• Transactions of the Korean hydrogen and new energy society
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• v.2 no.1
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• pp.15-21
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• 1990

Nickel-hydrogen battery systems with metal hydride alloys are expected to have both higher energy density and lower pollution than nickel-cadmium cells. Nickel-hydrogen storage cells are expected to be well-suited for use in space crafts for a large capacity power storage system. Their major advantages are not only a capability of deep DOD(depth of discharge) using but also with excellent durability under excessive overcharging and overdischarging. In this study, the charge/discharge capacities, anodic polarization characteristics and durability for the continious charge/diacharge cycling of the $Ti_{1-X}Zr_XVNi$ and $Ti_{1-X}Zr_XV_{0.5}Ni_{1.5}$ alloys were measured by electrochemical method. The electrode properties of the copper or nickel plated $Ti_{1-X}Zr_XV_{0.5}Ni_{1.5}$ alloys were examined with a battery charge/discharge testing system in the temperature range of -5 to $25^{\circ}C$.

• Korean Journal of Materials Research
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• v.20 no.11
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• pp.592-599
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• 2010

A porous nickel-tin nano-dendritic electrode, for use as the anode in a rechargeable lithium battery, has been prepared by using an electrochemical deposition process. The adjustment of the complexing agent content in the deposition bath enabled the nickel-tin alloys to have specific stoichiometries while the amount of acid, as a dynamic template for micro-porous structure, was limited to a certain amount to prevent its undesirable side reaction with the complexing agent. The ratios of nickel to tin in the electro-deposits were nearly identical to the ratios of nickel ion to tin ion in the deposition bath; the particle changed from spherical to dendritic shape according to the tin content in the deposits. The nickel to tin ratio and the dendritic structure were quite uniform throughout the thickness of the deposits. The resulting nickel-tin alloy was reversibly lithiated and delithiated as an anode in rechargeable lithium battery. Furthermore, the resulting anode showed much more stable cycling performance up to 50 cycles, as compared to that resulting from dense electro-deposit with the same atomic composition and from tin electrodeposit with a similar porous structure. From the results, it is expected that highly-porous nickel-tin alloys presented in this work could provide a promising option for the high performance anode materials for rechargeable lithium batteries.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2017.10a
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• pp.359-360
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• 2017

• The Journal of Korean Academy of Prosthodontics
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• v.30 no.2
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• pp.155-166
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• 1992

In dentistry, precious metal alloys are, mainly due to economic factors, increasingly displaced by alternatives containing Ni-Cr-Co. There are some reports where hypersensitive reactions to Ni-Cr-Co alloys are presented and discussed. The reactions reported vary from mucosa contact stomatitis to generalized dermatitis without any oral mucosal reaction. The purpose of this study was to investigate the incidence of nickel, chrome, cobalt and copper, and to know whether subjects with positive skin reaction to nickel would also demonstrate adverse intraoral reaction to a non-precious metal nickel. The patch tests were performed in 81 subjects(male 39, female 42) and nickel sulfate 5% aq., potassium bichromate 0.5% at., cobalt chloride 2% aq., & copper sulfate 1% aq., were used for test allergens. And then the intraoral tests were performed in 16 subjects, 8 subjects with positive allergic skin reaction to nickel and 8 subjects with negative allergic skin reaction. A pure metallic nickel plate was attached to the buccal side of the upper second premolar. The results are as follows : 1. The frequency of nickel sensitivity was 9.9% (2 men, 6 women), cobalt was 4.9% (1 man, 3 women), and chrome was 2.5% (2 men) respectively and there was no positive reaction to copper 2. The positive reactions were 8 of 23 (34.8%) with a history of jewelry allergic reactions and 3 of 58 (5.1%) without a history of jewelry allergic reactions. 3. Three of 8 subjects with positive skin reaction. gave reactions to the metal plates.

• Journal of the Korean institute of surface engineering
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• v.20 no.1
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• pp.4-14
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• 1987

The nickel-zinc alloy depositions have been studied in nickel chloride added chloride baths, to find out the effects of ultrasonic irradiation for the electrodeposition processes. The compositions of deposited alloys, the current efficiencies and the metallographic appearances in various conditions of Electrodeposition were investigated, in the range of ultrasonic irradiation of 50,500 and 1,000 Kc/s respectively. The results obtained are as follows; 1. Generally the nickel deposition process is more preferably activated than that of zinc by the ultrasonic irradiation. 2. The radios of nickel to zinc in the deposit are higher according to increase of nickel ion concentration and bath temperatures in irradiated baths. 3. The current efficiencies are also higher in the irradiated baths, so that the depolarization effect is noticeable. 4. The brightness and leveling effect of the deposits are appreciably better in the irradiated baths than in non-irradiated in 0.3M and 0.6M of nickel chloride and zinc chloride solutions and the current density of 3A/$dm^2$. 5. The mechanism of alloy deposition has been tentatively suggested in the case of ultrasonic irradiation.

• Journal of Technologic Dentistry
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• v.33 no.2
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• pp.121-128
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• 2011

Purpose: The purpose of this study is to investigate the level of each metal in non-precious metal alloys dental casting, still used even banned for use and trade by the law, for oral health. Methods: Two kinds of metal alloys were analyzed. One was Ticonium 100 for removable prosthesis and the other was Rexillium V for dental porcelain. Two samples of each metal alloy were made in 0.5g, 1.0g, and 1.5g. Total number of samples were 12. Two kinds of lactic acid Solution, pH7 and pH4.6, were injected into each samples. After injection, each samples had been for 21days ${\pm}$ 1 hour in the water tank of which temperature was $37^{\circ}C$. The level of metal was measured in each sample by inductively couplled plasma-atomic emission spectrometer. Results: In both metal alloys, metals, chrome, nickel, beryllium, and molybdenum, were founded. In Ticonium 1000, the highest level of nickel was 2.531ppm in 1.5g pH4.6 sample while the highest level of nickel was 4.062ppm in 1.5g pH4.6 sample of Rexillium V. In chemical composition of these methal alloys, chrome(14~17%) was much more than beryllium(1.95~1.99%) and molybdenum(5.0~9.0%) but berllium and molybdenum were founded more than chrome in samples. Therefore, chrome showed better anti-corrosion than other metal alloys. In both metal alloys, more metals were founded in higher pH level and more mass. Levels of chrome was significantly different in samples of both metal alloys in each pH level(p<0.05). Levels of nickels was significantly different in samples of both metal alloys in each pH level(p<0.05). Conclusion: For oral health, further studies are needed in nickel-chrome metal alloy and cobalt metal alloy of non-beryllium in addittion to beryllium metal alloy and also long-term studies needed in various period and other non-percious metal alloys for dental casting.

• Journal of the Korean institute of surface engineering
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• v.47 no.5
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• pp.215-220
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• 2014

Electrodeposition behaviors of Pd-Ni alloys were investigated from the polarization curves in a solution containing ethylenediamine as complexing agent. The microstructure and hardness of electrodeposited Pd-Ni alloys were also characterized. Codeposition of Pd-Ni alloys was successfully performed in the wide current density ranging from 2 to $5000A{\cdot}m^{-2}$ because the deposition potential of Pd became close to that of Ni in the ethylenediamine-contained solution. It was also found from X-ray diffraction patterns that the solid solution between Pd and Ni was formed with variation of the composition of alloys. The measured hardness of Pd-Ni alloys increased with increasing the contents of Ni due to solid solution strengthening and grain refinement. The electrodeposited Pd-Ni alloys also exhibited a crack free smooth surface morphology from the SEM observation.

• Journal of Technologic Dentistry
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• v.32 no.3
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• pp.195-207
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• 2010

Purpose: The purpose of this study was to observe the microstructural changes of surface in the specimens, performing the shear bond strength testing. The currently most used non-precious alloys are nickel-chromium based alloys with or without beryllium. However, their biocompatibility has been questioned concerning possible damages to the health of the patient and professionals involved in the fabrication of prosthesis caused by long exposure to Ni and Be. An option to nickel-chromium alloys is the cobalt-chromium alloy, an alternative that does not sacrifice the physical properties of the metal porcelain systems. Studies in the animals substantially show that the cobalt-chromium alloys are relatively well tolerated, being therefore more biocompatible than the nickel-chromium alloys. Methods: Non-addition Be to nickel-chromium based alloy(Bellabond plus) and cobalt-chromium alloy which has been widely used(Wirobond C) fused with ZEO light porcelain classified control group and cobalt-chromium alloy which is developing alloy of Alphadent company in Korea(Alphadent alloy) fused with ZEO light porcelain classified experimental group. The specimens of $4mm{\times}4mm{\times}0.5mm$ were prepared as-cast and as-opaque to cast body to analyze the mechanical characteristic change, the microstructure of alloy surface. The phase change was used to observe through XRD analysis and OM/SEM was used to observe the surface of specimens as-cast and as-opaque to cast body. Chemical formation of their elements was measured with EDS. Then hardness was measured with Micro Vicker's hardness tester. Shear bond strength test thirty specimens of $10mm{\times}10mm{\times}2mm$ was prepared, veneered, 3mm high and 3mm in diameter, over the alloy specimens. The shear bond strength test was performed in a universal testing machine(UTM) with a cross head speed of 0.5mm/min. Ultimate shear bond strength data were analyzed with one-way ANOVA and the Scheffe's test (P<0.05). Within the limits of this study, the following conclusions were drawn: The X-ray diffraction analysis results for the as-cast and as-opaque specimens showed that the major relative intensity of Bellabond plus alloy were changed smaller than Wirobond C and Alphadent Co-Cr based alloys. Results: Microstructural analysis results for the opaque specimens showed all the alloys increased carbides and precipitation(PPT). Alphadent Co-Cr based alloy showed the carbides of lamellar type. The Vickers hardness results for the opaque specimens showed Wirobond C and Alphadent Co-Cr based alloys were increaser than before ascast, but Bellabond plus alloy relatively decreased. The mean shear bond strengths (MPa) were: 33.11 for Wirobond C/ZEO light; 25.00 for Alphadent Co-Cr alloy/ZEO light; 18.02 for Bellabond plus/ZEO light. Conclusion: The mean shear bond strengths for Co-Cr and Ni-Cr based alloy were significantly different. But the all groups showed metal-metal oxide modes in shear bond strengths test at the interface.

• The Korea Journal of Herbology
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• v.21 no.2
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• pp.121-127
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• 2006

Objectives : Nickel is a major metal used in the nickel-chromium alloys of most orthodontic appliances, partial denture and implants. This study was carried out for the examination of the cytotoxicity on nickel sulfide in cultured NIH3T3 fibroblasts, and poncirin effect on nickel-induced cytotoxicity. Methods : Cell viability for the MTT assay and cell adhesion activity for the XTT assay. Results : The $IC_{50}$ of nickel sulfide by the MTT assay was $93.7\;{\mu}M$. Poncirin was significantly increased the cell viability and cell adhesion activity. Conclusion : Nickel was highly toxic and poncirin has the inhibitory effects against nickel induced cytotoxicity.

• Nuclear Engineering and Technology
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• v.55 no.3
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• pp.895-901
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• 2023

Oxide-dispersion- strengthened nickel alloys with Hf additions are expected to present high temperature mechanical properties and durable helium resistance based on first-principles density functional theory (DFT) calculations. Energetic and charge density evaluations of the helium behaviors were performed in Ni matrix, Y₂Hf₂O₇ oxide and the oxide/matrix interface. With the presence of coherent Y₂Hf₂O₇ in Ni matrix, chances of helium bubbles in Ni can be greatly diminished. The helium atoms shall occupy the interfacial site initially, then diffuse into in the octahedral sites of Y₂Hf₂O₇, and these oxide-captured He atoms prefer to separate individually. Much higher diffusion barrier of He in Y₂Hf₂O₇ than in nickel is related to the strong hybridization between interstitial He-1s and nearest-neighboring O-2p orbitals.