A Fundamental Study of the Bonding of Thermal Barrier Coatings.
Abstract
Two layer thermal barrier coatings are currently being developed for extending the performance of nickel base superalloy gas turbine engines. The best materials reported to data comprise a Ni-Cr-A1-Y bond coat and a Y2O3 partially stabilized ZrO2 (Y-PSZ) thermal barrier coat. The Y level of both the bond coat and the thermal barrier coat have been studied empirically but the fundamental factors that govern optimization of the thermal barrier system are not well understood. Optimized systems perform remarkably well during high temperature exposure and thermal cycling but failure still tends to occur by radial cracking in the ceramic coat and circumferential cracking at the various metal/ceramic interfaces, Two fundamental aspects of the behavior are discussed: firstly, phase stability in the zirconia-yttria system itself, particularly the desirable tetragonal phase, and secondly, the nature of the important zirconia-alumina interface which forms during oxidation of the underlying bond coat. The results of this research are described briefly below and in the various appendices.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1986
- Accession Number
- ADA174784
Entities
People
- A. H. Heuer
- T. E. Mitchell
Organizations
- Case Western Reserve University