• Title/Summary/Keyword: Cathodic

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The Development of the High-efficiency Rectifier on Marine Metallic Structures (해양금속구조물의 전기방식을 위한 고효율 정류기 개발)

  • Ha, Tae-Hyun;Kim, Dae-Kyeong;Bae, Jeong-Hyo;Lee, Hyun-Goo;Choi, Sang-Bong;Jeong, Seong-Hwan
    • Proceedings of the KIEE Conference
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    • 2000.07d
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    • pp.3130-3132
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    • 2000
  • The Cathodic Protection system which is usually applied to marine metallic structures in domestic is Sacrificial Anode Method. In general, low efficiency rectifiers are using in the field of Cathodic Protection. These rectifiers are not only low efficiency but also manual type which is not able to control remotely. In this paper we describe the high efficiency rectifier used the high speed switching method for optimum corrosion control of marine metallic structures.

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The development of On-Line Cathodic Protection Monitoring System (지중 금속구조물의 전기방식 원격감시시스템 개발)

  • 임헌호;정성우;하희천
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2001.05a
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    • pp.213-218
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    • 2001
  • These days, corrosion condition of a underground objects is measured by the electric potential between the subject and ground. But this method is implemented by means of manual work with analog voltmeter, which is uneconomic and inefficient. So, We developed real-time On-Line cathodic protection monitoring system that is able to detect corrosion potential conditions of metal objects or various steel structures in the ground continuously, display them with the graphic screen, construct a database, and analyze them simultaneously. Since the data of corrosion and corrosion protection of all underground objects is processed automatically, not manually in this system, It is possible to reduce the manipulated error, and perform precise safety management, maintenance and inspection. As as result, this system can not only guarantee long-life operation, reduction of manpower and cost, but prevent large accidents in advance.

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Electrochemical Multi-Coloration of Molybdenum Oxide Bronzes

  • Lee, Sang-Min;Saji, Viswanathan S.;Lee, Chi-Woo
    • Bulletin of the Korean Chemical Society
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    • v.34 no.8
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    • pp.2348-2352
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    • 2013
  • We report a simple electrochemical approach in fabricating multiple colored molybdenum (Mo) oxide bronzes on the surface of a Mo-quartz electrode. A three step electrochemical batch process consisting of linear sweep voltammetry and anodic oxidation followed by cathodic reduction in neutral $K_2SO_4$ electrolyte at different end potentials, viz. -0.62, -0.80 and -1.60 V (vs. $Hg/HgSO_4$) yielded red, blue and yellow colored bronzes. The samples produced were analyzed by XRD, EDS, and SIMS. The color variation was suggested to be associated with the cations intercalation into the oxide formed and the simultaneous structural changes that occurred during the cathodic reduction in neutral aqueous medium.

Chracterization of Ng alloy with dry and wet backfill under accelerated C.P. condition (백필 상태에 따른 마그네슘 양극의 가속수명시험 특성에 관한 연구)

  • Park, Kyung-Wha;Kim, Dae-Kyeong;Bae, Jeong-Hyo;Ha, Tae-Hyun;Lee, Hyun-Goo;Ha, Yoon-Cheol
    • Proceedings of the KIEE Conference
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    • 2005.07c
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    • pp.1933-1935
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    • 2005
  • In this investigation, the electrochemical behaviour of magnesium alloy anode was studied by using electrochemical methods and the performance of magnesium alloy anode was observed with dry and wet backfill under accelerated cathodic protection. This paper reports the data collected at the laboratory and field sites over one year exposure of magnesium anode under cathodic protection donditions.

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The TRS Terminal for Wireless Remote Corrosion Monitoring System (무선 원격 부식모니터링용 TRS 단말기)

  • Ha, Tae-Hyeon;Bae, Jeong-Hyo;Lee, Hyeon-Gu;Ha, Yun-Cheol;Kim, Dae-Gyeong
    • Proceedings of the KIEE Conference
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    • 2003.11c
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    • pp.544-547
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    • 2003
  • The owner of water pipeline has a burden of responsibility for the protection of corrosion and the prevention against leakage of water. So, they have been installed a CP(Cathodic Protection) System in odor to protect corrosion. And they also have been measured and analyzed the data about P/S(Pipe to Soil) potential of water pipeline. The P/S potential is basic data of evaluation for water pipeline corrosion. They need remote automatic corrosion monitoring system for easy maintenance. In this paper, The communication method was studied mainly. And the specifications of proposed TRS (Truncked Radio System ) terminal for corrosion monitoring are introduced briefly.

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The Remote Wireless Corrosion Monitoring System for Water Pipeline (상수도 배관용 무선 원격 부식모니터링 시스템)

  • Ha, Tae-Hyeon;Bae, Jeong-Hyo;Lee, Hyeon-Gu;Ha, Yun-Cheol;Kim, Dae-Gyeong
    • Proceedings of the KIEE Conference
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    • 2003.11c
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    • pp.637-640
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    • 2003
  • The owner of water pipeline has a burden of responsibility for the protection of corrosion and the prevention against leakage of water. So, they have been installed a CP(Cathodic Protection) System in oder to protect corrosion. And they also have been measured and analyzed the data about P/S(Pipe to Soil) potential of water pipeline. The P/S potential is basic data of evaluation for water pipeline corrosion. In this paper, results of development about remote wireless corrosion monitoring system for water pipe line are presented briefly.

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Preparation and Characterization of MgO Doped $Fe_2O_3$ Semiconductive Electrodes for Water Photodissociation

  • Kim, Il-Kwang;Somorjai, Gabor A;Kim, Youn-Geun
    • Bulletin of the Korean Chemical Society
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    • v.12 no.1
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    • pp.13-17
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    • 1991
  • The preparation and characterization of semiconductive electrodes of MgO doped $Fe_2O_3$ were investigated. Pellets of MgO doped $Fe_2O_3$ were sintered at high temperatures between 1300$^{\circ}$C and 1400$^{\circ}$C and quenched rapidly in distilled water. The surfaces were analyzed by X-ray diffraction and scanning Auger electron spectroscopy. The surfaces of pellets contained both corundum structure ($Fe_2O_3$) and spinel structure ($Mg_xFe_{3-x}O_4$). Electrodes made of this material gave comparable anodic and cathodic photocurrents under illumination. The cathodic and anodic photocurrent on these photoelectrodes were verified high at 5-10 wt. percent that is critical doping amounts.

Adsorption of Macrocyclic Cobalt Complex on a Glassy Carbon Electrode for the Electrocatalytic Reduction of $O_2$

  • 강찬
    • Bulletin of the Korean Chemical Society
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    • v.19 no.7
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    • pp.754-760
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    • 1998
  • It was found that the adsorption of a cobalt(III) complex with a macrocyclic ligand, C-meso-5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane (hmc), was induced on a glassy carbon electrode by heavily oxidizing the electrode surface. Adsorption properties are discussed. The glassy carbon electrode with the adsorbed complex was employed to see the catalytic activities for the electro-reduction of O2. In the presence of oxygen, reduction of (hmc)Co3+ showed two cathodic waves in cyclic voltammetry. Compared to the edge plane graphite electrode at which two cathodic waves were also observed in a previous study, catalytic reduction of O2 occurred in the potential region of the first wave while it happened in the second wave region with the other electrode. A rotating disk electrode after the same treatment was employed to study the mechanism of the O2 reduction and two-electron reduction of O2 was observed. The difference from the previous results was explained by the different reactivity of the (hmc)CoOOH2+ intermediate, which is produced after the two electron reduction of (hmc)Co3+ in the presence of O2.

EFFECTS OF NITROGEN AND CARBON ION IMPLANTATION INTO AUSTENITIC STAINLESS STEEL ON HYDROGEN ABSORPTION

  • Terashima, K.;Minegishi, T.;Matsusaka, K.
    • Journal of the Korean institute of surface engineering
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    • v.29 no.5
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    • pp.494-497
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    • 1996
  • The effect of implanted nitrogen and carbon ion into SUS 304 on the absorption of hydrogen by cathodic chaging were studied. Implantations of $N^+$, $C^+$ were performed with doses of $3\times10^{17}$ ions $\textrm{cm}^2$ and $5\times10^{17}N^+cm^2$, and $5\times10^{17}C^+cm^2$, at an energy of 90 keV. Nitrides and carbide were investigatedby X-ray diffraction, Auger electron spectroscopy (AES) and scanning electron microscope (SEM). Formation of hydrides during cathodic charging were depressed by a modified surface layer. It is concluded that the both nitrides and carbides act as the barrier of hydrogen migration and the catalyst of desorption of cathodically charged hydrogen.

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On the Corrosion Protection Characteristics of Port Steel Structures Corroded Naturally for a Long Period of Time (장기간 자연 부식된 항만부두 강구조물의 방식특성 연구)

  • Kim, K.J.;Choi, Y.S.
    • Journal of Korean Port Research
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    • v.12 no.1
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    • pp.145-154
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    • 1998
  • Protection characteristics of the corroded steel pile which was served as a pier structure over 8 years in seawater have been examined in terms of corrosion potential, electrochemical impedance spectroscopy(EIS) and anodic/cathodic polarization curves. The steel structure was sectioned into two parts, waterline(splash zone, just above the seawater surface) and in-water(underwater), and protection characteristics for the two parts were investigated with the application of cathodic protection(CP) by sacrificial anodes using Zn and Al alloys. The main results obtained were as follows; (1) The corrosion potential of waterline zone was higher than that of in-water, which implied that the corrosion of waterline was more severe than that of in-water, (2) As a result of EIS examination, the transition period from the apparent CP to the substantial CP took about twenty to thirty days according to the corrosion condition.

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