• Corrosion Science and Technology
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• 제14권5호
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• pp.207-212
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• 2015

The purpose of this research was to synthesize fluorine modified waterborne polyurethane dispersion (F-WPU) by soap-free (internal emulsifier) emulsion polymerization techniques, to prepare coating solution based on fluorine modified waterborne polyurethane dispersion (F-WPU) and to compare the chemical and thermo-mechanical properties on the electrogalvanized steel sheet. Environmentally friendly F-WPU was prepared with a fluorinated polyol containing 60 wt% of fluorine. There are various ways of combining a wide variety of fluorinated polyols and diisocyanate to exhibit novel properties of waterborne polyurethane dispersion. Components of coating solution were largely divided into 4 kinds i.e., F-WPU, acrylic emulsion, silane coupling agent, and colloidal silicate. F-WPU coating solution on the electro-galvanized steel sheet showed excellent properties of corrosion resistance, alkali resistance and heat resistance, as compared to other coating solutions using a general waterborne resin. The F-WPU coating solution's reliable effects are possibly due to the fluorine atoms incorporated even in a small amount of F-WPU.

• Korean Chemical Engineering Research
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• 제51권1호
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• pp.73-79
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• 2013

Polycarbonate diol (PCD), isophorone diisocyanate (IPDI)와 dimethylol propionic acid (DMPA)를 출발물질로 하여 수분산 폴리우레탄(waterborne polyurethane dispersion, WPUD)을 합성하였다. WPUD에 아크릴 단량체인 methyl methacrylate (MMA)를 첨가하여 수분산 아크릴 폴리우레탄(waterborne acrylic polyurethane dispersion, AUD)을 합성하였다. 이 AUD와 물에 분산되어 있는 multi-walled carbon nanotube (MWCNT)를 혼합하여 전도성 코팅 용액을 제조한 후 polycarbonate 시트 위에 도포하여 코팅 도막을 형성하였다. AUD 중의 MMA의 첨가량이 증가될수록 코팅 도막의 연필경도, 내마모성 및 내약품성은 향상되었으나 전기 전도도는 감소하였다. 반면에 전도성 코팅 용액 중의 MWCNT의 첨가량이 증가될수록 코팅 도막의 연필경도, 내마모성 및 내약품성은 감소되었으나 전기 전도도는 증가하였다.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.7-8
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• 2002

It is a time to introduce a concept of lubrication to space systems. Minimum amount of lubricant should be supplied to a contact interface instead of preparing too much lubricant on surfaces of the earth. In situ controllable lubrication method is wanted to overcome unexpected tribo-troubles in space. Tribo-coating, which forms a thin solid film in nm-scale by vacuum deposition during friction, is a promising lubrication method for space.

• 한국표면공학회지
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• 제30권5호
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• pp.347-354
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• 1997

Composite plating is a method of co-depositing fine particles of metallic, non-metallic compound or polymers in the plated layer to improve material properties such as were-resistance, lubrication, or corrosion resistance. Graded Ni-Sic composite coating were produced in this research. Prior to produce Graded Ni-SiC composite coatings, effects of particle size, particle content, pH of electrolyte, temperature, current density, stirring rate on the amount of SiC deposited in the Ni layer were investigated. By manipulating current density and plating time properties of these coating were evaluated by micro-indentation hardness test.

• 펄프종이기술
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• 제29권3호
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• pp.17-25
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• 1997

Natural water-soluble polymers such as starch, casein and carboxy methyl cellulose(CMC) have been limited in their uses. However, the proper water retention of coating colors can not be obtained without addition of these polymers. Furthermore, the coating runnability and the physical properties of coated paper were not also satisfied. Therefore, the objective of this study was to synthesize the water retention and flow modifiers which can improve the water retention and flow properties of coating colors. We have measured physical properties of flow modifiers and coating colors which included flow modifiers. The viscosity of flow modifiers was very low at acid pH, and rapidly increased at about pH 7, and gradually reached to equilibrium at alkali pH. Such an increase comes from the molecular weight of flow modifiers and the amount of acrylic and methacrylic acids. The viscosity of coating color containing the flow modifiers was lower than that containing CMC. However, both of them had little difference in water retention. The water-phase viscosity of synthetic modifier containing coating color was either higher or similar compared to that of CMC containing coating color. The high shear viscosity of coating colors was low. Therefore, it can be concluded that the synthetic flow modifiers are very useful for improvement of flow properties and water retentions.

• 대한안전경영과학회지
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• 제21권3호
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• pp.23-27
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• 2019

The first aim of the study is to improve the productivity by uniformizing the thickness of coating and reducing quality-inspection time. The second aim is to cut down on the raw materials for coating by prevent the waste of spraying in the air during a painting process through a real-time coating-size-recognition monitering to fit the target components. To achieve the two aims, a simplified version of automatic coating control system for recognition of coating for vessels and Spray. With the sytem, following effects are expected: First, quality improvement will be achieved by uniformizing the film-thickness. Second, it will reduce the waste of coating paint by constructing the speed of the coating, the spray gun robot transfer time, and the number of DBs according to the size of the vessel. Third, as a 3D industry, it will be able to solve the difficulty of supply of labors and save up the labor costs. Therefore, in the future, further research will be needed to be applied to various products with DB design that designates the variable value, which is added for each type of pieces by comparing the difference between various types of workpieces and linear ones.

• Smart Structures and Systems
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• 제32권2호
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• pp.123-133
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• 2023

This paper proposes a thermography-based coating thickness estimation method for steel structures using model-agnostic meta-learning. In the proposed method, a halogen lamp generates heat energy on the coating surface of a steel structure, and the resulting heat responses are measured using an infrared (IR) camera. The measured heat responses are then analyzed using model-agnostic meta-learning to estimate the coating thickness, which is visualized throughout the inspection surface of the steel structure. Current coating thickness estimation methods rely on point measurement and their inspection area is limited to a single point, whereas the proposed method can inspect a larger area with higher accuracy. In contrast to previous ANN-based methods, which require a large amount of data for training and validation, the proposed method can estimate the coating thickness using only 10- pixel points for each material. In addition, the proposed model has broader applicability than previous methods, allowing it to be applied to various materials after meta-training. The performance of the proposed method was validated using laboratory-scale and field tests with different coating materials; the results demonstrated that the error of the proposed method was less than 5% when estimating coating thicknesses ranging from 40 to 500 ㎛.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 1999년도 춘계학술발표회 초록집
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• pp.97-97
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• 1999

Dross formation in the zinc bath is inevitable under any condition as long as coating process on steel strip continues. Thus, bath aluminum and temperature are precisely managed to suppress the increase of dross. Also, excessive dross for normal coating process is generally eliminated physically by bubbling and skimming. Total amount of dross in the bath can be sometimes high enough to cause coating defect. On the other hand, local concentration of dross can make coating defect even with satisfactory level of total amount of dross. Reduction of dross in the bath was attempted by using ceramic foam filter made of mainly alumina. Dross in molten zinc was almost reduced to the levels of solubility of iron and aluminum in molten zinc at $450~460^{\circ}C$. Their solubility levels were confirmed by thermodynamic calculations or DEAL program. Two kinds of filters were tested for dross reduction. One was #20 ppi, porous per inch, and the other #30 ppi filter. Both were effective in reducing the bath dross to the solubility levels at the static state. Bath iron was reduced by 24 wt% and 19 wt% with #20 filter, and by 35 wt% and 29 wt% with #30 filter for GI and GA pot, respectively. Also, ceramic foam filter did not make any harm to the zinc bath composition after filtering test.

• 전기화학회지
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• 제1권1호
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• pp.55-59
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• 1998

방식도막의 수명에 가장 큰 영향을 미치는 물의 흡수과정을 quartz crystal microbalance법 및 임피던스 원리를 이용하여 연구하였다. 도막에 있어서 물의 흡수량과 전해질 농도 변화에 따른 도막의 capacitance를 조사하였다 방식도막에 대한 물의 흡수는 삼투압 작용에 의해서 이루어지고, 흡수 초기단계에서는 도막두께가 얇을수록 흡수량이 많은 것을 알 수 있었다 그리고 도막을 구성하고 있는 수지의 종류 및 결합 가교밀도에 따라서 흡수성이 큰 영향을 받는다는 것을 알 수 있었다. 또한 방식도막에 있어서는 접촉하는 전해질 용액의 농도 변화에 따라 흡$\cdot$탈수 현상이 발생하였으며, 같은 종류의 도막이라도 도막두께가 얇을수록 탈수현상에 따른 capacitance의 증가폭이 큰 것으로 나타났다

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.615-616
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• 2005

Carbon Nanotubes (CNT) on flexible indium tin oxide (ITO) PET films were prepared for dye-sensitized solar cell (DSSC). These CNTs were prepared by spray coating method for various amount of light transparency. Also, Pt counter electrode was prepared by electro deposition method. All $TiO_2$ electrodes were deposited on ITO-PET films by spray coating method. Micro structural images show that CNT counter electrodes prepared by spray-coating have more dense structure with increasing spraying time (0 to 60 seconds). DSSC consisting of $TiO_2$ electrode and CNT counter electrode was fabricated with various amount of light absorption. DSSC have higher light energy conversion efficiency with increasing the thickness of CNT counter electrode. CNT counter electrode is at least compatible to that of CNT counter electrode.