Strength Degradation and Failure Mechanisms of Electron-Beam Physical-Vapor-Deposited Thermal Barrier Coatings

Failure mechanisms were determined for electron‐beam physical‐vapor‐deposited thermal barrier coating (TBC) systems from the degradation of mechanical properties and microstructural changes in a furnace cycle test. Bond strength degradation for TBCs resulted from the initiation and growth of interfa...

Full description

Saved in:
Bibliographic Details
Published in:Journal of the American Ceramic Society 2001-07, Vol.84 (7), p.1545-1552
Main Authors: Ruud, James A., Bartz, Andi, Borom, Marcus P., Johnson, Curtis A.
Format: Article
Language:English
Subjects:
Applied sciences
coatings
Exact sciences and technology
failure
Metals. Metallurgy
Nonmetallic coatings
physical vapor deposition
Production techniques
Surface treatment
zirconia: yttria-stabilized
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Failure mechanisms were determined for electron‐beam physical‐vapor‐deposited thermal barrier coating (TBC) systems from the degradation of mechanical properties and microstructural changes in a furnace cycle test. Bond strength degradation for TBCs resulted from the initiation and growth of interfacial delamination defects between the yttria‐stabilized zirconia topcoat and the thermally grown alumina (TGO). It is proposed that defects started from concave depressions in the bondcoat surface created by the grit‐blast‐cleaning process and that defect growth was driven by the reduction in compressive strain in the TGO as the alumina deformed into and displaced the bondcoat during the cooling cycles. Inclusion of yttrium in the substrate resulted in a doubling of the furnace cycle life of the TBCs because of enhanced fracture toughness of the TGO‐bondcoat interface.
ISSN:0002-7820
1551-2916
DOI:10.1111/j.1151-2916.2001.tb00875.x