Evolution of residual stress in air plasma sprayed yttria stabilised zirconia thermal barrier coatings after isothermal treatment

Yang, Lixia; Yang, Fan; Liang, Ying Chun; Zhao, Yang; Xiong, Xiang; Zhao, Xiaofeng; Xiao, Ping

doi:10.1016/j.surfcoat.2014.04.009

Cited by 49 publications

(26 citation statements)

References 34 publications

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“…The volume fraction of the unwanted ZrO 2 monoclinic phase, V m , has been calculated (for the different machining tests performed) using the intensities (areas under the peaks), I, of three X-ray diffraction peaks (two of monoclinic phase and one of tetragonal phase) as indicated by Toraya et al [49] and gathered also by other authors [18,34,50]: …”

Section: Characterization Of Surface Integritymentioning

confidence: 99%

Surface integrity of rotary ultrasonic machined ZrO2–TiN and Al2O3–TiC–SiC ceramics

Navas¹,

Sandá²,

Sanz³

et al. 2015

Journal of the European Ceramic Society

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Section: Characterization Of Surface Integritymentioning

confidence: 99%

Surface integrity of rotary ultrasonic machined ZrO2–TiN and Al2O3–TiC–SiC ceramics

Navas¹,

Sandá²,

Sanz³

et al. 2015

Journal of the European Ceramic Society

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“…After the incident photons collide with the molecules, the vibrational energy or the rotational energy of the molecules and the photon energy superimpose each other to form a Raman spectrum. When there is stress in the material, some stress-sensitive bands may move and deform relative to the stress-free state, and the position of the spectral peak also may move, as shown in Figure 6 [39]. It is found that there is a linear relationship between Raman frequency shift and the stress.…”

Section: Raman Spectroscopymentioning

confidence: 97%

Stress among the APS-Prepared TBCs: Testing and Analysis

Qu¹,

He²,

Fang³

2020

Methods for Film Synthesis and Coating Procedures

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Stress state in thermal barrier coatings (TBCs) has an influence on the service property and safety of coatings. The stress in TBCs should be characterized and measured. This is helpful for the guidance of design and preparation, the study of failure mechanism and the promotion of application of TBCs. This chapter reviewed the research progress on the stress measurement for air plasma spray (APS)-prepared TBCs. The origin and category of stress during preparation process and service were discussed. Then, the measurement technology and characterization method for stress in APS-prepared TBCs were focused. The common stress measurement techniques such as X-ray diffraction, neutron diffraction, Raman spectroscopy, photoluminescence piezospectroscopy, curvature measurement, material removal and indentation method were detailed. Furthermore, some suggestions were presented for the future work by summarizing the shortcomings of the exiting research. Methods for Film Synthesis and Coating Procedures2 'partially stabilized' with about 6-8 wt.% yttria (7YSZ), which has the good heatinsulating property and long thermal cycle life. TGO, whose composition is α-Al 2 O 3 , is formed by the reaction between aluminum diffusing from the bond coat and exterior oxygen. TGO can provide good bonding of TBC to bond coat. The bond coat contains the source of elements to create TGO in oxidizing environment and provides oxidation protection, primarily of NiCoCrAlY-or NiAlPt-based compositions. The superalloy substrate, which has high strength at high temperatures, can experience complicated mechanical loads during service [1,2,4].Recently, many methods have been developed to prepare the ceramic top coat, such as air plasma spray (APS) and electron beam physical vapor deposition (EB-PVD) process [5,6]. In APS process, the ceramic feedstock are injected into the high temperature plasma plume, heated to the molten or high-plasticity condition, impinge onto the surface of specimen with a certain momentum, and rapidly solidify. Then the lamellar microstructures, which consist of a large number of overlapped splats, are formed, as shown in Figure 2(a). In EB-PVD process, ingots of a ceramic composition are vaporized in a vacuum chamber using a focused electron beam. The ceramic vapor gradually deposit on the specimen and form columnar microstructure, which are perpendicular to the surface of specimen, as shown in Figure 2(b).TBCs prepared by APS process, which has lower cost, has been widely used in the larger stationary components. However, the failure behavior such as premature spallation of TBCs during preparation and operation process is still an overriding concern. The premature spallation of TBCs may expose the superalloy substrate to hot gases, resulting in the oxidization of superalloy. This may influence the service performance, lifetime and safety of aircraft, even lead to catastrophic damage [7]. The premature spallation of TBCs mainly results from intralayer and interlayer fractures [8]. The fracture behavior of materials is closely...

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“…After heat exposure, the compressive strain increases slightly after initial heat exposure. Further heat exposure changes the compressive stress to tensile, and then the tensile stress gradually 21 increases. The analysis on this elastic strain evolution with heat exposure is also presented in Appendix A.…”

Section: Surface Roughness Measurementmentioning

confidence: 99%

“…The curvature of the sample can be obtained by fitting the X-Z profile using a circle function [21]. To ensure reliability of the results, a 50× optical lens was employed and 50 measurements were performed for each sample.…”

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confidence: 99%

High temperature stress and its influence on surface rumpling in NiCoCrAlY bond coat

et al. 2017

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The objective of this work is to develop a methodology to measure the high temperature stress in the bond coat, and investigate its role on the surface rumpling. We first presented an analytical model to evaluate the high temperature stress using X-ray sin 2 Ψ technique coupling with the curvature measurement at room temperature. A typical NiCoCrAlY bond coat with a Hastelloy-X substrate was employed as a model sample. During exposure at 1150 ºC , the bond coat was under tension at high temperature, increasing parabolically from 1.05 MPa after 12 h to 3.81 MPa after 120 h. To understand its effect on the surface rumpling, the bond coat surface roughness was recorded as a function of time, and compared with a bulk NiCoCrAlY alloy. A strong correlation between the bond coat stress and the surface roughness was identified. In addition, the origination of the bond coat stress and the rumpling mechanism were discussed. 2It was revealed that the high temperature stress in the bond coat was caused by the volume shrinkage from β-γ transformation, mainly due to the inter-diffusion. The grain sliding accompanied with diffusional creep in response to the bond coat stress controls the roughening.

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Evolution of residual stress in air plasma sprayed yttria stabilised zirconia thermal barrier coatings after isothermal treatment

Cited by 49 publications

References 34 publications

Surface integrity of rotary ultrasonic machined ZrO2–TiN and Al2O3–TiC–SiC ceramics

Surface integrity of rotary ultrasonic machined ZrO2–TiN and Al2O3–TiC–SiC ceramics

Stress among the APS-Prepared TBCs: Testing and Analysis

High temperature stress and its influence on surface rumpling in NiCoCrAlY bond coat

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