사료용 비타민제의 피복을 위한 aerothermal fluidization spraying(ATFS) system의 개발

이무준,이준엽,김창혁,오상집 강원대학교 동물생명과학연구소(구 강원대학교 동물자원공동연구소) 2004 동물자원연구 Vol.15 No.-

Hybridization system, Spraying chamber coating system and aerothermal fluidization spraying (ATFS) system, were tested to find an economic and practical method for vitamin coating. Ae coating by hybridization was done by commercial hybridizer. But both spraying chamber and aerothermal fluidization spraying system were developed by authors for this test. Two vitamins, Vit. E and Vit. C, were employed for coating with four different coating materials, such as eudragit, corn zein, ethylcellulose and gelatin. Coating by hybridization was unsuccessful due to high intake velocity, temperature increase, and bridge formation between vitamin particles. Spraying chamber system was marginally successful to coat vitamins. But the quality of coated vitamin was poor possibly because of the failure of uniform mixing between vitamin and coating materials inside the chamber. Vitamin coating was successfully achieved by ATFS system. The system enables to give not only uniform mixing between coating material and vitamin, but also drying of coated vitamin and uniform diffusion of vitamin particles by thermal aeration. This result was also confirmed through surface micrograph by scanning electron microscope. Therfore, the ATFS system can be considered as a practical system for coating sensitive materials such as vitamins as well as other feed additives.

Uniformity of Droplet of Eutectic NaCl-MgCl2 System for Corrosion Test of Coating Layer

Wonseok Lee,Wonseok Yang,Jihun Kim,Hyeongbin Kim,Taeho Jang,Sungyeol Choi 한국방사성폐기물학회 2023 한국방사성폐기물학회 학술논문요약집 Vol.21 No.1

Corrosion-related challenges remain a significant research topic in developing next-generation Molten Salt Reactors (MSRs). To gain a deeper understanding of preventing corrosion in MSRs, previous studies have attempted to improve the corrosion resistance of structural alloys by coating surfaces such as alumina coating. To conduct a corrosion test of coating alloys fully immersed in molten salt, it’s important to ensure that the coating application process is carefully carried out. Ideally, coating all sides of the alloy is necessary to avoid gaps like corners of the alloy, while only applying a one-sided coating alloy can lead to galvanic corrosion with the base metals. Using the droplet shape of eutectic salt applied to only one side of the coating alloy would avoid these problems in conventional corrosion immersion tests, as corrosion would occur solely on the coating surface. Although the droplet method for corrosion tests cannot fully replicate corrosion in the MSRs environment, it offers a valuable tool for comparing and evaluating the corrosion resistance of different coating surfaces of alloys. However, the surface area is important due to the effect of diffusion in the corrosion of alloy in molten salt environments, but it is difficult to unify in the case of droplet tests. Therefore, understanding the droplet-alloy properties and corrosion mechanism is needed to accurately predict and analyze these test systems’ behavior highlighting unity for corrosion tests of different coating surfaces of alloys. To analyze the molten salt droplet behavior on various samples, pelletized eutectic NaCl-MgCl2 was prepared as salt and W-, Mo-coating, and base SS316 as samples. At room temperature, the same mass of pelletized eutectic NaCl-MgCl2 was placed on different samples under an argon atmosphere and heated to a eutectic point of 500°C in a furnace. After every hour, the molten droplets were hardened by rapid cooling at room temperature outside the furnace. The mass loss of salts and the contact area of the samples were measured by mass balance and SEM. The shape, surface area to volume ratio, and evaporation of the droplets of NaCl-MgCl2 per each coating sample and hour were analyzed to identify the optimal mass to equalize the contact coating surface of alloys with salts. Furthermore, We also analyzed whether their results reached saturation of corrosion products through ICP-MS. This will be significant research for the uniformity of the liquid-drop shape corrosion test of the coating sample in molten eutectic salts.

The Effects of HVOF Coating of WC-CrC-Ni Powder on In718 and of CO2 Laser Heat Treatment on the Coating

Tong-Yul Cho,Jae-Hong Yoon,Yun-Kon Joo,Shihong-Zhang,Wei Fang,권식철,천희곤,Ming-Xi Li 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.54 No.3

High-velocity oxygen-fuel (HVOF) thermal-spray coating (coating) of micron-sized WC-CrC-Ni was carried out on an Inconel718 (In718) surface to improve the surface properties, friction and wear behaviors. During the spraying, binder metals were melted and a small portion of metal carbides, such as WC, Cr7C3 and Ni3C, were melted, partially melted, or decomposed to W2C, Cr, Ni and free carbon. A porous coating was formed by the evolution of carbon oxide gases formed by the reaction of the free carbon and the sprayed oxygen gas. For further improvement, a CO2 laser heat treatment (LH) was performed on the coating. Laser beam (10.6 μm, continuous mode, 400 W) irradiated an oval-shaped focal spot (5 mm × 4 mm) for 0.6 s at a scanning speed 400 mm/min, heating to about 950 - 1200℃ from the edge to the center of the spot. Laser tracks overlap each other 30 %. The porous coating was compacted by the LH, reducing the coating thickness by about 29 % from 280 μm to 200μm and the porosity by about 7 times from 2.6 ± 0.4 % to 0.35±0.06 %. The surface hardness of In718 (410±30 Hv) was increased more than twice to 983±101 Hv by the coating; furthermore, it was increased 45 % (1425±94 Hv) by LH for 0.6 s. The friction coefficient of the In718 surface (0.45±0.08) was reduced 29 % (0.32±0.02) and 9 % (0.29±0.03) by the coating and by the LH, respectively. The wear depth was reduced from 52μm to 30μm and to 12μm by the coating and by the LH, respectively. A HVOF coating of WC-CrC-Ni powder on a metal surface and a LH of the coating are highly recommended for improving the surface properties, the friction behavior and wear resistance.

DLC (ta-C) 후막코팅을 위한 트라이볼로지 코팅 연구

장영준(Young-Jun Jang),강용진(Yong-Jin Kang),김기택(Gi Taek Kim),김종국(Jongkuk Kim) 한국트라이볼로지학회 2016 한국윤활학회지(윤활학회지) Vol.32 No.4

In recent years, thick ta-C coating has attracted considerable interest owing to its existing and potential commercial importance in applications such as automobile accessories, drills, and gears. The thickness of the ta-C coating is an important parameter in these applications. However, the biggest problems are achieving efficient coating and uniformity over a large area with high-speed deposition. Feasibility is confirmed for the ta-C coating thickness of up to 9.0 μm (coating speed: 3.0 μm/h, fixed substrate) using a single FCVA cathode. The thickness was determined using multiple coating cycles that were controlled using substrate temperature and residual stresses. In the present research, we have designed a coating system using FCVA plasma and produced enhanced thick ta-C coating. The system uses a specialized magnetic field configuration with stabilized DC arc plasma discharge during deposition. To achieve quality that is acceptable for use in automobile accessories, the magnetic field, T-type filters, and 10 pieces of a multi-cathode are used to demonstrate the deposition of the thick ta-C coating. The results of coating performance indicate that uniformity is ±7.6 , deposited area is 400 mm, and the thickness of the ta-C coating is up to 5.0 μm (coating speed: 0.3 μm/h, revolution and rotation). The hardness of the coating ranges from 30 to 59 GPa, and the adhesion strength level (HF1) ranges from 20 to 60 N, depending on the ta-C coating.

대두종자의 polymer coating 연구 1 : polymer coating 종자의 conductivity 차이

李成春,J. S. Burris 韓國作物學會 1994 Korean journal of crop science Vol.39 No.2

Polyme coating 종자의 환경적응성을 구명하기 위한 일환으로 콩 종자에 10종의 polymer를 coating하여 각 coating polymer별 conductivity, 발아력, 수분흡수력을 조사하였던 바 그 결과를 요약하면 다음과 같다. 1. Conductivity는 polymer coating한 종자가 coating하지 않은 종자보다 높았으며, 가장 높았던 polymer는 waterlock이었다. 2. Conductivity는 침종 후 시간이 경과할 수록 높아졌고, 100립중이 무거울 수록 높았다. 3. 수확년도가 오래된 종자의 conductivity가 당년에 수확한 종자보다도 높게 나타났다 4. 수분흡수 정도는 coating polymer에 따라 각각 달랐는데 daran 8600은 질이 떨어지는 종자에서는 수분흡수를 크게 저 해하였다. 5. Coating polymer 중 waterlock, captan, klucel, sacrust 등은 발아율을 상승시켰고, daran 8600은 발아율을 저하시켰으며 나머지 polymer는 품종에 따라 각각 달랐고 그 정도는 질이 떨어지는 종자에서 훨씬 컸다. 6. Polymer의 특성에 따라 수분흡수를 저해하거나 조장하였다. These experiment were conducted to evaluate the environmentally acceptable polymers, and 10 polymers were used in these study, and to investigate conductivity, germination percentage, water uptake of polymeric coating soybean seed. The conductivity of polymeric coating seed is higher than that of none coating seed and the highest conductivity was obtained with waterlock coating seed among the 10 polymer coating seed. As the soaking time was long, the conductivity was increased. The conductivity of large seed was higher than that of small seed, and that of long period storage seed was higher than that of short period storage seed. The effects of seed coating polymers on uptake water were various, and daran 8600 inhibited uptake water of low quality seed. The waterlock, captan, klucel and sacrust was rised germination percentage, and daran 8600 was declined germination percentage, and the effect of coating polymers on germination percentage of low quality seed was higher than that of high quality seed.

Roll-to-Roll Coating Technology and Its Applications: A Review

박장훈,신기현,이창우 한국정밀공학회 2016 International Journal of Precision Engineering and Vol.17 No.4

Roll-to-roll (R2R) coating technologies, with their advantages in terms of high throughput and environmental friendliness, are expected to be used at various industrial sites. Thin-film and thick-film forming can be conducted by various techniques that can be installed with R2R systems including dip coating, knife-over-edge coating, slot-die coating, direct- and micro-gravure coating, and spray coating. In this review, coating techniques are introduced from the perspective of process optimization along with examples of applications. Moreover, R2R web handling is also covered for its relationship with the coating process. Process conditions are obtained by presenting the mathematical modeling of each process and a real coating window is presented with surveyed data. Applications of coating technologies focus on printed electronic devices because of their ability to use soluble materials. State-of-art R2R vacuum coating and lab-scale coating without R2R are not discussed in this review. This summary of R2R coating techniques and applications aims to give guidelines for operation and long-term prospects for advanced coating manufacturing.

Superior lubrication of dense/porous-coupled nanoscale C/WS₂ multilayer coating on ductile substrate

Xu, Shusheng,Liu, Yuzhen,Gao, Mingyu,Kang, Kyeong-Hee,Shin, Dong-Gap,Kim, Dae-Eun Elsevier 2019 APPLIED SURFACE SCIENCE - Vol.476 No.-

<P><B>Abstract</B></P> <P>Sputtered carbon material has been receiving much attention as a solid lubricant coating owing to its high hardness and low coefficient of friction. However, its relatively low wear resistance performance when applied on a ductile substrate has limited its use in certain applications. In this work, a porous WS<SUB>2</SUB> sublayer was introduced to the sputtered carbon-based nanoscale multilayer coating to improve its tribological properties. The microstructural, mechanical and tribological properties of the nanoscale C/WS<SUB>2</SUB> multilayer coating were systematically investigated using various analytical techniques. Through structural optimization, a durable coating with excellent wear resistance and low frictional performances could be attained for a ductile steel substrate. The excellent toughness allowed the coating to deform with the ductile substrate without fracturing during contact sliding process. Furthermore, the first self-destruction and then recombination behaviors of dense/porous-coupled nanoscale multilayer coating as well as the selective release of carbon component to the contact interface driven by the frictional interaction aided in maintaining low friction. As a result, the nanoscale multilayer coating showed approximately 100-fold greater wear resistance than that of pure hard carbon coating on a ductile steel substrate.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A hard/soft-coupled nanoscale C/WS<SUB>2</SUB> multilayer coating was constructed by sputtering. </LI> <LI> The multilayer coating exhibited excellent synchronized deformation with the ductile steel substrate. </LI> <LI> Multilayer coating on ductile steel showed 100-fold longer wear life than that of a stiff C coating. </LI> <LI> The rearranged coating on the formed deep wear track resulted in improved lubrication performance. </LI> <LI> That provided a novel way to develop lubricant protection layer on ductile material surface </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

TiO2 코팅 고정화 기술의 장기 공용성 시험에 따른 NOx 제거효율 평가

김광현,안희락,이승우,김영규 한국도로학회 2023 한국도로학회논문집 Vol.25 No.5

PURPOSES : The increase in particulate matter due to increased air pollutant emissions has become a significant social issue. According to the Ministry of Environment, air pollutants emitted from large-scale businesses in 2022 increased by 12.2% compared to the previous year, indicating that air pollution is accelerating owing to excessive industrialization. In this study, TiO2, which is used to reduce airborne particulate, was used. The TiO2 coating fixation and dynamic pressure coating-type TiO2 fixation methods were used to solve the material peeling phenomenon caused by gravity, which is a limitation when the TiO2 penetration method is applied to a vertical concrete structure along the road. The long-term durability and performance were analyzed through environmental resistance and NOx removal efficiency evaluation experiments. These analyses were then assessed by comparing the NOx removal efficiency with the dynamic pressure permeationtype TiO2 fixation method used in previous studies. METHODS : To evaluate the long-term durability and performance of the TiO2 coating fixation method and dynamic pressure coating TiO2 fixation method for vertical concrete structures, specimens were manufactured based on roadside vertical concrete structures. Environmental resistance tests such as the surface peeling resistance test (ASTM C 672) and freeze-thaw resistance test (KS F 2456) were conducted to evaluate the long-term durability. To evaluate the long-term performance, the NOx removal efficiency of TiO2 concrete owing to road surface deterioration during the environmental resistance test was evaluated using the NOx removal efficiency evaluation equipment based on the ISO 22197-1 standard. This evaluation was compared and analyzed using the dynamic pressure infiltration TiO2 fixation method. RESULTS : The long-term durability of the TiO2 coating fixation and dynamic pressure coating TiO2 fixation methods were evaluated using environmental resistance tests. During the surface peeling resistance test, the TiO2 material degraded and partially detached from the concrete. However, the NOx removal efficiency was ensured by the non-deteriorated and fixed TiO2 material. The long-term performance was confirmed through a freeze-thaw resistance test to evaluate the NOx removal efficiency after 300 cycles of surface deterioration. The results showed that when the TiO2 coating fixation and dynamic pressure infiltration TiO2 fixation methods were applied to vertical concrete structures, the durability of the structure was not compromised. In comparison to the dynamic pressure infiltration TiO2 fixation method, the NOx removal efficiency observed during the surface peeling resistance test was lower, while the freeze-thaw test exhibited notably higher removal efficiency. CONCLUSIONS : To solve the material peeling phenomenon caused by gravity, the long-term durability and performance were evaluated by applying the TiO2 coating fixation and dynamic pressurized coating TiO2 fixation methods to vertical concrete specimens. Long-term durability was confirmed through environmental resistance tests, and long-term utility was secured by measuring the NOx removal efficiency according to surface degradation. These findings show that implementing the TiO2 coating fixation method and dynamic pressure coating TiO2 fixation methods on-site effectively reduce NOx.

대면적 유체 코팅을 위한 기계학습 기반의 블레이드 코팅 조건 최적화

송륜근(Ryungeun Song),어솔(Sole Eo),이진기(Jinkee Lee) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.11

Large-scale liquid coating is an important technique in various industrial fields such as the fabricating of functional panels or surfaces. Blade coating with continuous liquid supply is one of the most cost-effective methods for large-scale coating. In order to coat liquid without defects, it is essential to stably maintain the coating bead trapped under the blade, but numerous experiments are required to obtain coating conditions that guide the appropriate operating parameters. To relieve the burden on this laborious work, we present a novel strategy to acquire coating conditions via physics-informed neural networks (PINNs). Whereas standard neural networks (NNs) predict the coating performance directly from the operating parameters, the PINNs predict parameters related to the state of the coating bead to enhance the coating performance. When the data collected from the experiments under the various parameters were trained on both networks, it was revealed that the PINNs predict with a superior performance than the purely data-driven NNs. Finally, a parametric study was performed with a well-trained PINN-based model to present the optimal coating conditional zones, and we experimentally demonstrated that the stable coating was achieved by using the operating parameters from the found optimal coating conditional zones.

Twin wire arc spray 용사코팅 공정을 통해 제작된 미끄럼 방지 코팅의 열적 특성 및 고온노출 거동 연구

권한솔,박영진,남욱희,변응선 대한금속·재료학회 2023 대한금속·재료학회지 Vol.61 No.9

Conventional non-skid coatings for marine construction contain polymeric materials. Thesematerials are generally susceptible to high temperature environments because of their low thermalconductivity and thermal resistance. A metal-based non-skid coating has great potential for hightemperature applications, yet, there has only been limited research. In this study, twin wire arc spray(TWAS) was used to fabricate Al and Al-3%Ti coatings on a high strength low alloyed (HSLA) steelsubstrate. The purpose of this study is to confirm the feasibility of TWAS Al-based coating for non-skidareas on marine construction. The static coefficient friction of TWAS Al-based coatings exhibited excellentand uniform values compared with a conventional epoxy-based non-skid coating. The specific heat andthermal conductivity of TWAS Al-based coating was measured and compared with that of the substrate. The thermal property values of the TWAS Al-based coating were reported for the first time in this study. The TWAS Al-based coating had A continuous interface with the substrate and the generalmicrostructural features of a thermal-sprayed metal coating. After exposure to 500oC for 24 hours, thean Fe-Al intermetallic compound and oxide were formed inside of the coating and coating-substrateinterface. The adhesion strength indicated that the TWAS Al-based coating sustained its strength afterthe isothermal exposure test. The Vickers hardness of the TWAS Al-3%Ti coating was higher than thatof the Al coating. The solid solution hardening of Ti atoms in the as-deposited coating and theprecipitation hardening of the TiAl3 compound in the heat-treated coating contributed to theimprovement of in Vickers hardness. Thus, the TWAS Al-3%Ti coating is proven to be a promising nonskidcoating for high temperature applications.