Abstract
Modern gas turbines rely on ceramic coatings to protect structural components along the hot gas path. These coatings are susceptible to accelerated degradation caused by silicate deposits formed when ingested environmental debris (dust, sand, ash) adheres to the coatings. This article reviews the current understanding of the deposit-induced failure mechanisms for zirconia-based thermal barrier coatings and silicate environmental barrier coatings. Details of the debris melting and crystallization behavior, the nature of the chemical reactions occurring between the deposits and coatings, and the implications for the thermocyclic durability of the coatings are described. Given the challenges posed in understanding how prospective coating materials and architectures will respond to a broad range of deposit compositions, it is proposed to develop an integrated framework linking thermochemical and thermomechanical models to predict coating durability. Initial progress toward developing this framework, and the requisite research needs, are discussed.
Original language | English (US) |
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Pages (from-to) | 297-330 |
Number of pages | 34 |
Journal | Annual Review of Materials Research |
Volume | 47 |
DOIs | |
State | Published - Jul 3 2017 |
Bibliographical note
Publisher Copyright:© 2017 by Annual Reviews. All rights reserved.
Keywords
- Apatite
- Environmental barrier coating
- Phase equilibria
- Rare earth silicate
- Rare earth zirconate
- Thermal barrier coating