• 제목/요약/키워드: Electrochemical Cavitation

검색결과 52건 처리시간 0.025초

ALBC3 합금의 표면 개질을 위한 쇼트피닝 분사거리가 전기화학적 특성에 미치는 영향 (Effects of shot peening stand-off distance on electrochemical properties for surface modification of ALBC3 alloy)

  • 한민수;현광용;김성종
    • Corrosion Science and Technology
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    • 제12권5호
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    • pp.233-238
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    • 2013
  • In the case of casting materials or ductile materials for marine equipment, it is common to employ a surface modification for achieving cost reduction and improvement in strength. In particular, aluminium bronze ALBC3 exhibits excellent corrosion resistance, and thus widely used for marine application. However, application of the material under high-velocity seawater flow may induce electrochemical corrosion damage and physical damage such as cavitation erosion, leading to shorter service life of equipment. In this study, surface modification was carried out on ALBC3 alloy for different shot peening stand-off distances, and the physical hardness and electrochemical characteristics before and after modification were investigated. The results in each case showed the hardness increase in comparison with non-peened specimen, and the maximum hardness improvement(50 %) was found in 10 cm of shot-peening stand-off distance. It is observed that the electrochemical characteristics were irrelevant to application of shot peening.

요산의 초음파 전기화학적 정량 (Sono-electrochemical Determination of Uric Acid)

  • 조형화;배준웅
    • 전기화학회지
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    • 제3권4호
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    • pp.232-234
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    • 2000
  • 전기화학적인 방법으로 요산을 정량함에 있어서 전극의 활성을 증가시키기 위하여 초음파를 조사하여 요산의 정량을 시도하였다. 요산의 정량의 최적조건을 조사하기 위하여 초음파의 세기, 시간, 전해질 용액의 pH, 온도 등의 영향을 조사하였고 전극의 안정성에 대해서도 조사하였다. 최적 조건은 $25.0^{\circ}C$, pH 7.0,초음파의 파워 $20W/cm^2$의 조건이었으며 $8.0{\times}10^{-6}\~5.0\times10^{-4}M$의 직선범위를 가졌고, 검출한계는 $6.5\times10^{-6}M$이었다.

캐비테이션 실험을 이용한 용사코팅 층의 전기화학적 복합손상 평가 (Evaluation on electrochemical hybrid damage of arc thermal sprayed layer by cavitation experiment)

  • 박일초;김성종
    • 한국표면공학회:학술대회논문집
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    • 한국표면공학회 2015년도 추계학술대회 논문집
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    • pp.319-319
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    • 2015
  • 본 연구에서는 강재의 부식 방지를 목적으로 기존의 도장 방식법에 비해 내식성 및 내구성을 향상시키기 위해 아크 용사코팅법을 적용하였다. 실험은 실제 환경을 고려하여 캐비테이션 환경 하에서 다양한 전기화학적 실험을 동시에 병행하여 캐비테이션-부식 복합손상 거동을 분석하고자 하였다.

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알루미늄 합금의 양극산화 조건에 따른 내구성 평가 (Evaluation of Durability for Al Alloy with Anodizing Condition)

  • 이승준;한민수;김성종
    • 한국표면공학회:학술대회논문집
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    • 한국표면공학회 2016년도 추계학술대회 논문집
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    • pp.152-152
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    • 2016
  • Anodizing is a technology to generate thicker and high-quality films than natural oxide films by treating metals via electrochemical methods. It is a technique to develop metals for various uses, and extensive research on the commercial use has been performed for a long time. Aluminum anodic oxide (AAO) is generate oxide films, whose sizes and characteristics depending on the types of electrolytes, voltages, temperatures and time. Electrochemical manufacturing method of nano structure is an efficient technology in terms of cost reduction, high productivity and complicated shapes, which receives the spotlight in diverse areas. The sulfuric acid was used as an anodizing electrolyte, controlling its temperature to $10^{\circ}C$. The anode was 5083 Al alloy with dimension of $5(t){\times}20{\times}20mm$ while the cathode was the platinum. The distance between the anode and the cathode was maintained at 3 cm. Agitation was introduced by magnetic stirrer at 300 rpm to prevent localized temperature rise that hinders stable growth of oxide layer. In order to observe surface characteristics with applied current density, the electrolyte temperature, concentration was maintained at constant condition for $10^{\circ}C$, 10 vol.%, respectively. To prevent hindrance of stable growth of oxide layer due to local temperature increase during the experiment, stirring was maintained at constant rate. In addition, using galvanostatic method, it was maintained at current density of $10{\sim}30mA/cm^2$ for 40 minutes. The cavitation experiment was carried out with an ultrasonic vibratory apparatus using piezo-electric effect with modified ASTM-G32. The peak-to-peak amplitude was $30{\mu}m$ and the distance between the horn tip and specimen was 1 mm. The specimen after the experiment was cleaned in an ultrasonic, dried in a vacuum oven for more than 24 hours, and weighed with an electric balance. The surface damage morphology was observed with 3D analysis microscope. As a result of the investigation, differences were observed surface hardness and anti-cavitation characteristics depending on the development of oxide film with applied current density.

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해양환경 중에서 Glass Flake 라이닝 강재의 부식방지에 관한 연구 (A Study on the Corrosion Control of Glass Flake Lining for Mild Steel in Marine Environment)

  • 임우조;김성훈
    • 수산해양교육연구
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    • 제12권2호
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    • pp.164-175
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    • 2000
  • Port facilities and marine structures used in marine environment were encountered to corrosion damages because of the influence of Cl-. Generally, to protect these accidents, anti-corrosion paint and epoxy coating have been used. But they were still remained erosion-corrosion damage like impingement erosion, cavitation erosion and deposit attack. It is necessary to develope the new composite lining material in order to protective those corrosion damages. In this paper, polyester glass flake, vinylester glass flake lining and epoxy coating for SS400 were investigated by the electrochemical polarization test and the impingement-cavitation erosion test for corrosion behaviour under the sea water. The main results obtained are as follows ; 1) Epoxy coating appear potentiodynamic polarization behaviour, but polyester glass flake and vinylester glass flake lining do not appear potentiodynamic polarization behaviour. 2) Open circuit potential of polyester glass flake lining is more noble than that of epoxy coating and corrosion current density of polyester glass flake lining is less drained than that of epoxy coating in sea water. 3) Open circuit potential of vinylester glass flake lining is more noble than that of polyester glass flake lining and corrosion current density of vinylester glass flake lining is less drained than that of polyester glass flake lining in the sea water.

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해수 열교환기용 재료의 부식특성에 관한 전기 화학적 연구 (An Electrochemical Study on the Corrosion Property of Materials for Sea Water Heat Exchange System)

  • 김진경;김강희;김성종;박근현;문경만
    • Journal of Advanced Marine Engineering and Technology
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    • 제26권1호
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    • pp.99-107
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    • 2002
  • Recently all kinds of structural materials are subjected to the severe corrosive environment. Especially corrosion problems of heat exchanger such as galvanic corrosion, erosion and cavitation raised by both contaminated solution and high velocity of fluid to increase cooling effect of heat exchanger have been frequently reported in these days. In this study two kinds of sheet materials and five kinds of tube materials are used for galvanic corrosion characteristics and their corrosion current density calculation. The tube materials having the most galvanic corrosion resistance between tube and sheet of heat exchanger were Al Brass(68700) and Al Brass(C6872TS) and although Ti tube predominantly indicated the highest individual corrosion resistance among those five tube materials. it appeared that Ti tube can be allowed as sheet materials to get galvanic corrosion easily. However it is considered that Cu-Ni tube materials is not only easy to produce galvanic corrosion significantly between tube and sheet regardless of kinds of sheet materials but also is appeared considerably its own high corrosion current density