• 한국해양공학회지
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• 제18권1호
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• pp.75-79
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• 2004

Organic coatings are widely used to control of the corrosion of a steel structure. The water in coatings may cause the coatings to swell, leading to the degradation of the coatings. In addition, water affects the permeation of oxygen and other corrosive agents, and consequently, the presence of such substances at coating-metal interface promotes corrosion of the metal substrate. In this study, the anticorrosive properties of 4 types of coating, such as epoxy-epoxy, epoxy-urethane, urethane-epoxy, urethane-urethane, were evaluated. The evaluation tests were conducted under cyclic water-absorption/desorption conditions, consisting of alternative exposure to diluted 0.001M-LiCl(a$H_2O$≒1) and concentrated 10M-LiCl(a$H_2O$≒0.15). The anticorrosive performance of coatings was found to decrease in the order of urethane-urethane > urethane-epoxy > epoxy-epoxy coating.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2003년도 춘계학술대회 논문집
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• pp.262-268
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• 2003

Organic coatings are widely used to control the corrosion of steel structure. The water in coatings may cause swelling or solvation of coatings, leading to the degradation of coatings. In addition, water affects the permeation of oxygen and other corrosive agents, and consequently the presence of such substances at coating-metal interface promotes corrosion of metal substrate. In this study, the anticorrosive properties of 4 types of coating, such as epoxy-epoxy, epoxy-urethane, urethane-epoxy, urethane-urethane, were evaluated. The evaluation tests were carried out under cyclic water-absorption/desorption conditions, consisting of alternative exposure to diluted 0.001M-LiCl($a_{1120}{\fallingdotseq}1$) and concentrated l0M-LiCl($a_{1120}{\fallingdotseq}0.05$). The anticorrosive performances of coatings were found to decrease in the order of urethane-urethane> urethane-epoxy> epoxy-epoxy coating.

• 한국해양공학회지
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• 제17권6호
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• pp.77-82
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• 2003

The absorption of water into an anti-corrosive organic coating, such as alkyd and urethane resin coating, was investigated, using a quartz crystal microbalance (QCM). Anticorrosive properties of the coatings were also measured, by means of electrochemical impedance spectroscopy (EIS). The overall absorption of water in the coating is determined by the chemical nature of resin, and decreases with increasing thickness. The enhancement of anti-corrosive performance, through increase of coating thickness, was more remarkable in the case of the coating that hadlower equilibrium water absorption. The absorption kinetics curves were Fickian in nature. The EIS analysis confirmed that the resin, having lower equilibrium water absorption, shows higher anti-corrosive performan.

• 대한조선학회논문집
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• 제41권1호
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• pp.88-93
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• 2004

Electrochemical impedance spectroscopy was used to evaluate the anticorrosive properties of resin(alkyd, epoxy, urethane) and pigment(hydroxy apatite(HAp), zinc potassium chromate(ZPC). red lead(RL)). The corrosion behavior of coatings applied on steel has been investigated during exposure to 0.5M-NaCl The anticorrosive performances of resins were found to depend on their chemical nature and decreased in the order of urethane > epoxy > alkyd resin coating. Hydroxy apatite and zinc potassium chromate pigment which have property to passivate the substrate showed relatively high anticorrosive performance.

• 폴리머
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• 제34권5호
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• pp.405-409
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• 2010

내부식성이 우수한 기능기를 함유하는 새로운 졸-젤 전구체를 합성하고 이를 함유하는 유무기 하이브리드 코팅 조성물을 제조하였다. 코팅 조성물에는 통상의 졸-젤 전구체로 tetraethoxysilane을 사용하였고 비스페놀 A 타입의 에폭시를 실란화합물로 개질하였으며, 졸-젤 반응을 위하여 물과 HCl을 촉매로 사용하였다. 각 조성물은 졸-젤 전구체의 종류, 함량 등을 변화하여 다양한 코팅 조성물을 제조하였고 iron 기판위에 딥코팅하여 열경화하였다. 코팅된 iron 기판의 내부식성을 평가하기 위하여 염수분무시험과 전기화학적 임피던스 분광법을 사용하였는데, 내부식성 기능기를 함유한 유무기 하이브리드 코팅재가 일반적인 하이브리드 코팅재에 비해 매우 향상된 내부식성을 나타냄을 확인할 수 있었다. 내부식성 기능기를 함유한 코팅재의 경우, 0.1 M NaCl에서 500시간 이상 초기의 임피던스를 유지하는 반면, 일반적인 코팅재는 24시간 이후에 임피던스가 감소하는 것을 관찰할 수 있었다.

• Corrosion Science and Technology
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• 제10권3호
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• pp.95-100
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• 2011

Protective coatings play an important role in the protection of metallic structures against corrosive environment. The main function of anticorrosive coating is to prevent the materials from corrosive agents, such as water, oxygen and ions. In the study, the corrosion protection properties of urethane and epoxy coating systems were evaluated using EIS methods exposed to the corrosion acceleration test such as Norsok M501, Prohesion and hygrothermal cyclic test. AFM analysis of the coating systems was carried out to monitor the change of roughness of coatings. Urethane coating system was more stable than the epoxy coating under given cyclic conditions. Water uptake into the urethane coatings was less than that into the epoxy coating. The urethane coating system showed better corrosion protection than epoxy coating system based on the changes of the impedance modulus at low frequency region with exposure time. Consequently, the corrosion protection properties of the epoxy and urethane coatings was well correspond with their surface roughness changes and water uptakes.

• 한국결정성장학회지
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• 제31권3호
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• pp.137-142
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• 2021

본 연구에서는 상온경화형 silica-based 코팅제의 제조 및 해양구조물에 적용하여 가혹한 해양환경에서 방식 및 방오 성능 발현을 위한 실용화 개발 연구를 수행하였다. 구조상 외부에 노출된 부분이 많은 해양(플랜트) 구조물은 강한 자외선, 극심한 온도차, 염수에 의한 부식 등 가혹한 해양환경에 고립되어 운용된다. 이러한 환경 하에서는 쉽게 열화 되고 파도 등 물리적 자극에도 쉽게 침식되는 유기계 페인트들은 그 역할을 제대로 할 수 없다. 해양구조물에 치밀한 세라믹 코팅을 형성시킬 경우 녹이 발생하지 않고 경도가 높아 시설물을 해수환경 하에서도 치밀하게 보호할 수 있다. 세라믹 코팅제의 경우 그 기능의 장점들로 인해 해양 구조물에서 그 용도와 적용범위는 크게 증진될 수 있을 것이다. 따라서 colloidal silica를 기반으로 실란계 커플링제, 경화제 및 세라믹 충진제로 구성된 silica-based 코팅제 조성개발과 해수중 방식 및 방오용 보호코팅제로의 응용에 대해 연구하였다.

• Corrosion Science and Technology
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• 제5권5호
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• pp.177-180
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• 2006

The anticorrosive performance of epoxy coating was examined by using the hygrothermal cyclic test and the degradation mechanism of the coating was investigated by using the AC impedance method. The relationship between the results obtained from different tests was studied. It was revealed that the hygrothermal cyclic test can be used as an effective acceleration test for the degradation of organic coating. It was also found in hygrothermal cyclic test that the epoxy coatings have the resistance to stresses at some extent. The degradation of organic coating seems to be caused by the decrease of resistance of coating and the increase of both capacitance and free volume in the organic coating.

• Smart Structures and Systems
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• 제29권2호
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• pp.301-309
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• 2022

Protective coatings are most widely used anticorrosive structures for steel structures. The corrosion under the coating damages the host material, but this damage is completely hidden. Therefore, a field-applicable under-coating-corrosion visualization method has been desired for a long time. Laser ultrasonic technology has been studied in various fields as an in situ nondestructive inspection method. In this study, a comparative analysis was carried out between a guided-wave ultrasonic propagation imager (UPI) and pulse-echo UPI, which have the potential to be used in the field of under-coating-corrosion management. Both guided-wave UPI and pulse-echo UPI were able to successfully visualize the corrosion. Regarding the field application, the guided-wave UPI performing Q-switch laser scanning and piezoelectric sensing by magnetic attachment exhibited advantages owing to the larger distance and incident angle in the laser measurement than those of the pulse-echo UPI. Regarding the corrosion visualization methods, the combination of adjacent wave subtraction and variable time window amplitude mapping (VTWAM) provided acceptable results for the guided-wave UPI, while VTWAM was sufficient for the pule-echo UPI. In addition, the capability of multiple sensing in a single channel of the guided-wave UPI could improve the field applicability as well as the relatively smaller size of the system. Thus, we propose a guided-wave UPI as a tool for under-coating-corrosion management.