• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2015.05a
• /
• pp.76-76
• /
• 2015

PVD에 의한 증착 대상 물질인 Ti, AlSi, Cr 및 각각의 타겟 전류, 바이어스, 압력 조건 들을 설계하여 적용시켰으며 PECVD와 CBC 코팅을 조합하여 발생되는 새로운 나노 멀티박막의 특성을 본 연구에서는 시험분석 및 평가하였다. 코팅층 깊이에 따른 조성 변화는 XPS를 이용하였으며 미세조직 및 표면 상태는 FE-SEM을 이용한 정밀 분석을 실시하였다. 또한, 박막의 경도는 나노인덴터를 이용하여 박막 자체의 경도만을 분석하였다. 한편, Pin-on-disk 방식의 마모시험기를 이용하여 표면조도와 상대재의 처리 상태에 따른 마찰계수를 시험 평가하였다.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2000.11a
• /
• pp.378-384
• /
• 2000

This paper presents the results of the repeated sliding tests to determine the wear-life of TiN coated AISI 52100 bearing balls deposited by PVD method and to show the wear mechanisms of those. The sliding tests were carried out using a ball-on-disk tribometer under ambient conditions. The coefficient of friction, wear volume and the cycles to failures of TiN coated bearing balls were measured with different normal loads and roughness of lower specimens. On the wear-life diagram, the normal loads and the cycles to failure showed the good linear relation on log-log coordinate. With a decreasing normal load, the diagram showed that the wear-limits, at which the coated bearing balls survived more than 4000cycles were under 0.1N of the normal load.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.36 no.2
• /
• pp.109-124
• /
• 2023

For decades, sputtering as a physical vapor deposition (PVD) method has been a widely used technique for film coating processes. The sputtering enables oxides, metals, alloys, nitrides, etc to be deposited on a wide variety of substrates from silicon wafers to polymer substrates. Meanwhile, transparent conductive oxides (TCOs) have played important roles as electrodes in electrical applications such as displays, sensors, solar cells, and thin-film transistors. TCO films fabricated through a sputtering process have a higher quality leading to an improved device performance than other films prepared with other methods. In this review, we discuss the mechanism of sputtering deposition and detail the TCO materials. Related technologies (processing conditions, materials, and applications) are introduced for electrical applications.

• Journal of the Korean Electrochemical Society
• /
• v.20 no.3
• /
• pp.49-54
• /
• 2017

We develop a ceramic composite separator prepared by coating $ZrO_2$ nanoparticles with a poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) copolymer on a polyvinyl alcohol (PVA) mechanical support prepared by electrospinning technique to improve thermal properties. The gurley number of the ceramic composite separator shows much lower value than that of a PE separator even though it possesses the polymeric coating layer with ceramic nanoparticles. In addition, the proposed sample shows higher electrolyte uptake than PE separator, leading to enhancing the ionic conductivity of the proposed sample and, by extension, the rate discharge properties of lithium ion batteries. Thermal stability of the ceramic composite separator is dramatically improved without any degradation in electrochemical performance compared to the performance of conventional PE separators.

• Journal of Surface Science and Engineering
• /
• v.49 no.2
• /
• pp.202-210
• /
• 2016

This study was intended to investigate the effect of the amount of magnesium addition and heat treatment in the Al-Mg coating film in order to improve corrosion resistance of aluminum coating. Al-Mg alloy films were deposited on cold rolled steel by physical vapor deposition sputtering method. Heat treatment was fulfilled in an nitrogen atmosphere at the temperature of $400^{\circ}C$ for 10 min. The morphology was observed by SEM, component and phase of the deposited films were investigated by using GDLS and XRD, respectively. The corrosion behaviors of Al-Mg films were estimated by exposing salt spray test at 5 wt.% NaCl solution and measuring polarization curves in deaerated 3 wt.% NaCl solution. With the increase of magnesium content, the morphology of the deposited Al-Mg films changed from columnar to featureless structure and particle size was became fine. The x-ray diffraction data for deposited Al-Mg films showed only pure Al peaks. However, Al-Mg alloy peaks such as $Al_3Mg_2$ and $Al_{12}Mg_{17}$ were formed after heat treatment. All the sputtered Al-Mg films obviously showed good corrosion resistance compared with aluminum and zinc films. And corrosion resistance of Al-Mg film was increased after heat treatment.

• Nuclear Engineering and Technology
• /
• v.50 no.2
• /
• pp.229-236
• /
• 2018

Accident-tolerant fuels (ATFs) are currently of high interest to researchers in the nuclear industry and in governmental and international organizations. One widely studied accident-tolerant fuel concept is multilayer cladding (also known as coated cladding). This concept is based on a traditional Zr-based alloy (Zircaloy-4, M5, E110, ZIRLO etc.) serving as a substrate. Different protective materials are applied to the substrate surface by various techniques, thus enhancing the accident tolerance of the fuel. This study focuses on the results of testing of Zircaloy-4 coated with pure chromium metal using the cold spray (CS) technique. In comparison with other deposition methods, e.g., Physical vapor deposition (PVD), laser coating, or Chemical vapor deposition techniques (CVD), the CS technique is more cost efficient due to lower energy consumption and high deposition rates, making it more suitable for industry-scale production. The Cr-coated samples were tested at different conditions ($500^{\circ}C$ steam, $1200^{\circ}C$ steam, and Pressurized water reactor (PWR) pressurization test) and were precharacterized and postcharacterized by various techniques, such as scanning electron microscopy, Energy-dispersive X-ray spectroscopy (EDX), or nanoindentation; results are discussed. Results of the steady-state fuel performance simulations using the Bison code predicted the concept's feasibility. It is concluded that CS Cr coating has high potential benefits but requires further optimization and out-of-pile and in-pile testing.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2001.06a
• /
• pp.14-14
• /
• 2001

Nitride films such as TiN, CrN etc. deposited on glass by PVD processes have been developed for many industrial applications. These nitride films deposited on glass were widely used for not only decorative and optical coatings but also wear and corrosion resistance coatings employed as dies and molds made of glass for the example of lens forming molds. However, the major problem of nitride coatings on glass by PVD process is non-uniform film owing to pin-hole and micro crack. It is estimated that nonuniform coating is influenced by a different surface energy between metal nitrides and glass due to binding states. In this work, therefore, for the evaluation of nucleation and growth mechanism of nitride films on glass TiN and CrN film were synthesized on glass with various nitrogen partial pressure by unbalanced magnetron sputtering. Prior to deposition, for the examination of relationship between surface energy and film microstructure plasma pre-treatment process was carried out with various argon to hydrogen flow rate and substrate bias voltage, duty cycle and frequency by using pulsed DC power supply. Surface energy owing to the different plasma pre-treatment was calculated by the measurement of wetting angle and surface conditions of glass were investigated by X-ray Photoelectron Spectroscopy(XPS) and Atomic Force Microscope(AFM). The microstructure change of nitride films on glass with increase of film thickness were analyzed by X-Ray Diffraction(XRD) and Scanning Electron Microscopy(SEM).

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2018.06a
• /
• pp.136-136
• /
• 2018

듀얼 페이즈(DP) 강철과 같은 고강도강(HSS), TRIP강, TWIP강은 무게를 줄이고 자동차의 안전을 향상시키기 위해서 자동차 산업에서 광범위하게 쓰이고 있다. HSS강의 내부식성을 향상시키기 위해서, 향상된 박막 재료와 기존의 아연도금 공정을 대체하는 공정 방법이 필요하다. Zn-Mg 박막은 강의 부식 방지에 대한 강력한 후보이며, 물리적 기상 증착 공정(PVD)은 강의 Zn-Mg 박막의 증착을 위한 유망한 공정이다. 그러나 이전 연구에서 보고 된 바와 같이 Zn-Mg 박막은 Zn-Mg 박막의 높은 취성으로 인하여 Zn 박막에 비하여 접착력이 매우 불충분하였다. 따라서 본 연구에서는 Zn-Mg 박막의 첩착력을 향상시키기 위해 TRIP강 기판 위에 증발 증착법을 활용하여 Zn-Mg/Zn 이중층 박막을 합성하고 진공에서 열처리를 실시하여 박막의 깊이에 따른 Mg의 함량 변화를 유도하였다. Zn-Mg/Zn 박막 합성 시 EMH-PVD를 활용하여 증착하였으며, Zn 중간층을 모재와 Zn-Mg 층 사이에 증착하고 진공중에서 열처리를 실시하여 박막 내에서 Mg 함량의 기울기 변화가 박막의 밀착력에 주는 영향을 평가하였다. 증착된 박막은 FE-SEM을 통하여 미세조직과 박막의 두께를 분석하였고 line-EDS를 통하여 깊이에 따른 Zn와 Mg의 변화를 분석하였으며 XRD를 사용하여 합금상을 분석하였다. Lap shear test를 활용하여 박막의 밀착력을 정략적으로 분석하였다. FE-SEM 및 EDS 분석 결과 Zn-Mg/Zn 박막을 진공에서 열처리를 실시한 후 FE-SEM으로 분석한 결과 미세조직의 큰 차이는 보이지 않았으나, line-EDS 결과 Mg이 확산되는 것을 확인 할 수 있었다. XRD 분석 결과 확산한 Mg에 의해서 Zn상은 감소하고 $Mg_2Zn_{11}$, $MgZn_2$와 같은 합금상은 증가하는 것을 확인하였다. Lap shear test 결과 $200^{\circ}C$에서 열처리한 Zn-15wt.%Mg/Zn 박막의 경우 밀착력이 19 MPa로 열처리를 하지 않았을 경우(11 MPa)보다 향상되는 것을 확인하였다. 이러한 결과는 통하여 Zn-Mg 박막의 두께의 Mg의 함량 변화에 의해서 박막의 밀착력이 변화되는 것을 알 수 있다.

• Journal of the Korean Electrochemical Society
• /
• v.15 no.1
• /
• pp.48-53
• /
• 2012

Polyethylene (PE) separator is the most popular separator for lithium-ion batteries. However, it suffers from thermal contraction and mechanical rupture. In order to improve the thermal/mechanical dimensional stabilities, this study investigated the effects of $Si_3N_4$ coating. SCS (Silicon-nitride Coated Separator) has been fabricated by applying 10 ${\mu}m$-thick $Si_3N_4$/PVdF coating on one side of PE separator. SCS exhibits enhanced thermal stability over $100{\sim}150^{\circ}C$: its thermal shrinkage is reduced by 10~20% compared with pristine PE separator. In addition, SCS shows higher tensile strength than PE separator. Employing SCS hardly affects the C-rate performance of $LiCoO_2$/Li coin-cell, even though its ionic conductivity is somewhat lower than that of PE separator.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.22 no.5
• /
• pp.227-232
• /
• 2012

Inconel 617 and Hastelloy X are the most promising candidate materials for the heat exchanger of next generation nuclear reactor. Surface coating and its effects on high temperature properties for the Inconel 617 and Hastelloy X under molten FLiNaK (LiF-NaF-KF) salt environment have been investigated. For TiAlN and $Al_2O_3$ overlay coatings, the two different PVD (physical vapor deposition) methods of an arc discharge and a sputtering were applied, respectively. A study for the thermal stability of the surface modified Ni-Cr alloy substrates has been conducted. To evaluate the corrosion mechanism of Ni-Cr alloys in the molten salt, a ruptured Inconel pipe used for the molten salt transportation has been analyzed. The thermal properties of morphological and structural properties each sample were characterized before and after heat-treatment at $600^{\circ}C$ in molten FLiNaK salt. The results showed that the TiAlN and $Al_2O_3$ overlay coated specimens had the enhanced high temperature stability.