University of Illinois Urbana-Champaign

Bond coat surface rumpling in thermal barrier coatings

Panat, Rahul P.; Zhang, Sulin; Hsia, K. Jimmy

Permalink

https://hdl.handle.net/2142/112685

Description

Title
Bond coat surface rumpling in thermal barrier coatings
Author(s)
  • Panat, Rahul P.
  • Zhang, Sulin
  • Hsia, K. Jimmy
Issue Date
2002-01
Keyword(s)
  • Stress Driven Surface Diffusion
  • Thermally Activated Processes
  • Coating
  • Thin Films
Abstract
"Long term durability of thermal barrier coatings is determined by the mechanisms responsible for the nucleation and growth of interfacial cracks between coating and substrate. One such mechanism is the progressive roughening or ""rumpling"" of the bond coat surface upon thermal cycling. A thermodynamic analysis is presented in this paper based on a stress-driven surface diffusion mechanism to explain the bond coat rumpling process. The surface chemical potential variation required for such a diffusion process is caused by the changes in the surface energy and the elastic strain energy in the system. It is found that the amplitude of surface fluctuations with a wavelength higher than a threshold value monotonically increases with thermal cycling, while the amplitude for fluctuations with lower wavelength than the threshold value monotonically decreases. A range of wavelengths is identified to have a high monotonic amplitude increase accounting for the surface rumpling of the bond coat upon thermal cycling. This range of wavelengths obtained from the model agrees reasonably well with experimental observations."
Publisher
Department of Theoretical and Applied Mechanics. College of Engineering. University of Illinois at Urbana-Champaign
Series/Report Name or Number
  • TAM R 993
  • 2002-6001
ISSN
0073-5264
Type of Resource
text
Language
eng
Permalink
http://hdl.handle.net/2142/112685
Copyright and License Information
Copyright 2002 Board of Trustees of the University of Illinois

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Technical Reports - Theoretical and Applied Mechanics (TAM) PRIMARY
TAM technical reports include manuscripts intended for publication, theses judged to have general interest, notes prepared for short courses, symposia compiled from outstanding undergraduate projects, and reports prepared for research-sponsoring agencies.