• 한국구조물진단유지관리공학회 논문집
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• 제17권4호
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• pp.66-74
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• 2013

본 연구에서는 부동태피막형 무기계 방청제와 흡착형 유기계 방청제를 대상으로, 시멘트세공용액을 모사한 포화 수산화칼슘 수용액내에서 염화물이온 농도와 방청성분 몰비를 변수로 하여 Potentiostat을 사용하여 부식전위, 부식속도, 분극저항을 측정하여 방식성능을 평가하였다. 그 결과, 무기계 방청제는 방청몰비 약 1.2 이상에서 방식성능을 확보하는 것으로 나타났고, 유기계 방청제는 방청몰비 약 0.3 이상에서 방식성능을 확보하는 것으로 나타났다. 또한, 부식속도와 분극저항, 부식속도와 부식전위의 관계는 선형 반비례 경향을 나타냈고, 분극저항과 부식전위는 선형 비례하는 것을 알 수 있었으며, 부식전위, 부식속도, 분극저항과의 상관관계는 유기계와 무기계 방청제에서 큰 차이가 없는 것으로 나타났다.

• 대한치과교정학회지
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• 제23권3호
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• pp.327-340
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• 1993

The purpose of this study was to estimate the possibility of practical application of TiN ion-plating method on orthodontic appliances. TiN was coated on the surface of orthodontic stainless steel roll band by means of ion-plating method, and colorimetric properties of its obtained TiN film were investigated by using color analyzer. Also its corrosion and discoloration properties were compared with those of non ion-plated stainless steel roll band by using immersion test, which was done in 1N HCl solution for 10 days. Both weight changes and surface corrosion appearances of specimens for each day were respectively investigated by using electronic weighing machine and SEM(Scanning Electron Microscope). The discoloration degress of TiN-coated specimens immersed in 1N HCl solution were investigated by using color analyzer and then judged by N.B.S.(National Bureau of Standard) Unit. The results of this study were summarized as follows. o TiN ion-plated films showed the hue of 5Y, the value of 7, and the chroma of 3 by Munsell notations. o The weight losses and surface changes of TiN ion-plated specimens immersed in 1N HCl solution were less than those of non ion-plated specimens. It was shown, therefore, that the corrosion resistance was significantly improved by TiN ion-plating. o The discoloration degrees of non ion-plated specimens were too significant to be examined by color analyzer, while those of TiN ion-plated specimens were slight when judged by N.B.S. Unit. It was also apparent, therefore, that the anti-discoloration property was significantly improved by TiN ion-plating.

• 콘크리트학회논문집
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• 제15권1호
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• pp.117-124
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• 2003

최근 강모래의 고갈로 인하여 해사의 사용이 증대되고 있는 실정에 있다. 그러나 해사는 철저하게 제염처리 하여 사용하지 않으면 철근 콘크리트 구조물의 철근에 막대한 영향을 미칠 수 있다. 본 연구에서는 제염처리하지 않은 해사를 시멘트 콘크리트에 직접 사용하여도 철근의 부식을 억제할 수 있는 방청재료를 개발하기 위한 연구의 일환으로서, 기존의 에폭시 철근과 비교하여 경제적이고 방식 성능면에서 우수한 재료로서 폴리머 시멘트 슬러리를 이용하고자 하였다. 각종 폴리머를 사용하고 여러 가지 부식촉진 실험을 통하여 도장하지 않은 철근과 도장한 철근과의 성능을 비교평가하였다. 연구결과, 폴리머 시멘트 슬러리로 도장한 철근은 도장하지 않은 철근에 비해 염화나트륨 수용액에 대한 침지 및 분무시험과 시멘트 콘크리트 속에서의 부식에 관한 실험에 있어서도 매우 우수한 방식성능을 발휘하였다. 다양한 부식촉진 실험결과, 철근의 부식은 염분, 중성화 및 촉진양생에 의해 크게 영향을 받으며, 복합적인 인자가 작용될 때, 더욱더 심한 부식이 발생하였다. 이러한 부식을 폴리머 시멘트 슬러리에 의한 도장으로 억제할 수 있는데, 폴리머 시멘트 슬러리의 매트릭스에 존재하는 폴리머 필림의 연속된 막에 의해 염화물 이온의 침투가 차단되었기 때문이며, 폴리머 시멘트 슬러리의 완벽한 방식효과는 도장두께로 조절할 수 있을 것이다.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2011년도 춘계학술대회 및 Fine pattern PCB 표면 처리 기술 워크샵
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• pp.196-197
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• 2011

Rudder, one of the most important component in the marine vessel, is now being decreased life time to serve due to cavitation erosion, vortex current, high flow speed suffer from ship speed going up dramatically. In this study, 10 kinds of thermal spray coating materials(2 of Zn alloy series, 3 of Al alloy series, 3 of Cu alloy series, 2 of STS alloy series) are chosen to apply on specimens and analyze micro structure, metallic composition, properties(porosity, oxidation) by using visual observation, XRD, EDX etc.. Additionally, to refine the characteristic of corrosion endurance for thermal spray coating layer, compared with thermal spray process and 5 kinds of heavy duty painting and AC paint (Anti-Corrosion Paint). Based on above mentioned experimental results, a priority of all coated specimens on corrosion-erosion endurances finalized and summarized there by desirable composition and process of thermal sprayed material properly.

• 콘크리트학회논문집
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• 제20권5호
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• pp.635-642
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• 2008

건설구조물에서 보통철근의 부식을 방지하기 위하여 에폭시 도장 철근이 널리 사용되고 있다. 그러나 에폭시 도장철근은 성능과 코스트 면에서 불리하며, 특히 취성적이고, 부착성 및 현장 가공성 등의 취약점 때문에 현장에서 사용상의 제약을 받고 있다. 본 연구는 에폭시 도장 철근을 대체할 수 있는 도장재료로서 유기계 폴리머와 시멘트의 무기계를 혼합한 하이브리드 (hybrid)형 폴리머 시멘트 슬러리를 개발하기 위한 것으로서, 특히 인장특성과 접착성에 관한 연구이다. 폴리머 시멘트 슬러리는 4종류의 폴리머 디스퍼션과 혼화재로서 플라이애쉬와 실리카퓸을 혼입하여 제작되었으며, 도장두께, 인장특성, 접착성 및 내굴곡성 시험을 실시하였다. 연구결과, 폴리머 시멘트 슬러리의 점도는 폴리머 디스퍼션의 종류에 따라 크게 영향을 받았으며, 플라이애쉬를 혼입함에 따라 약간 감소하였다. 또한 폴리머-결합재비 100%에서 폴리머 시멘트 슬러리의 적정 도장두께가 확보되었으며, 도장두께는 물-결합재비와 폴리머-결합재비에 의해 다양화 할 수 있었다. 철근의 도장을 위한 적정 도장 두께는 부착강도, 접착성 및 내굴곡성을 고려할 때, 보통 $150{\sim}250{\pm}50{\mu}m$ 범위였다. 본 연구에서 폴리머 시멘트 슬러리의 인장특성 및 접착성, 그리고 도장강의 내굴곡성은 양호하게 평가되어, 향후 에폭시 도장철근을 대체할 수 있는 재료로 사용가능성을 확인하였다.

• 한국표면공학회지
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• 제51권1호
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• pp.11-20
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• 2018

Hydrophobic and Superhydrophobic surfaces are promising technology for the surface finishing of metallic materials due to its water-repellency. Realization of highly water-repellent surface on aluminum and its alloys provides various functionalities for real application fields. In order to realize the hydrophobic/superhydrophobic surfaces on aluminum and its alloys, various technologies have been demonstrated. Especially, traditional anodic oxidation for aluminum has been widely employed for the morphological texturing of surfaces, which is essential to enhance the hydrophobic efficiency. De-wetting superhydrophobic surface on aluminum provides various exceptional properties, such as anti-corrosion, anti-/de-icing, anti-biofouling, drag reduction, self-cleaning and liquid separation. Nevertheless, the durability and stability of superhydrophobic surfaces still remain challenges for their actual applications in engineering systems and industry. In this review, the theoretical/experimental studies and current technical limitations on the hydrophobic and superhydrophobic surface using anodic oxidation of aluminum have been summarized.

• 한국안전학회지
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• 제20권3호
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• pp.9-13
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• 2005

Inconel 625 is useful in variety of industrial applications because of the resistance to attack on various corrosive media at temperature from $200^{\circ}C$ to over $1090^{\circ}C$, in combination with good low and high temperature mechanical strength. Recently, this material is also used widely in offshore processing piping in order to extend the maintenance term and improvement the quality of anti-corrosion. In general, high quality weldments for this material are readily produced by commonly used processes. Not all processes are applicable to this material group, Ni-alloys. Metallurgical characteristics or the unavailability of matching, position or suitable welding process. Nowadays, the flux cored wire is developed and applied for the better productivity in several welding position including the vertical position. In this study, the weldability and weldment characteristics(mechanical properties) of inconel 625 are considered in FCAW(Flux Cored Arc Welding) associated with the severial shielding gases($80%Ar+20%CO_2,\;50%Ar+50%CO_2,\;100%CO_2$) in viewpoint of welding productivity.

• Corrosion Science and Technology
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• 제21권5호
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• pp.412-417
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• 2022

Proton exchange membrane fuel cells (PEMFCs) provide zero emission power sources for electric vehicles and portable electronic devices. Although significant progresses for the widespread application of electrochemical energy technology have been achieved, some drawbacks such as catalytic activity, durability, and high cost of catalysts still remain. Pt-based catalysts are regarded as the most efficient catalysts for sluggish kinetics of oxygen reduction reaction (ORR). However, their prohibitive cost limits the commercialization of PEMFCs. Therefore, we proposed a NiCo@Au core shell structure as Pt-free ORR electrocatalyst in PEMFCs. NiCo alloy was synthesized as core to introduce ionization tendency and autoxidation reaction. Au as a shell was synthesized to prevent oxidation of core NiCo and increase catalytic activity for ORR. Herein, we report the synthesis, characterization, electrochemical properties, and PEMFCs performance of the novel NiCo@Au core-shell as a catalyst for ORR in PEMFCs application. Based on results of this study, possible mechanism for catalytic of autoxidation core@anti-oxidation shell in PEMFCs is suggested.

• Computers and Concrete
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• 제4권6호
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• pp.499-510
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• 2007

The densified mixture design algorithm (DMDA) was employed to manufacture high-performance lightweight concrete (LWAC) using silt dredged from reservoirs in southern Taiwan. Dredged silt undergoing hydration and high-temperature sintering was made into a lightweight aggregate for concrete mixing. The workability and durability of the resulting concrete were examined. The LWAC made from dredged silt had high flowability, which implies good workability. Additionally, the LWAC also had good compressive strength and anti-corrosion properties, high surface electrical resistivity and ultrasonic pulse velocity as well as low chloride penetration, all of which are indicators of good durability.

• Journal of Advanced Marine Engineering and Technology
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• 제29권1호
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• pp.98-106
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• 2005

The chemical conversion film formed on magnesium alloy was investigated by using the colloidal silica with some parameters such as solution pH. temperature, solution conditions, and treatment time. Moreover. the solutions consisted of colloidal silica titanium sulfate, and cobalt ions were used for the colloidal silica film to having a good corrosion resistance and adhesion properties. It was thought that the film at 298K was made with combination of Si-O. The quantity of film formed at high temperature such as 333K and 353K is smaller than dissolved quantity during chemical conversion treatment. Adding $CoSO_4$ to the colloidal silica solution enhanced the adhesion force between the silica film and magnesium substrate, The optimum conditions for the chemical conversion treatment solution were PH 2.90 s treatment, and 298K.