• 한국진공학회지
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• 제13권2호
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• pp.59-64
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• 2004

반도체 레이저를 광원으로 사용하는 원자흡수분광 방법으로 금속증기의 증착 공정을 감시하는 연구를 수행하였다. 전자빔 가열 방식을 이용하여 gadolinium (Gd) 금속을 대량으로 증발시켰다. 파장 영역이 770-794 nm (중심파장 780 nm)인 반도체 레이저빔과 388-396 nm 영역의 제 2 고조파 빔을 진공용기에 입사시켜 증발되는 금속증기의 원자흡수 스펙트럼을 실시간으로 기록하였다. 흡수 스펙트럼을 분석하여 증기의 원자밀도를 구했다. 전자빔 출력을 변화시키면서 측정한 원자밀도를 수정 결정 모니터 장치를 사용하여 측정한 증착률과 비교하였다. 산업적으로 많이 사용되는 Ti 등의 증착 공정 감시에 이 실험에서 구현한 레이저 분광장치를 적용할 수 있다는 것을 제시하였다.

• 한국세라믹학회지
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• 제43권5호
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• pp.299-303
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• 2006

In this paper, anode supported SOFC with columnar structured YSZ electrolyte was fabricated via Electron Beam Physical Vapor Deposition (EBPVD) method. Liquid condensation process was employed for the preparation of NiO-YSZ substrate and the high power electron beam deposition method was used for the deposition of YSZ electrolyte film. Double layered cathode with LSM-YSZ and LSM was printed on electrolyte via screen-printing method and fired at $1150^{\circ}C$ in air atmosphere for 3 h. The electrochemical performance and the long-term stability of $5{\times}5cm^2$ single cell were investigated with DC current-voltage characteristics and AC-impedance spectroscopy. According to the investigation, $5{\times}5cm^2$ sized unit cell showed the maximum power density of around $0.76W/cm^2$ at $800^{\circ}C$ and maintained the stable performance over 400 h.

• 한국표면공학회지
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• 제46권6호
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• pp.258-263
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• 2013

4 mol% Yttria-stabilized zirconia (4YSZ) coatings are fabricated by Air Plasma Spray (APS) and Electron Beam Physical Vapor Deposition (EB-PVD) with top coating of thermal barrier coating (TBC). NiCrAlY based bond coat is prepared as 150 ${\mu}m$ thickness by conventional APS (Air Plasma Spray) method on the NiCrCoAl alloy substrate before deposition of top coating. Each 4YSZ top coating shows different tribological behaviors based on the inherent layer structures. 4YSZ by APS which has splat-stacked structure shows lower friction coefficient but higher wear rate than 4YSZ by EB-PVD which has columnar structure. For 4YSZ by APS, such results are expected due to the sliding wear accompanied with local delamination of splats.

• 한국표면공학회지
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• 제44권4호
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• pp.155-164
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• 2011

Electron beam evaporation source is widely used to prepare thin films by physical vapor deposition because it is very effective to vaporize materials and there is virtually no limit to vaporize materials including metals and compounds such as oxide. In this study, evaporation characteristics of various metals and compounds from an electron beam evaporation source have been studied. The 180 degree deflection type electron beam evaporation source which has 6-hearth crucibles and is capable of inputting power up to 10 kW was employed for evaporation experiment. 36 materials including metals, oxides and fluorides have been tested and described in terms of optimum crucible liner, evaporation state, stability, and so on. Various crucible liners have been tried to find out the most effective way to vaporize materials. Two types of crucible liners have been employed in this experiment. One is contact type liner, and the other is non-contact type one. It has been tried to give the objective information and the most effective evaporation method on the evaporation of materials from the electron beam evaporation source. It is concluded that the electron beam evaporation source can be used to prepare good quality films by choosing the appropriate crucible liner.

• 한국세라믹학회지
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• 제43권2호
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• pp.85-91
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• 2006

Electron Beam Physical Vapor Deposition (EB-PVD) was applied to fabricate a thin film YSZ electrolyte with large area on the porous NiO-YSZ anode substrate. Microstructural and thermal stability of the as-deposited electrolyte film was investigated via SEM and XRD analysis. In order to obtain an optimized YSZ film with high stability, both temperature and surface roughness of substrate were varied. A structurally homogeneous YSZ film with large area of $12\times12\;cm^2$ and high thermal stability up to $900^{\circ}C$ was fabricated at the substrate temperature of $T_s/T_m$ higher than 0.4. The smoother surface was proved to give the better film quality. Precise control of heating and cooling rate of the anode substrate was necessary to obtain a very dense YSZ electrolyte with high thermal stability, which affords to survive after post heat treatment for fabrication a cathode layer on it as well as after long time operation of solid oxide fuel cell at high temperature.

• 한국분말재료학회지
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• 제20권6호
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• pp.460-466
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• 2013

4 mol% Yttria-stabilized zirconia (4YSZ) coatings with $200{\mu}m$ thick are fabricated by Electron Beam Physical Vapor Deposition (EB-PVD) for thermal barrier coating (TBC). $150{\mu}m$ of NiCrAlY based bond coat is prepared by conventional APS (Air Plasma Spray) method on the NiCrCoAl alloy substrate before deposition of top coating. 4 mol% YSZ top coating shows typical tetragonal phase and columnar structure due to vapor phase deposition process. The adhesion strength of coating is measured about 40 MPa. There is no delamination or cracking of coatings after thermal cyclic fatigue and shock test at $850^{\circ}C$.

• 세라미스트
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• 제9권6호
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• pp.24-29
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• 2006

Electron beam physical vapor deposition (EB-PVD) process has currently been applied to thermal barrier coatings (TBCs) for aircraft engines. Due to unique columnar structure, EB-PVD TBCs have advantages in resistances to thermal shock and thermal cycle for their applications, compared to films prepared by plasma spray By the EB-PVD equipment, we successfully obtained yttria-stabilized zirconia (YSZ) layer which has columnar and feather like structure including a large amount of nano size pores and gaps. The EB-PVD technique has been developed for coating functional perovskite type oxides such as (La, Sr)MnO3. Electrode properties have been improved by interface and structural control.

• 한국표면공학회지
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• 제39권4호
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• pp.147-152
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• 2006

Failure mechanisms of electron beam physical vapor deposited thermal barrier coatings(EB-PVD TBCs) that occur during thermal cyclic oxidation were investigated. The investigations include microstructural degradation of NiCrAIY bond coat, thermally grown oxides(TGOs) along the ceramic top coat-substrate interface and fracture path within TBCs. The microstructural degradation of the bond coat during cyclic oxidation created Al depleted zones, resulting in reduction of NiAl and ${\gamma}$-Ni solid solution phase. It was observed that the fracture took placed primarily within the TGOs or at the interfaces between TGOs and bond coat.

• 한국재료학회지
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• 제25권10호
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• pp.571-576
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• 2015

The effects of coating thickness on the delamination and fracture behavior of thermal barrier coating (TBC) systems were investigated with cyclic flame thermal fatigue (FTF) and thermal shock (TS) tests. The top and bond coats of the TBCs were prepared by electron beam-physical vapor deposition and low pressure plasma spray methods, respectively, with a thickness ratio of 2:1 in the top and bond coats. The thicknesses of the top coat were 200 and $500{\mu}m$, and those of the bond coat were 100 and $250{\mu}m$. FTF tests were performed until 1140 cycles at a surface temperature of $1100^{\circ}C$ for a dwell time of 5 min. TS tests were also done until more than 50 % delamination or 1140 cycles with a dwell time of 60 min. After the FTF for 1140 cycles, the interface microstructures of each TBC exhibited a sound condition without cracking or delamination. In the TS, the TBCs of 200 and $500{\mu}m$ were fully delaminated (> 50 %) within 171 and 440 cycles, respectively. These results enabled us to control the thickness of TBC systems and to propose an efficient coating in protecting the substrate in cyclic thermal exposure environments.

• 한국세라믹학회지
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• 제42권2호
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• pp.117-122
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• 2005

나노 코팅 기술로써 빠른 증착 속도와 미세구조 제어가 용이하여 항공기 엔진 부품 열차폐 코팅으로 널리 이용되는 Electron Beam Physical Vapor Deposition (EB-PVD)세라믹 코팅 기술을 연료전지 전해질 제조에 적용하였다. EB-PVD 법을 이용하여 NiO-YSZ 기판에 YSZ 전해질을 약 10$\mu$m의 두께로 짧은 시간에 코팅하였으며 증착온도에 따라 나노 구조의 표면을 가진 YSZ 막을 얻을 수 있었다. 연료전지 전해질로서의 특성을 평가하기 위하여, 같은 조건의 코팅으로 $Al_{2}O_3$기판에 전해질을 동일한 조건으로 코팅하여 전해질의 전기적 특성을 평가하였다. 또한 양극물질로서 $LaSrCoO_3$ 분말을 일반적인 스크린 프린팅 기법으로 코팅하여 EB-PVD의 코팅을 이용한 고체산화물 연료전지 제조 가능성에 대하여 논의하였다