• 한국표면공학회:학술대회논문집
• /
• 한국표면공학회 2016년도 추계학술대회 논문집
• /
• pp.136-136
• /
• 2016

Commonly used oil-based polymer resin has environmental and safety issues. Many researches for replacing the harmful solvent-borne resins to water-borne resins have been investigated to purify harmful environmental resources and follow the export and import of hazardous materials regulations. In this research, ultrasonic spray coatings of aqueous polymer resin were studied to fabricate thin insulating layer (${\sim}{\mu}m$) on the rectangular copper wire. It needs to have appropriate wettability between resin and substrate during the ultrasonic spray coating process to coat aqueous polymer uniformly. Furthermore, stabilities of coating solution and fabricating process are required to form thin insulating layer on the substrate. In here, physical characteristics such as viscosity of 6 types of commercial polymer dispersions and emersions were analyzed to confirm compatibility for ultrasonic spray coating process. These resins were dissolved in isopropyl alcohol, used for true solvent, and were diluted with ethanol, utilized for diluent. Also, solubilities, dispersion characteristics, and viscosities of these diluted polymer resin solutions were confirmed. Dispersion characteristic and viscosity of coating solution affects jetting of ultrasonic spray coating and these jetting characteristics influence morphologies of insulating layer. In conclusion, we have known that aqueous polymer solution should have outstanding dispersion characteristic and certain range of viscosity to fabricate thin polymer insulating layer uniformly with ultrasonic spray coating.

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

• Journal of Electrochemical Science and Technology
• /
• 제10권2호
• /
• pp.148-158
• /
• 2019

The corrosion protection of AA2024 PPy coated samples doping with nanosized metal oxides, including $TiO_2$ and $CeO_2$ nanoparticles and $Nd_2O_3$ nanorods, during exposure to the solutions of 0.1 M $H_2SO_4$ and 3.5% NaCl was evaluated by electrochemical impedance spectroscopy (EIS) and linear polarization resistance (LPR) techniques. The nanorods of $Nd_2O_3$ were synthesized by cathodic pulse electrochemical deposition technique. The barrier properties of the different PPy coatings containing nanosized metal oxides immersed in $H_2SO_4$ solution were ranked as follows: $Nd_2O_3$ > $TiO_2$ > $CeO_2$. Therefore, the $Nd_2O_3$ coating sample provided the highest corrosion protection at any time of immersion up to 72 hours after immersing in $H_2SO_4$ solution. On the other hand, the $CeO_2$ coating sample displayed the best anticorrosive properties among the other coating samples after immersion in NaCl solution up to 28 days. This is due to the inhibition effect of cerium ions on aluminum alloys at near-neutral solutions.

• 한국표면공학회:학술대회논문집
• /
• 한국표면공학회 2016년도 추계학술대회 논문집
• /
• pp.124.2-124.2
• /
• 2016

Corrosion resistance and adhesion of electro-paint (E-paint) with fluoride conversion coating (FCC) on AZ31 Mg alloy were studied. Corrosion resistance and adhesion were studied as a function of FCC-treatment time and concentration of FCC-bath. Aqueous hydrogen fluoride (HF) solutions, with concentrations ranging from 0.5 M to 5 M, were used to form FCC on chemically polished AZ31 Mg alloy samples for six different times; 10, 30, 60, 90, 120, and 180s. The results from salt spray test (SST) showed that corrosion resistance of E-paint appeared to decrease with increasing FCC treatment times in low concentration FCC baths. The number of blisters formed on the FCC-treated samples increased with increasing FCC treatment time of more than 1 min in low concentration (0.5 M to 1 M) solutions. On the other hand, samples treated in the 5 M HF solution for 120s showed no delamination or blistering even after 1200h of SST.

• 한국윤활학회:학술대회논문집
• /
• 한국윤활학회 1996년도 제24회 추계학술대회
• /
• pp.183-188
• /
• 1996

Films and coatings are used for an enormous and diverse set of applications including mechanical, electronic and optical devices, protection at high temperature, cutting tools enhancement and automotive use. Many of these applications require the various properties associated with inorganic and metallic / non-metallic materials; i.e., with ceramics. Therefore, a large number of coatings have been developed and used for a long time in the various fields, especially in mechanical one. As one of the mutual surface actions, the problems of contact stresses are complex. The relationship between load and stress are nonlinear. Besides, the material is often apt to deform plastically under low load. However, analytical solutions exist only for some simple problems. If a material has a complicated shape or inhomogeneous properties, numerical method must be used. In this paper, the analysis of the contact stress of the coating layer was solved, using the finite element method.

• 동력기계공학회지
• /
• 제8권4호
• /
• pp.38-43
• /
• 2004

Thermal spraying onto the metal substrate has been widely used as a technique of the surface treatment in the various industrial field. A wide range of thermal spray technologies exist and all rely on the fundamental process of fusing a metal feedstock, atomizing it and transporting it to the surface of a substrate. Specially, these methods have been taken into account as the protection method against the corrosion. In this study, the polarization characteristics were carried out on the thermal sprayed coating layer immersed in various pH of diluted aqueous solutions at $25^{\circ}C$. Aluminum, Zinc, Ni-base alloy, alumina and polyethylene powder were used with sprayed coating materials. From the polarization curves, the electrochemical corrosion potential($E_{corr}$) and the corrosion current density($I_{corr}$) were investigated.

• 한국표면공학회:학술대회논문집
• /
• 한국표면공학회 2015년도 추계학술대회 논문집
• /
• pp.189-189
• /
• 2015

In this study, the corrosion resistance and adhesion of electrophoretic paint (E-paint) were studied on AZ31 magnesium alloy pretreated in cerium chemical conversion coating solutions with the addition of various ethanol concentrations. It was found that with increasing ethanol concentration from 0 to 90 percent can decrease the formation of $Mg(OH)_2/MgO$ and increase the formation of nano-crystalline cerium oxides on the coating. Both corrosion resistance and adhesion of E-painted AZ31 increased with increasing ethanol concentration. The best E-paint sample was observed on the sample pretreatment in cerium chemical conversion coating solution with the addition of 80 percent of ethanol. This sample showed an excellent adhesion without paint detached after water immersion test for 500 h at $40^{\circ}C$, and only a few blisters observed at the near scratched sites after 1000 h salt-spray test.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
• /
• pp.1927-1929
• /
• 2005

Colloidal Silica(CS)/methyltrimethoxy silane(MTMS) sol solutions were prepared in variation with synthesizing parameters such as kinds of CS, acidity and reaction time. In order to understand its surface properties, sol-gel coating films on glass were fabricated. The coating film obtained from CS/MTMS sol had stable contact angle and more enhanced flat surface at reaction time of 24 hours. In case of the initial and final period of reaction, the coating films had unstable contact angle and more rough surface. In addition, surface of CS/MTMS sol-gel coating film was more rougher with increasing of acidity.

• 한국표면공학회지
• /
• 제22권3호
• /
• pp.109-117
• /
• 1989

The effect of heft treatment on the characteristic properties of insulation layer is studied for two kinds of non-oriented silicon steels, which were insulation-coates with various kinds of inorganic and inorganic-organic complex coating solutions. In addition, how the carbon contained in the insulation layer would affect the carbon content and the magnetic properties of the steel substrates is examined. Lower temperature heat treftment ($480^{\circ}C$ for 0.5hr) is found to render morw favorable surface qualities, wheras higher temperature heat treatment ($790^{\circ}C$ for 2hr) better core loss due to grin growt occurred during the heat treatment. Decarburization of the steel substrate is also found unaffectrd by the presence of carbon in the insulation layer.

• Korean Chemical Engineering Research
• /
• 제57권2호
• /
• pp.177-184
• /
• 2019

Methyltrimethoxysilane (MTMS)과 trimethylethoxysilane (TMES)을 전구체로 사용하여 비 불소계 발수 코팅 용액을 제조하였다. 이 코팅 용액을 냉연 강판 위에 스핀 코팅하고 열 경화시켜 발수 코팅 도막을 제조 하였다. 이 과정 중 코팅 도막의 소수성에 미치는 TMES/MTMS의 몰 비 영향이 연구되었다. 코팅 도막의 소수성은 접촉각 측정, 표면 형상 분석 및 적외선 분광법을 사용하여 연구되었다. TMES/MTMS의 몰 비를 0에서 30까지 변화 시켰을 때, 코팅되지 않은 냉연강판의 접촉각은 $30^{\circ}$인 반면에 TMES/MTMS의 몰 비가 1인 경우는 접촉각이 $104^{\circ}$로 크게 증가하여 발수성이 향상되었다. 또한 TMES/MTMS의 몰 비가 10, 15, 25, 30인 경우는 각각 접촉각이 $109^{\circ}$, $114^{\circ}$, $117^{\circ}$, $144^{\circ}$로 TMES/MTMS의 몰 비가 증가할수록 냉연강판의 접촉각이 점차 증가하는 경향을 보였다. 이때 코팅 도막의 소수성은 표면 거칠기의 증가와 코팅 표면에서의 메틸 성분의 함량 증가로 인해 향상되었다. 특히 TMES/MTMS의 몰 비가 30인 경우에는 TMES의 메틸기로 인한 발수성뿐만 아니라 표면 입자의 존재로 인해 전체적인 표면 거칠기가 크게 증가하였기 때문에 $144^{\circ}$의 초발수성을 나타내었다.