• Journal of Power System Engineering
• /
• v.12 no.3
• /
• pp.66-71
• /
• 2008

Diamond-like-carbon (DLC) coatings could be good candidates as solid lubricants for cutting tools in dry machining of aluminum alloy. In this work, DLC thin films were produced as a friction reduction coating for WC-Co insert tip using the plasma immersion ion beam deposition (PIIED) technique. DLC coatings were also coated on $Al_2O_3$ specimens and high temperature wear tested up to $400^{\circ}C$ in dry air to observe the survivability of the DLC coating in simulated severe cutting conditions using a pin-on-disc tribotester with Hertzian contact stress of 1.3GPa. It showed reduced friction coefficients of minimum 0.02 up to $400^{\circ}C$. And cutting performance of DLC coated WC-Co insert tips to Al 6061 alloy were conducted in a high speed machining center. The main problems of built-up edge formation in aluminum machining are drastically reduced with improved surface roughness. The improvements were mainly related to the low friction coefficient of DLC to Al alloy and the anti-adhesion of Al alloy to WE due to the inertness of DLC.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2012.11a
• /
• pp.66-67
• /
• 2012

As polymer coatings of nano-structured surface become significant to obtain functionalized materials, catechol derived from a mussel protein has attracted increasing attention for its universal adhesiveness. In addition to the unique adhesion property, its reducing ability of metal ions during oxidative polymerization to polydopamine (pD) widely expands the application of catechol molecules in the field of surface modification. In this study, we present the catechol conjugated smart polymer coatings for regulating surface properties such as wettability and anti-fouling effects. In additino, the in situ silver coating of electrospun polymer nanofibers using a silver-catechol redox reaction is presented as a simple method to produce metal nanostructures.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.11 no.2
• /
• pp.120-129
• /
• 2023

Marine structures are subject to damage not only from sea salt but also from the adhesion of marine microorganisms and suspended particles, which cause additional damages. In order to prevent this, periodic coating is employed in the case of vessels to maintain the necessary performance. However, it is true that periodic coating is difficult for concrete or steel support structures, and there is a risk of marine environmental pollution. In this study, authors developed an anti-fouling coating agent using eco-friendly materials that possess hydrophilic cellulose nanofibers and AKD(alkyl ketene dimer). To achieve a homogeneous mixture, the content of cellulose nanofibers was fixed at 1 %, and AKD, distilled water, and waste glass were mixed using a digital mixer and homogenizer. The contact angle of the prepared coated surface was observed to be over 130°, indicating sufficient performance even in a water droplet flow test with a 15° slope, suggesting self-cleaning capability. Furthermore, through the analysis of viscosity characteristics at different temperatures, it was confirmed that the application is feasible at room temperature. Microstructure analysis also verified that the coating agent is uniformly applied to the concrete surface.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2018.06a
• /
• pp.40-40
• /
• 2018

강원도 혹한지역에 설치된 ACSR cable(Aluminium Conductor Steel Reinforced, 강심 알루미늄 연선)에 겔러핑(Galloping), 슬릿점핑(Sleet jumping) 등 빙설해로 인한 단전 및 단락 사고가 발생하여 전력망 운영에 심각한 문제를 초래하고 있다. 특히, 빙설해로 인한 정전사고는 전기 품질의 저하 뿐만 아니라, 국지적으로 발생하여 광범위하게 영향을 미치기 때문에 이에 대한 대응 및 예방기술이 요구되고 있다. 본 연구에서는 ACSR cable의 원 소재인 알루미늄 합금(Al 6061)을 대상으로 낮은 표면에너지를 갖는 결빙방지 코팅소재로 표면처리하여 결빙방지 성능을 향상하고자 하였다. 코팅소재와 얼음과의 접합특성은 결빙접합 특성 시험기를 사용하여 정량적으로 측정하였으며 시험기의 신뢰성 확보를 위해 FEM Modeling을 수행하였다. 결빙특성 지표인 ARF(Adhesion reduction factor)를 적용하여 소재별 결빙방지 효과를 비교 평가하였다. 코팅소재는 현재 해외 국내에서 상용화되고 있는 소수성, 초소수성 소재를 선정하였으며, 결빙접합강도와 매우 밀접하게 연관되어 있는 표면 에너지, 표면 거칠기와의 상관관계를 분석함으로써 결빙방지 코팅소재의 적합성을 평가하였다. 본 연구에서 개발한 상온 경화형 실리콘 러버 코팅소재는 원 소재 Al 대비 약 8~9배 낮은 탁월한 방빙성(Anti-icing) 효과를 나타내었으며, 내구성 또한 상용소재 대비 우수한 특성을 나타내었다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.27 no.8
• /
• pp.516-521
• /
• 2014

An excellent hydrophobic surface has a high contact angle over 147 degree and the contact angle hysteresis below $5^0$ was produced by using roughness combined with hydrophobic PTFE coatings, which were also confirmed to exhibit an extreme adhesion to glass substrate. To form the rough surface, the glass was etched by Ar-plasma. A very thin PTFE film was coated on the plasma etched glass surface. Roughness factors before or after PTFE coating on the plasma etched glass surface, based on Wensel's model were calculated, which agrees well with the dependence of the contact angle on the roughness factor is predicted by Wensel's model. The PTFE films deposited on glass by using a conventional rf-magnetron sputtering. The glass substrates were etched Ar-plasma prior to the deposition of PTFE. Their hydrophobicities are investigated for application as a anti-fouling coating layer on the screen of displays. It is found that the hydrophobicity of PTFE films mainly depends on the sputtering conditions, such as rf-power, Ar gas content introduced during deposition. These conditions are closely related to the deposition rate or thickness of PTFE film. Thus, it is also found that the deposition rate or the film thickness affects sensitively the geometrical morphology formed on surface of the rf-sputtered PTFE films. In particular, 1,950-nm-thick PTFE films deposited for 30 minute by rf-power 50 watt under Ar gas content of 20 sccm shows a very excellent optical transmittance and a good anti-fouling property and a good durability.

• Journal of the Korean Vacuum Society
• /
• v.13 no.1
• /
• pp.39-45
• /
• 2004

Ultraviolet-nanoimprint lithography (UV-NIL) is a promising method for cost-effectively defining nanoscale structures at room temperature and low pressure. A 5${\times}$5${\times}$0.09 in. quartz stamp is fabricated using the etch process in which a Cr film was employed as a hard mask for transferring nanostructures onto the quartz plate. FAS(Fluoroalkanesilane) is used as a material for anti-adhesion surface treatment on the stamp and a thin organic film to improve adhesion on a wafer is formed by spin-coating. The low viscosity resin droplets with a nanometer scale volume are dispensed on the whole area of the coated wafer. The UV-NIL experiments have been performed using the EVG620-NIL. 370 nm - 1 m features on the stamp have been transferred to the thin resin layer on the wafer using the multi-dispensing method and UV-NIL process. We have measured the imprinted patterns and residual layer using SEM and AFM to evaluate the potential of the process.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.40 no.2
• /
• pp.81-86
• /
• 2003

To measure the pressure using semiconductor type pressure sensor in water or chemical solution, the sensor must be protected from the solution using proper packaging materials. stainless steel isolated type pressure sensor packaged with SUS316 can be widely used to measure the pressure in water or chemical due to its high corrosion-resistance and good performance in tensility and welding. Even if the surface of SUS316 has a plenty of nickel and chromium, the SUS316 is highly corrosive in acidic or alkaline solution. We coated parylene and adhesion promoting copper layer are 5${\mu}{\textrm}{m}$ and 200nm, respectively. The parylene coated stainless steel pressure sensor showed good anti-corosive characteristics in various strong acids. The accuracy of pressure sensor wasn't varied after parylene coating with 0.5%FSO.

• Journal of the Korea Furniture Society
• /
• v.21 no.4
• /
• pp.284-292
• /
• 2010

This research was carried out to examine the properties of fancy cherry veneer overlaid on the PF resin bonded Meranti plywood floor, which 2.5% green tea leaf powder was applied in the UV varnishes and the adhesives for scavenging the volatile organic compounds. The results were as follows: 1. The various properties of the treated samples, such as density, moisture content, thickness swelling, bending strength(MOR), adhesion shear strength, surface abrasion, curling, cyclic delamination test with boiling water, boiling property, cold-resistance and heat resistance, acid resistance and alkali resistance, and anti-contamination property showed no significant difference between the properties of the control samples. 2.5% green tea leaf powder treated floor gave a little better results than the control for surface scratch test. 2. In case of QUV and weathering test, no difference between the treated sample and control was found. 3. The floor was discolored by adding 10% green tea leaf powder to UV coating, and the floor was also discolored to light green during by the soaking test. The color of floor was not changed up to 5% addition level.

• Journal of the Korean Society for Heat Treatment
• /
• v.13 no.6
• /
• pp.398-404
• /
• 2000

The Ti-Al-V-N films have been deposited on various substrates by d.c and r.f reactive magnetron sputtering from a Ti-6Al-4V alloy target in mixed $Ar-N_2$ discharges. The films were investigated by means of XRD, AES, SEM/EDX, microhardness, TG and scratch test. The XRD and SEM results indicated that the films were of single B1 NaCl phase having dense columnar structure with the (111) preferred orientation. The composition of Ti-Al-V-N film was the Ti-7.1Al-4.3V-N(wt%) films. Adhesion and microhardness of Ti-Al-V-N films deposited by r.f magnetron sputtering method were better than those deposited by d.c magnetron sputtering method. The anti-oxidation properties of Ti-Al-V-N films were also superior to that of Ti-N film deposited by the same deposition conditions.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2011.08a
• /
• pp.187-187
• /
• 2011

Nowadays, the issue of solar cell durability in local weather and environment is a crucial issue. Above all, surface corrosion on solar cell multilayers is a major factor that determines the durability of commercial solar cells; corrosive chemical interactions between air, humidity and chemical species and solar cell multilayers can unfavorably affect the durability. Here, we study microscopic and spectroscopic surface techniques to investigate the corrosive interaction on the antireflective layers of solar cell multilayers under various conditions such as acid, base, constant temperature and humidity. Surface morphology and adhesion force were characterized with atomic force microscopy before and after chemical treatment. Chemical composition, and transmittance factors were studied with X-ray photoelectron spectroscopy, and ultraviolet-visible spectroscopy, respectively. Based on these studies, we suggest the dominant factors in the corrosive chemical processes, and their influences on the structural, compositional, and optical properties of the antireflective layers.