Ytterbium Disilicate/Monosilicate Multilayer Environmental Barrier Coatings: Influence of Atmospheric Plasma Spray Parameters on Composition and Microstructure

SiC/SiC ceramic matrix composites (SiCf/SiC CMCs) are regarded as the new materials for the hot-section components of aircraft gas turbine engines, since they have one-third of the density of metallic superalloys, a higher temperature capability, good mechanical strength, and excellent thermal shock...

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Bibliographic Details
Published in:Coatings (Basel) 2023-09, Vol.13 (9), p.1602
Main Authors: Di Iorio, Giulia, Paglia, Laura, Pedrizzetti, Giulia, Genova, Virgilio, Marra, Francesco, Bartuli, Cecilia, Pulci, Giovanni
Format: Article
Language:English
Subjects:
Aeronautics
Aircraft
Aircraft engines
Aviation
Ceramic fiber reinforced ceramics
Ceramic matrix composites
Ceramics
Coatings
Combustion
Composition
Corrosion and anti-corrosives
Corrosion resistance
Density
Deposition
Energy consumption
Gas turbine engines
Heat conductivity
High temperature
Microstructure
Multilayers
Oxidation
Parameters
Phase transitions
Polymorphism
Porosity
Protective coatings
Shock resistance
Silica
Silicon
Silicon carbide
Substrates
Superalloys
Thermal expansion
Thermal properties
Thermal resistance
Thermal shock
Thermodynamics
Turbines
Vapor resistance
Water vapor
Ytterbium
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Summary:SiC/SiC ceramic matrix composites (SiCf/SiC CMCs) are regarded as the new materials for the hot-section components of aircraft gas turbine engines, since they have one-third of the density of metallic superalloys, a higher temperature capability, good mechanical strength, and excellent thermal shock resistance. However, high-temperature water-vapor-rich combustion gases can induce severe surface recession phenomena in SiC/SiC leading to component failure. For this reason, it is necessary to design protective coatings, i.e., environmental barrier coatings (EBCs), able to protect the SiC/SiC surface in combustion environments. In the present work, ytterbium monosilicate (Yb2SiO5), stable when exposed to water vapor at high temperatures, and ytterbium disilicate (Yb2Si2O7), characterized by a thermal expansion coefficient closer to that of the substrate, were selected for a multilayer EBC system. EBCs were processed using the atmospheric plasma spray (APS) technique. A set of deposition parameters were tested, varying the power of the torch, and the composition and microstructure of the deposited coatings were studied in terms of porosity, crack density, and post-deposition phase retention by performing SEM, EDS, and XRD analysis. The results allow for the definition of the influence of deposition parameters on the final properties of multilayer EBC coatings.
ISSN:2079-6412
2079-6412
DOI:10.3390/coatings13091602