Silicate Deposit Degradation of Engineered Coatings in Gas Turbines: Progress Toward Models and Materials Solutions

David L. Poerschke, R. Wesley Jackson, Carlos G. Levi

Research output: Contribution to journalArticlepeer-review

70 Scopus citations

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 languageEnglish (US)
Pages (from-to)297-330
Number of pages34
JournalAnnual Review of Materials Research
Volume47
DOIs
StatePublished - Jul 3 2017

Keywords

  • Apatite
  • Environmental barrier coating
  • Phase equilibria
  • Rare earth silicate
  • Rare earth zirconate
  • Thermal barrier coating

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