• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 봄 학술발표회 논문집
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• pp.201-206
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• 2002

The purpose of this study is to improve the anti-corrosive properties of coated reinforcing bar using polymer cement slurry. Poymer cement slurry are prepared with three types of polymer dispersions and corrosion inhibiting admixture. And tested for corrosion accelerating tests such as immersion in NaCl 10% solution NaCl 10% solution spray, high temperature and pressure steam in condition of 8cycles, carbonation before and after, penetration of NaCl solution. From the test results, it is concluded that the anti-corrosive properties are considerably improved by coating using polymer cement slurry at surface of reinforcing bar. And this trend is marked by adding of corrosion inhibiting admixture. The difference of the anti-corrosive properties is hardly recognized according to types of polymer dispersions. The anti-corrosive properties of coated reinforcing bar using polymer foment slurry are improved to a great extent compared to those of plain reinforcing bar accordiy to increasing content of chloride ion in cement concrete.

• Corrosion Science and Technology
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• 제7권2호
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• pp.92-98
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• 2008

This paper describes the experiments of the corrosion and the sliding tests of the nickel-based alloys for the gate valve seating materials used at high pressure and temperature. The general corrosion rates and IGC susceptibility are tested in pressurized water at 533 K and 575 K and in Strauss test solution. The sliding tests have been done in pressurized water at 293 k, 473 K and 573 k. The alloys containing above 10% chromium may have the anti-corrosion properties that could be applied to the valve seats for the power plants. The good sliding performance and the good pressure tightness are obtained when the disc specimens that have hardness 500 to 600 Hv combined with the seat specimens that have hardness 250 to 410 Hv containing about 40 percent of iron. The large size gate valves sliding tests have certified the test results. The anti-wear properties of the seat alloy and the anti-IGC susceptibility of the disc alloy could be improved by the addition of silicon and niobium, respectively.

• Corrosion Science and Technology
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• 제17권6호
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• pp.257-264
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• 2018

Anti-graffiti coatings have become more important. These layers must guarantee excellent corrosion protection properties, and graffiti must be easily removable, without reducing protection and aesthetic properties. In this study, anti-graffiti and corrosion behavior of two anti-graffiti polyurethane powder coatings were studied. These layers were deposited on aluminum substrate, with two different surface finishes, smooth, and wrinkled. The action of four different removers are investigated. Graffiti were drawn on coatings by means of red acrylic spray paint. Methyl-ethyl-ketone (MEK) and a "commercial" remover were the most effective solvents, in terms of graffiti removal capability, producing limited change in aesthetical surface aspect for smooth finishing. The wrinkled surface was less resistant. Corrosion protection properties, after removal action and contact with the remover, were evaluate by electrochemical impedance spectroscopy. After approximately 5 hours, coatings were no longer protective due to formation of defects. To simulate the weathering effect, UV-B cyclic test (4 hours of UV exposure followed by 4 hours of saturated humidity at $50^{\circ}C$) were performed for 2000 hours. Gloss and color changes were measured, and electrochemical impedance spectroscopy measurements were performed after aging and graffiti removal.

• Corrosion Science and Technology
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• 제7권6호
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• pp.370-374
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• 2008

In this study, we evaluated anti-corrosion properties of both commercial unleaded and lead epoxy primer for automotive substrate before applying to actual painting lines by salt spray test, and cyclic corrosion test, potentiodynamic test and electrochemical impedance spectroscopy. The difference in the corrosion resistance between automotive epoxy primers contained $Bi(OH)_{3}$ and leaded one was investigated. And it was also discussed the effect of zinc phosphate pretreatment to the epoxy primers. The specimen coated epoxy primer contained $Bi(OH)_{3}$ showed 0.5 V higher corrosion potential than that of bare steel. The result of salt spray test did not indicate remarkable difference of corrosion resistance in all specimens above $10{\mu}m$ thickness up to 1200 hours. In the cyclic corrosion test, epoxy primers contained $Bi(OH)_{3}$ on phosphated substrate performed good corrosion properties until 800 hours. The epoxy primer contained $Bi(OH)_{3}$ performed the equivalent corrosion resistance as leaded coating on phosphated steel, but slightly inferior to that of leaded on bare steel. These results show that the pre-treatment of zinc phosphate is effective as well as pigment changing in performing anti-corrosion properties in automotive bodies.

• Corrosion Science and Technology
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• 제8권6호
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• pp.243-250
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• 2009

When a steel sheet pipe applied to marine environment, an anti-corrosive coating should be treated to obtain long-term life-time for steels, especially, splash zone. Although anti-corrosive property of coatings is required to be tested in real marine environment, it is difficult because of long test time such as 20 years or more time. Therefore, we used cyclic corrosion tester in a laboratory, which has similar conditions with salt-dry-wet process such as real marine environment. Anti-corrosive properties of the coatings and two steels were tested their anti-corrosive properties under cyclic corrosion test conditions(KS D ISO 14993) and the results were compared with estimate life-time in real marine environment. According to cyclic corrosion test, accelerated corrosive factor of each anti-corrosive coating was investigated accelerated corrosive factor from impedance with EIS method. Accelerated corrosive factor of type SS400 carbon steel and A690 was also investigated their accelerated corrosive factor from the regression curves of weigh loss results. One of the anti-corrosive coatings showed about 50 years life-time compared with standard sample life-time. Carbon steel SS400 showed from 0.1 mm/yr to 0.06 mm/yr as its corrosion rate.

• International Journal of Naval Architecture and Ocean Engineering
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• 제13권1호
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• pp.707-717
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• 2021

To the date, shipbuilding companies have applied shop primer coating which protects the steel surface from global oxidization in environment. Proper shop primer requires either anti-corrosion ability during construction or anti-porosity ability during welding, and those properties contradict to each other. This report tried to derive an optimizing parameter on these conflicting properties to select a proper shop primer. First, sufficient amounts of the natural salt spray tests were carried out to achieve a series of data for the anti-corrosion ability. Second, lots of T-joint fillet welding test were performed to evaluate the trapped porosity formed in the weld pool. According to the experimental data, we could achieve either the rust-formation rate or the porosity-formation rate, then, each rate was generalized as formulae. Then, we tried to combine these conflicting properties to decide an optimum shop primer.

• Corrosion Science and Technology
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• 제14권5호
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• pp.213-217
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• 2015

Recently, household electronic industries require environmentally-friendly and highly functional steels in order to enhance the quality of human life. Customers especially require both excellent corrosion and abrasion resistant anti-fingerprint steels for digital TV panels. Thus POSCO has developed new functional electro-galvanized steels, which have double coated layers with organic-inorganic composites on the zinc surface of the steel for usage as the bottom chassis panel of TVs. The inorganic solution for the bottom layer consists of inorganic phosphate, magnesium, and zirconium compounds with a small amount of epoxy binder, and affords both improved adhesion properties by chemical conversion reactions and corrosion resistance due to a self-healing effect. The composite solution for the top layer was prepared by fine dispersion of organic-inorganic ingredients that consist of a urethane modified polyacrylate polymer, hardener, silica sol and a titanium complex inhibitor in aqueous media. Both composite solutions were coated on the steel surface by using a roll coater and then cured through an induction furnace in the electro-galvanizing line. New anti-fingerprint steel was evaluated for quality performance through such procedures as the salt spray test for corrosion resistance, tribological test for abrasion resistance, and conductivity test for surface electric conductance regarding to both types of polymer resin and coating weight of composite solution. New composite coated anti-fingerprint steels afford both better corrosion resistance and abrasion properties compared to conventional anti-fingerprint steel that mainly consists of acrylate polymers. Detailed discussions of both composite solutions and experimental results suggest that urethane modifications of acrylate polymers of composite solutions play a key role in enhanced quality performances.

• 공업화학
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• 제22권4호
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• pp.367-375
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• 2011

숙신산 에스테르 유도체는 방청성능 및 윤활성능이 우수하여 금속가공유 및 유압작동유 등의 첨가제로 많이 사용되고 있다. 본 연구에서는 광유계 윤활기유의 방청제로 사용하기 위하여 알킬 무수 숙신산과 여러 가지 지방 알콜과의 개환반응을 행하여 카르복실 그룹과 에스테르 그룹을 동시에 함유하는 숙신산 알킬 하프-에스테르 유도체를 97% 이상의 수율로 합성하였으며 1 중량% 농도범위에서 광유계 오일에 잘 용해되었다. 합성 유도체는 $^1H-NMR$ 및 FT-IR 스펙트럼으로 구조를 확인하였으며, GC 분석을 통하여 화합물의 순도를 확인하였다. 또한, 합성 유도체의 해수에 대한 방청성능을 ASTM D665 표준방법과 무게 중량법으로 평가하여 카르복실산 그룹을 함유하지 않는 숙신산 알킬 에스테르 유도체와 비교하였다. 방청성능 평가 결과, 합성 유도체의 농도가 증가하고 분자 내에 포함된 알킬기의 사슬이 짧을수록 상대적으로 방청성능이 우수하였으며 비교물질인 숙신산 알킬 에스테르 유도체는 방청성능을 전혀 나타내지 않았다. 무게 중량법으로 평가한 80 중량ppm 농도를 첨가한 오일의 방청효율 % (IE%)는 알킬기의 사슬이 짧을수록 높은 값을 나타내어 최고 95% 이상이었다. 또한, 발청속도(Corrosion rate, CR)는 알킬기의 사슬이 짧을수록 낮은 값을 나타내어 80 중량ppm에서 최고 0.3 mm/year 이하를 나타내었다. 즉, 숙신산 알킬 하프-에스테르 유도체의 해수에 대한 방청성능은 분자 내에 함유되어 있는 카르복실산 그룹으로 인하여 나타나는 것으로 판단되었다.

• 한국응용과학기술학회지
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• 제24권4호
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• pp.399-409
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• 2007

Characteristics of polyaniline anti-corrosive coatings with various primer coating resins(epoxy resin, urethane resin, and others) and top coating resins(epoxy and acrylic urethane resins) were investigated through adhesion, acid resistance, alkaline resistance, water resistance, and anti-corrosion tests. As a result, the anti-corrosive properties of the prepared coatings using polyaniline varied with the types of primer and top coating resins. In this condition, the properties of adhesion, chemical resistance, and water resistance were found to be very satisfactory when using emeraldine base (EB) of polyaniline blended with single-packaged urethane and acrylic urethane resins as the primer coatings, and using acrylic urethane resin as the top coatings. Also, the anti-corrosive function of these anti-corrosive coatings was well preserved for 1000 hr in the salt spray experiment.

• 청정기술
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• 제17권4호
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• pp.314-324
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• 2011

아마이드 유도체는 방청성능 및 윤활성능이 우수하여 금속가공유 및 유압작동유등의 첨가제로 많이 사용되고 있다. 본 연구에서는 광유계 윤활기유의 방청제로 사용하기 위하여 알킬 무수 숙신산과 여러 가지 아민과의 링개환 반응을 행하여 카르복실 그룹과 아마이드 그룹을 동시에 포함하는 숙신산 알킬 하프-아마이드 유도체들을 97% 이상의 수율로 합성하였으며 합성구조에 따라 1 중량% 농도범위에서 광유계 오일에 용해되었다. 합성 유도체의 구조는 $^1H$-NMR 및 FT-IR 스펙트럼으로 행하였으며 GC 크로마토그램을 통하여 화합물의 순도를 확인하였다. 또한, 합성 유도체의 해수에 대한 방청성능을 ASTM D665 표준방법과 무게 중량법으로 평가한 결과, 합성 유도체의 농도가 증가하고 알킬기의 사슬이 짧고 2차 아민으로 합성한 숙신산 알킬 하프-아마이드의 방청성능이 1차 아민으로 합성한 유도체보다 상대적으로 방청성능이 우수하였다. 무게 중량법으로 평가한 방청효율% (IE%)는 알킬기의 사슬이 짧을수록 우수한 방청효율을 나타내었으며 구조에 따라 방청효율에 차이를 나타내었다. 40 ppm 농도를 첨가한 오일의 IE%는 최고 93% 이상이었다. 또한, 발청속도(Corrosion Rate, CR)는 알킬기의 사슬이 짧을수록 낮은 값을 나타내어 합성 유도체 40 ppm 농도를 첨가한 오일의 CR 값은 최고 0.5 mm/year 이하로 나타났다.