Abstract
The influences of void growth and bond coat impurities on premature failure of electron beam-physical vapor deposition (EB-PVD) thermal barrier coatings (TBC) were studied. Results show that numerous fine voids were present beneath alumina scales that formed on as-deposited commercial CVD NiPtAl bond coat surfaces during EB-PVD of YSZ. Voids were not observed beneath scales that formed on grit-blasted NiPtAl surfaces. The benefits of grit-blasting primarily involved prevention of void growth. Surface treatments that remove S and/or accelerate alpha alumina formation without roughening the bond coat surface will likely extend the ultimate durability of state-of-the-art EB-PVD TBC.
Original language | English |
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Pages (from-to) | 1147-1152 |
Number of pages | 6 |
Journal | Scripta Materialia |
Volume | 44 |
Issue number | 7 |
DOIs | |
State | Published - Apr 17 2001 |
Funding
The author thanks B. Pachman, B. Warnes and K. Murphy of Howmet Research Corporation for superalloy casting and coating fabrication. Thanks are extended to T. Geer for metallography, L. W. Walker for microprobe analysis, M. J. Lance, P. F. Tortorelli, I. G. Wright and B. A. Pint, all at ORNL, for helpful reviews. Research sponsored by the U.S. Department of Energy, Office of Power Technologies, Advanced Turbine Systems Program under Contract DE-AC05-00OR22725 with UT-Battelle, LLC.
Keywords
- Chemical vapor deposition (CVD)
- Coating
- Intermetallic
- Oxidation
- Thermal barrier coating