• Nuclear Engineering and Technology
• /
• v.53 no.8
• /
• pp.2629-2639
• /
• 2021

Within the frame of the EMPIrE test, four monolithic mini-plates were irradiated in the ATR reactor. In two of them, the monolithic U(Mo) foil had been PVD-coated with Zr before the plate manufacturing. Extensive microstructural characterizations were performed on a fresh archive mini-plate, using Optical Microscopy (OM), Scanning Electron Microscopy (SEM) combined with Energy Dispersive Spectroscopy (EDS), Electron Backscattered Diffraction (EBSD) and Focused Ion Beam (FIB)/Transmission Electron Microscopy (TEM) with nano EDS. A particular attention was paid to the examination of the U(Mo) foil, the PVD coating, the cladding/Zr and Zr/U(Mo) interfaces. The Zr coating has a thickness around 15 ㎛. It has a columnar microstructure and appears dense. The cohesion of the cladding/Zr and Zr/U(Mo) interfaces seems to be satisfactory. An almost continuous layer with a thickness of the order of 100-300 nm is present at the cladding/Zr interface and corresponds to an oxidized part of the Zr coating. At the Zr/U(Mo) interface, a thin discontinuous layer is observed. It could correspond to locally oxidized U(Mo). This work provides a basis for interpreting the results of characterizations on EMPIrE irradiated plates.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2014.02a
• /
• pp.193.2-193.2
• /
• 2014

열차폐 코팅(Thermal Barrier Coating)은 주로 항공기 엔진이나 화력발전용 터빈 등의 $1300^{\circ}C$ 이상의 고온에서 사용되는 부품에 적용되어 모재(내열합금)의 손상 방지 및 에너지 효율 향상을 위해 사용되고 있다. 열차폐 코팅의 경우 Plasma Spray 공법과 EB-PVD(전자빔 물리 증착법) 공법이 가장 많이 사용되고 있다. Plasma Spray에 의한 열차폐 코팅 공정은 생산 비용이 저렴하고 수평형 적층 구조를 통한 높은 열전도율을 가지는 장점이 있으며, EB-PVD 공정은 수직형 구조의 열차폐막을 통해 내열 충격성과 내열 사이클성이 양호하다는 장점이 있다. 본 연구에서는 열 사이클의 내구성이 뛰어난EB-PVD를 이용하여 열차폐 코팅 공정연구를 진행하였다. 본 연구소에서 사용하고 있는 EB-PVD 는 종래의 장치와는 달리 70 kW급 전자총 5기가 장착 되어 있으며, 각각 시편 가열용 전자총 2기 및 피코팅용 가열 전자총 3기로 구성되어 있다. 이런 구성을 통해 다양한 종류의 열차폐 박막과 높은 결정성과 치밀도를 가지는 박막 형성할 수 있을 것이다. 본 발표에서는 EB-PVD 공정 연구결과 및 향후 실용화를 위한 개발 연구 방향에 대해서 기술하였다.

• Journal of the Korean Electrochemical Society
• /
• v.12 no.4
• /
• pp.324-328
• /
• 2009

The internal short-circuit between cathodes and anodes has been known to be a critical concern for the safety failures of lithium-ion batteries, which is strongly influenced by the thermal stability of separators. In this study, to effectively suppress the internal short-circuit failures, we developed a new composite separator with the improved thermal stability compared to conventional polyolefin-based separators. The composite separators were prepared by introducing a ceramic coating layer ($Al_2O_3$/PVdF-HFP) onto both sides of a polyethylene (PE) separator. The microporous structure of ceramic coating layers is determined by controlling the phase inversion of coating solutions and becomes more developed with the increase of nonsolvent (water) content. This structural change of ceramic coating layers was observed to greatly affect the thermal stability as well as the electrochemical performance of composite separators, which was systematically discussed in terms of phase inversion.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2016.11a
• /
• pp.33-55
• /
• 2016

PVD(Physical Vapour Deposition)코팅은 70년대 미국의 Multi-arc이란 기업에 의해 질화물계나 탄화물계 피막 증착이 가능한 아크이온플레팅(Arc Ion Plating) 기술이 산업에 소개되어, 주로 내마모나 내구성을 요구하는 금형, 절삭공구, 산업용 부품 분야 등에 적용되면서 꾸준한 성장세를 거듭해 왔다. 최근 들어 PVD기술은 그 수요의 급증과 더불어 보다 진화된 형태의 코팅장치 및 코팅피막들이 산업에 소개 되고 있다. 먼저 절삭가공분야에는 new composition, nano composite, multi-element composition, multi-layer, SML(Self Modification Layer)등의 코팅피막들이 단독 또는 조합된 형태로 개발되어 철계 소재를 대상으로 고경도 소재의 고속가공, 저경도~중경도 소재의 중속~고속 광범위영역에서 동시 절삭을 가능케 하였고, 비철.비금속 소재 절삭용으로 종전의 가스방식의 DLC(a-C:H)코팅을 훨씬 능가하는 ta-C Plus(Ultra super DLC) 코팅이 개발되어 고 Si함량의 Al-Si계 합금, Cu-W계, 고 섬유 CFRP, CFRM 및 반소결 상태의 세라믹 소재들을 황삭에서 정삭까지 단일 공정으로 절삭이 가능한 고성능 공구들이 개발보급되고 있다. 금속 성형분야에는 고장력 강판을 냉간에서 성형 가능한 Lubricative multi-layer coating, 열간 또는 고온에서 성형이 가능한 functional multi layer과 이형성이 더한층 개선된 dimpled(or embossed) functional multi layer 코팅들이 개발되어 산업현장에 빠르게 확산되고 있다. PVD 코팅의 또 다른 주요 적용분야로 의료분야를 들 수 있는데, 이는 코팅의 대다수가 고경도의 생체친화적인 특성을 가진데 착안되었으며, 흔히 현대성 질환이라 일컫는 과민성 체질, 과체중 및 허약체질 환자의 증가와 각종 재해 및 사고의 증가 및 인간 수명 증가에 따른 인공적인 시술의 요구증가에 편승하여 이 분야의 시장 또한 가파르게 성장하고 있다. 또한 대량으로 양산 적용단계에 접어든 자동차 핵심부품들을 비롯해서 각종 산업용, 방산용 기계 부품에도 성능 향상, 내구성 향상, 환경친화성 등 다양한 목적으로 확대 적용되고 있는 사례들을 본 발표를 통해 간략하게나마 소개하고자 한다.

• Journal of the Korean institute of surface engineering
• /
• v.31 no.6
• /
• pp.400-406
• /
• 1998

Tool life characteristics were investigated for the TiN coated (PVD) tungsten carbide cutting tools to improve the tool life Experimental variables for Tin coating were coating time and cathode bias voltage and cuting variables were cutting speed and feel rate. As a experiment result, TiN coated tool was extended about from 2.14 to 2.7 times than that of not coated tungsten carbide tools. Also, coating thinkness is much affected to tool life.

• Journal of the Korean Ceramic Society
• /
• v.53 no.1
• /
• pp.81-86
• /
• 2016

The effect of substrate rotation speed on the phase forming behavior and microstructural variation of 8 wt% yttria ($Y_2O_3$) stabilized $ZrO_2$ (8YSZ) coatings as a thermal barrier coating has been investigated. 8YSZ coatings with $100{\sim}200{\mu}m$ thickness were deposited by electron beam-physical vapor deposition onto a super alloy (Ni-Cr-Co-Al) substrate with a bond coating (NiCo-CrAlY). The width of the columnar grains of the 8YSZ coatings increased with increasing substrate rotation speed from 1 to 30 rpm at a substrate temperature range of $900{\sim}950^{\circ}C$. In spite of the different growth behaviors of coatings with different substrate rotation speeds, the phases of each coating were not changed remarkably. Even after post heat treatments with various conditions of the coated specimens fabricated at 20 rpm, only a change of color was noticeable, without any remarkable change in the phase or microstructure.

• Transactions of Materials Processing
• /
• v.32 no.5
• /
• pp.247-254
• /
• 2023

This study conducted the wear tests on bending punches coated with PVD CrN and examined the surface quality of the product formed by each punch in the forming of uncoated TRIP1180 sheets. The study quantitatively estimated the surface quality of the product by measuring the roughness and imaging the product surface. The correlation between the punch wear depth and the product surface roughness was quantitatively analyzed. The results showed that before failure occurs, the product roughness was comparable with that of the as-received, and the product surface was smooth without scratches and defects. However, after failure, the punch wear is caused by fretting wear mechanism, and a punch whose coating is not completely peeled plows the product surface, resulting in severe scratches with grooves and ridges on the product surface. Severe wear on the punch surface caused by fretting wear can rapidly degrade the product surface quality as it is directly affected by the punch surface condition, and the product surface quality accurately reflects the punch wear condition.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
• /
• 2006.05a
• /
• pp.350-356
• /
• 2006

• Proceedings of the Korean Ceranic Society Conference
• /
• 2003.10a
• /
• pp.210.2-210
• /
• 2003

• Journal of the Korean institute of surface engineering
• /
• v.36 no.6
• /
• pp.423-429
• /
• 2003

It has been investigated corrosion resistance and crystal structure of Zn-Cr coatings fabricated by electroplating method and electron-beam physical vapor deposition method(EB-P VD). The electroplated Zn-Cr alloy consists mainly of η'-Zn phase for the lower Cr content than 7.9 wt% Cr and ${\gamma}$'-ZnCr phase for the higher Cr content. In the Zn-Cr alloy fabricated by EB-PVD the ${\gamma}$'-ZnCr phase appeared clearly at 3 wt% Cr and it became the sole phase at 50 wt%Cr. The amount of η'-Zn phase decreased obviously with increasing Cr content when it exceeded 15 wt% Cr. The electrochemical measurement of the electroplated Zn-Cr film has shown corrosion potential of about -1000 mV. The current density of active region and the amount of dissolved Zn and Cr decreased significantly with increasing Cr content. The electrochemical characteristics of Zn-Cr alloy fabricated by EB-PVD have shown that the alloy of 50 wt% Cr had the highest corrosion potential(-500 mV) and the lowest critical passive current density than that of the electroplated.