• Korean Chemical Engineering Research
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• 제45권5호
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• pp.442-447
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• 2007

투명 플라스틱 필름의 표면강도를 향상시키기 위하여 유-무기 혼성 코팅용액을 Sol-Gel 법을 이용하여 합성하였다. 코팅용액은 입자 직경이 12 nm 크기의 무기물인 colloidal silica 용액(Ludox)에 유기물인 GPTMS(glycidoxypropyl trimethoxysilane)를 첨가하여 제조하였다. 그 후에 기재인 PC(polycarbonate) 필름에 담금 코팅(dip-coating)시키고, 상온에서 10분 동안 건조시킨 후, $80^{\circ}C$에서 30분 동안 열 경화시켜 하드 코팅 막을 제조하였다. 이 과정 중 코팅용액의 pH 변화와 GPTMS 첨가량의 변화가 코팅 막의 물성에 미치는 영향을 살펴보았다. pH 4의 산성 조건에서 제조된 코팅용액으로 PC 필름 위에 코팅한 경우는 중성이나 염기성 조건으로 제조된 경우 보다 우수한 연필경도 및 기재와의 부착력을 보였다. 또한 GPTMS의 첨가량이 증가할수록 코팅 막의 연필경도 및 기재와의 부착력이 증가하였다.

• Korean Chemical Engineering Research
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• 제49권3호
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• pp.277-284
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• 2011

본 연구에서는 알루미나 졸과 아크릴레이트 단량체를 이용하여 UV 경화형 유-무기 하이브리드 하드코팅 용액을 제조하였다. Aluminum isopropoxide로부터 얻어진 알루미나 졸에 실란커플링제인 methacryloxypropyl trimethoxysilane(MPTMS)을 첨가하여 제조된 졸을 무기물 성분으로 사용하였다. 유기물 성분으로는 다양한 아크릴레이트 단량체인 pentaerythritol triacrylate(PETA), 1,6-hexanediol diacrylate(HDDA), dipentaerythritol hexaacrylate(DPEHA)를 혼합하여 사용하였다. 이후 무기물 성분과 유기물 성분을 혼합하여 유-무기 하이브리드 코팅 용액을 제조한 후, 이를 polycarbonate 기판 위에 스핀 코팅 후 UV 경화를 실시하여 도막을 형성하였다. 이때 무기물 성분 중의 MPTMS의 첨가량과 UV 경화 시간 변화가 코팅 막의 물성에 미치는 영향을 연구하였다. 그 결과 MPTMS가 0.20 mole 첨가 될 경우 코팅 막은 3H의 우수한 연필경도를 나타내었으며 haze값이 2%로 내마모성도 우수하였다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2010년도 춘계학술발표대회
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• pp.4.1-4.1
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• 2010

In the first part, after discussing works on nacre, a soft-hard composite found in nature, including a simulation on network mimicking nacre [1-4], we talk on a simple model of spider webs, another example of natural soft-hard structure [5]. We demonstrate that the web network is free of stress concentrations because the radial threads are stronger than the spiral threads. In the second part, after reviewing our works on wetting on textured surfaces [6-8], we discuss penetration into textured surface and instability of a liquid film on textured substrates during spin coating [9,10].

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 춘계학술대회 논문집
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• pp.375-378
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• 2007

Abrasive wear between piston ring face and cylinder liner is an extremely unpredictable and hard-to-reproduce phenomenon that significantly decreases engine performance. Wear by abrasion are forms of wear caused by contact between a particle and solid material. Abrasive wear is the loss of material by the passage of hard particles over a surface. From the pin-on-disk test, particle dent test and scuffing test, abrasive wear characteristics of diesel engine cylinder liner-piston ring have been investigated. Pin-on-disk test results indicate that abrasive wear resistance is not simply related to the hardness of materials, but is influenced also by the microstructure, temperature, lubricity and micro- fracture properties. In particle dent test, dent resistance stress decreases with increasing temperature. From the scuffing test by using pin-on-disk tester, scuffing mechanisms for the soft coating and hard coating were proposed and experimentally confirmed.

• 한국결정성장학회지
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• 제10권1호
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• pp.55-61
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• 2000

리튬이온전지의 음극재료로서 hard carbon에 PVC를 이용한 탄소를 코팅함으로써 비가역용량 감소와 가역용량 증가 등 전기화학적 특성이 향상되었다. 이러한 특성 향상은 PVC코팅에 의한 표면개질로 대기와의 반응을 억제함에 기인한 것으로 생각되며, 또한 Ni 첨가에 의해 PVC 탄소의 흑연화 정도를 조절할 수 있었으며, 이들과 관련된 전기화학적 특성을 비교 고찰하였다.

• Korean Chemical Engineering Research
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• 제53권6호
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• pp.776-782
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• 2015

$TiO_2$ 나노입자의 광촉매 반응을 억제하기 위해 평균 직경 3~5 nm의 $TiO_2-SnO_2$ 나노입자가 titanium tetraisopropoxide(TTIP)와 tin chloride의 가수분해 반응에 의해 합성되었다. 생성된 $TiO_2-SnO_2$ 나노입자를 졸-겔법에 의해 3-glycidoxypropyl trimethoxysilane(GPTMS)과 반응시킴에 의해 유-무기 혼성 코팅 용액이 제조되었다. 그 후 코팅 용액을 기재인 polycarbonate(PC) 시트 위에 스핀 코팅시키고, $120^{\circ}C$에서 열경화 시켜 고굴절률 하드코팅 도막이 제조되었다. $TiO_2-SnO_2$ 나노입자로부터의 코팅 도막은 $TiO_2$ 나노입자로부터 얻어진 코팅 도막의 2H에 비해 증가된 3H의 연필경도를 보였다. 또한 $TiO_2-SnO_2$ 나노입자로부터의 코팅 도막의 굴절률은 Sn/Ti 몰 비가 0에서 0.5로 증가함에 따라 633 nm 파장에서 1.543으로부터 1.623으로 향상되었다.

• 한국표면공학회지
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• 제39권4호
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• pp.179-189
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• 2006

High velocity oxygen fuel(HVOF) thermal spray coating of WC-Co powder is one of the most promising candidate for the replacement of the traditional hard chrome plating and ceramics coating because of the environmental problem of the very toxic $Cr^{6+}$ known as carcinogen and the brittleness of ceramics coating. WC-Co micron and nano powder were coated by HVOF thermal spraying method for the study of durability improvement of the high speed spindle. Coatings were planned by Taguchi program for the four spray parameters of spray distance, flow rates of hydrogen, oxygen and powder feed rate. Optimal coating process was obtained by the studies of coating properties such as porosity, surface roughness, micro hardness, and micro structure. WC-Co micron and nano powder were coated on the Inconel 718 substrate by the optimal coating process obtained in this study. The wear behaviors were studied by the sliding wear tester at room temperature and at an elevated temperature of $500^{\circ}C$ for the application to high speed spindle. Sliding wear test was carried out for four most promising hard coatings of chrome coating, ceramics coatings such as $A1_2O_3,\;Cr_2O_3$ and HVOF Co-alloy T800 for the comparison of their wear behaviors. HVOF WC-Co coating was better than other coatings showing highest micro hardness of 1400 Hv and comparable friction coefficients with others. HVOF WC-Co coating is a strong candidate for the replacement of the traditional hard chrome plating for the high speed spindle.

• Journal of Advanced Marine Engineering and Technology
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• 제19권3호
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• pp.62-69
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• 1995

In order to investigate the effect of TiN coating on corrosion fatigue behavior of metal, the rotary bending corrosion fatigue tests were carried out in 3% NaCl solution by using the round bar specimens of high-speed steel, SKH-9, coated with TiN by PVD method. From the experimental results, fatigue strength of TiN coating steel in air was obvious improvement as compared with that of the substrate because of the restriction of dislocation movement in near surface of the substrate by hard thin film. In 3% NaCl solution, corrosion fatigue life of TiN coating specimen in high stress level was improvement same as in air. But in low stress level, corrosion fatigue life of TiN coating one was equivalent to that without coating, due to much crack initiated from corrosion pits formed at the substrate by failure of coating layer.

• Advances in materials Research
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• 제1권3호
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• pp.233-243
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• 2012

Thermal reactive diffusion coating of vanadium carbide on DIN 2714 steel substrate was performed in a molten borax bath at $950-1050^{\circ}C$. The coating formed on the surface of the substrate had uniform thickness ($1-12{\mu}m$) all over the surface and the coating layer was hard (2430-2700 HV), dense, smooth and compact. The influence of the kinetics parameters, temperature and time, has been investigated. Vanadium carbide coating was characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDX) and X-ray diffraction analysis (XRD). The corrosion resistance of the coating was evaluated by potentiodynamic polarization in 3.5% NaCl solution. The results obtained showed that decrease of coating microhardness following increasing time and temperature is owing to the coarsening of carbides and coating grain size.

• 한국공작기계학회논문집
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• 제14권5호
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• pp.80-86
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• 2005

High velocity oxy-fuel thermally sprayed coating of the WC-Co cermet material is a well-established process for modifying the surface properties of the structural components exposed to the corrosive and wear attacks. The hard WC phase in the coating resists to the wear while the soft metallic Co increases the adhesive and cohesive bonding properties. The coating properties deposited by the HVOF process are greatly dependent on the feedstock materials and processing parameters. The effects of the feedstock material and process coating parameters including the in-flight particle parameters and resultant coating microstructures were observed in this paper.