• 제목/요약/키워드: Thermal Barrier Performance

검색결과 115건 처리시간 0.033초

Lifetime Performance of EB-PVD Thermal Barrier Coatings with Coating Thickness in Cyclic Thermal Exposure

  • Lu, Zhe;Lee, Seoung Soo;Lee, Je-Hyun;Jung, Yeon-Gil
    • 한국재료학회지
    • /
    • 제25권10호
    • /
    • pp.571-576
    • /
    • 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.

서스펜션 플라즈마 용사로 제조된 란타눔/가돌리늄 지르코네이트 열차폐코팅의 구조와 열전도도 특성 (Structure and Thermal Conductivity of Thermal Barrier Coatings in Lanthanum/Gadolinium Zirconate System Fabricated via Suspension Plasma Spray)

  • 권창섭;이성민;오윤석;김형태;장병국;김성원
    • 한국표면공학회지
    • /
    • 제47권6호
    • /
    • pp.316-322
    • /
    • 2014
  • With increase in demand for higher operating temperatures of gas turbines, extensive research efforts have been carried out to enhance the performance of thermal barrier coatings (TBCs) in the field of coating processing as well as materials. In this study, thermal barrier coatings in lanthanum/gadolinium zirconate system, which is one of the most promising candidates for replacing yttira-stabilized zirconia (YSZ) in thermal barrier coating applications, are fabricated via suspension plasma spray. Dense, $300{\sim}400{\mu}m$ thick coatings of fluoritephase zirconate with modest amount of segmented microstructures are obtained by using suspension plasma spray with suspensions of planetary-milled mixture between lanthanum and/or gadolinium oxide and nano zirconia. These coatings exhibit thermal conductivities of 1.6 ~ 1.7 W/mK at $1000^{\circ}C$, which is relatively lower than that of YSZ.

Optimization of a straight fin heat sink in 3D LCos projector considering bypass flow and a flow barrier

  • Kim, Jin-Wook;Kim, Sang-Hoon;Lee, Seung-Gyu
    • 한국정보디스플레이학회:학술대회논문집
    • /
    • 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
    • /
    • pp.1265-1268
    • /
    • 2009
  • In this paper, the effect of a flow barrier and bypass on the cooling performance for a straight fin heat sink is presented. Both side directions and upward direction of bypass are controlled using various ducts which have different width and heights. In addition, a flow barrier is used to control flow toward heat sink. Through experiments, the distance from leading edge of a heat sink to a flow barrier is varied for various bypasses under fixed volume flow rate condition. This study shows possibility to improve cooling performance when bypass and a flow barrier exist.

  • PDF

가스버너 열충격에 의한 NiCr/ZrO2계 경사기능재의 열적 파괴특성 (Fracture Characteristics of NiCr/ZrO2 Functionally Graded Material by Gas Burner Thermal Shock)

  • 송준희
    • 한국세라믹학회지
    • /
    • 제43권4호
    • /
    • pp.247-252
    • /
    • 2006
  • Joining Yittria Stabilized Zirconia (YSZ) to NiCr metal was fabricated using YSZ/NiCr Functionally Graded Materials (FGM) Interlayer by hot pressing process. Microscopic observations demonstrate that the composition and microstructure of YSZ/NiCr FGM distribute gradually in stepwise way, eliminating the macroscopic ceramic/metal interface such as that in traditional ceramic/metal joint. The thermal characteristics of this YSZ/FGM/NiCr joint were studied by thermal shock testing and therml barrier testing. Thermal shock test was conducted by gas burner rig. Acoustic Emission (AE) monitoring was performed to analyze the microfracture behavior during the thermal shock test. It could be confirmed that FGM was the excellent performance of thermal shock/barrier resistance at above $1000^{\circ}C$.

Barrier Layers and Pulsed Laser Annealing Effects on TFEL Device with Cu and Ag co-doped SrS blue Phosphor Layer

  • Nam, Tae-Sung;Liew, Shan-Chun;Koutsogeorgis, Demosthenes C;Cranton, Wayne M
    • 한국정보디스플레이학회:학술대회논문집
    • /
    • 한국정보디스플레이학회 2003년도 International Meeting on Information Display
    • /
    • pp.910-913
    • /
    • 2003
  • In order to enhance performance, stability, and brightness of inorganic blue-light emitting EL device, barrier layer structure and pulsed laser annealing(PLA) treatment were introduced. The barrier layer structure was utilized for improving brightness of the device and instead of thermal annealing, pulsed laser annealing process was used. From this study, optimum barrier layer thickness and number of pulsed laser irradiation are established.

  • PDF

Sand particle-Induced deterioration of thermal barrier coatings on gas turbine blades

  • Murugan, Muthuvel;Ghoshal, Anindya;Walock, Michael J.;Barnett, Blake B.;Pepi, Marc S.;Kerner, Kevin A.
    • Advances in aircraft and spacecraft science
    • /
    • 제4권1호
    • /
    • pp.37-52
    • /
    • 2017
  • Gas turbines operating in dusty or sandy environment polluted with micron-sized solid particles are highly prone to blade surface erosion damage in compressor stages and molten sand attack in the hot-sections of turbine stages. Commercial/Military fixed-wing aircraft engines and helicopter engines often have to operate over sandy terrains in the middle eastern countries or in volcanic zones; on the other hand gas turbines in marine applications are subjected to salt spray, while the coal-burning industrial power generation turbines are subjected to fly-ash. The presence of solid particles in the working fluid medium has an adverse effect on the durability of these engines as well as performance. Typical turbine blade damages include blade coating wear, sand glazing, Calcia-Magnesia-Alumina-Silicate (CMAS) attack, oxidation, plugged cooling holes, all of which can cause rapid performance deterioration including loss of aircraft. The focus of this research work is to simulate particle-surface kinetic interaction on typical turbomachinery material targets using non-linear dynamic impact analysis. The objective of this research is to understand the interfacial kinetic behaviors that can provide insights into the physics of particle interactions and to enable leap ahead technologies in material choices and to develop sand-phobic thermal barrier coatings for turbine blades. This paper outlines the research efforts at the U.S Army Research Laboratory to come up with novel turbine blade multifunctional protective coatings that are sand-phobic, sand impact wear resistant, as well as have very low thermal conductivity for improved performance of future gas turbine engines. The research scope includes development of protective coatings for both nickel-based super alloys and ceramic matrix composites.

고온, 마모 및 부식환경에 적용가능한 Al2O3, Cr2O3, WC-Ni 및 크로마이징 코팅층의 기계적 특성 평가 (Characteristics of Al2O3, Cr2O3, WC-Ni, and Chromizing Surface Coatingsunder Environment with HighTemperature, Wear, and Corrosion)

  • 조희근
    • 한국생산제조학회지
    • /
    • 제22권6호
    • /
    • pp.895-900
    • /
    • 2013
  • Several plasma spray and metallurgical surface coatings such as $Al_2O_3$, $Cr_2O_3$, WC-Ni, and chromizing coating have been examined for their application in environments with high temperature, wear, and corrosion. The chromizing coating is different from others coatings in the manufacturing process the surface. These coatings' characteristics were tested experimentally, and the results were compared. WC-Ni shows good performance against thermal barrier, wear, and corrosion and is one of the best candidates for the environment considered herein. These coatings were studied for their application in the steel manufacturing industry. The most commonly required functions in this industry are thermal and wear resistance.

Comparison study of heatable window film using ITO and ATO

  • Park, Eun Mi;Lee, Dong Hoon;Suh, Moon Suhk
    • 한국진공학회:학술대회논문집
    • /
    • 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
    • /
    • pp.300.2-300.2
    • /
    • 2016
  • Increasing of the demand for energy savings for buildings, thermal barrier films have more attracted. In particular, as heat loss through the windows have been pointed out to major problems in the construction and automobile industries, the research is consistently conducted for improving the thermal blocking performance for windows. The main theory of the technology is reflect the infrared rays to help the cut off the inflow of the solar energy in summer and outflow of the heat from indoors in winter to save the energy on cooling and heating. Furthermore, this is well known for prevent glare, reduces fading caused by harmful ultraviolet radiation and easy to apply on constructed buildings if it made as a film. In addition to these advantages, apply the transparent electrode to eliminate condensation by heating. Generally ITO is used as a transparent electrode, but is has a low stability in environmental factors. In this study, ITO and its alternative, ATO, is deposited by sputtering system and then the characteristic is evaluated each material based thermal barrier thin film. The optical property was measured on wide range of wavelength (200 nm 2500 nm) to know the transparency in visible wavelength and reflectivity in IR wavelength range. The electrical property was judged by sheet resistivity. Finally the changes of the temperature and current of the deposited film was observed while applying a DC power.

  • PDF

고준위폐기물처분장 공학적방벽의 열-수리-역학적 거동 연구: 엔지니어링 규모의 실증실험 (Thermal-Hydro-Mechanical Behaviors in the Engineered Barrier of a HLW Repository: Engineering-scale Validation Test)

  • 이재완;조원진
    • 터널과지하공간
    • /
    • 제17권6호
    • /
    • pp.464-474
    • /
    • 2007
  • 고준위폐기물처분장의 성능 및 안전성 향상을 위해서 공학적방벽(engineered barrier)에 대한 실증이 필요하다. 우리나라 기준처분시스템에 대한 엔지니어링 규모의 실험장치(KENTEX)를 제작 설치하고, 공학적방벽에서의 열-수리-역학적 거동 규명을 위한 실증실험을 수행하였다. KENTEX 실험은 2005년 5월 31일에 시작되어 현재 성공적으로 진행 중에 있으며, 지금까지 얻어진 실험결과로부터 공학적방벽에서의 열-수리-역학적 거동에 대한 중간결론을 얻을 수 있었다. 벤토나이트 블록 내 온도는 실험 시작 후 수 주 만에 정상상태에 도달하였고, 온도분포는 히터에 가까울수록 높고 멀어질수록 낮은 값을 보였다. 수분함량은 히터 쪽보다는 지하수가 유입되는 실린더 벽면 부근에서 높은 값을 가졌고, 건조-습윤 과정에 의한 벤토나이트 블록의 수화는 측정위치에 따라 달랐다. 실험기간 동안 벤토나이트 블록에 작용하는 압력은 블록의 포화도 (그 결과, 팽윤압)이 증가할수록 증가하였다. 히터 부근에서는 벤토나이트의 열응력이나 블록 공극 내 증기압도 중요한 역할을 하였다.

N형 Ge-on-Si 기판에 형성된 Pd Germanide의 열안정성 및 Schottky 장벽 분석 (Analysis of Thermal Stability and Schottky Barrier Height of Pd Germanide on N-type Ge-on-Si Substrate)

  • 오세경;신홍식;강민호;복정득;정의정;권혁민;이가원;이희덕
    • 한국전기전자재료학회논문지
    • /
    • 제24권4호
    • /
    • pp.271-275
    • /
    • 2011
  • In this paper, thermal stability of palladium germanide (Pd germanide) is analyzed for high performance Schottky barrier germanium metal oxide semiconductor field effect transistors (SB Ge-MOSFETs). Pd germanide Schottky barrier diodes were fabricated on n-type Ge-on-Si substrates and the formed Pd germanide shows thermal immunity up to $450^{\circ}C$. The barrier height of Pd germanide is also characterized using two methods. It is shown that Pd germanide contact has electron Schottky barrier height of 0.569~0.631 eV and work function of 4.699~4.761 eV, respectively. Pd germanide is promising for the nanoscale Schottky barrier Ge channel MOSFETs.