Comprehensive microstructural characterization and predictive property modeling of plasma-sprayed zirconia coatings

Kulkarni, Anand; Wang, Z.; Nakamura, Tsuneyoshi; Sampath, Sanjay; Goland, A.N.; Herman, H.; Allen, James D.; Ilavský, Ján; Long, Gabrielle G.; Frahm, J.; Steinbrech, R. W.

doi:10.1016/s1359-6454(03)00030-2

Cited by 216 publications

(144 citation statements)

References 20 publications

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“…There has been extensive study [31,[48][49][50][51][52][53][54] of microstructural features exhibited by PS YSZ and of changes induced under service conditions [26,55,56]. The main features are a series of interfaces parallel to the plane of the coating (normal to the heat flow direction), representing boundaries between the splats formed from incident molten droplets.…”

Section: Composition and Microstructurementioning

confidence: 99%

Heat Transfer Through Plasma-Sprayed Thermal Barrier Coatings in Gas Turbines: A Review of Recent Work

2009

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A review is presented of how heat transfer takes place in plasma sprayed (zirconia-based) thermal barrier coatings (TBCs) during operation of gas turbines. These characteristics of TBCs are naturally of central importance to their function. Current state-of-the-art TBCs have relatively high levels of porosity (~15%) and the pore architecture (ie its morphology, connectivity and scale) has a strong influence on the heat flow. Contributions from convective, conductive and radiative heat transfer are considered, under a range of operating conditions, and the characteristics are illustrated with experimental data and modelling predictions. In fact, convective heat flow within TBCs usually makes a negligible contribution to the overall heat transfer through the coating, although what might be described as convection can be important if there are gross through-thickness defects such as segmentation cracks. Radiative heat transfer, on the other hand, can be significant within TBCs, depending on temperature and radiation scattering lengths, which in turn are sensitive to the grain structure and the pore architecture. Under most conditions of current interest, conductive heat transfer is largely predominant. However, it is not only conduction through solid ceramic that is important. Depending on the pore architecture, conduction through gas in the pores can play a significant role, particularly at the high gas pressures typically acting in gas turbines (although rarely applied in laboratory measurements of conductivity). The durability of the pore structure under service conditions is also of importance, and this review covers some recent work on how the pore architecture, and hence the conductivity, is affected by sintering phenomena. Some information is presented concerning the areas in which research and development work needs to be focussed if improvements in coating performance are to be achieved.

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Section: Composition and Microstructurementioning

confidence: 99%

Heat Transfer Through Plasma-Sprayed Thermal Barrier Coatings in Gas Turbines: A Review of Recent Work

2009

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“…3 and Table 1, it can be concluded that the bending strength values of the coating exhibit obvious anisotropic behavior: bending strength values measured by loading parallel or antiparallel to the spraying direction (BS 1 , BS 2 ) larger than that while loading perpendicular to the spraying direction (BS 3 ). This may be attributed to the intrinsic microstructure anisotropy of plasma sprayed coatings formed by successive overlaying of molten or semimolten droplets (Ref 14,15). Compared to BS 1 and BS 2 , the BS 3 data present larger variability reflected by a lower Weibull modulus (m) of 10.1 and a larger variation coefficient (V c ) of 0.0999.…”

Section: Methodsmentioning

confidence: 99%

Evaluating Bending Strength of Plasma Sprayed Al2O3 Coatings

et al. 2009

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The bending strength of plasma sprayed Al 2 O 3 coatings was evaluated using three-point bending tests. The measured strength data sets were statistically analyzed by employing Weibull distribution. It was found that the bending strength values of coatings show obvious anisotropic behavior. Additionally, the bending strength values measured by loading parallel to the spraying direction are lower than those antiparallel to the spraying direction, and larger variability was realized for the former. This may be related mainly to the distribution of residual stress and microstructural defects within coatings.

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“…Geometric models of such thermally sprayed microstructures are used in a wide variety of simulations to predict different physical properties of the manufactured workpieces that are relevant for the application at hand. Examples include the investigation of residual stress distributions, elastic modulus, fracture toughness, erosion resistance, or heat transfer for thermal barrier coatings (Ref [1][2][3][4].…”

Section: Introductionmentioning

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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Comprehensive microstructural characterization and predictive property modeling of plasma-sprayed zirconia coatings

Cited by 216 publications

References 20 publications

Heat Transfer Through Plasma-Sprayed Thermal Barrier Coatings in Gas Turbines: A Review of Recent Work

Heat Transfer Through Plasma-Sprayed Thermal Barrier Coatings in Gas Turbines: A Review of Recent Work

Evaluating Bending Strength of Plasma Sprayed Al2O3 Coatings

Efficient Large-Scale Coating Microstructure Formation Using Realistic CFD Models

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