• Journal of the Korean Ceramic Society
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• v.23 no.2
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• pp.43-49
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• 1986

By simple substitution of divalent cobalt nickel copper ion in the calcium-fluorapatite the ability to produce color was explored. To determine the solubility limit of cobalt nickel copper in the calcium-fluorapatite and the absorption spectrum with the addition of each transition elements XRD and visible range Spectroscopy were emp-loyed.

• Journal of Magnetics
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• v.10 no.3
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• pp.118-121
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• 2005

We have investigated the magnetic properties of electroplated thin Cu/Co multilayers by using electrolytes made of copper sulphate and cobalt sulphate and by applying alternating plating voltage. While the multilayers plated with pure electrolyte showed superparamagnetism, those plated with organic additives showed ferromagnetic behavior. These changes are attributed to the so-called 'self-annealing' effect and reduction of grain size caused by the organic additives.

• Resources Recycling
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• v.14 no.6 s.68
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• pp.16-20
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• 2005

The selective sulphide precipitation of copper from sulphate solution containing nickel and cobalt was studied with adding $Na_{2}S$ solution. Precipitation efficiency of copper increased with raising pH of solution and increasing the amount of $Na_{2}S$ added and lowing its concentration. The increase in reaction time and temperature also improved the precipitation of copper. However, attempts to selectively precipitate copper met with limited success because of co-precipitation of nickel and cobalt. With adding $20\%$ $Na_{2}S$, 3 times equivalent of Cu, at pH 1.0 of solution, $25^{\circ}C$ and 30 minutes of reaction time, precipitation efficiencies of copper, nickel and cobalt were $94.1\%$, $4.3\%$ and $4.5\%$ respectively.

• Journal of the Korean Chemical Society
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• v.32 no.2
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• pp.122-129
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• 1988

The rates of aquation of sparteine cobalt(II) halide and sparteine copper(II) halide were investigated in the citrate buffer solutions. The aquation of cobalt(II) complexes proceeds via D-mechanism and the catalytic effect of halide ions is not observed. The aquation of copper(II) complexes proceeds via $I_d$-mechanism and is catalyzed by the presence of cyanide and halide ions, and the aquation rate is pH dependent. The different mechanistic behavior of cobalt(II) complexes from corresponding copper(II) complexes seems to be attributed to the weakness of Co-N bond in the coordination sphere.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2006.11a
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• pp.14-20
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• 2006

During the 11 year period of 1995-2005, there was about a 40% increase in the world copper demand mainly because of the Asian economic growth. In the increase, about a half was consumed by China. Most of the China's copper demand increase has been taken place over the final 5-6 years of that period. The growth is expected to continue for several years, and in 10 years or sooner the same situation is expected for India. Copper is the third metal in global demand, but its little abundance in the Earth's crust is not well recognized. From the production rate and the abundance, a copper shortage, or crisis, has a high probability than the other metals. Deep ocean mineral resources such as manganese nodules in the Clarion-Clipperton Fracture Zones, Kuroko-type massive seafloor sulfides (SMS), and cobalt-rich manganese crusts in the EEZ and the high sea areas have big potentials for the future sources. We need to re-evaluate their potentials as copper resources and other metals to realize their developments. The same situation is under progress in the hydro-carbon markets. Methane hydrates that are classified into non-conventional hydro-carbon resources have an important role as the future sources, too.

• Nutrition Research and Practice
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• v.2 no.4
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• pp.317-321
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• 2008

Macrophages play a key role in iron metabolism by recycling iron through erythrophagocytosis. Ferroportin-l (FPN1) is a transporter protein that is known to mediate iron export from macrophages. Since divalent metals often interact with iron metabolism, we examined if divalent metals could regulate the expression of FPN1 in macrophages. J774 macrophage cells were treated with copper, manganese, zinc, or cobalt at 10, 50, or $100\;{\mu}M$ for 16 to 24 h. Then, FPN1 mRNA and protein levels were determined by quantitative real-time PCR and Western blot analyses, respectively. In addition, effects of divalent metals on FPN1 promoter activity were examined by luciferase reporter assays. Results showed that copper significantly increased FPN1 mRNA levels in a dose-dependent manner. The copper-induced expression of FPN1 mRNA was associated with a corresponding increase in FPN1 protein levels. Also, copper directly stimulated the activity of FPN1 promoter-driven reporter construct. In contrast, manganese and zinc had no effect on the FPN1 gene expression in J774 cells. Interestingly, cobalt treatment in J774 cells decreased FPN1 protein levels without affecting FPN1 mRNA levels. In conclusion, our study results demonstrate that divalent metals differentially regulate FPN1 expression in macrophages and indicate a potential interaction of divalent metals with the FPN1-mediated iron export in macrophages.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.140-140
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• 2018

The 3D interconnect technologies have been appeared, as the density of Integrated Circuit (IC) devices increases. Through Silicon Via (TSV) process is an important technology in the 3D interconnect technologies. And the process is used to form a vertically electrical connection through silicon dies. This TSV process has some advantages that short length of interconnection, high interconnection density, low electrical resistance, and low power consumption. Because of these advantages, TSVs could improve the device performance higher. The fabrication process of TSV has several steps such as TSV etching, insulator deposition, seed layer deposition, metallization, planarization, and assembly. Among them, TSV metallization (i.e. TSV filling) was core process in the fabrication process of TSV because TSV metallization determines the performance and reliability of the TSV interconnect. TSVs were commonly filled with metals by using the simple electrochemical deposition method. However, since the aspect ratio of TSVs was become a higher, it was easy to occur voids and copper filling of TSVs became more difficult. Using some additives like an accelerator, suppressor and leveler for the void-free filling of TSVs, deposition rate of bottom could be fast whereas deposition of side walls could be inhibited. The suppressor was adsorbed surface of via easily because of its higher molecular weight than the accelerator. However, for high aspect ratio TSV fillers, the growth of the top of via can be accelerated because the suppressor is replaced by an accelerator. The substitution of the accelerator and the suppressor caused the side wall growth and defect generation. The suppressor was used as Single additive electrodeposition of TSV to overcome the constraints. At the electrochemical deposition of high aspect ratio of TSVs, the suppressor as single additive could effectively suppress the growth of the top surface and the void-free bottom-up filling became possible. Generally, copper was used to fill TSVs since its low resistivity could reduce the RC delay of the interconnection. However, because of the large Coefficients of Thermal Expansion (CTE) mismatch between silicon and copper, stress was induced to the silicon around the TSVs at the annealing process. The Keep Out Zone (KOZ), the stressed area in the silicon, could affect carrier mobility and could cause degradation of the device performance. Cobalt can be used as an alternative material because the CTE of cobalt was lower than that of copper. Therefore, using cobalt could reduce KOZ and improve device performance. In this study, high-aspect ratio TSVs were filled with cobalt using the electrochemical deposition. And the filling performance was enhanced by using the suppressor as single additive. Electrochemical analysis explains the effect of suppressor in the cobalt filling bath and the effect of filling behavior at condition such as current type was investigated.

• 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.

• The Journal of Korean Academy of Prosthodontics
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• v.27 no.1
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• pp.143-179
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• 1989

To observe the bonding behavior of palladium-based alloys to porcelain; 1. Pd-Co binary alloy with the higher cobalt content, 2. Pd-Co binary alloy with the lower cobalt content, 3. Pd-Ag-Sn ternary alloy, 4. Pd-Ag binary alloy, 5. Pd-Cu-Au ternary alloy and 6. Pd-Cu binary alloy were made as 6 groups of experimental alloys. Each group of alloy was divided into 4 sub-groups such as one sub-group that was not degassed and three sub-groups that degassed for 5 minutes, 10 minutes and 15 minutes. On each specimen, weight changes after degassing, morphological changes of oxide layer by changing the degassing time, compositional changes at metal-ceramic interface and bond strength of metal-ceramic measured with planar shear test were observed and compared. The results of the present study allow the following conclusions to be drawn: 1. The alloy showing the greatest bond strength was Pd-Cu alloy without gold and bond strength was decreased by alloying gold to them. 2. Although Pd-Co alloy showed the most prominent oxidation behavior, bond strength of them to porcelain was not greatly high by the formation of porosities at metal-ceramic interfaces. 3. Likewise tin, cobalt formed the peaks on line profiles at metal-ceramic interface, however copper did not exhibit such peaks on line profiles. 4. Mainly, oxide layer on Pd-Co alloy was composed with cobalt, and for Pd-Co alloy with higher cobalt content the rise of bond strength was not significant by increased degassing time. 5. On Pd-Ag alloy not containing tin, during degassing for 15 minutes silver content was increased at metal-ceramic interface. 6. As an oxidized element, tin formed the oxide layers that widen their area by increasing the degassing time, while cobalt and copper showed the morphological changes of particle or crystal on oxide layer.

• Resources Recycling
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• v.30 no.2
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• pp.53-60
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• 2021

Leaching experiments from single metal and metallic mixtures were conducted to develop a process for the recovery of cobalt, copper, and nickel in spent lithium ion batteries. Inorganic and organic acid solutions without oxidizing agents were employed. No copper was dissolved in the absence of an oxidizing agent in the leaching solutions. The leaching condition to completely dissolve single metal of cobalt and nickel was determined based on acid concentration, reaction temperature and time, and pulp density. The leaching condition to dissolve all of cobalt and nickel from the metallic mixtures was also obtained. Leaching of the metallic mixture with methanesulfonic acid led to selective dissolution of cobalt at low temperatures.