• 한국표면공학회지
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• 제48권5호
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• pp.199-204
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• 2015

Recently, fuel cell is a good alternative for energy source. Separator is a important component for fuel cell. In this study, The surface of separator was modified for corrosion resistance and electric conductivity. Reduced graphene oxide (rGO) was made by Staudenmaier's method. Nickel, phosphorus and rGO were coated on 6061 aluminum alloy as a separator of proton exchange membrane fuel cell by composite electroless plating. Scanning electron microscope, energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy were used to examine the morphology of Ni-P-rGO. Surface images were shown that the rGO was dispersed on the surface of Ni-P electroless plating, and nickel was combined with the un-reduced oxygen functional group of rGO.

• Composites Research
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• 제20권5호
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• pp.43-48
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• 2007

전자기파의 흡수와 간섭 문제는 상업적, 군사적 용도에서 중요한 문제로 다루어져 왔다. 스텔스 기술은 전자기파 흡수 기술의 가장 전형적인 적용 방법 중에 하나이다. 본 연구는 유전성 및 자성 손실을 함유한 복합성의 필러를 개발하고자 시작되었다. 전도성 나노 소재인 탄소나노섬유 (CNFs)에 자성을 부여하기 위해 두 가지의 니켈-인과 니켈-철을 무전해 도금을 적용하여 각각 코팅하는 실험에 성공하였다. 제작된 복합 소재의 미세 구조를 SEM/TEM을 통해 관찰하였고, 이들의 성분 분석(EDS/ELLS)을 수행하였다. 코팅 층의 평균 두께는 약 $50\;{\sim}\;100\;nm$의 결과를 나타내었으며, 코팅 층의 성분은 Ni-6wt%P와 Ni-70wt%Fe의 결과를 각각 나타내었다.

• 대한금속재료학회지
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• 제46권11호
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• pp.725-729
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• 2008

Deposition characteristics of electroless plated Ni-W-P films were investigated for various complexing agents. Used complexing agents are sodium citrate, sodium gluconate and sodium malonate. In this study, the existing mixed potential theory could explain the overall mechanism of Ni-W-P electroless plating for all complexing agents. The deposition rate could be also expected by the theory. The deposited Ni-W-P films were evaluated in term of surface hardness and corrosion resistance. Microhardness of the deposit increased about 1,000 Hv after heat treatment for one hour at $400^{\circ}C$, because it was above the crystallization temperature of $Ni_3P$. The deposited Ni-W-P films can exhibit excellent corrosion resistance in using sodium malonate as a complexing agent, the other hand the using sodium gluconate was the worst corrosion resistance. The worst corrosion resistance was due to a large number of nano-sized pin-holes or small pores. The plating current at the mixed potential increases when the using sodium malonate as a complexing agent, it was explained by the cross section.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2008년도 추계학술대회 초록집
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• pp.153-154
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• 2008

High velocity oxy-fuel (HVOF) thermal spraying coating has been used widely throughout the last 60 years mainly in defense, aerospace, and power plants. Recently this coating technique is considered as a promising candidate for the replacement of the traditional electrolytic hard chrome plating (EHC) which pollutes the environment and causes lung cancer by toxic hexa-valent $Cr^{6+}$. In this study, two kinds of cermet coatings, WC-CoCr and WC-CrC-Ni, are formed by HVOF spraying. The wear properties of coatings are evaluated comparatively by reciprocating sliding wear tests at $25^{\circ}C$, $250^{\circ}C$ and $450^{\circ}C$ respectively. Wear rates show that WC-CoCr coatings have better sliding wear resistance than WC-CrC-Ni coatings regardless of temperature due to more, compact and homogeneously distributed WC particles, less metal content, Co, Cr rich metallic bindermatrix with higher fracture strength and better adhesive strength with WC particles.

• Advances in nano research
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• 제14권2호
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• pp.195-200
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• 2023

Safety in sports is important because if an athlete has an accident, he may not be able to lead an everyday life for the rest of his life. The safety of sports facilities is very effective in creating people's sports activities, with the benefits of staying away from physical injury, enjoying sports, and mental peace. Everyone has the right to participate in sports and recreation and to ensure that they want a safe environment. This study prepares a very good Nickel-Cobalt -Silicon carbide (Ni/Co-SiC) nanocomposite with convenient geometry on the leg press machine rod, employing the pulse electrodeposition technique to reduce the rod's wear and increase the durability of sports equipment and control sports damages. The results showed that the Ni/Co-SiC nanocomposite formed at 2 A/dm2 shows extraordinary microhardness. The wear speed for the Ni/Co-SiC nanocomposite created at 4 A/dm2 was 15 mg/min, showing superior wear resistance. Therefore, the Ni/Co-SiC nanocomposite can reduce sports equipment's wear and decrease sports injuries. Ni-Co/SiC nanocomposite layers with various scopes of silicon carbide nanoparticles via electrodeposition in a Ni-Co plating bath, including SiC nanoparticles to be co-deposited. The form and dimensions of Silicon carbide nanoparticles are watched and selected using Scanning Electron Microscopy (SEM).

• 공업화학
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• 제27권2호
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• pp.210-216
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• 2016

본 연구에서는 무전해 니켈 도금 시간을 달리하여 제조한 자동차 시트용 탄소섬유 발열체의 발열 및 전기적 특성에 관하여 고찰하였다. 무전해 니켈 도금된 탄소섬유의 비저항 및 비열은 4-point probe method 및 differential scanning calorimetry (DSC)를 이용하여 분석하였으며, 표면 형상 및 표면 온도는 scanning electron microscope (SEM) 및 열화상 카메라를 이용하여 관찰하였다. 실험 결과, 도금시간의 증가에 따라 니켈 도금 두께 및 표면 온도는 증가하였으며, 반면에 비열 및 비저항은 도금시간이 증가함에 따라 감소하였다. 결과적으로 무전해 니켈 도금은 자동차 시트용 탄소섬유 발열체의 저항 발열 및 전기적 특성을 크게 향상시키는 것으로 판단된다.

• 공업화학
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• 제22권1호
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• pp.98-103
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• 2011

DSSC의 광전 효율 증대와 Pt 상대전극의 접착성 향상을 위하여 FTO (Fluorine-doped Tin Oxide) 유리면에 Ni underlayer를 전기 도금 후 Pt 층을 전기 도금하였다. Ni underlayer는 $10mA/cm^2$에서 2 min 동안 도금한 경우 Ni 층과 FTO 면사이의 접착성이 가장 우수하게 나타났으며, Ni underlayer를 $10mA/cm^2$에서 2 min, Pt 층을 $5mA/cm^2$에서 1 min 동안 전기 도금한 상대전극의 XRD 분석 결과 Ni 및 Pt의 금속 회절 peak들을 관찰 할 수 있었다. 이렇게 제조한 상대전극을 사용하여 DSSC의 impedance 측정 결과 75 ohm의 가장 낮은 저항을 나타냈으며, 광전 효율은 5.6%로서 가장 높은 값을 나타내었다.

• 전기화학회지
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• 제10권2호
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• pp.88-93
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• 2007

Nano-sized Sn particles were coated with Ni-P layer using an electroless deposition method and their anodic performance was tested for lithium secondary batteries. Uniform coating layers were obtained, of which the thickness was controlled by varying the $Ni^{2+}$ concentration in the plating bath. It was found that the Ni-P layer plays two important roles in improving the anodic performance of Sn powder electrode. First, it prevents the inter-particle aggregation between Sn particles during the charge/discharge process. Second, it provides an electrical conduction pathway to the Sn particles, which allows an electrode fabrication without an addition of conductive carbon. A pseudo-optimized sample showed a good cyclability and high capacity ($>400mAh\;g^{-1}$) even without conductive carbon loading.

• Corrosion Science and Technology
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• 제2권4호
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• pp.197-201
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• 2003

In this study, Ni-P layers were electroplated on the surface of stainless steel in order to investigate the effects of an additive and agitation on their mechanical properties and microstructure. The concentration of the additive in the plating solution increased, the pores formed in the layer decreased, while the residual stress developed in the layers during electroplating increased. Agitation of the solution during electroplating was observed to force to increase local pores in the layer, which lowers its tensile properties. Grain growth was suppressed due to very fine $Ni_3P$ precipitates formed at its grain boundaries during heat treatment at $343^{\circ}C$ for 1 hr in air.

• Nano
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• 제13권11호
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• pp.1850134.1-1850134.10
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• 2018

Increasing active sites and enhancing electric conductivity are critical factors to improve sensing performance toward phenol. Herein, Ni nanoparticle was successfully anchored on acidified multiwalled carbon nanotube (a-MWCNT) surface by electroless plating technique to avoid Ni nanoparticle agglomeration and guarantee high conductivity. The crystal structure, phase composition and surface morphology were characterized by XRD, SEM and TEM measurement. The as-prepared Ni/a-MWCNT nanohybrid was immobilized onto glassy carbon electrode (GCE) surface for constructing phenol sensor. The phenol sensing performance indicated that Ni/a-MWCNT/GCE exhibited an amazing detection performance with rapid response time of 4 s, a relatively wide detection range from 0.01 mM to 0.48 mM, a detection limit of $7.07{\mu}M$ and high sensitivity of $566.2{\mu}A\;mM^{-1}\;cm^{-2}$. The superior selectivity, reproducibility, stability and applicability in real sample of Ni/a-MWCNT/GCE endowed it with potential application in discharged wastewater.