Thermophysical properties and thermal cycling behavior of plasma sprayed thick thermal barrier coatings

Guo, Hongbo; Vaßen, Robert; Stöver, D.

doi:10.1016/j.surfcoat.2004.02.004

Cited by 158 publications

(64 citation statements)

References 27 publications

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“…7. The appearance of this kind of cracks is due to the gradient of temperature inside the coatings, which is originated during the temperature changes [23]. Regarding the porosity, the cracks were detected as pores by the image analysis software; therefore, a slight porosity increment can also be observed in Fig.…”

Section: Thermally Cycled Treatmentmentioning

confidence: 97%

Thermal behaviour of multilayer and functionally-graded YSZ/Gd2Zr2O7 coatings

Carpio

Salvador

Borrell

et al. 2017

Ceramics International

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Zirconates with pyrochlore structure, such as Gd2Zr2O7, are new promising thermal barrier coatings because of their very low thermal conductivity and good chemical resistance against molten salts. However, their coefficient of thermal expansion is low, therefore their thermal fatigue resistance is compromised. As a solution, the combination of yttria-stabilised zirconia (YSZ) and Gd2Zr2O7 can reduce the thermal contraction mismatch between the thermal barrier coating parts.In the present study, two possible designs have been performed to combine YSZ/ Gd2Zr2O7. On the one hand, a multilayer coating was obtained where YSZ layer was deposited between a Gd2Zr2O7 layer and a bond coat. On the other hand, a functionallygraded coating was designed where different layers with variable ratios of YSZ/Gd2Zr2O7 were deposited such that the composition gradually changed along the coating thickness.Multilayer and functionally-graded coatings underwent isothermal and thermally-cycled treatments in order to evaluate the oxidation, sintering effects and thermal fatigue resistance of the coatings. The YSZ/Gd2Zr2O7 multilayer coating displayed better thermal behaviour than the Gd2Zr2O7 monolayer coating but quite less thermal fatigue resistance compared to the conventional YSZ coating. However, the functionally-graded coating displays a good thermal fatigue resistance. Hence, it can be concluded that this kind of design is ideal to optimise the behaviour of thermal barrier coatings.

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Section: Thermally Cycled Treatmentmentioning

confidence: 97%

Thermal behaviour of multilayer and functionally-graded YSZ/Gd2Zr2O7 coatings

Carpio

Salvador

Borrell

et al. 2017

Ceramics International

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“…Coatings with higher densities of segmentation cracks density perform better under thermal cycling. 4,5 Hence these microstructural features observed could be beneficial.…”

Section: Resultsmentioning

confidence: 99%

“…Similar results have been observed by other researchers. 4,18,19 The numerical model developed by Clyne and coworkers 10,11,13,20,21 was used to calculate the stresses in the top coat and get further insight into other possible mechanisms for the generation of the segmentation and branching cracks. The measured thermal history was compared to that obtained using the numerical model.…”

Section: Resultsmentioning

confidence: 99%

“…Microstructural modifications that induce microcracks, segmentation cracks and porosity can increase the thermal shock resistance of thick TBCs. [4][5][6][7] The scope of this work is to successfully deposit thick TBCs and investigate how processing parameters can be related to the microstructural features that will increase the thermal shock resistance of thick TBCs. Not only is the effect of substrate temperature on the microstructural features established, but also the mechanisms of generation of these features is related to residual stresses in the coatings, which are estimated using a model.…”

Section: Introductionmentioning

confidence: 99%

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Effect of substrate temperature on the microstructure and properties of thick plasma-sprayed YSZ TBCs

Tsipas

Golosnoy

2011

Journal of the European Ceramic Society

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Thick (∼1.2 mm) thermal barrier coatings (TBCs) consisting of YSZ were deposited by plasma spraying. Spraying parameters were varied in a controlled manner to produce different microstructures. The effect of substrate temperature on the microstructural features and subsequently on the Young's modulus was investigated. In addition, the residual stresses in the coatings were estimated using a numerical model and they were related to the microstructural features observed. Results showed that crack segmentation density, residual stresses in the coatings and thus coating properties are strongly affected not only by the average substrate temperature during spraying but also the variations between the minimum and maximum substrate temperature.

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“…[1][2][3] Such macrocracks can be developed by post treatment such as laser glazing, 4,5) or directly introduced during the deposition by applying high heat input to the substrate and high lamellar thickness. 2,3,6) The formation mechanism of segmentation cracks and thermo-physical properties of the segmented coatings have been investigated. [7][8][9] However, the thermal cycling behavior and associated failure mechanism of the segmented TBCs are seldom reported.…”

Section: Introductionmentioning

confidence: 99%

Thermal Cycling Behavior of Plasma Sprayed Segmented Thermal Barrier Coatings

2006

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Thermal barrier coatings (TBCs) with different levels of segmentation crack densities (D s ) were sprayed at different substrate temperatures (T s ). Thermal cycling resistance of the TBC specimen was examined. The segmented coating significantly improved the thermal cycling resistance as compared to the traditional non-segmented coating. Maximum thermal cycling lifetimes were achieved in the coating with a crack density level of 2.2 mm À1 . New segmentation cracks were hardly generated during thermal cycling testing. Spallation of segments within the segmented coating occurred, which is different from spallation of the whole coating from substrate in the case of traditional coating. Oxidation of bond coat and limited phase decomposition of YSZ topcoat were considered as not responsible for the failure of TBCs.

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Thermophysical properties and thermal cycling behavior of plasma sprayed thick thermal barrier coatings

Cited by 158 publications

References 27 publications

Thermal behaviour of multilayer and functionally-graded YSZ/Gd2Zr2O7 coatings

Thermal behaviour of multilayer and functionally-graded YSZ/Gd2Zr2O7 coatings

Effect of substrate temperature on the microstructure and properties of thick plasma-sprayed YSZ TBCs

Thermal Cycling Behavior of Plasma Sprayed Segmented Thermal Barrier Coatings

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