• 한국표면공학회지
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• 제21권2호
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• pp.39-46
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• 1988

Corrosion behavior of 5-26wt% Ni-Zn electrodeposited alloys was investigated by means of dipping electrochmical polarization measurement and galvanic coupling test. The weight loss and anodic polarization curve of coatings were measured by means of dipping and polarization measurement respectively. The galvanic protection effect of alloy coatings was measured by galvanic coupling test and the surface morpholgy of coatings was observed after corrosion testing. Our findings support thous of previous investigations showing that ${\gamma}$single phase coatings, while galvanic pprotection effect of dual phase coatings improved in comparison with ${\gamma}$single phase coating. The formation of colony in coating of ${\gamma}$and η+${\gamma}$ dual phsae caused the localized corrsion and increased the corrosion rate of the Ni-Zn coating.

• 한국표면공학회지
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• 제40권2호
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• pp.98-102
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• 2007

[ $NiCl_2$ ] and poly-L-lysine coated protein chip plates have been fabricated using a spin coating system. Water has been used as solvent and scratching effects on glass slides and ITO have been investigated. We also observed the surface properties of $NiCl_2$ and poly-L-lysine coated slides by using PSA(Particle size analyzer) and AFM(Atomic force microscope). The AFM results imply that the surface patterns created in the spin coating system determine the protein adsorption. Adsorption of histidine-tagged KRS proteins immobilized on glass slides and ITO was analyzed using a BAS image system. The results suggest that the scratching effect was increased ability of protein adsorption.

• 한국표면공학회지
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• 제32권2호
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• pp.157-164
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• 1999

In this study the effect of nickel addition on the coating weight of mini-mill steels containing silicon has been studied. It is shown that the pure zinc accelerated growth of the alloy layers occurred by a rapid growth of the zeta phase at 0.06%Si. The addition of 0.06%Ni to a pure zinc bath was found to be very effective in reducing the coating weight and promoting preferential development of the delta phase. The coating obtained by immersion in the Zn-Ni bath shows the presence of a nickel-rich region between the zeta phase and the eta phase. It is suggested that nickel prevents the rapid growth of the zeta phase due to the formation of the Zn-Ni-Fe ternary compound, which may act as a barrier to inward diffusion of zinc or iron at the zeta-eta boundary.

• Journal of Welding and Joining
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• 제32권5호
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• pp.72-79
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• 2014

Shaped charge(SC) ammunition is a weapon that penetrates directly the target by made jet from metal liner on impacting at a target. In SC, the liner occupies significantly important role causing an explosion and penetration of the target. The Al-Ni composite coating was deposited on copper liner in a solid state via kinetic spraying to improve the explosive force. The mechanical properties, reactivity and microstructure were investigated to confirm the possibility of kinetic sprayed Al/Ni composite coating as a reactive liner material. Reactive liner using Al/Ni composite exhibited much enhanced reactivity than pure copper liner due to Self-propagating High-temperature Synthesis (SHS) reaction with significantly improved adhesive bond strength. Especially, among the Al/Ni composite coatings, AN11 (the Al versus Ni atomic percent ratio is 1:1) showed the greatest reactivity due to its widest reaction area between deposited Al and Ni.

• 한국표면공학회지
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• 제52권3호
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• pp.156-162
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• 2019

Electroless Ni-P coatings are widely used in the chemical, mechanical, and electronic industries because of their excellent wear and abrasion resistance. In this study, The influence of pH values on properties of Ni-P-PTFE composite coatings was investigated. To improve mold lubrication, Ni-P-PTFE composite coatings at different pH value were studied. The morphology and phase structure of Ni-P-PTFE composite coatings were analyzed by scanning electron microscopy(SEM) and X-ray diffractometry(XRD). The result showed that Ni-P-PTFE composite coating is composed of Ni, P and PTFE. It exhibits an amorphous structure and good Corrosion Resistance to the substrate. Ni-P-PTFE composite coatings have higher open circuit potential than that of the substrate, which obtained at pH value of 5.0 optimal integrated properties.

• The Korean Journal of Ceramics
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• 제4권3호
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• pp.231-234
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• 1998

LaNiO3 thin films were fabricated on various substrates by spin-coating technique using metal naphthenates as starting materials. Highly-oriented LaNiO3 films with smooth and crack-free surfaces were grown on SrTiO3 (100) and LaAlO3(100) substrates, while films on MgO(100) and Si(100) substrates showed random orientation. In this study, we concluded that lattice-mismatches between LaNiO3 films and substrates used affect film's properties.

• 반도체디스플레이기술학회지
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• 제12권3호
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• pp.7-12
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• 2013

Ni-CNT(Carbon Nanotube) composite coatings is were formed by electrodeposition and their physical properties were investigated with variations of CNT content(1, 3, 6. 9 g/L) in the electrolyte solution, while the current density and electroplating time were fixed respectively at $6A/dm^2$ and 90 min.. With increasing CNT content from 1 to 9 g/L, incorporated CNTs into the composite coating were limited from 4.65 wt.% to 7.38 wt.%. Microhardness and contact angle values were increased with increasing CNT content of upto 3 g/L. With increasing the CNT content further, physical properties were degraded due to agglomeration, poor adhesion of CNTs to Ni matrix and thus rough surfaces. Optimum electroplating conditions were found to be the CNT content of 3 g/L, current density of 6 A/dm2 and electroplating time of 90 min.

• 한국재료학회지
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• 제29권5호
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• pp.328-335
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• 2019

Nb-doped $TiO_2$(NTO) coated NiCrAl alloy foam for hydrogen production is prepared using ultrasonic spray pyrolysis deposition(USPD) method. To optimize the size and distribution of NTO particles based on good physical and chemical stability, we synthesize particles by adjusting the weight ratio of the Nb precursor solution(5 wt%, 10 wt% and 15 wt%). The morphological, chemical bonding, and structural properties of the NTO coated NiCrAl alloy foam are investigated by X-ray diffraction(XRD), X-ray photo-electron spectroscopy(XPS), and Field-Emission Scanning Electron Microscopy(FESEM). As a result, the samples of controlled Nb weight ratio exhibit a common diffraction pattern at ${\sim}25.3^{\circ}$, corresponding to the(101) plane, and have chemical bonding(O-Nb=O) at 534 eV. The NTO particles with the optimum weight ratio of N (10 wt%) show a uniform distribution with a size of ~18.2-21.0 nm. In addition, they exhibit the highest corrosion resistance even in the electrochemical stability estimation. As a result, the introduction of NTO coated NiCrAl alloy foam by USPD improves the chemical stability of the NiCrAl alloy foam by protecting the direct electrochemical reaction between the foam and the electrolyte. Thus, the optimized NTO coating can be proposed for excellent protection of NiCrAl alloy foam for hydrocarbon-based steam methane reforming(SMR).

• 한국재료학회지
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• 제28권6호
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• pp.324-329
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• 2018

Needle-like NiO protecting layers on NiCrAl alloy foam, used as support for hydrogen production, are introduced through electroplated Ni and subsequent microwave annealing. To improve the stability of the NiCrAl alloy foam, oxygen concentration of microwave annealing to form a needle-like NiO layer with good chemical stability and corrosion resistance is controlled in a range of 20 and 50 %. As the oxygen concentration increases to 50 %, needle-like NiO forms a dense coating layer on the NiCrAl alloy foam; this layer formation can be attributed to accelerated growth of the (200) plane. In addition, the increased oxygen concentration causes increased NiO/Ni ratio of the resultant coating layer on NiCrAl alloy foam due to improved rate of the oxidation reaction. As a result, the introduction of dense needle-like NiO layers formed at 50 % oxygen concentration improves the chemical stability of the NiCrAl alloy foam by protecting the direct electrochemical reaction between the electrolyte and the foam. Thus, needle-like NiO can be proposed as a superb protecting layer to improve the chemical stability of NiCrAl alloy form.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2003년도 춘계학술발표강연 및 논문개요집
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• pp.219-219
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• 2003

HVOF(High Velocity Oxygen Fuel)법을 사용한 MCrAlY(M=Ni, Co, Fe)계 열차폐 코팅(thermal barrier coating)은 열기관 내부의 극심한 환경 부하에 대해 구조물 표면에 열적, 화학적 장벽을 형성함으로써 구조물의 내구성을 향상시킨다 이와 동시에 열차폐 효과는 구조물의 온도상승 없이 내부 가동 온도를 높일 수 있게 함으로써 열효율을 상승시키고 연료 효율을 높여 가동비용 절감을 이룰 수 있는 동시에 고 연소를 통한 오염원의 배출을 감소시킬 수 있다. 본 연구에서는 $H_2O$$_2$=5:1 분위기 하에서 HVOF법을 사용하여 Hastelloy-X 기판위에 125$\mu\textrm{m}$의 두께로 다음 5종류의 (Ni, Co, Cr)계 MCrAlY 코팅을 용사시켰다. 준비된 (Ni, Co)-Cr-Al-(Y, Ta, Re), (Ni, Co)-Cr-Al-(Y, Re), (Ni, Co)-Cr-Al-(Y, Ta), (Ni, Co)-Cr-Al-Y, (Ni,Co)-Cr-Al-Ir 코팅시편에 대한 산화성질을 조사하기 위해 대기 중 1000, 1100, 120$0^{\circ}C$에서 50, 100, 150, 200시간 등온실험(Isothermal oxidation)을 실시하였고, XRD, SEM/EDS, EPMA를 이용하여 생성된 산화막과 코팅 시편의 조직 변화를 조사하였다. 산화온도와 산화시간이 증가할수록 산화막의 박리가 많이 발생하였으며, 분석 결과 미세하게 분포된 a-Al$_2$O$_3$ 입자, NiCr$_2$O$_4$스피넬 상, 미세한 Cr$_2$O$_3$가 관찰되었고, 코팅 조성 변화에 따라 형성되는 이들 산화물의 존재비가 달라졌으며, 산화온도가 높아질수록 산화속도가 가속화되었다.