2025/04/16 更新

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写真a

キム アラン
KIM ARAN
KIM ARAN
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工学研究院 社会基盤部門 助教
工学部 土木工学科(併任)
工学府 土木工学専攻(併任)
職名
助教
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論文

  • Effect of the Spraying Process on Corrosion Resistance and Durability of Al-5Mg Coating on Carbon Steel: A Comparison of Transferred Arc Plasma Spraying and Flame Spraying Methods 招待 査読

    Wang Q., Kainuma S., Ju Y., Kim A., Nishitani T.

    Surfaces and Interfaces   64   2025年5月   ISSN:24680230

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Surfaces and Interfaces  

    This study investigated the corrosion resistance and durability of Al-5Mg coatings deposited by transferred arc plasma spraying (TAPS) and flame spraying (FS) methods. The corrosion performance was evaluated through a 6000-hour accelerated corrosion test, complemented by electrochemical impedance spectroscopy and polarization measurements. The TAPS coating exhibited significantly lower initial porosity of 3.78%, reducing further to 1.09% after 1000 corrosion cycles, compared to the FS coating with an initial porosity of 9.93%, decreasing to 5.46%. Electrochemical tests revealed a lower corrosion current density in the TAPS coating (1.90 μA/cm²) than in the FS coating (2.54 μA/cm²) after 1000 cycles, indicating a superior corrosion resistance of the TAPS coating. Additionally, adhesion strength measurements indicated that the TAPS coating exhibited approximately 20% higher adhesion strength compared to the FS coating, further enhancing its durability and mechanical reliability. The enhanced performance of TAPS is attributed primarily to its dense and uniform pore structure and the resultant formation of a compact, protective oxide passive layer, effectively inhibiting electrolyte penetration. Overlay tests further confirmed that TAPS coatings exhibited significantly reduced blistering under linear defect conditions. These findings suggest that the TAPS process is a highly effective method for enhancing the corrosion protection of Al-5Mg coatings on complex steel structures.

    DOI: 10.1016/j.surfin.2025.106377

    Scopus

  • Effect of abrasive water-jet treatment on surface characteristics and epoxy adhesive bonding performance of carbon steel 招待 査読

    Park, S; Kim, A; Kainuma, S; Ikeda, T; Toyota, Y; Arakawa, T

    PROGRESS IN ORGANIC COATINGS   201   2025年4月   ISSN:0300-9440 eISSN:1873-331X

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Progress in Organic Coatings  

    The effects of abrasive water-jet treatment (AWT) on the deformation of carbon steel surfaces and the adhesion of epoxy adhesives were analyzed. Different abrasive sizes and standoff distances were considered to evaluate the changes in surface properties of carbon steel produced during the AWT process in terms of surface roughness, surface topography, and residual abrasive distribution. Compared to conventional abrasive blasting, the AWT processing provided higher surface roughness and surface deformation ratio (DR), and significantly lower residual abrasives amount. Notably, the study found a tendency for adhesion to decrease with increasing surface roughness. This is in contrast to the conventional literature, which suggests that adhesion to paints and adhesives improves with increasing surface roughness up to a certain threshold level. On the other hand, DR showed a strong positive correlation with adhesion, but above a certain value, adhesion tended to be lower than that of the blast treatment. The findings indicate that it is preferable to consider both conventional surface roughness and DR concurrently when assessing adhesion. This study will contribute to a deeper understanding of the influence of surface properties during AWT on the adhesion performance of epoxy adhesives and suggest optimal surface treatment conditions for practical engineering applications.

    DOI: 10.1016/j.porgcoat.2025.109137

    Web of Science

    Scopus

  • Deterioration mechanism of overlaid heavy-duty paint and thermal spray coatings on carbon steel plates in marine atmospheric environments 招待 査読

    Wang, QD; Kainuma, S; Yang, HX; Kim, A; Nishitani, T

    PROGRESS IN ORGANIC COATINGS   200   2025年3月   ISSN:0300-9440 eISSN:1873-331X

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Progress in Organic Coatings  

    Thermal spray coatings, such as Zn, Zn-15Al, Al, and Al-5Mg, combined with heavy-duty paint, are increasingly used to enhance the corrosion resistance of steel structures. However, the overlaid areas of these coatings, particularly in damaged regions, can become weak points for corrosion initiation. To investigate the deterioration mechanisms at the overlaid zones of heavy-duty paint and thermal spray coatings on carbon steel plates, this study designed atmospheric exposure experiments and employed 3D scanning, electrochemical testing, and scanning electron microscope (SEM) - energy-dispersive X-ray spectrometer (EDX) analysis to systematically assess the degradation of the overlaid coatings in marine atmospheric environments. The results indicate that electrochemical reactions at coating defects drive the blistering and delamination of the overlaid coatings. Zn-based coatings, which provide sacrificial protection, exhibit slower failure progression compared to Al-based coatings, which show blistering due to passivation film formation. These findings provide valuable insights for optimizing thermal spray selection and overlaid coating strategies in marine atmospheric environments.

    DOI: 10.1016/j.porgcoat.2025.109057

    Web of Science

    Scopus

  • Surface texture evolution of weathering steel in corrosive marine atmospheres: Geospatial variability and explainable machine learning models 招待 査読

    Cai, LH; Kim, A; Kainuma, S

    CORROSION SCIENCE   243   2025年2月   ISSN:0010-938X eISSN:1879-0496

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Corrosion Science  

    The surface texture of 144 weathering steel samples were analyzed under marine atmospheres to assess the effects of the exposure conditions and structural factors. Comprehensive methods were used to characterize the corrosion evolution and pitting performance. Geospatial variability was introduced as a new method for quantifying non-uniform and irregular surface substrates. The results showed significant variations in corrosion severity under identical environmental conditions. Closely spaced pits formed clustered patterns with an increased range, whereas isolated sparse pits demonstrated the converse. Sill effectively captured serrated surface variations. Explainable machine learning models were developed to regenerate and predict the steel surface texture.

    DOI: 10.1016/j.corsci.2024.112602

    Web of Science

    Scopus

  • Advancements in abrasive water-jet treatment for efficient surface cleaning and comprehensive corrosion removal in steel structures 招待 査読

    Park, S; Kainuma, S; Yang, MY; Kim, A; Ikeda, T; Toyota, Y; Arakawa, T

    JOURNAL OF BUILDING ENGINEERING   84   2024年5月   eISSN:2352-7102

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    記述言語:日本語   出版者・発行元:Journal of Building Engineering  

    The effects of a newly developed nozzle type, with divergent flow, and abrasive particle size on the surface preparation properties of steel substrate using abrasive water-jet treatment (AWT) were analyzed. The corrosion and chloride removal efficiencies were evaluated by applying this technique to parts of severely corroded steel structures. The evaluation of the surface characteristics of the treated specimens included analysis of the treatment area, maximum erosion depth, surface roughness profile, and residual abrasive material quantity. The corrosion removal efficiency was assessed using surface salinity measurements and SEM-EDX analysis. The experimental results demonstrated that the application of the developed divergent nozzle and smaller abrasive particle sizes in the AWT process resulted in an expanded treatment range and effective prevention of excessive erosion depth and surface roughness. Additionally, ultra-high-pressure water with abrasives completely eliminated corrosion products and chlorides present on both the surface and interiors of the corroded steel surface, achieving a cleanliness level exceeding Sa 3. This process prevented the formation of flash rust on the cleaned surface for up to 24 h and prolonged the time before the reoccurrence of corrosion on the treated surface. To summarize, the AWT with a divergent nozzle and smaller abrasive particles creates the most ideal surface preparation characteristics for subsequent coating and provides higher surface cleanliness suitable for practical engineering applications.

    DOI: 10.1016/j.jobe.2024.108623

    Web of Science

    Scopus

共同研究・競争的資金等の研究課題

  • 研削材と超高圧水の混相流体による重度腐食部の塩・さびの超高速・極限除去技術の開発

    研究課題/領域番号:24K17341 

    キム アラン

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    資金種別:科研費

    本研究では鋼構造物の重度腐食部の塩類・さびを超高速で極限除去し,部材表面を蘇生化するためのAbrasive Water-jet Treatment(AWT)を確立し,鋼構造物に実装展開することを目的とする.そのために,AWTによる基本特性を表面科学,電気化学,材料科学および力学を横断する学際的視点で分析・解明し,その有用性を定量評価する.これらの知見に基づき,処理条件と基本特性の関連を解明した上で,鋼素地品質と処理効率を最適化するAWT拡散型ノズルを開発する.さらに,実構造物に対する適用性を検討した上で,ブラストなどの従来技術の課題をブレイクスルーする塩・さびの超高速・極限除去技術を開発する.

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