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Key Durability Issues with Mullite-Based Environmental Barrier Coatings for Si-Based CeramicsPlasma-sprayed mullite (3Al2O3.2SiO2) and mullite/yttria-stabilized-zirconia (YSZ) dual layer coatings have been developed to protect silicon -based ceramics from environmental attack. Mullite-based coating systems show excellent durability in air. However, in combustion environments, corrosive species such as molten salt or water vapor penetrate through cracks in the coating and attack the Si-based ceramics along the interface. Thus the modification of the coating system for enhanced crack-resistance is necessary for long-term durability in combustion environments. Other key durability issues include interfacial contamination and coating/substrate bonding. Interfacial contamination leads to enhanced oxidation and interfacial pore formation, while a weak coating/substrate bonding leads to rapid attack of the interface by corrosive species, both of which can cause a premature failure of the coating. Interfacial contamination can be minimized by limiting impurities in coating and substrate materials. The interface may be modified to improve the coating/substrate bond.
Document ID
20010016778
Document Type
Reprint (Version printed in journal)
Authors
Lee, Kang N. (Cleveland State Univ. Cleveland, OH United States)
Date Acquired
August 20, 2013
Publication Date
October 1, 2000
Publication Information
Publication: Transactions of the ASME
Volume: 122
Subject Category
Nonmetallic Materials
Distribution Limits
Public
Copyright
Other