• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.114.1-114.1
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• 2010

A highly performed Pd-based hydrogen membrane has prepared successfully on a modified porous nickel support. The porous nickel support modified by impregnation method of $Al(NO_3)_3{\cdot}9H_2O$ (Aldrich Co.) over the nickel powder showed a strong resistance to hydrogen embrittlement and thermal stability. Plasma surface modification treatment was introduced as a pre-treatment process instead of conventional HCl wet activation. Ceramic barrier was coated on the external surface of the prepared nickel supports to prevent intermetallic diffusion and to enhance the affinity between the support and membrane. Palladium and copper were deposited at thicknesses of $4\mu}m$ and $0.5{\mu}m$, respectively, on a barrier-coated support by DC sputtering process. The permeation measurement was performed in pure hydrogen at $400^{\circ}C$. The single gas permeation of our membrane was two times higher than that of the previous membrane which do not have ceramic barrier.

• Bulletin of the Korean Chemical Society
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• v.27 no.9
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• pp.1323-1328
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• 2006

Mesoporous nickel intercalated aluminosilicate nanohybrid has been synthesized through a recombination reaction between the colloidal suspension of exfoliated montmorillonite nanosheets and aqueous nickel acetate solution. According to powder X-ray diffraction and field emission-scanning electron microscopic analyses, the intercalation of nickel species expands significantly the basal spacing of the host montmorillonite clay and the crystallites of the intercalation compound are assembled to form a house-of-card structure. $N_2$ adsorption-desorption isotherm measurements with BJH pore analyses clearly demonstrated that the porosity of the intercalate originates mainly from mesopores (diameter $\sim50\;\AA$) formed by the house-of-card type stacking of clay crystallites. From FT-IR and X-ray absorption spectroscopic analyses, it becomes certain that intercalated nickel ion is stabilized in an isolated $NiO_6$ octahedral unit. The present mesoporous intercalation compound is expected to be applicable as efficient catalysts or absorbents.

• Particle and aerosol research
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• v.10 no.4
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• pp.177-182
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• 2014

In this study, nickel-coated aluminum (Ni/Al) powders were synthesized for the utilization of energetic applications. Oxide materials present at the surface of Al powders of $45{\mu}m$ in averaged size were removed by using sodium hydroxide(NaOH) solution which is used for controlling pH. Nickel material is coated into the surface of oxide-removed Al powders by electroless-plating process. The microstructure of fabricated Ni/Al powders shows that nickel layers with a few hundreds nm were very homogeneously formed onto the surface of Al powders. The oxidation behavior of Ni/Al exihibit somewhat faster oxidation rate than that of pure Al with surface oxidation. Also, the higher exothermic reaction was observed from the Ni/Al powders. From the result of this, nickel coating is very promising method to obtain highly reactive and safe Al powders for energetic applications.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.2
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• pp.11-17
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• 2016

Powder metallurgy nickel based superalloy has been used in a high temperature part of turbine engine for airplane. The fatigue crack growth behavior was investigated using CT specimens for the materials at room temperature(R.T.), $600^{\circ}C$ and $700^{\circ}C$. The direct current potential drop(DCPD) method suggested by ASTM E647 was used to measure the crack length during fatigue crack growth at various stress ratios. The fatigue crack growth rate at R=0.5 was faster than that at R=0.1 for all temperature conditions and increased with the increase of stress ratio and temperature. Fractography was conducted for analysis of fracture mechanism.

• Journal of the Korean Electrochemical Society
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• v.11 no.2
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• pp.115-119
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• 2008

Single particle of nickel hydroxide and the surface-treated one with cobalt element were performed to review the effect of LiOH additive in alkaline electrolyte for Ni-MH batteries using microelectrode test system. As a result of cyclic voltammetry, the electrochemical behaviors such as the oxidation/reduction and oxygen evolution reaction are clearly observed for a single particle of nickel hydroxide, respectively. Furthermore, the reduction current peak of nickel hydroxide added with LiOH in electrolyte was very low and broad compared with the normal nickel hydroxide without an additive LiOH, which had a bad effect to the crystallization structure of nickel hydroxide. However, it was found that capacity and cycle properties of the nickel hydroxide treated with cobalt greatly increased by the addition of LiOH.

• Resources Recycling
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• v.17 no.2
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• pp.63-69
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• 2008

The adsorption features of $Ni^{2+}$ onto spent alkaline manganese batteries powder have been investigated with the adsorbent dose, initial concentration of adsorbate and temperature as the experimental variables. The adsorption reaction of $Ni^{2+}$ ion followed the pseudo-second order rate model, and the adsorption rate constants($k_2$) decreased with increasing initial concentration of nickel ion. The equilibrium adsorption data were fitted to the Langmuir and Freundlich models. The Freundlich model represents the equilibrium data better than the Langmuir model in this initial adsorbate concentration range. As the temperature increased, the adsorbed amount of nickel ion at equilibrium was also increased, which indicated that the adsorption reaction was endothermic. Based on the experimental results obtained along with temperatures, thermodynamic parameters such as ${\Delta}H^{\circ},\;{\Delta}G^{\circ},\;and\;{\Delta}S^{\circ}$ were calculated.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 1994.04c
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• pp.7-7
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• 1994

For more than a decade components of low alloy iron powder with nickel and/or molybdenum for general engineering applications have been manufactured from powder metal. In the time to come such PM steel components will gain increasing significance. Because of various manufacturing difficulties they are mostly produced in two separate steps - sintering and hardening - which means high energy and labour requirements. The paper describes how such PM components are produced in just one run through a conveyor belt furnace with automatic atmosphere control and gas quenching zone. Energy and labour costs are low and reproducible quality is exceilent. The mechanical properties obtained with some powder alloys are presented as well.

• Korean Chemical Engineering Research
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• v.54 no.3
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• pp.410-418
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• 2016

In this study, we prepared electrically conducting composites using epoxy resin of diglycidyl ether of bisphenol A (DGEBA) as a matrix, triethylenetetramine (TETA) as a hardener and nickel powder or multi-walled carbon nanotubes (MWCNTs) grafted with $-NH_2$ groups (MWCNT-$NH_2$) as electrically conducting fillers. Electrical conductivity of composite films were measured by coating on the slide glass with a doctor blade. We measured modification reactions of MWCNT and reaction of MWCNT-$NH_2$ with DGEBA epoxy resin by fourier transform infrared spectrometer (FTIR), thermogravimetric analyzer (TGA) and elemental analyzer (EA). Morphology of composites was investigated by scanning electron microscope (SEM) and sheet resistances of composites were measured by 4-point probe. We found $(9.87{\pm}1.09){\times}10^4{\Omega}/sq$ of sheet resistance for epoxy composite containing both 40 wt% nickel powder and 0.5 wt% of MWCNT-$NH_2$ as fillers, equivalent to epoxy composite containing 53.3 wt% nickel powder only as a filler.

• KIEE International Transactions on Electrophysics and Applications
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• v.4C no.2
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• pp.68-72
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• 2004

The performance of copper-tungsten for electrodes used in an ultra high voltage interruption system was evaluated by means of an interruption test, which requires a large-scale apparatus and high cost. In this study, prior to the interruption test, the characteristics of a Cu-W electrode were estimated through the DC arc test, which is a simple, low cost procedure. The DC arc characteristics of a 20wt%Cu-80wt%W electrode were investigated with the change of tungsten powder size distribution and the addition of nickel. In specimens containing a high volume fraction of large sized tungsten particles, the relative density and hardness of sintered Cu-W electrodes increased while the electrical conductivity and the DC arc resistance decreased. Furthermore, the relative density became enhanced with the increase of the amount of nickel while the hardness and electrical conductivity diminished and the DC arc resistance worsened.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.05a
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• pp.139-142
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• 2004

Nickel base superalloys are widely used for high temperature applications due to heat resisting capability and corrosion resistance at high temperatures. Superalloys with many strengthening alloying elements are frequently used in powder form to alleviate harmful effects of alloy segregation. HIP (hot isostatic pressing) and DB (diffusion bonding) as a form of solid-state bonding process is used to make turbine components, such as integrated turbine rotors. HIP/DB process requires many technical overcomes related to dimensional changes as well as microstructural control. In this research, HIP/DB process for nickel base superalloys, Udimet 720 and MM 247, were investigated with a view to control the dimensional change during the consolidation process. Simple disc-shaped cans were used to select the conceptual die design for the control of the dimensional change especially in radial direction. The change in the shape of consolidated shape was investigated using commercial FE code with constitutive equations fur low temperature plasticity deformation.