• 동력기계공학회지
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• 제9권1호
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• pp.64-69
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• 2005

In evaluation of electronic reliability on the PCB(Print Circuit Borad),electrochemical migration is one of main test objects. The phenomenon of electrochemical migration occurs in the environment of the hight humidity and the hight temperature under bias through a continuous aqueous electrolyte. In this paper, the generating mechanism of electrochemical migration is investigated by using water drop acceleration test under various waters. The waters used in the water drop test are city water, distilled water and ionic water. It found that the generated velocity of electrochemical migration depended on electrolyte quantity which included in the various waters.

• Journal of Advanced Marine Engineering and Technology
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• 제14권1호
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• pp.83-89
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• 1990

Electrochemical methods have been proposed as non-destructive, rapid and quantitative means for determining the degree of sensitization associated with Chromium depleted zones surrounding precipitates of Cr carbide and formation of secondary phase in stainless steel. In this study, the specimen of AISI 304 stainless steel and its welded sections, which welded by TIG, MIG, $CO_2$ and ARC, were tested corrosion resistance by electrochemical methods in 0.5N HCl and 1N $H_2SO_4$ with or without 0.01N KSCN. The results were confirmed that electrochemical methods could be used as a test method of corrosion resistance evaluation for the welded AISI 304 stainless steel.

• Corrosion Science and Technology
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• 제7권5호
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• pp.296-299
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• 2008

High order statistical parameters were evaluated using the electrochemical noise data collected during corrosion of type 430 stainless steel coupled to a inert, platinum electrode in 3.5% NaCl solution. High order statistical parameters are shown to predict uniform corrosion properly. However, Localization index, skewness of current, kurtosis and skewness of potential are capable of predicting pitting corrosion only when the transients are large with long life time. Of the high order statistical parameters evaluated, kurtosis of current is found to be the most sensitive parameter for detecting uniform and pitting corrosion.

• 한국응용과학기술학회지
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• 제29권4호
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• pp.653-658
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• 2012

고농도 유기질 폐수처리를 위해 전기화학적 방법의 사용에 있어 관심이 고조되고 있다. 전기화학적 방법의 기술은 음식물폐수 및 공업적 폐수 문제를 해결하는데 이상적 처리 방법이다. 다른 화학적 처리 방법과는 다르게 전기화학적 처리장치는 2차 폐수의 부피를 증가시키지 않고 용수와 유기질 비료로 재활용한다. 전기화학적 방법은 전해부상장치를 무기화학적 약품과 병행하여 더욱 효과적으로 음식물 폐수를 처리한다. 이 연구는 2차 처리로 초음파와 오존처리로 탈색, COD와 BOD가 격감함으로 용수 및 유기질 비료로 활용하도록 실험하였다.

• 대한기계학회논문집A
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• 제22권1호
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• pp.44-51
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• 1998

In order to develop the evaluation methods of degradation for the Ni-Cr-Mo-V steel, which is in use for turbine rotor in nuclear power plant, the degraded materials were prepared by simulated degradation methods. The result of impact test and fatigue crack growth test shows that the FATT(Fracture Appearance Transition Temperature) and fatigue crack growth rate increased with the increase of degradation. And the result of new electrochemical polarization test method was suggested for the evaluating FATT, fatigue crack growth exponent and coefficient C values based on the results of relationship between corrosion current density(Icorr) & FATT, and the m & C and Icorr.

• 한국표면공학회지
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• 제41권6호
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• pp.341-350
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• 2008

In friction stir welding for 6061-T6 with various traveling speed and rotation speed conditions, the best mechanical characteristics presented in traveling speed of 507 mm/min and rotation speed of 1100RPM. The maximum tensile strength and yield strength increased with the increasing of traveling speed. The result of the electrochemical characteristic evaluation in friction stir welding at optimum conditions for 6061-T6 Al alloy presented a good characteristics compare to base metal.

• 한국재료학회지
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• 제17권1호
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• pp.43-49
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• 2007

Electrochemical migration phenomenon is correlated with ionization of anode electrode, and ionization of anode metal has similar mechanism with corrosion phenomenon. In this work, in-situ water drop test and evaluation of corrosion characteristics for SnPb solder alloys in $Na_2SO_4$ solutions were carried out to understand the fundamental electrochemical migration characteristics and to correlate each other. It was revealed that electrochemical migration behavior of SnPb solder alloys was closely related to the corrosion characteristics, and Sn Ivas primarily ionized in ${SO_4}{^2-}$ solutions. The quality of passive film formed at film surface seems to be critical not only for corrosion resistance but also for electrochemical migration resistance of solder alloys.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집A
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• pp.143-148
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• 2001

This research was undertaken to clarify effects of thermal aging on electrochemical and mechanical properties of superaustenitic stainless steel. The steel was artificially aged at $300{\sim}650^{\circ}C$ for $240{\sim}10,000hrs$. and investigated at $-196{\sim}650^{\circ}C$ using small punch(SP) test. Also, the change in electrochemical properties caused by effects of thermal aging was investigated using electrochemical anodic polarization test in a KOH electrolyte. Carbides and ${\eta}-phase(Fe_2Mo)$ precipitated in the grain bounderies seem to deteriorate the mechanical properties by decreasing cohesive strength in the grain bounderies and promote the current density observed in electrochemical polarization curves. The electrochemical and mechanical properties of superaustenitic stainless steel was drastically decreased in the specimen aged at $650^{\circ}C$.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집A
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• pp.268-273
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• 2001

Fossil power plants operated in high temperature condition are composed of components such as turbine, boiler, and piping system. Among these components, turbine blades made with 12%Cr steel operate at a temperature above $500^{\circ}C$. Due to the long term service, turbine blades experience material degradation manifested by change in mechanical and microstructural properties. The need to make life assessment and to evaluate material degradation of turbine blade is strongly required but in reality, there is a lack of knowledge in defining failure mechanism and fundamental data for this component. Therefore, in making life assessment of turbine blade, evaluation of material degradation must be a priority. For this purpose, evaluation of toughness degradation is very important. The major cause of toughness degradation in 12Cr turbine blade is reported to be critical corrosion pitting induced by segregation of impurity elements(P etc.), coarsening of carbide, and corrosion, but the of materials for in-service application. In this study, the purpose of research is focused on evaluating toughness degradation with respect to operation time for 12%Cr steel turbine blade under high temperature steam environment and quantitatively detecting the degradation properties which is the cause of toughness degradation by means of non-destructive method, electrochemical polarization.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2005년도 전기학술대회논문집
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• pp.382-387
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• 2005

An electrochemical evaluation on the corrosion resistance for heavy anticorrosive paint was carried out for 5 kinds of heavy anticorrosive paints such as High solid epoxy(HE), Solvent epoxy(SE), Tar epoxy(TE), Phenol epoxy(PE), and Ceramic epoxy(CE) as parameters of DFT(Dry Film Thickness, 25${\mu}m$50${\mu}m$, solution condition(Flow of Nonflow). Corrosion current density of HE(DFT 50${\mu}m$ in case of flow condition was larger than that of nonflow condition. However, their values of the other anticorrosive paints were decreased compared to the nonflow condition. The values of AC impedance were increased with increasing of DFT regardless of kinds of anticorrosive paints. And the polarization resistance of cyclic voltammogram showed a good tendency to correspond with well the values of AC impedance measurement. HE and CE had a relatively good corrosion resistance than other heavy anticorrosive paint.