Publication detail

Finite element simulation of stresses in a plasma-sprayed thermal barrier coating with a crack at the TGO/bond-coat interface

SKALKA, P. SLÁMEČKA, K. POKLUDA, J. ČELKO, L.

Original Title

Finite element simulation of stresses in a plasma-sprayed thermal barrier coating with a crack at the TGO/bond-coat interface

Type

journal article in Web of Science

Language

English

Original Abstract

Plasma-sprayed TBCs typically consist of a ceramic top-coat and a metallic bond-coat with an irregular metal/ceramic interface, which is required for better adhesion and, at the same time, generates tensile stresses responsible for in-service failure. Exposure to high-temperatures results in formation of a third, thin layer of thermally grown oxide (TGO) at the top-coat/bond-coat interface. One of the cracking mechanisms experimentally observed in these coatings is delamination at the TGO/bond-coat interfacial peaks. Such delamination cracks increase tensile stresses in the ceramic top-coat layer and may induce its cracking. This article provides the numerical study of the residual stress state of the YSZ (yttria partially-stabilized zirconia) top-coat in a conventional plasma-sprayed TBC system with a delamination crack centred at the TGO/bond-coat 3D cosine interfacial peak. The results show that the delamination crack induces considerable stresses in the YSZ layer; the small interfacial peaks are more likely to cause cracking above the peak, whereas the large peaks are more likely to cause off-peak cracking. Furthermore, it is shown that the aspect ratio (the ratio of amplitude to wavelength), which is often used in numerical studies to distinguish between various geometries, is not a unique parameter, since the changes in amplitude and wavelength are not equivalent.

Keywords

Thermal barrier coatings; Thermal stresses; Roughness; Delamination; FEM

Authors

SKALKA, P.; SLÁMEČKA, K.; POKLUDA, J.; ČELKO, L.

Released

10. 1. 2018

Publisher

ELSEVIER

ISBN

0257-8972

Periodical

Surface and Coatings Technology

Year of study

337

Number

1

State

Swiss Confederation

Pages from

321

Pages to

334

Pages count

14

URL

https://www.sciencedirect.com/science/article/pii/S025789721830032X?via%3Dihub

BibTex

@article{BUT145405,
  author="Petr {Skalka} and Karel {Slámečka} and Jaroslav {Pokluda} and Ladislav {Čelko}",
  title="Finite element simulation of stresses in a plasma-sprayed thermal barrier coating with a crack at the TGO/bond-coat  interface",
  journal="Surface and Coatings Technology",
  year="2018",
  volume="337",
  number="1",
  pages="321--334",
  doi="10.1016/j.surfcoat.2018.01.024",
  issn="0257-8972",
  url="https://www.sciencedirect.com/science/article/pii/S025789721830032X?via%3Dihub"
}