• 한국표면공학회지
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• 제50권6호
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• pp.523-530
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• 2017

In this study, we developed the h-BN interphase for ceramic matrix composites (CMCs) through a wet chemical coating method, which has excellent price competitiveness and is a simple process as a departure from the existing high cost chemical vapor deposition method. The optimum condition for nitriding an h-BN interphase using boric acid and urea as precursors were derived, and the h-BN interphase coating through a wet method on a carbon preform of 2.5 D was conducted to apply the optimum conditions to the CMCs. In order to control the coating property via the wet coating method, four parameters were investigated such as dipping time of the specimen in the precursor solution, the ratio of boric acid and urea in the precursor, the concentration of solution where the precursor was dissolved, and the cycle of dipping and dry process. The CMCs was fabricated through polymer impregnation and pyrolysis (PIP) processes and a three-point flexural strength test was conducted to verify the role of the coated h-BN interphase.

• 반도체디스플레이기술학회지
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• 제16권4호
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• pp.91-96
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• 2017

In this computational study of optical fiber manufacturing, WOW (wet-on-wet) double coating process on freshly drawn glass fiber has been numerical modelled and simulated using a simplified geometry of typical optical fiber coating apparatus. The numerical domain includes primary and secondary coating dies along with secondary coating cup and the interface between primary and secondary coating liquids are investigated using level set method. Coating liquid viscosity is an important parameter and its dependence on temperature is also considered. Since there would be possibility for pressure and temperature of primary coating liquid to be increased substantially at high fiber drawing speed, the effects of increased pressure and temperature of primary coating liquid are examined on flow patterns of coating liquids in secondary coating cup. In case that both pressure and temperature of primary coating liquid are high enough, liquid interface becomes noticeably unstable and this flow instability could adversely affect the uniform coatings and final quality of produced optical fiber.

• 현장농수산연구지
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• 제15권1호
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• pp.63-73
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• 2013

Pot시험에서 코팅소재별 벼 종자의 발아 및 유묘생육 특성을 구명하기 위하여 무처리, 규산코팅, 천매암코팅, 철분코팅, 규산복토, 철분코팅+규산복토 처리에서 유묘의 입모율, 경시적 입묘양상의 변화, 초장의 특성을 벼 무논점파와 무논조파재배에서 조사결과를 요약하면 다음과 같다. 입모율 1. 벼 무논점파재배의 경우 규산복토, 무처리 100%, 천매암코팅 91.5%, 규산코팅 88%, 철분코팅+규산복토 86%, 철분코팅 75.5%이었다. 2. 벼 무논조파재배에서는 무처리, 규산복토 100%, 철분코팅+규산복토 97.5%, 천매암코팅 96%, 규산코팅 94.8%, 철분코팅 86%로 각각 나타났다. 본 시험에서는 규산복토와 무처리에서 가장 높게 나타났지만 실제 각종 제한요인(새 피해, 건조, 부묘현상 등)이 많은 포장조건에서는 무처리 조건이 상반된 결과가 나타나고 있으며 천매암코팅, 규산코팅 또는 복토조건에서 철분코팅보다 높은 입묘율을 각각 보였다. 유묘의 초장 생장 1. 벼 무논점파재배에서 유묘의 초장생장은 파종 후 35일 조사한 유묘 초장의 경우 벼 무논점파재배에서는 규산복토 23.8cm, 무처리 23.6cm, 규산코팅 21.4cm, 천매암코팅 20.3cm, 철분코팅+규산복토 16.8cm, 철분코팅 15.4cm이었다. 2. 벼 무논조파재배에서 파종 후 35일 조사한 유묘의 초장생장은 규산복토 22.1cm, 무처리 21.2cm, 규산코팅 20.0cm, 천매암코팅 19.0cm, 철분코팅 17.7cm, 철분코팅+규산복토 17.0cm 순으로 각각 나타났다.

• 한국분말재료학회지
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• 제21권2호
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• pp.93-96
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• 2014

Cobalt coated tungsten carbide-cobalt composite powder has been prepared through wet chemical reduction method. The cobalt sulfate solution was converted to the cobalt chloride then the cobalt hydroxide. The tungsten carbide powders were added in to the cobalt hydroxide, the cobalt hydroxide was reduced and coated over tungsten carbide powder using hypo-phosphorous acid. Both the cobalt and the tungsten carbide phase peaks were evident in the tungsten carbide-cobalt composite powder by X-ray diffraction. The average particle size measured via scanning electron microscope, particle size analysis was around 380 nm and the thickness of coated cobalt was determined to be 30~40 nm by transmission electron microscopy.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1998년도 제28회 추계학술대회
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• pp.221-226
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• 1998

The processing conditions for the mass production of platelet WS$_2$ lubricant powder were optimized. The mixture of tungsten and sulfur powders was sealed in a vacuum of 10$^{-3}$ torr and heat-treated at 850$\circ$C for 2 h. The internal pressure of reaction chamber was maintained at certain level by controlling the release valve automatically. The reaction product was the platelet WS$_2$ powder with an average size of 15 $\mu$m. The synthesized WS$_2$ powder was then coated on the wiper-blade of automobiles and the commercial deep-grooved ball bearing using wet and dry coating methods, respectively. High lubricity and wear resistance of wet coated wiper-blade were confirmed by the life test of 70,000 cycles. The life-time of the ball bearing assembled after WS$_2$ coating onto each part increased 50 times compared to the non-coated ball bearing.

• Food Science and Biotechnology
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• 제18권5호
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• pp.1155-1160
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• 2009

Poly(lactide) (PLA)-coated paperboards were prepared by solution coating and thermo-compression coating methods and their effect of coating on the packaging properties such as tensile, water resistance, water vapor barrier, and heat sealing properties was tested. Compared with uncoated control paperboard, tensile strength (TS) of PLA-coated paperboard increased profoundly (2.2-2.6 folds) with slight increase in elongation at break (E). Water absorptiveness (WA) of the paperboard decreased 74-170 folds and water vapor permeability (WVP) decreased 6.3-22.1 folds by coating with PLA, which indicates an increase in the hydrophobicity of the surface of paperboard. Compared with polyethylene (PE)-coated paperboard, both PLA-coated paperboard exhibited 2.3 time higher heat sealing strength. In addition, the PLA-coated paperboards showed equal or higher wet TS than PE-coated paperboard. All the test results showed that the paperboard coated by the thermo-compression coating method was similar to or better than those of coated by the solution coating method.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.137-137
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• 2010

This research proposed an advanced Electronic bead (EB) using MMA (Methy methacrylate) and CCA (Charge Control Agent). In the first, this paper presents about measurement method and characterization analysis of EB with wet coating method. Furthermore, this work presents the positive and negative EB fabrication procedure. As the experimental results, the proposed EB with charge to ratio[Q/M] is very attractive to Electronic paper driving characterization.

• 대한화장품학회지
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• 제36권3호
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• pp.227-231
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• 2010

파우더 파운데이션은 사용이 간편하고 수정화장이 용이하여 고객들이 많이 사용하고 있으며, 파우더 파운데이션을 만드는 방법은 건식방식, 소성방식, 그리고 습식방법으로 크게 분류할 수가 있다. 이 중 습식방법은 이미 잘 알려진 바와 같이 back injection 방법과 front injection 방법이 있으며, 본 논문에서는 front injection 방법을 사용해 실험을 진행하였다. 실험결과 용매의 종류에 따른 경도 변화를 살펴보면 휘발성 실리콘이나 탄화수소계 휘발성 물질을 이용할 때 보다 정제수를 이용할 때 경도가 높게 나타났으며, 사용감 측면에서는 물보다는 탄화수소계 휘발성 물질과 휘발성 실리콘 등을 사용했을 때, 고객 선호도가 높게 나타났다. 또한 코팅물질 변화에 따른 경도 변화로는 아미노산계 코팅물질을 사용하였을 때 경도가 상승하는 효과를 나타냈으며, 실리콘 코팅 물질을 사용했을 때 경도 상승효과가 미비한 것으로 나타났다. 이러한 결과를 토대로 각 대상 고객에 맞는 처방을 개발하고자 할 때 사용감과 경도의 상관관계를 알고, 처방설계에 이용한다면 고객이 원하는 사용감에 한발 더 접근할 수 있으리라 생각된다.

• Corrosion Science and Technology
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• 제5권1호
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• pp.33-38
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• 2006

Current coating practice requires the thickness of anti-corrosion organic coatings to be over $250{\mu}m$ for immersion parts of ships and offshore structures and the corrosion resistance of these coatings has been evaluated by destructive and qualitative analysis. Recently, Electrochemical Impedance Spectroscopy(EIS) method has been employed, as an alternative, to evaluate corrosion resistance of organic coatings. This method is characterized as being nondestructive, reproducible, and quantitative in evaluating aging of organic coatings. In this study, EIS method was adopted to quantitatively and effectively select the coating systems having optimized protective performance. Evaluations of several epoxy and epoxy/polyurethane coating systems typically used for ships and offshore structures were carried out in wet($50^{\circ}C$, $90^{\circ}C$) and dry(room temp.) environments to accelerate the degradation of the organic coatings. These results were compared with the conventional scribed(scratched) test results. The plausible prediction model for determining the remaining life-time of coating systems was also proposed based on variations of impedance data, FT-IR and $T_g$ measurements results.

• 한국세라믹학회지
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• 제29권5호
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• pp.403-409
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• 1992

The titania membrane thickness coated on the porous alumina support by the sol-gel method was analyzed using the slipcasting model. The thickness of calcined membrane layers increased linearly from 1.3 to 3.8 ${\mu}{\textrm}{m}$ with the square root of the dipping time (4~40 min). Growth rates of the thickness of wet gels and calcined layers were well described quantitatively by the slipcasting model. Through the regression of experimental data using model equations, the permeability and the pressure drop across wet gels, and the thickness and their growth rate constants of wet gels and calcined layers could be determined. It was also known that the gellation concentration of the TiO2 sol used in this work and the porosity of wet gel layes were 25 mol/ι and 0.53, respectively.