• Transactions of Materials Processing
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• v.22 no.8
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• pp.470-476
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• 2013

The aim of the current study was to predict shape recovery behavior of Ni-Ti shape memory alloy (SMA) wire after loading-unloading and after wire drawing. The superelasticity of SMA was analyzed by a hyper-elastic model for the Mullins effect using ABAQUS. Firstly, tensile tests and loading-unloading tests of the Ni-Ti SMA wire with a diameter 1.0 mm were performed using an MTS servo-hydraulic tester. The parameters for the Mullins effect were computed by ABAQUS based on curve-fitting of the loading-unloading test data. The proposed FE-model predicted the shape recovery of Ni-Ti SMA after wire drawing. Finally, the effectiveness of the model was verified by drawing experiments. The wire drawing experiments using the Ni-Ti SMA were conducted on a drawing machine(1ton, 50mm/s). In order to evaluate the shape recovery of Ni-Ti SMA, the drawn wires are annealed for 30min at $450^{\circ}C$.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.10a
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• pp.139-141
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• 2003

Multiple CeO$_2$/YSZ/Y$_2$O$_3$buffer layers, and subsequent YBCO films were deposited on the biaxially textured pure Ni and Ni ＋ 3at％W substrates using pulsed laser deposition. The deposition conditions of buffer layers on Ni and NiW were studied and compared. Good biaxial textures of buffer layers have been obtained on both substrates. The Jc's of YBCO films on these metal substrates were greater than 1$\times$10$^{6}$ A/$\textrm{cm}^2$ at 77K, 0T.

• Proceedings of the KIEE Conference
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• 1996.11a
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• pp.224-226
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• 1996

The purpose of this study is to research and develop $Li_xNi_{2-x}O_2$ cathode for lithium rechargeable battery. We investigated XRD, cyclic voltammetry, AC impedance response and charge/discharge cycling of $Li_xNi_{2-x}O_2$/Li cells. The cell resistance was decreased much at initial charge process from 100% SOC to 0% SOC. The discharge capacity based on $Li_xNi_{2-x}O_2$ of 1st and 15th cycles was 135mAh/g and 108mAh/g, respectively. The $Li_xNi_{2-x}O_2$/Li cell had a good properties.

• Resources Recycling
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• v.7 no.1
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• pp.27-33
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• 1998

A study on thc recovcry oi nickel from waste pickling solutions removed li-ee nil~ica cid and hydmflnoric acid is carried out with pulsed column extractor for thc industrial application. The ~esults show that thc Iron and chromium arc efteclively elunmatcd from the waste solution by precipitalion as the form of hydraxidc with thc adjustment of pH with CaCO;, whlle the nickel is not prcc~pitatcd. Thc cxlraction eficicncy ol nickel with column cxtraclor generally improves 8s the pulse velosity (product of amplmde and frequency) incrcascs, optimum pcrfarmancc typically occuring slightly below an amplihldefrecluency product which results in flooding the column because of excessive emulsiIicalian And the nickel loaded in the organic is erfeclively conce~~trtratebdy ZM H2S0,, ~ I It he stlipping stage. The solubility of NiSO, in the H,SO, solution dccreaaes w~th thc higher H,SO, concentralion and appears to be 55 grL in the 2M HSO* solulian.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.1069-1072
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• 2003

Germane-sillicide phase formation on S $i_{0.25}$G $e_{0.75}$ with Ni 100$\square$, Co 10$\square$/Ni 100$\square$ and Ni 50$\square$/Co 10$\square$/Ni 50$\square$ layer was studied by sheet resistance and Field Emission Scanning Electron Microscopy(FESEM). Thermal stability of nickel germane-silicide is found to be improved by sputtering Ni/Co/Ni on the SiGe. After annealing at 600, 650, $700^{\circ}C$, 30min., the nickel germane-silicide formed by Ni 50$\square$/Co 10$\square$/Ni 50$\square$ layer achieved a sheet resistance less than 17ohms/sq.(almost the same to the value before furnace annealing for 30min.) , while the process of the other two ways result in high sheet resistance and even sheet resistance fail due to Ge segregation.ion.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.28-29
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• 2006

The magnetic properties of a series of both annealed and as-rolled Ni-$W_y$ alloy tapes with compositions y = 0, 1, 3, and 5 at.%, were studied. To compare with Ni-W alloys, the magnetic properties of a series of both annealed and as-rolled $[Ni_{97at.%}W_{3at.%}]_{100-x}Cu_x$ alloy tapes with compositions x = 0, 1, 3, 5 and 7 at.%, were studied, as well. Both the isothermal mass magnetization M(H) of a series of samples, such as both Ni-W and [Ni-W]-Cu alloy tapes, at different fixed temperatures and M(T) in fixed field, were measured using a PPMS-9 (Quantum Design). The degree of ferromagnetism of Ni-$W_y$ alloys have reduced as W-content y increases. Both the saturation magnetization $M_{sat}$ and Curie temperature $T_c$ decrease linearly with W-content y, and both $M_{sat}$ and $T_c$ go to zero at critical concentration of $y_c$ ~ 9.50 at.% W. The effect of Cu addition on both the saturation magnetization $M_sat$ and Curie temperature $T_c$ decrease linearly with Cu-content x in $[Ni_{97at.%}W_{3at.%}]_{100-x}Cu_x$ alloy tapes with compositions x = 0, 1, 3, 5, and 7 at.%. The results confirm that [Ni-W]-Cu alloy tapes can have much reduced ferromagnetism as Cu-content x increases.

• Journal of the Korean Society for Heat Treatment
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• v.20 no.1
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• pp.11-16
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• 2007

The fatigue properties of Ti-Ni shape memory alloy wires were investigated. In Ni-rich Ti-Ni shape memory alloys, $Ti_3Ni_4$ precipitates formed by aging treatments are believed to vary the shape memory and mechanical properties. In this study, the effect of aging temperature and aging time on shape memory properties and fatigue life were investigated using Ti-50.9 at% Ni alloy wires. The specimens were solution-treated at 1073 K for 3.6 ks followed by aging at 573 K, 673 K and 773 K for periods between 3.6 ks and 3600 ks. It was found that the fatigue life under a constant stress decreased with increasing aging temperature. When the specimens were aged at 573 K for periods between 36 ks and 360 ks, superior shape memory and fatigue properties were obtained. The fatigue life also decreased when the test temperature and strain amplitude increased. It was concluded that the fatigue life exhibited a linear relationship with the critical stress for slip.

• Journal of the Korean Ceramic Society
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• v.39 no.12
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• pp.1119-1123
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• 2002

Nanostructured spinel NiZn ferrites were prepared by the sol-gel method from metal nitrate raw materials. Analyses by X-ray diffraction and scanning electron microscopy showed the average particle size of NiZn ferrite was under 50 nm. The single phase of NiZn ferrites was obtained by firing at 250${\circ}C$, resulting in nanoparticles exhibiting normal ferrimagnetic behavior. The nanostructured $Ni_{1-X}Zn_XFe_2O_4$ (x=0.0∼1.0) were found to have the cubic spinel structure of which the lattice constants ${\alpha}_2$ increases linearly from 8.339 to 8.427 ${\AA}$ with increasing Zn content x, following Vegard's law, approximately. The saturation magnetization $M_s$ was 48 emu/g for x=0.4 and decreased to 8.0 emu/g for higher Zn contents suggesting the typical ferrimagnetism in mixed spinel ferrites. Pure NiZn ferrite phase substituted by Cu was observed before using the additive but hematite phase was partially appeared at $Ni_{0.2}Zn_{0.2}Cu_{0.6}Fe_2O_4$. On the other hand, the hematite phase in this NiZn Cu ferrite was disappeared after using the additive of acethyl aceton with small amount. The saturation magnetization Ms of $Ni_{0.2}Zn_{0.8-y}Cu_yFe_2O_4$(y=0.2∼0.6) as measured was about 51 emu/g at 77K and 19 emu/g at room temperature, respectively.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.953-954
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• 2006

Ti-Cu-Ni-Sn quaternary amorphous alloys of $Ti_{50}Cu_{32}Ni_{15}Sn_3$, $Ti_{50}Cu_{25}Ni_{20}Sn_5$, and $Ti_{50}Cu_{23}Ni_{20}Sn_7$ composition were prepared by mechanical alloying in a planetary high-energy ball-mill (AGO-2). The amorphization of all three alloys was found to set in after milling at 300rpm speed for 2h. A complete amorphization was observed for $Ti_{50}Cu_{32}Ni_{15}Sn_3$ and $Ti_{50}Cu_{25}Ni_{20}Sn_5$ after 30h and 20h of milling, respectively. Differential scanning calorimetry analyses revealed that the thermal stability increased in the order of $Ti_{50}Cu_{32}Ni_{15}Sn_3$, $Ti_{50}Cu_{25}Ni_{20}Sn_5$, and $Ti_{50}Cu_{23}Ni_{20}Sn_7$.

• Korean Journal of Materials Research
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• v.9 no.6
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• pp.622-629
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• 1999

Effects of the fluorination in the $K_2$TiF\ulcorner solution and in-situ KF+ KOH electrolyte on the electrochemical charge-discharge properties of CaNi\ulcorner and the Mg-CaNi\ulcorner electrodes were investigated. In-situ fluorination in the KF+ KOH electrolyte compared with pre-fluorination in the$ K_2$TiF\ulcorner solution could improve the electrochemical cycling durability of CaNi\ulcorner and MG-CaN\ulcorner electrodes. The fluorinated layer on the alloy surface by pre-fluorination to improve the activity and anti-corrosion of the electrodes was dissolved in the pure KOH electrolyte during the cycling. The fluorinated layer was formed continuously on the surface of the electrode by thee2N KF addition in the 6N KOH electrolyte. The excess F\ulcorner ion addition in KOH electrolyte could improve the electrochemical cycling durability of CaNi\ulcorner and Mg-CaNi\ulcorner electrode. But, in case of MG-CaNi\ulcorner electrode, the discharge capacity of the electrode was reduced and the poor cycling property was shown with increasing of the MG process times.