Creep Behavior of Plasma‐Sprayed Zirconia Thermal Barrier Coatings

Soltani, Reza; Coyle, Thomas W.; Mostaghimi, J.

doi:10.1111/j.1551-2916.2007.01822.x

Cited by 14 publications

(4 citation statements)

References 22 publications

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“…These should be the results of both dislocation strengthening caused by previous C‐F tests and the protective effects of self‐healing coatings. Similar results were reported in previous work, 42 which mentioned that the healing of defects such as microcracks in the coating could significantly reduce the creep rate of the coating and substrate. Moreover, the coating structure remains relatively intact, and the spalling of the coating is hardly observed in the sample with 50% prior C‐F lifetime fraction.…”

Section: Resultssupporting

confidence: 91%

Improved creep‐fatigue and remnant tensile/creep properties of 321 stainless steel by self‐healing coating

Li,

Qin,

Zhu

et al. 2023

Fatigue Fract Eng Mat Struct

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AISI 321 steels used as intake valves in turbines are frequently subjected to creep‐fatigue (C‐F) exposure during service. Improving C‐F resistance and assessing remnant creep/tensile properties are therefore required for their safe service. In this work, the self‐healing coating consisting of Al2O3‐13TiO2 layer, TiC layer, and NiCrAlY layer was prepared for 321 steel. The effects of such self‐healing coating on the C‐F and remnant creep/tensile properties were studied. The results showed that the initial hardening phenomena of the studied steel during C‐F exposure was mainly attributed to the dislocation strengthening and a certain level of carbides precipitation strengthening, while the subsequent softening behaviors were resulted from dynamic recovery and coarsening of carbides. Moreover, as compared to other coatings, the self‐healing coating is able to improve the mechanical properties of steels due to dislocation strengthening, precipitation strengthening, and the self‐healing behavior resulting from the reaction between the TiC layer and oxygen.

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Section: Resultssupporting

confidence: 91%

Improved creep‐fatigue and remnant tensile/creep properties of 321 stainless steel by self‐healing coating

Li,

Qin,

Zhu

et al. 2023

Fatigue Fract Eng Mat Struct

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show abstract

“…Several experimental studies have revealed that the activation energy associated with the creep deformation of YSZ or Ni-YSZ at a temperature approximating that of SOFC operation (<1100 • C) was found to be in the range of 1.0-2.0 eV [5,54,55]. Laurencin et al suggested that these barriers characterized the surface diffusion of a cation, which was also consistent with our KMC simulations.…”

Section: Cation Diffusion At the Surfacesupporting

confidence: 88%

Atomistic study of segregation and diffusion of yttrium and calcium cations near electrolyte surfaces in solid oxide fuel cells

Sun

Hara

2015

Journal of the European Ceramic Society

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Segregation behaviors of yttrium (Y) and calcium (Ca) cation dopant species near zirconia (1 1 1) surfaces have been investigated utilizing atomistic simulations. The results reveal that surface segregation of both species can be achieved when the density of cation and oxygen vacancies near the surface is relatively high compared to the bulk. Comparing Y with Ca, the local equilibrium concentration at the surface of Ca is estimated to be lower than that of Y; however, Ca is kinetically much easier to diffuse from bulk to the surface than Y. The analysis of in-plane cation and oxygen diffusion at Y-or Ca-rich surfaces shows that the cation diffusivity is enhanced with increasing Ca-concentration at the surface, whereas oxygen diffusivity is inhibited. This tendency is more remarkable than that of the Y-rich surface, suggesting that Ca segregation has a greater negative impact than Y segregation on electrolyte performance in solid oxide fuel cells.

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“…Such free-standing coatings allow measurements of properties that are difficult or rather impossible to determine with a substrate underneath. These measurements can be mechanical tests, e.g., for the evaluation of Young's modulus [1], bending strength [2], creep [3,4] or sintering properties [5][6][7], toughness [8], and crack propagation [9,10]. Additionally, functional properties like thermal diffusivity [11], optical properties [12], phase evolution [13], and attack by corrosive species as Calcium-Magnesium-Aluminum-Silicate (CMAS, [14]) are measured on free-standing coatings.…”

Section: Introductionmentioning

confidence: 99%

Influence of Substrate Removal Method on the Properties of Free-Standing YSZ Coatings

2021

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Thermally sprayed ceramic coatings are often tested as free-standing layers to investigate different properties such as thermal expansion coefficient, thermal conductivity, sintering, mechanical behavior, corrosion resistance, gas tightness, or electrical properties. In this paper, four different substrate removal methods were used to obtain free-standing YSZ coatings. At first, spraying on a steel substrate and subsequent dissolution of the substrate-coating interface by hydrochloric acid (HCl) was used. Second, the steel substrate was removed by applying an electrical field via electrochemical corrosion of the surface of the substrate. In a third method, the coating was sprayed on a salt (NaCI) interlayer, which was removed later by dissolution in water. At last, the coating was sprayed on a graphite substrate and the substrate was removed by heat treatment. After the preparation of free-standing coatings, these were characterized using scanning electron microscopy, mercury porosimetry, indentation tests, and room temperature three-point bending tests, which allowed the determination of Young’s modulus and viscosity. The results revealed measurable differences in coating properties as a result of the substrate removal methods, i.e., HCl method led to higher porosity and lower modulus in the YSZ coating.

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Creep Behavior of Plasma‐Sprayed Zirconia Thermal Barrier Coatings

Cited by 14 publications

References 22 publications

Improved creep‐fatigue and remnant tensile/creep properties of 321 stainless steel by self‐healing coating

Improved creep‐fatigue and remnant tensile/creep properties of 321 stainless steel by self‐healing coating

Atomistic study of segregation and diffusion of yttrium and calcium cations near electrolyte surfaces in solid oxide fuel cells

Influence of Substrate Removal Method on the Properties of Free-Standing YSZ Coatings

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