• Journal of Advanced Marine Engineering and Technology
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• v.20 no.2
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• pp.24-31
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• 1996

Recently, with the rapid development in the oceanic systems such as the oceanic structures and vessel, there occurs much interest in the impingement erosion-corrosion. In this paper, Cu-metal was tested by using of erosion apparatus with water-jet type and was investigated under the behaviour of impingement erosion-corrosion according to various environmental conditions, and the properties of Cu-metal were evaluated through the measurement by weight loss, weight loss rate, protective efficiency. The results were compared with those obtained using Cu-metal applied to cathodic protection and Cu-alloys added to Zn or Al-metal. As a basis of those results, the best protective efficiencies could be taken as using cathodic protection method and Cu-alloy with Al & Zn material addings, and will be suggested as the fundamental data of the anti-impingement erosion-corrosion on Cu-metal of impeller material for oceanic centrifugal pump.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.33 no.3
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• pp.202-208
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• 1997

The component materials threatened by cavitation include ship propellers as well as turbine runners, pump impellers, pipe lines and radiators. Today it is known that cavitation damage takes place on many other components including on the coding water side of the cylinder liners of diesel engines. Cavitation erosion - corrosion implies damage to materials due to the shock pressure or shock wave that results when bubbles form and collapse at a metal surface within a liquid. To suppress cavitation erosion as well as cavitation erosion - corrosion to hydraulic equipment, innovations such as the improvement in the geometric design of the equipment or the selection of suitably resistant construction materials are necessary. In this study, we investigated that the cavitation erosion - corrosion damage under vibratory cavitation can be reduced by adding of side now velocity to the cavitation bubble group in order to eliminate bubbles formed in sea water environment.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.31 no.4
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• pp.413-422
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• 1995

Cavitation erosion-corrosion implies damage to materials due to the shock pressure or shock wave that results when bubbles form and collapse at a metal surface within a liquid. If the liquid is corrosive to the material, a condition typically encountered in industry, the component materials may suffer serious damage by a combination of mechanical and electrochemical attack. In this study, the mild steel(SS41) was tested by using the piezoelectric vibrator with 20kHz, 24$\mu$m to cavity generation apparatus. The damage behaviour of vibration cavitation erosion-corrosion and the environment characteristics were investigated in various solutions which are seawater, tap water and distilled water. The main results obtained are as follows; 1) The cavitation erosion-corrosion damage behaviour in the seawater increases to occur at the equal degree on the middle portion and the outside portion of specimen. The distilled water specimen, on other hand, occurs beginning on the outside portion across to the middle portion of specimen. 2) The cavitation erosion-corrosion damage in the tap water of low specific resistance more increases than that in the distilled water of high specific resistance at the initial testing time and more decreases than that in it by the CaCO sub(3) film with testing time. 3) Cavitation erosion-corrosion damage characteristic divides into four regions; incubation region, acceleration region, deceleration region and steady state region.

• Transactions of Materials Processing
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• v.12 no.4
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• pp.394-400
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• 2003

TiN coated films exhibit excellent mechanical properties such as high wear, erosion and corrosion resistances and a high thermal stability. Therefore, they are widely applied to a coating material in tools, ornaments, parts and semiconductors. However, the fracture of TiN coated films frequently occurs. The distribution of preferred orientations, i.e., texture, of TiN coated films strongly influences the fracture behavior of these films. In the present study. various TiN coating layers having different textures were prepared by the reactive ion physical vapor deposition and the texture dependence of friction coefficient, erosion and corrosion in these coating layers was investigated. The sample depicting the (115) texture parallel to the coating layer normal displayed a flatter surface than that observed from the sample having the (111) texture. The friction coefficient of TiN thin films was hardly dependent on the texture of coated samples. The samples having (115) texture displayed higher wear, erosion and corrosion resistances than the samples having (111) texture.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.99-104
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• 2003

TiN coated films show a good mechanical properties, high thermal properties and wear, erosion and corrosion resistance and are widely used as a coating materials in tools, ornaments, parts and semiconductors. In spite of these good properties, the fracture of TiN coated films occur during use. The fracture of TiN thin films is related to their microstructure. Especially, the life of TiN coated layer is related to the texture of the TiN films. One researcher suggested that the corrosion and erosion resistance of the TiN thin films is related to a uniform and dense structure of films. In this study, we studied the relationships between textures and friction coefficient, erosion and corrosion in TiN coated films. The flatness of (115) texture surface of TiN thin films is flatter than that of (111) texture surface. The friction coefficient of (115) texture surface of TiN thin films is similar with that of (111) texture surface. The wear resistance of (115) texture surface of TiN thin films is better than that of (111) texture surface. The erosion and corrosion resistance of (115) texture surface of TiN thin films is better than that of (111) torture surface. As well as texture, the wear, erosion and corrosion of TiN thin films has to consider defects such as pinholes, cracks, surface roughness and open columnar structure. The life of TiN coated products is influenced by the properties of wear, erosion, and corrosion resistance of TiN thin films and is related to texture of TiN coated films, density of pinholes and cracks, density of structure, and surface flatness.

• Journal of Fisheries and Marine Sciences Education
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• v.12 no.2
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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.

• Corrosion Science and Technology
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• v.19 no.6
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• pp.318-325
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• 2020

Generally, Al alloys of 5000 and 6000 series show excellent weldability, workability, and specific strength, and are widely used in ship building. A combined experiment via cavitation erosion and corrosion damage involving 6061-T6 Al alloy was performed using potentiodynamic polarization under cavitation erosion (hybrid experiments) with amplitude (cavitation strength). The corrosion current density was approximately 52-fold higher at 30 μm than under static conditions, suggesting that the amplitude greatly affected the damage. The degree of damage increased with increasing cavitation amplitude. After the hybrid experiment, the corrosion rate was compared according to the weight loss and damage depth, and the relationship between the two values was expressed as alpha value. The alpha (α) values at amplitudes of 5 μm, 10 μm and 30 μm were 5.11, 12.81 and 8.74, respectively, suggesting that the α value at 10 μm was greater than at 5 μm, and indicating local corrosion damage. However, the α value at 30 μm was smaller than that of 10 μm, which is attributed to higher damage via uniform corrosion than damage induced by local corrosion.

• Corrosion Science and Technology
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• v.4 no.2
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• pp.64-68
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• 2005

Various metallic materials are coated on Fe base materials via thermal spraying or welding process to improve both corrosion resistance as well as erosion resistance of the Fe base materials used in buildings and special works. The mechanical properties and corrosion resistance of the coat are estimated by means of hardness measurement and anodic polarization test. In additions, the effect of alloying elements and microstructure of the coatings on the mechanical and chemical properties of the coat is investigated using X- ray diffraction, Optical microscope, Transmission electron microscopy and Auger analysis. The coating deposited by tungsten inert gas (TIG) welding exhibit a good combination of hardness and corrosion properties.

• Journal of the Korean institute of surface engineering
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• v.51 no.2
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• pp.87-94
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• 2018

Various sealing techniques were applied to the anodized 5083 aluminum alloy for marine environment to reduce corrosion and cavitation erosion damage. Electrochemical experiments and cavitation erosion tests were conducted to evaluate the corrosion resistance and cavitation resistance of the anodic oxide film treated with sealing in natural seawater solution. Then, damaged surface morphology was analyzed by scanning electron microscope(SEM) and 3D microscope. As the results of the electrochemical experiments, it was observed that the surface damage of all the experimental conditions in the anodic polarization experiment was locally grown by the combination of crack and corrosion damage. In the Tafel analysis, the corrosion resistance of all sealing treatment conditions was improved compared to the anodizing. On the other hand, cavitation erosion tests showed that the anodizing and all the sealing treatment conditions generated local pit damage by cavitation erosion attack and grew to crater damage in the observation of damaged surface by SEM. Also, the weight loss and the surface damage depth measured with the experiment time presented that most of the sealing treatment conditions showed better cavitation erosion resistance than the anodizing, and they had an incubation period at the beginning of the experiment.

• Defense and Technology
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• no.6 s.244
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• pp.40-47
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• 1999

모든 타이타늄 합금은 해수의 흐름에 잘 견디어 진흙이 쌓인 해수에서 4~5m/sec의 속도까지 erosion corrosion에 대해 잘 견딘다. Grade 5 합금처럼 경도가 높을수록, 강도가 높을수록 최적의 erosion 및 cavitation 저항을 보유하므로 극히 중요한 핵심부품인 Hydrofoil부품, 추진부품, 프로펠러, 펌프 등 해수의 심한 부딪힘 등 erosion corrosion을 받는 부품에 대해 아주 매력적인 재료로 고려되고 있다