• Title/Summary/Keyword: coating layer

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Determination of Deformation Behavior of Coating Layer on Electronic galvanized Sheet Steel using Nano-indentation and FEM (나노 인덴테이션 실험과 유한요소해석을 이용한 전기아연도금강판의 코팅층 체적 거동 결정)

  • Ko, Young-Ho;Lee, Jung-Min;Kim, Byung-Min
    • Journal of the Korean Society for Precision Engineering
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    • v.22 no.10 s.175
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    • pp.186-194
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    • 2005
  • This study was designed to investigate the mechanical properties of the coating layer on electronic galvanized sheet steel as a part of the ongoing research on the coated steel. Those properties were determined using nano-indentation, the finite element method, and artificial neural networks. First and foremost, the load-displacement curve (the loading-unloading curve) of coatings was derived from a nano-indentation test by CSM (continuous stiffness measurement) and was used to measure the elastic modulus and hardness of the coating layer. The properties derived were applied in FE simulations of a nano-indentation test, and the analytical results were compared with the experimental result. A numerical model for FE simulations was established for the coating layer and the substrate separately. Finally, to determine the mechanical properties of the coating, such as the stress-strain curve, functional equations of loading and unloading curves were introduced and computed using the neural networks method. The results show errors within $5\%$ in comparison with the load-displacement measured by a nano-indentation test.

Characteristics of the Surface Coating Layer of Ti5Si3 Intermetallic Compound Obtained by Shock Compaction and Reaction Synthesis Through Underwater Shock Compression (수중충격파를 이용하여 충격고화와 반응합성으로 제조된 Ti5Si3 금속간 화합물의 표면코팅 층의 특성에 관한 연구)

  • Lee, Sang-Hoon
    • Journal of Powder Materials
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    • v.15 no.2
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    • pp.101-106
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    • 2008
  • The objective of the present study is to investigate the increase in the functional characteristics of a substrate by the formation of a thin coating layer. Thin coating layers of $Ti_5Si_3$ have high potential because $Ti_5Si_3$ exhibits high hardness. Shock induced reaction synthesis is an attractive fabrication technique to synthesize uniform coating layer by controlling the shock wave. Ti and Si powders to form $Ti_5Si_3$ using shock induced reaction synthesis, were mixed using high-energy ball mill into small scale. The positive effect of this technique is highly functional coating layer on the substrate due to ultra fine substructure, which improves the bonding strength. These materials are in great demand as heat resisting, structural and corrosion resistant materials. Thin $Ti_5Si_3$ coating layer was successfully recovered and showed high Vickers' hardness (Hv=1183). Characterization studies on microstructure revealed a fairly uniform distribution of powders with good interfacial integrity between the powders and the substrate.

Development of Hybrid Insulating Coating for Fe-based Soft Magnetic Powder (철계 연자성 분말용 하이브리드 절연 코팅막 개발)

  • Kim, Jungjoon;Kim, Sungyeom;Kim, Youngkyun;Jang, Taesuk;Kim, Hwi-jun;Kim, Youngjin;Choi, Hyunjoo
    • Journal of Powder Materials
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    • v.28 no.3
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    • pp.233-238
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    • 2021
  • Iron-based amorphous powder attracts increasing attention because of its excellent soft magnetic properties and low iron loss at high frequencies. The development of an insulating layer on the surface of the amorphous soft magnetic powder is important for minimizing the eddy current loss and enhancing the energy efficiency of high-frequency devices by further increasing the electrical resistivity of the cores. In this study, a hybrid insulating coating layer is investigated to compensate for the limitations of monolithic organic or inorganic coating layers. Fe2O3 nanoparticles are added to the flexible silicon-based epoxy layer to prevent magnetic dilution; in addition TiO2 nanoparticles are added to enhance the mechanical durability of the coating layer. In the hybrid coating layer with optimal composition, the decrease in magnetic permeability and saturation magnetization is suppressed.

Glucose Diffusion Limiting Membrane Based on Polyethyleneimine (PEI) Hydrogel for the Stabilization of Glucose Sensor

  • Kim, Suk-Joon;Shin, Woonsup
    • Journal of Electrochemical Science and Technology
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    • v.12 no.2
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    • pp.225-229
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    • 2021
  • Commercially available continuous glucose sensors require the operation stability for more than two weeks. Typically, the sensor comprises a sensing layer and an over-coating layer for the stable operation inside the body. In the sensing layer, enzymes and mediators are cross-linked together for the effective sensing of the glucose. The over-coating layer limits the flux of glucose and works as a biocompatible layer to the body fluids. Here, we report the simple preparation of the flux-limiting layer by the condensation of polyethyleneimine (PEI), tri-epoxide linker, and trimethylolpropane triglycidyl ether (PTGE). The sensor is constructed by a layer-by-layer drop-coating of the sensing layer containing glucose dehydrogenase and the PEI-derived blocking layer. It is stable for more than 14 days, which is enough for the sensor in the continuous monitor glucose monitoring (CGM) system.

Effects of Stoichiometry on Properties of NiAl Intermetallics coated on Carbon Steel through Combustion Synthesis (연소합성 코팅된 NiAl 금속간화합물의 화학양론이 미끄럼 마모특성에 미치는 영향)

  • Lee, Han-Young;Lee, Jae-Sung
    • Tribology and Lubricants
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    • v.36 no.3
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    • pp.124-132
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    • 2020
  • The effect of the stoichiometry on the sliding wear properties of NiAl coatings has been investigated. Three different powder mixtures with the compositions of Ni-50at%Al, Ni-54at%Al and Ni-42at%Al were diepressed respectively, and which were subsequently coated on mild steel through combustion synthesis in an induction heating system. Sliding wear behavior of the coatings was examined against an alloyed tool steel using a pin-on-disc type sliding wear test machine. As results, it could be seen that powder mixture(Ni-54at%Al) with displaying Al-rich deviations from the stoichiometry of NiAl(Ni-50at%Al) was promoted the most the synthetic reactivity. The microstructure of the coating layer with the compositions of Ni-54at%Al exhibits the porous NiAl single phase structure. However, the microstructure of the coating layer of the compositions of Ni-42at%Al exhibits the denser multi-phase structure containing several intermediate phases in addition to NiAl. Densification of the coating layer was enhanced by increasing the reacting temperature. On the other hand, the wear properties of the coating layers showed that the wear mode at speeds of around 1 m/s was severe wear, regardless of the stoichiometry and reacting temperature. However, wear properties of coating layer with the compositions of Ni-42at%Al were superior to those of coating layer with the compositions of Ni-54at%Al. This would be attributed by the fact that coating layer with the compositions of Ni-42at%Al develops little void and much intermediate phases with high strength.

Effect of Spin Coating Speed on Characteristics of Polyimide Alignment Layer for Liquid Crystal Display (스핀 코팅 공정에 따른 액정디스플레이용 폴리이미드 배향막 특성 분석)

  • Kim, Jin-Ah;Choi, Se-Hoon;Park, Hong-Gyu
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.35 no.1
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    • pp.58-65
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    • 2022
  • The field of liquid crystal display (LCD) is constantly in the spotlight and the process of depositing an alignment layer in the LCD manufacturing process is very important to obtain excellent performance such as low-power driving and high-speed response to improve LCD performance. Therefore, research on liquid crystal (LC) alignment is being actively conducted. When manufacturing LCD, it is necessary to consider the effect of the alignment layer thickness as one of the factors affecting various LCD performances. In addition, previous studies confirmed the LC alignment characteristics correlate with the rotation speed in the spin coating process. Therefore, the electro-optical properties of the LCD were investigated by manufacturing a polyimide alignment layer by varying the rotation speed in the spin coating process in this study. It was confirmed that the thickness of the polyimide alignment layer was controlled according to the spin coating conditions. The average transmittances of anti-parallel LC cells at the spin coating speed of 2,500 rpm and 3,000 rpm are about 60%, which indicates that the LC cell has relatively higher performance. At the spin coating speed of 3,000 rpm, the voltage-transmittance curve of twisted nematic (TN) LC cell was below 1.5 V, which means that the TN LC cell operated at a low power. In addition, high-speed operating characteristics were confirmed with a response time of less than 30 ms. From these derived data, we confirmed that the ideal spin coating speed is 3,000 rpm. And these results provide an optimized polyimide alignment layer process when considering enhanced future LCD manufacturing.

Morphology Characteristics of Insulating Laser based on Aqueous Polymer Resin Fabricated by Ultrasonic Spray Coating Process (수성 폴리머 도료를 이용한 초음파 스프레이 공정으로 형성된 폴리머 절연층 미세구조 특성)

  • Yu, Jeong-Mo;Park, Chae-Won;Eom, Hyeon-Jin
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2016.11a
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    • pp.136-136
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    • 2016
  • Commonly used oil-based polymer resin has environmental and safety issues. Many researches for replacing the harmful solvent-borne resins to water-borne resins have been investigated to purify harmful environmental resources and follow the export and import of hazardous materials regulations. In this research, ultrasonic spray coatings of aqueous polymer resin were studied to fabricate thin insulating layer (${\sim}{\mu}m$) on the rectangular copper wire. It needs to have appropriate wettability between resin and substrate during the ultrasonic spray coating process to coat aqueous polymer uniformly. Furthermore, stabilities of coating solution and fabricating process are required to form thin insulating layer on the substrate. In here, physical characteristics such as viscosity of 6 types of commercial polymer dispersions and emersions were analyzed to confirm compatibility for ultrasonic spray coating process. These resins were dissolved in isopropyl alcohol, used for true solvent, and were diluted with ethanol, utilized for diluent. Also, solubilities, dispersion characteristics, and viscosities of these diluted polymer resin solutions were confirmed. Dispersion characteristic and viscosity of coating solution affects jetting of ultrasonic spray coating and these jetting characteristics influence morphologies of insulating layer. In conclusion, we have known that aqueous polymer solution should have outstanding dispersion characteristic and certain range of viscosity to fabricate thin polymer insulating layer uniformly with ultrasonic spray coating.

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Characteristic Evaluation of TiMoN Coating Layer Deposited by Current Control available AIP-PVD Method (전류제어가 가능한 AIP-PVD법으로 증착된 TiMoN 코팅층 특성평가)

  • Shin, Hyun-Jung;Kim, Dong-Bea;Kim, Seong-Chul;Kim, Nam-Su
    • Journal of the Korean Society for Heat Treatment
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    • v.32 no.5
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    • pp.224-229
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    • 2019
  • PVD coating is a technology that can be applied to various industries, and is widely used for processing molds and machinery, improving performance of core parts, and extending the life. Therefore, there is a need for a research on a device and a process technology that can adjust the performance to suit each application. In this study, a PVD coating device with ion density control was used to deposit a coating layer on SKD 11, a cold die steel, with magnetron currents of 1 A, 2 A, 3 A at arc currents of 80 A, 100 A, 130 A. It examined the mechanical properties for each condition. Increasing the arc current and magnetron current could improve the thickness, adhesion, and hardness of the coating layer. Especially, When the magnetron current was high, it suppressed the droplets that could be generated by the high arc current, showing excellent surface uniformity and adhesion of the coating layer.

Parameter Analysis for the Lateral Thickness of the Coated Layer to Improve Product Quality in Large Area Roll-to-Roll Slot-Die Coating Process (대면적 롤투롤 슬롯-다이 코팅의 횡 방향 두께 품질 개선을 위한 공정 파라미터 분석)

  • Park, Janghoon;Lee, Changwoo
    • Journal of the Korean Society for Precision Engineering
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    • v.32 no.2
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    • pp.159-166
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    • 2015
  • Slot-die coating is well known technique to guarantee a uniformly coated layer and is compatible with roll-to-roll process. In actual roll-to-roll slot-die coating process, the lateral difference of coated layer thickness is observed. An experimental study was performed to improve the coating quality. Coating speed and coating gap were selected as the experimental factors. A full factorial, statistical method was conducted to optimize the process conditions. Based on the results of repeated experiment, the lowest deviation of lateral thickness (700 nm, <10%) was achieved at 10 m/min coating speed and $300{\mu}m$ coating gap. This result has significance because such optimized process guideline can be utilized with all process improvement in various coating applications.

Improving Gas Barrier Property of Polymer Based Nanocomposites Using Layer by Layer Deposition Method for Hydrogen Tank Liner

  • Lee, Suyeon;Han, Hye Seong;Seong, Dong Gi
    • Composites Research
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    • v.35 no.3
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    • pp.121-126
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    • 2022
  • Owing to advantages of polymeric materials for hydrogen tank liner like light-weight property and high specific strength, polymer based composites have gained much attention. Despite of many benefits, polymeric materials for fuel cell tank cause problems which is critical to applications as low gas barrier property, and poor processability when adding fillers. For these reasons, improving gas barrier property of polymer composites is required to study for expanding application fields. This work presents impermeable polymer nanocomposites by introducing thin barrier coating using layer by layer (LBL) deposition method. Also, bi-layered and quad-layered nanocomposites were fabricated and compared for identifying relationship between deposition step and gas barrier property. Reduction in gas permeability was observed without interrupting mechanical property and processability. It is discussed that proper coating conditions were suggested when different coating materials and deposition steps were applied. We investigated morphology, gas barrier property and mechanical properties of fabricated nanocomposites by FE-SEM, Oxygen permeation analyzer, UTM, respectively. In addition, we revealed the mechanism of barrier performance of LBL coating using materials which have high aspect ratio.