• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.270-274
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• 2001

With Increasing importance of electroless nickel plating technology in many fields such as electronic and automobile industries, the treatment of the spent baths is becoming a serious problem. These spent baths contain iron and zinc as impurities, organic acids as complexing reagents, and phosphonate ions as oxidized species of tile reducing reagent. as well as several grams per liter of nickel. The spent baths are currently treated by conventional precipitation method. but a mettled with no sludge generation is desired. This work aims at establishing a recycling process of nickel from tile spent baths using solvent extraction. Extraction behaviors of nickel. iron. and zinc in various 쇼pes of real spent baths are investigated as a function of pH using LIX841, di (2-ethylhexyl)phosphoric acid (D2EHPA), and PC88A as tile extractants. Nickel is extracted by LIX84I at the equilibrium pH of more than 6 with high efficiency. For the weakly acid baths. iron and zinc are extracted by D2EHPA or PC88A without adjusting the pH of the baths leaving nickel in the aqueous phase. Stripping of nickel from LIX84I with sulfuric acid is also investigated. It is shown that concentrated nickel sulfate solution (> 100 ㎏-Ni/㎥) is obtained. This solution can be reused in the electroless plating process. Based on these findings, flow sheets for recovering nickel from the spent baths are proposed.

• 한국분말재료학회지
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• 제27권6호
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• pp.464-467
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• 2020

Nickel nanopowders are obtained by the spark discharge method, which is based on the evaporation of the electrode surface under the action of the discharge current, followed by vapor condensation and the formation of nanoparticles. Nickel electrodes with a purity of 99.99% are used to synthesize the nickel nanoparticles in the setup. Nitrogen is used as the carrier gas with a purity of 99.998%. XRD, TEM, and EDX analyses of the nanopowders are performed. Moreover, HRTEM images with measured interplanar spacings are obtained. In the nickel nanopowder samples, a phase of approximately 90 wt% with an expanded crystal lattice of 6.5% on average is found. The results indicate an unusual process of nickel nanoparticle formation when the spark discharge method is employed.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.276.2-276.2
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• 2016

Dye-sensitized solar cells (DSCs) are promising candidates for light-to-energy conversion devices due to their low-cost, easy fabrication and relative high conversion efficiency. An important component of DSCs is counter electrode (CE) collect electrons from external circuit and reduct I3- to I-. The conventional CEs are thermally decomposed Pt on fluorine-doped tin oxide (FTO) glass substrates, which have shown excellent performance and stability. However, Pt is not suitable in terms of cost effect. In this report, we demonstrated that nickel sulfide thin films by atomic layer deposition (ALD)-using Nickel(1-dimethylamino-2-methyl-2-butanolate)2 and hydrogen sulfide at low temperatures of $90-200^{\circ}C$-could be good CEs in DSCs. Notably, ALD allows the thin films to grow with good reproducibility, precise thickness control and excellent conformality at the angstrom or monolayer level. The nickel sulfide films were characterized using X-ray photoelectron spectroscopy, scanning electron microscopy, X-ray diffraction, hall measurements and cyclic voltammetry. The ALD grown nickel sulfide thin films showed high catalytic activity for the reduction of I3- to I- in DSC. The DSCs with the ALD-grown nickel sulfide thin films as CEs showed the solar cell efficiency of 7.12% which is comparable to that of the DSC with conventional Pt coated counter electrode (7.63%).

• Molecular & Cellular Toxicology
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• 제1권2호
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• pp.73-77
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• 2005

Nickel is the one of potent environmental, the occupational pollutants and the classified human carcinogens. It is a serious hazard to human health, when the metal exposure. To prevent human diseases from the heavy metals, it is seemingly important that understanding of how nickel exerts their toxicity and carcinogenic effect at a molecular and a genomic level. The process of nickel absorption has been demonstrated as phagocytosis, iron channel and diffusion. Uptaked nickel has been suggested to induce carcinogenesis via two pathways, a direct DNA damaging pathway and an indirect DNA damaging pathway. The former was originated from the ability of metal to generate Reactive Oxygen Species (ROS) and the reactive intermediates to interact with DNA directly. Ni-generated ROS or Nickel itself, interacts with DNAs and histones to cause DNA damage and chromosomal abnormality. The latter was originated from an indirect DNA damage via inhibition of DNA repair, or condensation and methylation of DNA. Cells have ability to protect from the genotoxic stresses by changing gene expression. Microarray analysis of the cells treated with nickel or nickel compounds, show the specific altered gene expression profile. For example, HIF-I (Hypoxia-Inducible Factor I) and p53 were well known as transcription factors, which are upregulated in response to stress and activated by both soluble and insoluble nickel compounds. The induction of these important transcription factors exert potent selective pressure and leading to cell transformation. Genes of metallothionein and family of heat shock proteins which have been known to play role in protection and damage control, were also induced by nickel treatment. These gene expressions may give us a clue to understand of the carcinogenesis mechanism of nickel. Further discussions on molecular and genomic, are need in order to understand the specific mechanism of nickel toxicity and carcinogenicity.

• 대한기계학회논문집A
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• 제31권1호
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• pp.50-54
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• 2007

Nickel nano and microstructures are fabricated with simple process. The fabrication process consists of nickel deposition, lithography, nickel ion etching and plasma ashing. Well-aligned nickel nanowalls and nickel self-encapsulated microchannels were fabricated. We found that the ion etching condition as a key fabrication process of nickel nanowalls and self-encapsulated microchannels, i.e., 40 sccm Ar flow, 550 W RF power, 15 mTorr working pressure, and $20^{\circ}C$ water cooled platen without using He backside cooling unit and with using it, respectively. We present the experimental results and discuss the formational conditions and the effect of nickel redeposition on the fabrication of nickel nano and microstructures.

• 한국표면공학회지
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• 제28권2호
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• pp.92-100
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• 1995

To increase the capacity of positive electrode materials for matching the high capacity negative electrode materials in alkaline rechargeable batteries, high-density nickel hydroxide powders were made through a continuous process from nickel sulfate reacted with ammonia and sodium hydroxidc. The effect of operating conditions on structure, shape, size distribution, apparent density and tap density of powders were investigated. Crystal structure of nickel hydroxide powder was hcp according to Bravais Lattice. The increase of mean residence time promoted the growth of (101) plane. The shape of powder was nearly spherical. Their size was in the range of $2~50\mu\textrm{m}$. The size distribution of the powders prepared was narrower than that of commercially obtained nickel hydroxide. Apparent density and tap density were 1.6~1.7g/cc and 2.0~2.1g/cc, respectively.

• 한국표면공학회지
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• 제19권3호
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• pp.109-120
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• 1986

The electroless nickel plating on high alumina ceramics was performed in the bath containing nickel chloride, sodium hypophosphite and mono- or bi-carboxylic acid as a complexing agent in order to examine the empirical rate law as well as the effects of the complexing agent, plating temperature and pH on the rate of deposition. Adding the carboxylic acid to the plating bath, the rate of deposition was increased considerably, and each of the complexing agents showed a maximum deposition rate plateau around a particular concentration of the complexing agent. The rate of deposition was increased with increasing either temperature or pH, but microstructure of the surface became more rough. Furthermore, empirical rate law of the elecltroless nickel deposition on high alumina ceramics was discussed with the activation energy and other rate parameters calculated.

• 한국표면공학회지
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• 제20권1호
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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.

• 한국표면공학회지
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• 제18권4호
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• pp.153-163
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• 1985

In the electroless nickel plating bath which contained nickel sulfate, sodium hypophosphite, boric acid and triethanolamine, effect of their concentration on the rate of deposition was tested by gravimetric method and polarization method. The polarization method that polarize small range of voltage anodicaly and cathodicaly at the mixed potential in the electroless plating bath can calculate mixed current (depositing rate) from $i_{mp}=\frac {i}{\eta}\;\frac{RT}{nF}\;or\;i_{mp}=\frac{i}{\eta}\;\frac{1}{2.3}(\frac{b_a\;\;b_c}{b_c+b_a})$ Where $i_{mp}$ is the depositing current, i is the polarized current, ${\eta}$ is the polarized voltage, $b_a\;and\;b_c$ are the Tafel slop of anodic and cathodic polarization curves respectively. The calculated mixed current ($i_{mp}$) is proportional to the depositing rate obtained by gravimetric method and corresponded mostly to the real depositing rate by multifying supplementary constant. The polarization method can be used for founding inclination of reaction on various concentration of each composition. Decreasing or increasing concentration of triethanolaminc as a complexing agent , the depositing rate is decreased and when the bath contained 25-50mL/L of triethanoloamine, the depositing rate is increased. The depositing rate is increased with increasing the concentration of boric acid, and when the bath contained 0.5M of boric acid, the depositing rate is increased abruptly. The optimum composition of the electroless nickel bath was estimated 0.1M of nickel sulfate, 0.25M of sodium hypophosphite, 0.5M of boric acid, and 25-50mL/L of triethanalamine.

• 대한화학회지
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• 제36권5호
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• pp.709-719
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• 1992

이핵성 네자리 Schiff base 의 cobalt(II), nickel(II) 및 copper(II) 착물인 [Co(II)_2(TSBP)(L)_4], [Ni(II)_2(TSBP)(L)_4] 및 [Cu(II)_2(TSBP)] (TSBP: 3,3',4,4'-tetra(salicylideneimino)-1,1'-biphenyl, L: Py, DMSO 및 DMF)들을 합성하여 원소분석, IR-spectrum, UV-visible spectrum, T.G.A. 및 D.S.C.를 측정하여 이핵성 착물로 주어짐을 확인하였다. 지지전해질로서 0.1M TEAP-L (L; Py, DMSO 및 DMF)에서 1mM-착물용액의 순환전압-전류법과 D.P.P.법으로 전기화학적 성질을 측정한 결과 이핵성 cobalt(II) 착물은 일전자의 확산 지배적인 네단계의 산화-환원과정이 Co(III)_2 {^\longrightarrow \\_\longleftarrow^e^-}Co(III)Co(II)_2{^\longrightarrow \\_\longleftarrow^e^-}Co(II){^\longrightarrow \\_\longleftarrow^e^-}Co(I){^\longrightarrow \\_\longleftarrow^e^-}Co(I)_2 으로 일어나고 이핵성 nickel(II) 및 copper(II) 착물들은 일전자의 확산지배적인 두 단계의 산화-환원과정이 M(II)_2 {^\longrightarrow \\_\longleftarrow^e^-}M(I)M(I){^\longrightarrow \\_\longleftarrow^e^-}M(I)_2 (M; Ni 및 Cu)으로 일어남을 알았다.