Image-based multi-scale simulation and experimental validation of thermal conductivity of lanthanum zirconate

Guo, Xingye; Hu, Bin; Wei, Changdong; Sun, Jie; Jung, Yeon‐Gil; Li, Li; Knapp, James

doi:10.1016/j.ijheatmasstransfer.2016.04.067

Cited by 14 publications

(6 citation statements)

References 26 publications

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“…Due to the difficulties in preparing specimens from pistons for the experimental measurements of thermal properties of the coatings, e.g., LFA, an alternative is to calculate them by modeling using the object-oriented finite element (OOF) method [34][35][36]. A method developed by Ganvir et al [34] using two different magnifications was used.…”

Section: Thermal Properties (Simulation)mentioning

confidence: 99%

Microstructural Changes in Suspension Plasma-Sprayed TBCs Deposited on Complex Geometry Substrates

2020

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Thermal barrier coatings (TBCs) are considered a promising solution for improving the efficiency of internal combustion engines. Among the thermal spray processes, the relatively newly developed suspension plasma spray (SPS) is an attractive candidate due to its unique microstructural features that have already demonstrated increased performance in gas turbine applications. To achieve these features, thermal spray conditions play an essential role. In specific uses, such as piston of diesel engines, parameters as spray angle and spray distance pose challenges to keep them constant during the whole spray process due to the complex geometry of the piston. To understand the effect of the spray distance and spray angle, a comprehensive investigation of the produced thermal spray microstructure on the piston geometry was conducted. Flat and complex geometry surfaces were coated using the same plasma parameters while the spray angle and distance were changed. Characterization was performed using scanning electron microscopy (SEM) combined with the image analysis technique to perceive the variation of the thickness and microstructures features such as pores, cracks, column density, and column orientation. The results showed that the changes in spray angles and spray distances due to the complex shape of the substrate have a significant influence on the microstructure and thermal properties (thermal conductivity and thermal effusivity) of the coatings. The thermal conductivity and thermal effusivity were calculated by modeling for the different regions of the piston and measured by laser flash analysis combined with modeling for the flat-surfaced coupon. It was shown that the modeling approach is an effective tool to predict the thermal properties and thus to understand the influence of the parameters on the coating properties. Connecting the observations of the work on the microstructural and thermal properties, the complex geometry’s influence on the produced coatings could be diminished by tailoring the process and generating the most desirable TBC for the internal combustion engines in future applications.

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Section: Thermal Properties (Simulation)mentioning

confidence: 99%

Microstructural Changes in Suspension Plasma-Sprayed TBCs Deposited on Complex Geometry Substrates

2020

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“…9, the thermal conductivities of the LZ coating decrease with the increase of temperature till 1200 K due to lattice scattering, and the conductivities increase again above 1200 K due to radiation contribution. The conductivities also depend on coating porosity [10,31,38,45,46,51]. In Vassen and Zhu's works, the porosities of the LZ samples were very low so the thermal conductivities were much larger than those of the porous coatings in Guo,…”

Section: Thermal Conductivitymentioning

confidence: 97%

“…by Chen [46] Calc. by Guo [51] Low thermal conductivity is the primary advantage of LZ coatings over the YSZ coatings.…”

Section: Thermal Conductivitymentioning

confidence: 99%

“…The calculated effective thermal conductivities were in good agreement with experimental results. Guo et al predicted the thermal conductivity of porous LZ coatings using an image based multi-scale simulation method, which combined the MD and FE calculations [51]. The reverse non-equilibrium molecular dynamics approach was used in Guo's work to compute the temperature-dependent thermal conductivity of single crystal LZ.…”

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confidence: 99%

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Lanthanum zirconate based thermal barrier coatings: A review

Zhang

Guo

Jung

et al. 2017

Surface and Coatings Technology

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192

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This review article summarizes the latest information about the manufacturing techniques of lanthanum zirconate (La2Zr2O7, LZ) powder and La2Zr2O7 based thermal barrier coatings (TBCs). Lanthanum zirconate is a promising candidate material for TBC applications, due to its lower thermal conductivity and higher thermal stability compared to other traditional TBC systems. In this work, the physical, thermal, and mechanical properties of the powder and coatings are evaluated. The durability experiments of the TBCs in various thermal, mechanical, and corrosive conditions is also reviewed. In addition, theoretical studies on the powder and coatings properties are presented. Finally, future research directions of lanthanum zirconate as TBC applications are proposed.

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“…From the calculated mechanical properties of ZrO2/Ni C-M interface, the layer thickness of bond coat film, NiCrAlY, at the interface makes a major impact on the coating's mechanical behavior. Typically, fracture or delamination in as-sprayed TBC system occurs near the interfaces between the top and bond coats [7,26,27]. Therefore, the mechanical properties near the interface are important to enhance the lifetime performance of TBC system.…”

Section: Shear Deformations Along {111}<110> and {111}<112 > Directionsmentioning

confidence: 99%

Ideal tensile strength and shear strength of ZrO2(111)/Ni(111) ceramic-metal Interface: A first principle study

et al. 2016

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The ideal mechanical strengths of ZrO2(111)/Ni(111) ceramic-metal (C-M) interface are calculated through simulated tensile and shear deformations using the first principles calculations. The structures of ZrO2(111)/Ni(111) interfaces with 1-and 3-layer Ni thicknesses are optimized and the mechanical properties are investigated. For tensile deformation in [111] direction, the Young's moduli of the 1-layer Ni and 3-layer Ni M-C models are 139.9 GPa and 60.2 GPa, respectively; and ultimate tensile strengths are 11.6 GPa and 7.9 GPa, respectively. For shear deformation in {111}<110> system, the shear moduli of the 1-layer Ni and 3-layer Ni M-C models are 43.9 GPa and 30.4 GPa, respectively; and ultimate shear strengths are 7.0 GPa and 3.0 GPa, respectively. For shear deformation in {111}<112 > system, the shear moduli of the 1-layer Ni and 3-layer Ni M-C models are 30.9GPa and 17.3 GPa, respectively; and ultimate shear strengths are 6.0 GPa and 1.8 GPa, respectively. Overall, 1-layer Ni C-M interface models have better mechanical properties than those of 3-layer models. The observed strengths are explained by using charge distribution, electron localization function, and Bader charge transfer analyses. The results are important for designing robust thermal barrier coating through optimizing bond coat thickness.

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Image-based multi-scale simulation and experimental validation of thermal conductivity of lanthanum zirconate

Cited by 14 publications

References 26 publications

Microstructural Changes in Suspension Plasma-Sprayed TBCs Deposited on Complex Geometry Substrates

Microstructural Changes in Suspension Plasma-Sprayed TBCs Deposited on Complex Geometry Substrates

Lanthanum zirconate based thermal barrier coatings: A review

Ideal tensile strength and shear strength of ZrO2(111)/Ni(111) ceramic-metal Interface: A first principle study

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