In this paper, graphene-coated Al powders prepared by in situ reduction method were directly used for cold spraying, obtaining a graphene-reinforced Al matrix composite coating with more compact structure and better performance. Cross-sectional analysis revealed that compared with the pure Al powders, the graphene-coated Al powders were more severely deformed, and the resulting coating was denser and its porosity was reduced by over 80%. The hardness of the graphene-coated Al coating was increased by 40%, and its brine immersion time was prolonged by nearly three times. However, the graphene increases the pitting sensitivity of the Al coating; so, the enhanced corrosion resistance of the graphene-coated Al coating is mainly attributed to the improvement of its structure densification.

This study dealt with passenger safety assessment of roadside barrier structures using high anti-corrosion steels, which are called hot-dip zinc-aluminium-magnesium alloy-coated steels. We performed a simulation with high anti-corrosion barriers capable of absorbing impacts and calculated the breakage stress to assess passenger safety. Passenger safety was assessed by calculating the THIV (Theoretical Head Impact Velocity) and PHD (Post-Impact Head Deceleration). This process compares normal steel materials and high anti-corrosion steel materials. The simulation test results for the roadside barriers built with high strength anti-corrosion steels with reduced sectional thickness meet the safety evaluation criteria, hence the proposed roadside barrier made by high strength and high anti-corrosion hot-dip zinc-aluminium-magnesium alloy-coated steel will be a good solution to serve passenger safety as well as save maintenance cost and better structural performance.

As wrought stainless steel, sintered stainless steel (STS) has excellent high-temperature anti-corrosion even at high temperature of 800ºC and exhibit corrosion resistance in air. The oxidation behavior and oxidation mechanism of the sintered 316L stainless was reported at the high temperature in our previous study. In this study, the effects of additives on high-temperature corrosion resistances were investigated above 800ºC at the various oxides (SiO2, Al2O3, MgO and Y2O3) added STS respectively as an oxidation inhibitor. The morphology of the oxide layers were observed by SEM and the oxides phase and composition were confirmed by XRD and EDX. As a result, the weight of STS 316L sintered body increased sharply at 1000oC and the relative density of specimen decreased as metallic oxide addition increased. Compared with STS 316L sintered parts, weight change ratio corresponding to different oxidation time at 900oC and 1000oC, decreased gradually with the addition of metallic oxide. The best corrosion resistance properties of STS could be improved in case of using Y2O3. The oxidation rate was diminished dramatically by suppression the peeling on oxide layers at Y2O3 added sintered stainless steel.

To improve the chemical stability of metal, the ceramic coatings on metallic materials have attracted interest from many researchers due to the chemical inertness of ceramic materials. To endure strong acids, SiOC coating on metal substrate was carried out by dip coating method using 20wt% polyphenylcarbosilane solution; SiC powder was added to the solution at 10wt% and 15wt% to improve the mechanical properties and to prevent cracks of the film. Thermal oxidation as a curing step was carried out at 200˚C for crosslinking of the polyphenylcarbosilane, and the coating samples were pyrolysized at 800˚C under argon to convert the polyphenylcarbosilane to SiOC film. The thicknesses of the SiOC coating films were 2.36μm and 3.16μm. The quantities of each element were measured as SiO1.07C6.33 by EPMA, and it can be confirmed that the SiOC film from polyphenylcarbosilane was formed in a manner that was carbon rich. The hardness of the SiOC film was found to be 3.2Gpa through nanoindentor measurement. No defect including cracks appeared in the SiOC film. The weight loss of the SiOC coated stainless steel was within 2% after soaking in 10% HCl solution at 80˚C for one week. From these results, SiOC coating shows good potential for application to protect against severe chemical corrosion of stainless steel.

The acrylic coating emulsions were prepared by the emulsion polymerization to protect the surface of steel plate from the corrosion chemicals like acid, base and salt water. MMA(methyl methacrylate), styrene, BA(butyl acrylate), and 2-HEMA(2-hydroxyethyl methacrylate) were used as monomer. KPS(potassium persulfate) and SBS(sodium bisulfite) as redox initiator and SDBS(sodium dodecylbenzene sulfonate) as emulsifier were used on the emulsion polymerization reaction. The most stable in-situ coating was obtained when 10% of MMA was added. Both particle size and quantity in emulsion were decreased as increasing the mount of SDBS. the most stable prepared coating emulsion with polyisocyanate crosslinker showed very high anticorrosion properties on the coated steel layer to salt water, whereas no significant improvement of anticorrosion property to acdic and basic condition it showed.

이 연구에서는 강교량 노후화의 주요 원인인 부식손상에 대하여 현재 작성 중인 강교량 방식 가이드라인을 소개하고자 한다. 강교량 방식 가이드라인은 최근 연구 성과 및 최신 기술 등을 바탕으로 강재의 부식과 방식, 강교량의 부식 상태 조사 및 평가, 강교량의 보수 도장 및 방식대책, 강교량의 폐합 단면 및 폐합 부재의 부식상태 조사 및 평가, 방식대책으로 구성 되어 있다. 이처럼 가이드라인은 강교량의 일반적인 부식, 방식을 포함하여 인력점검이 어려운 부재, 폐합 부재의 부식조사, 평가법 등까지 실무에서 활용할 수 있도록 개발 중이다.

산업화, 도시화로 인해 수자원의 오염이 악화 되면서 기존에 염소를 이용한 정수처리 방법으로는 깨끗한 물을 공급하는데 어려운 실정이다. 이에 오존을 이용한 고도정수 처리 시설의 도입이 증가하고 있다. 그러나 기존의 방수⋅방식 공법으로 사용되는 에폭시계 방수⋅방식제 및 스테인리스는 오존의 강력한 산화력으로 인해 열화되어 박리 등 문제 발생하였으며, 콘크리트까지 영향을 미쳐 내구성 저하의 원인이 된다. 이에 따라 본 연구에서는 내오존성 및 내화학성이 뛰어난 금속 패널을 기존의 시공법 보다 손쉬운 방법으로 시공하기 위한 방법으로 금속용사 공법을 이용하여 수처리 시설 콘크리트 구조물의 열화를 원천적으로 방지하기 위한 마감공법 개발 연구의 일원으로 용사금속 종류 에 따른 내오존성 평가를 실시하였으며, 실제 하수처리장 환경에서의 전기화학적 안정성능 평가를 실시하였다. 실험결과 용사금속 Ti이 용사 후에도 내오존성이 뛰어난 것으로 나타났으며, 하수처리장 환경에서의 전기화학적 안정성능 평가 결과 용사금속 Ti가 403.83k∙ Ω∙cm2의 가장 높은 분극저항을 나타남으로써 높은 수준의 내구성을 확보하는 것을 확인할 수 있었다.

부식 현상은 발전소 및 대규모 난방가동시설 등의 각종 산업 현장에서 해결해야할 중대한 문제 중 하나이다. 특히 보일러 시스템의 높은 가동 온도 조건은 부식의 주된 원인으로 이러한 고온 부식 현상을 억제하기 위한 다양한 재료 및 방법들에 대한 연구가 활발히 진행되고 있다. 본 연구에서 우리는 직접 개발한 세라믹 코팅을 현장 보일러 시스템에 적용하는 실험을 통해 보일러 가동조건에 따른 내부식성에 대해 고찰해보았다. 특히, 현장 보일러 시스템에 적용하는 연구를 통해 고온 환경에서의 내부식성 뿐만 아니라 연소 후 발생하는 각종 생성물에 의한 보일러 관 부착 현상에 대해서도 상대적으로 평가할 수 있었다. 또한, 세라믹 코팅의 내부식성에 대한 효과로 인해 발생하는 보일러 관의 수명연장효과(잔여 수명 분석)에 대해서도 정량적으로 분석하였다.

This paper presents a study on the adhesive strength testing of self-adhesive waterproofing/anti-corrosion sheet used for waterproofing of the large diameter steel pipe interior of water treatment facilities. After the sheet has been applied, similar physical and chemical immersion conditions are simulated in the testing to determine the effects of deterioration through adhesion strength testing.

Background : Corrosion is one of the most devastating problems faced by most industries. Mild steel has played a vital role in various fields due to the excellent mechanical properties of mild steel such as low density, high strength-to-weight ratios, good environmental stability, high thermal conductivity, and corrosion resistance. Methods and Results : The total phenolic contents (TPC) and total flavonoid contents (TFC) of the methanolic extract of C. grandiflora and R. verniciflua leaf have been examined, and its corrosion inhibition performance was investigated by weight loss and electrochemical impedance spectroscopy (EIS) and polarization measurements. The surface morphology of mild steel was analyzed by scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDX) and by atomic force microscopy (AFM). The percentage composition of polyphenolic compounds was found to be higher in C. grandiflora and R. verniciflua plant extracts, and it was proved to be a superior, eco-friendly, and anti-corrosive inhibitor for mild steel in 1M of H2SO4. The Tafel polarization studies indicate that the plant extract is a mixed-type inhibitor. Scanning electron microscopy/energy -dispersive X-ray spectroscopy (SEM-EDS), and atomic force microscopy (AFM) studies confirmed the formation of a protective film on the metal surface. The corrosion inhibition of the C. grandiflora and R. verniciflua plant extracts was characterized by Fourier transform infrared (FT-IR), UV-visible spectra, and wide-angle X-ray diffraction (XRD) studies; these show the strong interaction between the metal surface and the inhibitor. Conclusion : The methanolic extract was prepared the two different plants like C. grandiflora, and R. verniciflua was studied the corrosion inhibition on the mild steel specimen in acidic medium through various methods involving weight loss measurements, EIS, and potentiodynamic polarization. The results shows that the C. grandiflora, and R. verniciflua plant extracts illustrate an effective corrosion inhibitor for mild steel with good anticorrosion properties in acidic environmen

This study proposes a selection method of a performance evaluation index of waterproofing and anti corrosion materials used in domestic water treatment facilities for material and construction failures based on different usage and environmental conditions to study the possibility of structural performance maintenance. Different types of waterproofing･anti-corrosion materials have been evaluated based on their respective properties, and have been classified into separate categories based on their case studies of material failures in construction. As a result, 12 different performance evaluation indexes have been produced for the performance evaluation method. Among the 12 performance evaluation index 5 were selected with relatively low importance that produced a low value of 60% importance using AHP analysis method, and conclusively proposed 7 performance evaluation index criteria (wet surface adhesion, fatigue resistance, crack resistance, adhesion performance, joint performance, impact resistance, impermeability)

In this study, review anti-corrosion performance of the metal spraying sealing agents in according to molecular weight. It was evaluated according to KS D 9502 CASS test for determine anti-corrosion performance of sealing agents. Results showed, the molecular weight range of 20,000∼30,000 molecular sealing treatment manufactured through the control material exhibited the best performance.

Concrete structure is a construction material with durability and cost-benefit, however the corrosion in embedded steel causes a critical problem in structural safety. This paper presents an evaluation of chloride resistance and pull-off performance with various corrosion level. For the work, OPC(Ordinary Portland Cement) concrete and GGBFS(Ground Granulated Blast Furnace Slag) concrete are prepared with normal steel. Artificially notch induced FRP Hybrid Bar is also prepared and embedded in OPC concrete and accelerated corrosion test is performed. Through the test, FRP Hybrid Bar with notch is evaluated to have insignificant effect on pull-off capacity when corroded steel shows only 21% level of pull-off capacity. Furthermore GGBFS concrete with normal steel shows over 70% level of pull-off capacity due to reduced corrosion currency.

Recently, Advanced water treatment facilities with Ozone are being introduced domestically. However, waterproofing/corrosion prevention construction method of concrete structure for existing advanced water treatment makes waterproofing/corrosion prevention materials and concrete deteriorated because of strong oxidation of ozone. Therefore, in this study, As a one of studies for improving durability of advanced water treatment plant applied by metal spray system, electrochemical corrosion protection of metal spraying film according to surface treatment in pH 5 acid solution which is similar to pH concentration in real ozone treatment was evaluated..

최근 ‘먹는 물’에 대한 인식이 높아지고 양질의 물에 대한 요구가 이어짐에 따라 정수처리 시설은 수처리 시설을 확대하고 있다. 이에따라 수처리시설에 적용되는 콘크리트 구조물 내부 방수⋅방식재의 개발 및 기준 마련의 필요성이 높아지면서 최근 활발한 연구가 진행중이다. 하지만, 주로 상도의 내구성 향상에 집중된 연구의 한계성으로 콘크리트 표면과 하도 (프라이머)와의 부착력에 대한 연구가 부족한실정이다. 이에 본 연구에서는 수처리시설의 내부 방수⋅방식재로서 사용되는 프라이머와 콘크리트 표면간의 부착력을 확인하고, 콘크리트 표면 상태 (건조 상태, 습윤 상태, 수압상태)에 따른 부착강도 및 특성에 대하여 알아보고자 한다.

In this study, corrosion potential (Ecorr), corrosion rate, and polarization resistance were measured aimed at inorganic inhibitors (passive film type) and organic inhibitors (absorption type). The experiment was conducted using potentiostat for the variable molar ratio and chloride ion concentration of the components of inhibitors in an aqueous solution of saturated calcium hydroxide targeting corrosion. As a result, it was possible to ensure an anticorrosive performance of at least a 1.2 molar ratio of inorganic inhibitors. Also, the organic inhibitors ensured the prevention of the anticorrosive performance of at least about a 0.3 molar ratio. It also showed the tendency that between polarization resistance and corrosion rate, Ecorr and corrosion rate is inversely proportional to the linear. Conversely, the tendency between polarization resistance and Ecorr is proportional to the linear. Also, a distinct difference in organic and inorganic inhibitors’ relationship to Ecorr, corrosion rate, and polarization resistance was not shown.

In this study, in order to comprehend performance of corrosion inhibitor, the experiment study was conducted about corrosion characteristic 3 steps(0.0, 0.6, 1.2) of Chloride by added amount of inorganic(Ca(NO2)2) and organic(DMEA) corrosion inhibitor by the corrosion inhibitor types about 0.6kg/m3, 2.4kg/m3 based on Chloride ion content 1.2kg/m3 for service life prediction of concrete structure by using Poteniostat. As a results, the excellent anti-corrosive performance of organic corrosion inhibitor was seen that absorption types organic corrosion inhibitor has excellent anti-corrosive performance compared to the inorganic nitrous acid corrosion inhibitor by the added amount of corrosion inhibitor

In this study, in order to comprehend performance of corrosion inhibitor, the experiment study was conducted about corrosion characteristic of 3 steps(0.0, norm 1/2, norm) compared to organic corrosion inhibitor standard use of liquid and molar 3 steps(0.0, 0.3, 0.6%) of Chloride by added amount of inorganic corrosion inhibitor by the corrosion inhibitor types about 2.4kg/m3, 4.8kg/m3 based on Chloride ion content 1.2kg/m3 for service life prediction of concrete structure by using Poteniostat.