A sintering model for plasma-sprayed zirconia thermal barrier coatings. Part II: Coatings bonded to a rigid substrate
A sintering model for plasma-sprayed zirconia thermal barrier coatings. Part II: Coatings bonded to a rigid substrate
The sintering model described in Part I, which relates to free-standing plasma-sprayed thermal barrier coatings, is extended here to the case of a coating attached to a rigid substrate. Through-thickness shrinkage measurements have been carried out for coatings attached to zirconia substrates, and these experimental data are compared with model predictions. The model is then used to explore the influence of the substrate material (zirconia vs. a nickel superalloy), and of the in-plane coating stiffness. Both differential thermal expansion stresses and tensile stresses arising from the constraint imposed on in-plane shrinkage can be relaxed via two diffusional mechanisms: Coble creep and microcrack opening. This relaxation allows progression towards densification, although the process is somewhat inhibited, compared with the case of a free-standing coating. Comparison of the stored elastic strain energy with the critical strain energy release rate for interfacial cracking allows estimates to be made of whether debonding is energetically favoured.
Plasma-sprayed thermal barrier coatings, Modelling, Sintering, Diffusion, Variational principle
993-1003
Cipitria, A.
53f2ee50-b925-41f3-a195-ecb46fce2c01
Golosnoy, I.O.
40603f91-7488-49ea-830f-24dd930573d1
Clyne, T.W.
00678bf7-17de-46e8-9b35-bf1ca73bce9b
April 2009
Cipitria, A.
53f2ee50-b925-41f3-a195-ecb46fce2c01
Golosnoy, I.O.
40603f91-7488-49ea-830f-24dd930573d1
Clyne, T.W.
00678bf7-17de-46e8-9b35-bf1ca73bce9b
Cipitria, A., Golosnoy, I.O. and Clyne, T.W.
(2009)
A sintering model for plasma-sprayed zirconia thermal barrier coatings. Part II: Coatings bonded to a rigid substrate.
Acta Materialia, 57 (4), .
(doi:10.1016/j.actamat.2008.10.058).
Abstract
The sintering model described in Part I, which relates to free-standing plasma-sprayed thermal barrier coatings, is extended here to the case of a coating attached to a rigid substrate. Through-thickness shrinkage measurements have been carried out for coatings attached to zirconia substrates, and these experimental data are compared with model predictions. The model is then used to explore the influence of the substrate material (zirconia vs. a nickel superalloy), and of the in-plane coating stiffness. Both differential thermal expansion stresses and tensile stresses arising from the constraint imposed on in-plane shrinkage can be relaxed via two diffusional mechanisms: Coble creep and microcrack opening. This relaxation allows progression towards densification, although the process is somewhat inhibited, compared with the case of a free-standing coating. Comparison of the stored elastic strain energy with the critical strain energy release rate for interfacial cracking allows estimates to be made of whether debonding is energetically favoured.
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Published date: April 2009
Keywords:
Plasma-sprayed thermal barrier coatings, Modelling, Sintering, Diffusion, Variational principle
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EEE
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Local EPrints ID: 267088
URI: http://eprints.soton.ac.uk/id/eprint/267088
ISSN: 1359-6454
PURE UUID: 87f103d1-4ae6-4d44-8334-d23da4a74a88
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Date deposited: 09 Feb 2009 11:34
Last modified: 14 Mar 2024 08:41
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Author:
A. Cipitria
Author:
I.O. Golosnoy
Author:
T.W. Clyne
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