shows the highest adsorption capacity with 1.8 mg/g and 1.6 mg/g of nickel and cobalt uptake, respectively. The metals adsorbed on the biomass were found to disperse into nanosize range.
Authors: A. Hürner, T. Schlegl, B. Adelmann, H. Mitlehner, R. Hellmann, A.J. Bauer, L. Frey
Abstract: In this study, we present the results of alloying nickel as ohmic contact material to n-type 4H-SiC via a continuous wave fiber laser with different laser beam powers and processing times. The laser system exhibits an emitting wavelength of 1070 nm and a beam propagation factor M2 smaller than 1.1. Contact resistance was determined by current-voltage measurement using the two-terminal contact resistance method. The results indicate that a laser beam power of at least 100 W is mandatory to initialize contact silicidation. Although the contact resistance is improvable by longer processing times, our experiments outline the much higher impact of laser beam power to contact silicidation compared with processing time. For laser beam powers of 300 W and processing times of 0.5 s a contact resistance of 6.5 , comparable to contacts alloyed in a lamp heated furnace at 910 °C for 2 min with a contact resistance of 10.3 , was achieved.
Authors: Chao Huang, Hong You Li, Hao Ping Zeng, Yu Ying Shi, Kai Yong Jiang
Abstract: An experimental study of bipolar pulse electroforming nickel is presented in this paper. Based on the principles of electric double layer and double diffusing layer, the advantages of pulse electroforming over direct current electroforming, bipolar pulse electroforming over single pulse and pulse-reverse current were explained in the view of microcosmic. The influence of major technological parameters on the process of electroforming was investigated. The experimental results indicate that the the quality and precision of the electroformed coating, as well as the mechanical properties of electroformed parts, can be improved, with the bipolar pulse power.
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