• 한국표면공학회지
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• 제36권3호
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• pp.284-289
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• 2003

In this study, the prediction on the quality of tools after coating process has been investigated. Under different coating conditions, cutting resistances have been obtained and analyzed with a tool dynamometer to provide optimized coating conditions. The optimized coating conditions Lhave been computed with the most effective factors found by S/N ratio of Taguchi method. To evaluate the influence of the factors on cutting efficiency through the minimum of number of experiment times, the way of neural network design using Taguchi method has been employed.

• 한국전기전자재료학회논문지
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• 제17권9호
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• pp.967-972
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• 2004

Hardness and surface property of coated gel materials are considerably different according to kinds(particle size/stabilized ion) of colloidal silica(CS), kinds of silanes, content ratio of silane versus CS, and reaction degree in sol solution. We report the properties of sol-gel coating materials in which the factors of reaction are kinds of CS, contents ratio of CS and MTMS, and reaction time of sol. The contact angles of the coated films obtained from the mixed CS system showed a little good relationship with MTMS content increase to those from HSA CS reaction system and the change of contact angle didn't have much effect on reaction time of sol. In the coating films obtained from HSA CS reaction system, the surface was much rough in case of that the content MTMS decreased and the reaction of sol kept long. The surface roughness of films obtained from the mixed CS reaction system showed similar tendency, though its degree was a little different. In synthesis of sol-gel coating materials, we could identify that choice of CS kinds and content ratio of CS and silane were important and it was desirable the reaction time of sol is not long.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.126.1-126.1
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• 2015

A quantitative relationship between Leidenfrost point and surface characteristics such as surface material and roughness is investigated. Based on the relationship, we have fabricated the surfaces with their Leidenfrost points (LFP) tuned by controlling surface coating and structures. As discovered by Leidenfrost, liquids placed on a hot plate levitate on the gas phase-air gap formed by the vaporization of liquids. This phenomenon is called 'Leidenfrost effect'. A change of LFP has attracted many researchers for several years but the ability to tune LFP is still a remaining issue. Many of previous work has progressed for various conditions so the systematic approach and analysis are needed to clearly correlate the LFP and the surface conditions. In this report, we investigate a relation of surface energy and LFP using various coating materials such as Octadecyltrichlorosilane (OTS) and 1H, 1H, 2H, 2H-Perfluorooctyltrichlorosilane (FOTS). Also, we analyze how surface roughness affects LFP via surface micro structuring with ICP-RIE fabrication process. The improved understanding can have potential applications such as the control of liquid droplet behavior at elevated temperatures for efficient cooling system.

• 한국분말재료학회지
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• 제24권1호
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• pp.46-52
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• 2017

Fecralloy coating layer with large surface area is suitable for use as a filter media for efficient removal of hot gaseous pollutants exhausted from combustion processes. For uniform preparation of a Fecralloy coating layer with large surface area and strong adhesion to substrate, electrospray coating and thermal treatment processes are experimentally optimized in this study. A nano-colloidal solution with 0.05 wt% Fecralloy nanoparticles is successfully prepared. Optimized electrospraying conditions are experimentally discovered to prepare a uniform coating layer of Fecralloy nano-colloidal solution on a substrate. Drying the electrospray coated Fecralloy nano-colloidal solution layer at $120^{\circ}C$ and subsequent heating at $600^{\circ}C$ are the best post-treatment for enhancing the adhesion force and surface roughness of the Fecralloy coating layer on a substrate. An electrospray coating system, consisting of several multi-groove nozzles, is also experimentally confirmed as a reasonable device for uniform coating of Fecralloy nano-colloid on a large area substrate.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2007년도 추계학술대회 논문집
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• pp.61-62
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• 2007

HVOF thermal spray coating of micron size Co-alloy powder has been studied for the durability improvement of high velocity spindle (HVS). Optimal coating process of this system for the best surface properties is hydrogen flow rate 75 FMR, oxygen flow rate 38-42 FMR, feed rate 30 g/min at spray distance 5 inch. Friction coefficient (FC) and wear trace (WT) decrease increasing coating surface temperature from 25$^{\circ}$C to 538$^{\circ}$C due to the higher lubricant effects of the oxides at the higher temperature. At the study of adhesion of T800 coating on a light metal alloy Ti-6Al-4V (Ti64) tensile bond strength (TBS) and tensile fracture location (TFL) of Ti64/T800 are 8,740 psi and near middle of T800 coating respectively. This shows that adhesion of Ti64/T800 is higher than the cohesion strength (8,740 psi) of T800 coating. Therefore T800 coating is strongly advisable for the surface coating on HVS such as high speed air-bearing spindle.

• 접착 및 계면
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• 제3권3호
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• pp.22-29
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• 2002

하층에 유 무기 전도성 물질을 코팅하고 상층은 다관능성 아크릴레이트를 코팅한 다층코팅의 자외선 경화형 시스템을 도입하였다. 이러한 다층코팅은 투명한 PMMA, PC, PET 등의 기재 위에 wet and wet 방식의 코팅 방법을 사용하여 제조하였다. 도막의 표면저항과 물성은 상층 두께의 변화와 상대 습도를 다르게 하여 측정하였다. 상층두께가 $10{\mu}m$ 이하일 때 $10^8{\sim}10^{10}{\Omega}/cm^2$의 표면저항을 나타냈으며 표면 물성은 단층코팅에 비해서 다층코팅이 더 우수하게 나타났다. 그리고 다층코팅에서의 도판트 이동효과는 접촉각과 FT-IR/ATR을 통해 관찰하였다. 하층이 무기 전도성 물질인 경우에는 관찰되지 않는 도판트(DBSA)의 필름-기재 계면에서 필름-공기 계면 쪽으로 이행되는 거동이 유기전도성 물질인 경우에는 관찰되었다.

• 한국표면공학회지
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• 제56권1호
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• pp.69-76
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• 2023

The effects of hairline treatment on surface blackening and thermal diffusion behaviors of Zn-Al-Mg alloy coated steel sheet were evaluated by the three-dimensional surface profiler and laser-flash technique. The metallographic observation of coating damages by hairline treatments showed that several cracks were initiated and propagated along the interface between primary Zn/eutectic phases. As the hairline processing became more severe, the crack occurrence frequency in eutectic phase of coating layer and the surface roughness increased, which had a proportional relationship with the level of blackening on the coating surface. In addition, the higher interfacial areas of the blackened coating surface, caused by the hairline process, led to an increase in thermal diffusivity and conductivity of the coated steel sheet. On the other hand, when the coating damage by hairline treatment was excessive and the steel substrate was exposed, there was little difference between the thermal diffusivity/conductivity of the untreated sample though the blackening degree was higher than that of untreated sample. This work suggests that the increase in the surface areas of the coating layer without exposure to steel substrate through hairline treatment can be one of the effective technical strategies for the development of Zn-Al-Mg alloy coated steel sheets with higher blackening level and thermal diffusivity.

• Journal of Welding and Joining
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• 제19권5호
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• pp.512-519
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• 2001

Sink roll has been used in molten Zn-0.2%Al alloy bath of continuous galvanizing line in sinking and stabilizing process of the steel strip in molten metal bath. In this process, although the scraper scraps off the sink roll surface, the dross compounds is builded up on the sink roll surface and the life time of the sink roll is shorten by the dross compounds. The present study was investigated the application of the spray coating layer on sink roll body for improving durability In molten Zn-0.2%Al alloy. Through the durability tests in molten Zn-0.2%Al alloy with various ceramic and cermet coating layer, the optimum bond and top coating material was obtained. As the results, the system of STS430F base metal, WC-l7Co bond and $ZrO_2-SiO_2$ top coating was clarified to be the best quality of durability in molten Zn-0.2%Al alloy.

• 설비공학논문집
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• 제17권2호
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• pp.183-190
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• 2005

In the process of ice-slurry making, ice adhesion on cooling wall or in narrow flow Path disturbs continuous ice formation. In this study, the effect on the ice adhesion to cooling surface by some freezing experiments was investigated, quantitatively. Three types of solutions were frozen in various coating vessels with stirring. In the experiment, the ice adhesion between cooling wall and Ice-slurry was evaluated by measuring stirring power. From the result, the stirring power of slurry mixture in PTFE-coating vessel was smaller than those in PE-coating, PFA-coating and bare SUS vessel. Especially, in EG H PG 1.S/ HD 1.5 mass$\%$ solution, the stirring power in the PE-coating vessel was smaller than that in the PFA-coating or SUS vessel.

• 한국표면공학회지
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• 제32권3호
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• pp.472-483
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• 1999

Hard coatings playa continuously increasing role in the field of tribology as well as for decorative applications. In both areas they are often also exposed to corrosive media. While especially hard nitride coatings show a high corrosion resistance for themselves, hard $coating_strate systems may suffer from a severe corrosion attack due to the defects in the coating structure (pores, pinholes) resulting from the PVD-typical film morphology. While a huge number of investigations cover the tribological properties, only limited studies deal with the corrosion behavjour of coating substrate systems and attempts are made to improve their corrosion resistance. The present paper shortly describes the corrosion mechanisms and repots characteristic examples of the system behaviour. Special emphasis is laid on recent investigations to improve the corrosion resistance by alloying, interlayers or multilayered coating structures.es.