• Corrosion Science and Technology
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• 제21권2호
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• pp.100-110
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• 2022

Corrosion of steel reinforcement is the most important mode of concrete structures damages. It strongly depends on the composition and physicochemical properties of the cementitious medium. The use of waste materials as lightweight aggregates in concrete is environmentally recommended in polluted environments such as marine and/or industrial atmospheres in order to reduce its porosity and ensure the requested protection of reinforcing steel. The present study investigated the effect of waste cork addition on corrosion resistance of steel rebar in mortar specimen prepared in the laboratory. The main objective of this study was to improve the corrosion resistance of reinforcing steel. Another objective of this study was to valorize this ecological product and preserve the environment. Results obtained from various electrochemical tests indicated that the presence of a fine cork powder substantially improved the corrosion resistance of steel in the mortar contaminated by chloride ions. This improvement was reflected by a notable decrease in corrosion current density and a shift of corrosion potential of the steel towards more noble values. Moreover, the presence of a fine cork powder in the mortar had no adverse effect on its mechanical properties.

• Journal of Advanced Marine Engineering and Technology
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• 제29권6호
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• pp.654-661
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• 2005

Copper is a well known alloying element that is used to improve the resistance to general corrosion of stainless steel And also Cu cation have the anti-fouling effect to inhibit adhesion of the marine algae and shellfish to the surface of heat exchanger cooling pipe or outside wall of the ship, Therefore there are some anti-fouling methods such as anti-fouling Paint mixed with copper oxide or MGPS(Marine Growth Preventing System) by using Cu cation dissolved to the sea wather solution. Cu cation can be dissolved spontaneously by galvanic current due to Potential difference between Cu and cooling pipe of heat exchanger with Ti material, which may be one of the anti-fouling designs. In this study the effect of annealing heat treatment to galvanic current and Polarization behavior was investigated with a electrochemical points of view such as measurement of corrosion Potential, anodic polarization curve. cyclic voltammetric curve, galvanic current etc The grain size of the surface in annealed at $700^{\circ}C$ was the smallest than that of other annealing temperatures. and also the corrosion Potential showed more positive potential than other annealing temperatures. The galvanic current between Ti and Cu with annealed at $700^{\circ}C$ was the largest value in the case of static condition. However its value in the case of flow condition was the smallest than the other temperatures. Therefore in order to increase anti-fouling effect by Cu cation, the optimum annealing temperature in static condition of sea water is $700^{\circ}C$, however non- heat treated specimen in the case of flow condition may be desirable.

• Korean Chemical Engineering Research
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• 제49권6호
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• pp.745-751
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• 2011

내부식성이 강화된 새로운 방청안료를 개발하기 위한 연구의 일환으로, 본 연구에서는 높은 내부식성을 제공하는 아연 및 세륨 이온 교환된 제올라이트를 도입하였다. 그리고 이온교환 제올라이트를 이용하여 프라이머 도료 제조 및 도장을 수행한 후, 그것의 방식성능을 측정하였다. 도장을 위한 금속 기재는 아연도금(galvanized, GI) 강판이었고, 도장된 강판의 방식성능은 electrochemical impedance spectroscopy(EIS)와 scanning vibrating electrode technique(SVET)으로 측정되었다. EIS 및 절단면의 내부식성을 확인하기 위한 SVET 측정으로부터 세륨이온 교환된 제올라이트가 가장 높은 효율을 제시하였고, 아연 및 세륨 이온 교환된 제올라이트의 경우 GI 강판에 대하여 cathodic 부식 방지제로 기여함을 확인할 수 있었다.

• 한국해양공학회지
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• 제21권3호
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• pp.65-70
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• 2007

There are many kinds of protection methods for marine structures, with varyingeconomical and environmental advantages. The coating protection method is being widely used in both continental and marine structures. In this study, by adding some additives, such as Zn powder(Zn), carbon black(CB) to epoxy anti-corrosive paint, the effect on the corrosion resistance was investigated throughan electrochemical method. The additive of Zn(20)+CB(10) showed the lowest passivity current density. Polarization resistance in both cyclic voltammogram and impedance measurement of an additive of Zn(20)+CB(10) was also the largest value, compared to other additives. Furthermore, rusting and bubbling was not observed on the surface of the test specimen with the additive of Zn(20)+CB(10), compared to other specimens. It is suggested that the corrosion resistance of the anti-corrosive paint can be improved by using some additives.

• Corrosion Science and Technology
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• 제17권3호
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• pp.123-128
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• 2018

The fabrication of a controlled surface is of great interest because it can be applied to various engineering facilities due to the various properties of the surface, such as self-cleaning, anti-bio-fouling, anti-icing, anti-corrosion, and anti-sticking. Controlled surfaces with micro/nano structures were fabricated using an ion beam focused onto a polypropylene (PP) surface with a fluoridation process. We developed a facile method of fabricating hydrophobic surfaces through ion beam treatment with argon and oxygen ions. The fabrication of low surface energy materials can replace the current expensive and complex manufacturing process. The contact angles (CAs) of the sample surface were $106^{\circ}$ and $108^{\circ}$ degrees using argon and oxygen ions, respectively. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR) spectroscopy were used to determine the chemical composition of the surface. The morphology change of the surfaces was observed by scanning electron microscopy (SEM). The change of the surface morphology using the ion beam was shown to be very effective and provide enhanced optical properties. It is therefore expected that the prepared surface with wear and corrosion resistance might have a considerable potential in large scale industrial applications.

• 한국자동차공학회논문집
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• 제13권1호
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• pp.159-165
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• 2005

Shot peening can be defined as the process of work hardening of the surface of components by means of propelled stream of spherical shot. Benefits due to shot peening are increase in resistance to fatigue, stress corrosion cracking, fretting, galling, erosion and closing of pores. In this study, the influence of shot peening on the corrosion was investigated on spring steel immersed in $3.5\%\;NaCl$. The immersion test was performed on the two kinds of specimens. Corrosion potential, polarization curve, residual stress and etc. were investigated from experimental results. From test results, the effect of shot peening on the corrosion was evaluated. The important results of the experimental study on the effects of shot peened spring steels on the environment corrosion are as follows; In case of corrosion potential, shot peened specimen shows more activated negative direction as compared with parent metal. Surface of specimen, which is treated with the shot peened, is placed as more activated state against inner base metal. It can cause the anti-corrosion effect on the base metal.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2010년도 춘계 학술논문 발표대회 1부
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• pp.77-81
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• 2010

This study deals with the analysis of color-difference and physical property of anti-corrosion coatings using at inside of concrete tank for drinking water. Because anti-corrosion coatings are effected by chemical attack, color and physical property are changed. So in this study when epoxy resin coatings of 3 types were received chemical attack by Cl- and NaOH, we present the co-relationship between color-difference and bond strength. For this study, we used the colorimetry, which can measure the degree of color difference on surface of materials. As the results, in case of Cl-, color change is appeared, bond strength also is decreased. From this experiment, we could know that color change due to chemical aging has the deep relationship with physical performance(bond strength) materials. further researches are needed.

• Corrosion Science and Technology
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• 제7권6호
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• pp.315-318
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• 2008

The atmospheric corrosion performance of Al-alloying, Si-alloying and Al-Si-alloying steel were studied by wet/dry cyclic corrosion tests (CCT) at $30^{\circ}C$ and 60% relative humidity (RH). The corrosion electrolyte used for CCT was 0.052 wt% $NaHSO_{3}$ (pH~4) solution. The result of gravimetry demonstrated that Al-Si-bearing steels showed lower corrosion resistance than other rusted steels. But the rusted 0.7%Si-alloying steel showed a better corrosion resistance than rusted mild steel. Polarization curves demonstrated that Al-/Si-alloying and Al-Si-alloying improved the rest potential of steel at the initial stage; and accelerated the cathodic reduction and anodic dissolution after a rust layer formed on the surfaces of steels. XRD results showed that Al-Si-alloying decreased the volume fraction of $Fe_{3}O_{4}$ and $\alpha-FeOOH$. The recycle of acid accelerated the corrosion of steel at the initial stage. After the rust layer formed on the steel, the leak of rust destabilized the rust layer due to the dissolution of compound containing Al (such as $FeAl_{2}O_{4}$, $(Fe,\;Si)_{2}(Fe,\;Al)O_{4}$). Al-Si-alloying is hence not suitable for improving the anti-corrosion resistance of steel in industrial atmosphere.

• 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.

• 한국신뢰성학회지:신뢰성응용연구
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• 제17권2호
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• pp.122-128
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• 2017

Purpose: To investigate the corrosion inhibition effect of the natural spearmint oil extracted from Mentha Spicata plants on 304 stainless steel in different concentrations of hydrochloric acid. Method: The anti-corrosive effect has been investigated in 0.5m, 1m and 2m HCl using weight loss test and electrochemical polarization method as a function of inhibitor concentration and immersion time in strong chloride environment. The surface morphology was analysed by scanning electron microscopy (SEM). Results: The corrosion rate of steel decreased and inhibition efficiency increased with the increase in inhibitor concentration. Microscopic evaluation revealed significant corrosion in the specimens immersed in uninhibited conditions. Potentiodynamic polarization test results showed an increase in corrosion potential (Ecorr) and decrease in corrosion current (icorr) value with increasing concentration of inhibitor. Conclusions: Immersion of steel in higher concentration of inhibitor resulted in greater surface coverage value and hence lesser number of surface corrosion sites/pores were formed; thus lowering the corrosion rate.