EB-PVD Y2O3- and -stabilized zirconia thermal barrier coatings — crystal habit and phase composition

Schulz, Uwe; Fritscher, K.; Peters, M.

doi:10.1016/0257-8972(95)02727-0

Cited by 97 publications

(41 citation statements)

References 15 publications

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“…14). However, it should be stressed up that despite many attempts, it was not possible to achieve so regular columnar structure using SPS similar to that obtained with the physical vapor deposition (PVD) technology (Ref 19,20). This can be explained by the fact that the particles used in SPS have a size many orders of magnitude greater than the atoms or molecules forming islands which become the columns during PVD processes.…”

Section: Discussionmentioning

confidence: 90%

Advanced Microscopic Study of Suspension Plasma-Sprayed Zirconia Coatings with Different Microstructures

et al. 2015

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The present paper is focused on the characterization of the differences between two microstructures that can be obtained using SPS technology, namely (i) columnar and (ii) two-zone microstructure including lamellas and fine unmelted particulates. The optimization of spray parameters was made, and the advanced microstructural studies of obtained coatings were performed. The work was focused on zirconia stabilized by yttria (YSZ, ZrO 2 + 14 wt.% Y 2 O 3 ) and both by yttria and ceria (YCSZ, ZrO 2 + 24 wt.% CeO 2 + 2.5 wt.% Y 2 O 3 ) which are frequently used as thermal barrier coatings. Two types of microstructure were achieved using two different plasma torches, namely SG-100 of Praxair and Triplex of Oerlikon Metco. The microstructure of prepared coatings was analyzed using scanning electron microscopy with secondary electrons detector and backscattered electrons. Energy dispersive spectroscopy was performed to analyze the chemical composition of sprayed coatings. By electron backscatter diffraction grain shape, size, and crystal orientation were determined. The analysis enabled the discussion of the coatings growth mechanism. Finally, the Shape From Shading technique was applied to recreate and to analyze 3D views of coatingsÕ topographies, and using laser confocal microscopy, the surface roughness was examined.

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Section: Discussionmentioning

confidence: 90%

Advanced Microscopic Study of Suspension Plasma-Sprayed Zirconia Coatings with Different Microstructures

et al. 2015

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“…Column widths for the highest power/lowest pressure conditions were 10-20 microns, which are thicker than standard PVD growth methods, which produce column widths on the order of 5-10 microns. 9 Lower power settings (and likely lower substrate temperatures) resulted in wider columns. Coating thicknesses did not have any impact on column width.…”

Section: Results -Coatingsmentioning

confidence: 99%

“…The literature has many examples of both splat (via APS processing) as well as columnar (via EB-PVD processing) microstructures for YSZ. 1,9 Although this material is traditionally used for thermal barrier coatings, this study will assist in understanding process-properties relationships, which will be used in developing more advanced turbine EBCs for ceramic matrix composites where high temperature capability is required.…”

Section: Introductionmentioning

confidence: 99%

Plasma Spray‐Physical Vapor Deposition (PS‐PVD) of Ceramics for Protective Coatings

Harder¹,

Zhu²

2011

Ceramic Engineering and Science Proceedings

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In order to generate advanced multilayer thermal and environmental protection systems, a new deposition process is needed to bridge the gap between conventional plasma spray, which produces relatively thick coatings on the order of 125-250 microns, and conventional vapor phase processes such as electon beam physical vapor deposition (EB-PVD) which are limited by relatively slow deposition rates, high investment costs, and coating material vapor pressure requirements. The use of Plasma Spray -Physical Vapor Deposition (PS-PVD) processing fills this gap and allows thin (< 10 m) single layers to be deposited and multilayer coatings of less than 100 m to be generated with the flexibility to tailor microstructures by changing processing conditions. Coatings of yttria-stabilized zirconia (YSZ) were applied to NiCrAlY bond coated superalloy substrates using the PS-PVD coater at NASA Glenn Research Center. A design-of-experiments was used to examine the effects of process variables (Ar/He plasma gas ratio, the total plasma gas flow, and the torch current) on chamber pressure and torch power. Coating thickness, phase and microstructure were evaluated for each set of deposition conditions. Low chamber pressures and high power were shown to increase coating thickness and create columnar-like structures. Likewise, high chamber pressures and low power had lower growth rates, but resulted in flatter, more homogeneous layers. INTRODUCTIONThermal and environmental barrier coatings (TBCs, EBCs) are necessary for the protection of metal and ceramic components in high temperature turbine engine environments. To meet everincreasing temperature demands for improving efficiency, these coatings have become increasingly complex in composition and architecture. Thermal spray technology has been a longstanding processing method for depositing TBCs and EBCs.1 In traditional air plasma spray (APS), coatings are formed by the buildup of molten ceramic material as a torch traverses the substrate. Electron beamphysical vapor deposition (EB-PVD) has been used to create smooth and more strain tolerant TBCs by growth of columnar grains. In this process, vaporized ceramic material condenses onto the hot substrate surface under high vacuum conditions (<10 -4 torr). The resultant coating has a microstructure that is well suited for turbine airfoil components.2 However, these processes both exhibit limitations, as APS methods produce rough coatings on the order of 125-250 microns thick (a single pass is 50-80 microns), and conventional EB-PVD processing is limited by slower growth rates, high equipment investment costs, and coating material vapor pressure requirements.A new processing technology, known as Plasma Spray -Physical Vapor Deposition (PS-PVD) has been developed in order to bridge the gap between conventional APS and PVD techniques to create unique microstructures.3,4 The PS-PVD system at the NASA Glenn Research Center is one of only four systems currently available at this time. Conventional low pressure plasma spray (LPPS) is a...

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“…탑 코팅의 증착 방법으로는 원료분 말을 대기중에 형성된 플라즈마에 투입, 용융시켜 분사하는 대기 플라즈마 용사(APS, Air Plasma Spray) 방식이 대표적으로 사용되고 있다. 이와 같은 방법 은 생산비용이 낮고, splat 적층 구조에 따른 층간 기공이 다수 형성되어 열전도성을 낮추는 효과를 기대할 수 있으나, 다수의 기공과 함께 존재하는 미 용융입자, 결함등에 의해 고온에서의 장시간 사용 시 내구성이 저하되는 것으로 보고되고 있다 7) . .…”

Section: 서 론unclassified

High Temperature Tribology Behavior of 4YSZ Coatings Fabricated by Air Plasma Spray (APS) and Electron Beam Physical Vapor Deposition (EB-PVD)

Yang¹,

Park²,

Lee³

et al. 2013

Journal of the Korean institute of surface engineering

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Abstract4 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 µm 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.

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EB-PVD Y2O3- and -stabilized zirconia thermal barrier coatings — crystal habit and phase composition

Cited by 97 publications

References 15 publications

Advanced Microscopic Study of Suspension Plasma-Sprayed Zirconia Coatings with Different Microstructures

Advanced Microscopic Study of Suspension Plasma-Sprayed Zirconia Coatings with Different Microstructures

Plasma Spray‐Physical Vapor Deposition (PS‐PVD) of Ceramics for Protective Coatings

High Temperature Tribology Behavior of 4YSZ Coatings Fabricated by Air Plasma Spray (APS) and Electron Beam Physical Vapor Deposition (EB-PVD)

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