• 청정기술
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• 제25권1호
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• pp.14-18
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• 2019

여러 금속 부품을 가공하기 위하여 사용된 염화제이철 에칭 폐액은 유가금속인 니켈 등을 함유하고 있다. 본 연구에서는 식각공정을 완료한 에칭폐액을 재생하고 부산물로 나온 니켈 함유 폐액으로부터 정제하여 니켈 금속분말로 제조하는 공정을 개발하였다. 부산물인 니켈함유용액을 철 등의 불순물을 침전 제거하기 위하여 수산화나트륨 수용액을 실험을 통하여 가수분해 중화제로서 선정하였고, 이를 통하여 철 등의 불순물을 pH = 4 조건하에 침전 제거하였다. 그 후, 불순물로 잔류하는 망간 및 아연과 같은 금속이온들을 D2EHPA (Di-(2-ethylhexyl) phosphoric acid)를 사용하여 용매추출 하였다. 정제된 염화니켈은 99% 이상의 순도를 가지고 있으며, 그 후 환원제로 하이드라진을 이용하여 99% 이상의 순도와 약 150 nm의 크기를 가지는 니켈 금속분말로 제조하였다. 염화니켈 및 니켈 금속분말의 성분은 EDTA 적정법과 유도결합 플라즈마 방출분광법(inductively coupled plasma optical emission spectrometer, ICP-OES)을 이용하여 확인하였으며, 전계방사 주사전자현미경(field emission scanning electron microscope, FE-SEM), X-선 회절분석기(X-ray diffraction, XRD) 및 투과전자현미경(transmission electron microscopy, TEM)을 통하여 금속분말의 형태, 입자 크기 및 결정성과 같은 물리적 특성을 확인하였다.

• 한국결정성장학회지
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• 제27권5호
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• pp.268-273
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• 2017

In this study, nickel hydroxide crystalline powders were synthesized by continuous reaction in the taylor fluid flow using nickel chloride, nickel sulphate and sodium hydroxide as raw materials and compared with those prepared by a conventional batch type reaction. The crystallinity of nickel hydroxide prepared by the Taylor fluid flow reaction was higher than that of nickel hydroxide obtained by batch reaction. The particle size of nickel hydroxide decreased about 2.5 to 3.6 times, and the specific surface area was increased.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.568-569
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• 2006

The use of the nickel free, high nitrogen stainless steel powder and nitriding during sintering of iron based materials have been shown as an alternative way to the conventional PM stainless steels containing nickel. Nitrogen as an alloying element for iron improves in an effective way the properties of sintered alloyed steels. The powder metallurgy route is a suitable way to introduce nitrogen into these alloys and, in particular, to produce high nitrogen (close to the solubility limit) stainless steels. The paper presents and discusses the nitriding behavior of nickel-free stainless steels produced by powder metallurgy method. Alloyed melt was atomized by nitrogen and in this way nitrogen was introduced into the powder. Further nitriding occurred during sintering in a nitrogen atmosphere. For comparison, compacts having the same composition as an alloyed powder were produced from elemental powders mixture. Sintering-nitriding behaviour of investigated materials has been controlled by dilatometry, chemical and X-Ray phase analysis and metallography. Mechanical properties of sintered compacts were also measured.

• 한국수소및신에너지학회논문집
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• 제7권1호
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• pp.63-69
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• 1996

Effect of nickel powder to added to the hydrogen absorbing alloy electrode of $MmNi_{4.5}-xCoxMn_{0.3}Al_{0.2}$ system alloy was investigated. The addition of nickel powder was effective for the improvement of discharging characteristic. It was found that the discharge capacity was 310mAhig when the alloy negative electrode was mixed $MmNi_{3.75}CO_{0.75}Mn_{0.3}Al_{0.2}$ and nickel powder with a mix of one to three. Still another, we have investigated thermodynamic stability of hydrogen in the alloy negative electrode. As a result, enthalpy of hydrogen and hydrogen equilibrium pressure in the alloy negative electrode were a suitable value to easy hydrogen absorption-desorption.

• 한국재료학회지
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• 제22권8호
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• pp.426-432
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• 2012

This study involves using nickel chloride solution as a raw material to produce nano-sized nickel oxide powder with average particle size below 50 nm by the spray pyrolysis reaction. The influence of the inflow speed of raw material solution on the properties of the produced powder is examined. When the inflow speed of the raw material solution is at 2 ml/min., the average particle size of the powder is 15~25 nm and the particle size distribution is relatively uniform. When the inflow speed of the solution increases to 10 ml/min., the average particle size of the powder increases to about 25 nm and the particle size distribution becomes much more uneven. When the inflow speed of the solution increases to 20 ml/min., the average particle size of the powder increases in comparison to the case in which the inflow speed of the solution was 10 ml/min. However, the particle size distribution is very uneven, showing various particle size distributions ranging from 10 nm to 70 nm. When the inflow speed of solution increases to 50 ml/min., the average particle size of the powder decreases in comparison to the case in which the inflow speed was 20 ml/min., and the particle size distribution shows more evenness. As the inflow speed of the solution increases from 2 ml/min. to 20 ml/min., the XRD peak intensities gradually increase, while the specific surface area decreases. When the inflow speed of solution increases to 50 ml/min., the XRD peak intensities rather decrease, while the specific surface area increases.

• 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.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.602-603
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• 2006

Micro-porous nickel (Ni) with an open cell structure was fabricated by powder metallurgy. The pore size of the micro-porous Ni approximated $30{\mu}m$ and $150{\mu}m$. For comparison, porous Ni with a macro-porous structure were also prepared by both powder metallurgy (pore size $800{\mu}m$) and the traditional chemical vapour deposition method (pore size $1300{\mu}m$). The mechanical properties of the micro-and macro-porous Ni samples were evaluated using compressive tests. Results indicate that the micro-porous Ni samples exhibited significantly enhanced mechanical properties, compared to those of the macro-porous Ni samples.

• 한국재료학회지
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• 제14권10호
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• pp.725-730
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• 2004

Nickel ultrafine powder have been synthesized by chemical reduction of aqueous $NiSO_4$ with hydrazine at various reaction conditions. The effect of reaction conditions such as the amount of surfactant and reductor, and reaction temperature on the particle size and shape was investigated by the mean of XRD, SEM and SEM-PSA. Experiments showed that the ratio of $N_{2}H_4/Ni$ and the reaction temperature were affected on the particle size of the nickel powder. The average particle size of synthesized nickel powder increased with increasing reaction temperature regardless of the ratio of $N_{2}H_4/Ni$. Also the surfactant could influence the size and agglomeration of ultrafine powder with the reaction temperature.

• 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.

• 한국분말재료학회지
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• 제18권6호
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• pp.496-501
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• 2011

In this study, the effect of milling time on the microstructure and phase transformation behaviors of Ni-12 wt.%B powders was investigated using vibratory ball milling process. X-ray diffraction patterns showed that the phase transformation of mixed Ni-B elemental powder occurred after 50 hours of milling, with a formation of nickel boride phases. Through the study of microstructures in mechanical alloying process, it was considered that ball milling strongly accelerates solid-state diffusions of the Ni and B atoms during mechanical alloying process. The results of X-ray photoelectron spectroscopy showed that most of B atoms in the powder were linked to Ni with a formation of nickel boride phases after 200 hours of milling. It was finally concluded that mechanical alloying using ball milling process is feasible to synthesize fine and uniform nickel boride powders.