• Title/Summary/Keyword: Al coating

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Corrosion resistance performance of arc thermal sprayed Al and Al/epoxy dual metal polymeric coating in 3.5 wt.% NaCl-contaminated concrete pore solution (3.5 wt.% NaCl로 오염된 콘크리트 기공 용액에서 아크 용사 Al 및 Al/에폭시 이중 금속 고분자 코팅의 내식성 성능)

  • Singh, Jitendra Kumar;Lee, Han-Seung
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2023.11a
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    • pp.119-120
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    • 2023
  • Corrosion of the steel rebar in coastal environment caused huge economical loss of the globe. Therefore, coating on the steel rebar being used to mitigate the corrosion. In the present study, we have applied epoxy coating on arc thermal sprayed Al coating (a dual metal/polymeric coating) vis-à-vis compared with as coated one (Al coating). The corrosion studies were performed in simulated concrete pore solution with 3.5 wt. % NaCl solution. The morphology of the dual epoxy/Al coating is smooth while Al coating shows rankle and defects. Due to defects, Al coating is susceptible to corrosion while dual epoxy/Al coating has performed excellent compared to as coated one at extended period of immersion.

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Microstructure and Hardness of Al-Cu Alloy Coating on Monel 400 by Hot Dipping (액상 침적에 의한 Monel 400기지상에 형성된 Al-Cu 합금 코팅층의 조직 및 경도)

  • 조선욱;이임렬
    • Journal of the Korean institute of surface engineering
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    • v.29 no.4
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    • pp.278-285
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    • 1996
  • The structure of coating layer formed by hot dip Al-Cu alloy coating on Monel 1400 metal was studied. The coating layer consists of alloyed layer adjacent to the Monel 400 substrate and Al-Cu alloy. It was found that the hardness of coating increased with dipping time and heat treatment associated with the diffusion and the formation of intermetallic compound at the interface. However the thickness of coating layer was decreased at high dipping temperature due to tile higher viscosity of liquid coating alloy. Diffusion heat treatment at $600^{\circ}C$ after coating resulted in the disappearence of adhered Al(Cu) and $CuAl_2$ phases, and then they transformed into the new phases of CuAl and Al7Cu4Ni at coating layer.

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Lifetime Evaluation of AI-Fe Coating in Wet-seal Environment of MCFC

  • Jun, JaeHo;Jun, JoongHwan;Kim, KyooYoung
    • Corrosion Science and Technology
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    • v.3 no.4
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    • pp.161-165
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    • 2004
  • Aluminum source in an Al-Fe coating reacts with molten carbonate and develops a protective $LiAlO_2$ layer on the coating surface during operation of molten carbonate fuel cells (MCFC). However, if aluminum content in an Al-Fe coating decreases to a critical level for some reasons during MCFC operation, a stable and continuous $LiAlO_2$ protective layer can no longer be maintained. The aluminum content in an Al-Fe coating can be depleted by two different processes; one is by corrosion reaction at the surface between the aluminum source in the coating and molten carbonate, and the other is inward-diffusion of aluminum atoms within the coating into a substrate. In these two respects, therefore, the decreasing rate of aluminum concentration in an Al-Fe coating was measured, and then the influences of these two aspects on the lifetime of Al-Fe coating were investigated, respectively.

EFFECT OF ALUMINIDE-YTTRIUM COMPOSITE COATING ON THE OXIDATION RESISTANCE OF TiAl ALLOY

  • Jung, Hwan-Gyo;Kim, Jong-Phil;Kim, Kyoo-Young
    • Journal of the Korean institute of surface engineering
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    • v.29 no.6
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    • pp.607-614
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    • 1996
  • Yttrium(Y) coating was incorporated by ion-plating method either directly on the TiAl substrate or after pack aluminizing on TiAl to improve the oxidation resistance of TiAl alloy. After Y-coating, heat treatment at low oxygen partial pressure was carried out. Performance of various coating was evaluated by isothermal and cyclic oxidation tests. A simple Y-coating without pack aluminizing can give a detrimental effect on the. oxidation resistance of TiAl alloy, because it enhances formation of $TiO_2$. On the other hand, a composite coating of aluminide-yttrium has shown excellent oxidation resistance. A continuous protective $Al_2O_3$ scale is formed on the aluminized TiAl, and Y-coating improves $Al_2O_3$ scale adherence and substantially prevents depletion of Al in the aluminide-coating layer.

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Comparative study on impact behavior of TiN and TiAlN coating layer on WC-Co substrate using Arc ion Plating Technique (아크이온 플레이팅법으로 WC-Co에 증착된 TiN 및 TiAlN박막의 충격특성 비교)

  • 윤순영;류정민;윤석영;김광호
    • Journal of the Korean institute of surface engineering
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    • v.35 no.6
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    • pp.408-414
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    • 2002
  • TiN and TiAlN coating layer were deposited on WC-Co steel substrates by an arc ion plating(AIP) technique. The crystallinity and morphology for the deposited coating layers were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The impact behaviors of the deposited TiN and TiAlN coating layer were investigated with a ball-on-plate impact tester. Beyond $10^2$ impact cycle, TiAlN coating layer showed superior impact wear resistance compared to TiN coating layer. On the other hand, both TiN and TiAlN coating layers started to be partially failed between $10^2$ and $10^3$ impact cycle. Above $10^3$ impact cycle, TiN and TiAlN coating layers showed similar impact behavior because of the substrate effect.

A Study for Ni-Al based Intermetallics Coating onto Aluminum Substrate by Induction Heating (고주파 유도가열을 통한 알루미늄 기판재위 Ni-Al계 금속간화합물의 연소합성코팅에 관한 연구)

  • Lee, Han-Young
    • Tribology and Lubricants
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    • v.28 no.2
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    • pp.56-61
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    • 2012
  • In order to investigate the possibility of Ni-Al based intermetallics coating onto aluminum substrate, the coating process for induction heating has been evaluated by microscopically analyzing the intermetallic layers coated at temperatures lower than the melting temperature of aluminum. The coating layers were divided into two parts with different microstructure along the depth. Hard $NiAl_3$ layer was found at lower parts of the coatings near the interface with aluminum substrate. This layer was formed by the diffusion of aluminum atoms from the substrate into the coating layer across the interface during the induction heating. Meanwhile, at the upper parts of the coating near the surface, a large amount of un-reacted Ni was still remained and surrounded by several Ni-Al based intermetallic compounds, such as $Ni_3Al$, NiAl and $Ni_2Al_3$ formed by the lattice diffusion.

Manufacturing and Properties of Al-Al2O3 Composite Coating Layer Using Warm Spray Process (Warm spray를 이용한 알루미늄-알루미나 복합 코팅층의 제조 및 특성)

  • Kwon, Eui-Pyo;Lee, Jong-Kweon
    • Korean Journal of Materials Research
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    • v.27 no.7
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    • pp.374-380
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    • 2017
  • Properties of coatings produced by warm spray were investigated in order to utilize this technique as a repair method for Al tire molds. $Al-(0-10%)Al_2O_3$ composite powder was sprayed on Al substrate by warm spraying, and the microstructure and mechanical properties of the composite coating layer were investigated. For comparative study, the properties of the coating produced by plasma spray, which is a relatively high-temperature spraying process, were also investigated. The composite coating layers produced by the two spray techniques exhibited significantly different morphology, perhaps due to their different process temperatures and velocities of particles. Whereas the $Al_2O_3$ particles in the warm sprayed coating layer maintained their initial shape before the spray, flattened and irregular shape $Al_2O_3$ particles were distributed in the plasma sprayed coating layer. The coating layer produced by warm spray showed significantly higher adhesive strength compared to that produced by plasma spray. Hardness was also higher in the warm sprayed coating layer compared to the plasma sprayed one. Moreover, with increasing the fraction of $Al_2O_3$, hardness gradually increased in both spray coating processes. In conclusion, an $Al-Al_2O_3$ composite coating layer with good mechanical properties was successfully produced by warm spray.

The Effect of Ball-milling Energy on Combustion Synthesis Coating of Cu-Al-Ni Based Intermetallics (Cu-Al-Ni계 금속간화합물의 연소합성 Coating에 미치는 Ball Mill처리의 영향)

  • Lee, Han-Young
    • Tribology and Lubricants
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    • v.27 no.1
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    • pp.1-6
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    • 2011
  • The possibility of Cu-Al-Ni intermetallic coating on the mild steel through the combustion synthesis has been investigated. In particular, the effect of the ball milling energy on the microstructure of the coating layer was examined to obtain the best coating condition. Experimental results show that Cu-Al-Ni powder compact was explosively synthesized and successfully coated with the steel matrix. It was revealed that the formation of $Cu_9Al_4$ intermetallic decreased with increase in the ball milling energy. This result supports that the high energy ball milling would be effective for obtaining the most suitable microstructure for Cu-Al-Ni coating layer. However, the excessive ball milling energy seems to decrease the bonding strength between the coating layer and the matrix.

Sliding Wear Behavior of $Al_2O_3/NiCr$ Coating ($Al_2O_3/NiCr$ 코팅의 미끄럼 마멸 특성)

  • Chae, Young-Hun;Park, Byung-Hee;Kim, Seock-Sam
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.23 no.7 s.166
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    • pp.1245-1252
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    • 1999
  • The sliding wear behavior of $Al_2O_3/NiCr$ coating deposited on steel(SM45C) was investigated under lubrication. The parameters of sliding wear are normal loads, coating thickness. As a result, the wear resistance of $Al_2O_3/NiCr$ coating was remarkably greater than that of $Al_2O_3$ coating. The optimized coating thickness was found to be $300{\mu}m$ to ensure good anti-wear. The bond coating played important role in decreasing residual stress. The residual stress had much influence on wear mechanism. These results were correlated with the stress state of coating and the microstructure of coating.

Property and formation behavior of TiAlSiWN nanocomposite coating layer by the AIP process (AIP 공정 적용 TiAlSiWN 나노 복합체 코팅층의 형성 거동 및 특성 평가)

  • Lee, Jeong-Han;Park, Hyeon-Guk;Jang, Jun-Ho;Hong, Seong-Gil;O, Ik-Hyeon
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2018.06a
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    • pp.97.2-97.2
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    • 2018
  • This study formed a hard TiAlSiWN coating layer using Ti, Al, Si and W raw powders that were mechanically alloyed and refined. The TiAlSi and TiAlSiW coating targets were fabricated using a single PCAS process in a short time with the optimal sintering conditions. The coating targets were deposited on the WC substrate by forming coating layers using TiAlSiN and TiAlSiWN nitride nano-composite structures with an AIP process. The properties of the nitride nano-composite coating layers were compared according to the addition of W. The microstructure of the nitride nano-composite coating layer was analyzed, focusing on the distribution of the crystalline phases, amorphous phases ($Si_3N_4$), and growth orientation of the columnar crystal depending on the addition of W. The mechanical properties of the coating layers were exhibited a hardness of approximately $3,000kg/mm^2$ and adhesion of about 117.77N in the TiAlSiN. In particular, the TiAlSiWN showed excellent properties with a hardness of more than $4,300kg/mm^2$ and an adhesion of about 181.47N.

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