A 3D finite-difference model for the effective thermal conductivity of thermal barrier coatings produced by plasma spraying

Qiao, Jianghao; Bolot, Rodolphe; Liao, Hanlin; Bertrand, Pierre; Coddet, Christian

doi:10.1016/j.ijthermalsci.2012.09.008

Cited by 29 publications

(15 citation statements)

References 38 publications

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“…The quantitative effect of grain boundaries on the thermal conductivity was analyzed, showing that the thermal conductivity of small grains is lower than that of large grains [16][17][18]. Unfortunately, most studies have focused on the qualitative effect of microstructure on the thermal conductivity in the thermal barrier coating [19][20][21]. Nevertheless, very limited literature on the quantitative relationship between the microstructure and thermal conductivity is available.…”

Section: Materials and Preparationmentioning

confidence: 99%

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Effect of Microstructure on the Thermal Conductivity of Plasma Sprayed Y2O3 Stabilized Zirconia (8% YSZ)

Khan

Wang

et al. 2017

Coatings

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Abstract:In this paper, the effect of microstructure on the thermal conductivity of plasma-sprayed Y 2 O 3 stabilized ZrO 2 (YSZ) thermal barrier coatings (TBCs) is investigated. Nine freestanding samples deposited on aluminum alloys are studied. Cross-section morphology such as pores, cracks, m-phase content, grain boundary density of the coated samples are examined by scanning electron microscopy (SEM) and electron back-scattered diffraction (EBSD). Multiple linear regressions are used to develop quantitative models that describe the relationship between the particle parameters, m-phase content and features of the microstructure such as porosity, crack-porosity, and the length density of small and big angle-cracks. Moreover, the relationship between the microstructure and thermal conductivity is investigated. Results reveal that the thermal conductivity of the coating is mainly determined by the microstructure and grain boundary density at room temperature (25 • C), and by the length density of big-angle-crack, monoclinic phase content and grain boundary density at high temperature (1200 • C).

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Section: Materials and Preparationmentioning

confidence: 99%

“…Unfortunately, most studies have focused on the qualitative effect of microstructure on the thermal conductivity in the thermal barrier coating [19][20][21]. Nevertheless, very limited literature on the quantitative relationship between the microstructure and thermal conductivity is available.…”

Section: Introductionmentioning

confidence: 99%

Effect of Microstructure on the Thermal Conductivity of Plasma Sprayed Y2O3 Stabilized Zirconia (8% YSZ)

Khan

Wang

et al. 2017

Coatings

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“…The modeled distributions are usually based on experimentally obtained data and may comprise amongst others diameter, elongation, orientation, and volume fraction information (Ref 4,20,21). Based on these distributions, volumes are randomly filled with pores of different types (globular, interlamellar, cracks).…”

Section: Related Workmentioning

confidence: 99%

Efficient Large-Scale Coating Microstructure Formation Using Realistic CFD Models

Wiederkehr

Müller

2014

J Therm Spray Tech

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For the understanding of physical effects during the formation of thermally sprayed coating layers and the deduction of the macroscopic properties of a coating, microstructure modeling and simulation techniques play an important role. In this contribution, a coupled simulation framework consisting of a detailed, CFD-based single splat simulation, and a large-scale coating build-up simulation is presented that is capable to compute large-scale, three-dimensional, porous microstructures by sequential drop impingement of more than 10,000 individual particles on multicore workstation hardware. Due to the geometry-based coupling of the two simulations, the deformation, cooling, and solidification of every particle is sensitive to the hit surface area and thereby pores develop naturally in the model. The single splat simulation employs the highly parallel Lattice-Boltzmann method, which is well suited for GPUacceleration. In order to save splat calculations, the coating simulation includes a database-driven approach that re-uses already computed splats for similar underground shapes at the randomly chosen impact sites. For a fast database search, three different methods of efficient pre-selection of candidates are described and compared against each other.

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“…In general these studies aim to predict the bulk properties of the material to validate the modelling route before using the model to investigate underlying mechanics and directions for future materials or processing parameters. In addition some studies have attempted to computationally generate equivalent images of microstructures so individual parts of the structure can be optimised [1,6,7].…”

Section: Introductionmentioning

confidence: 99%

A Novel Image Segmentation Approach for Microstructure Modelling

Watson

Marshall

2017

Coatings

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Microstructure models are used to investigate bulk properties of a material given images of its microstructure. Through their use the effect of microstructural features can be investigated independently. Processes can then be optimised to give the desired selection of microstructural features. Currently automatic methods of segmenting SEM images either miss cracks leading to large overestimates of properties or use unjustifiable methods to select a threshold point which class cracks as porosity leading to over estimates of porosity. In this work, a novel automatic image segmentation method is presented which produces maps for each phase in the microstructure and an additional phase of cracks. The selection of threshold points is based on the assumption that the brightness values for each phase should be normally distributed. The image segmentation method has been compared to other available methods and shown to be as or more repeatable with changes of brightness and contrast of the input image than relevant alternatives. The resulting modelling route is able to predict density and specific heat to within experimental error, while the expected under predictions for thermal conductivity are observed.

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A 3D finite-difference model for the effective thermal conductivity of thermal barrier coatings produced by plasma spraying

Cited by 29 publications

References 38 publications

Effect of Microstructure on the Thermal Conductivity of Plasma Sprayed Y2O3 Stabilized Zirconia (8% YSZ)

Effect of Microstructure on the Thermal Conductivity of Plasma Sprayed Y2O3 Stabilized Zirconia (8% YSZ)

Efficient Large-Scale Coating Microstructure Formation Using Realistic CFD Models

A Novel Image Segmentation Approach for Microstructure Modelling

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