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Revisiting the Birth of 7YSZ Thermal Barrier Coatings: Steve StecuraThermal barrier coatings are widely used in all turbine engines, typically using a 7 wt% Y2O3-ZrO2 formulation. Extensive research and development over many decades have refined the processing and structure of these coatings for increased durability and reliability. New compositions demonstrate some unique advantages and are gaining in application. However, the "7YSZ" formulation predominates and is still in widespread use. This special composition has been universally found to produce nanoscale precipitates of metastable t' tetragonal phase, giving rise to a unique toughening mechanism via ferro-elastic switching under stress. This note recalls the original study that identified superior properties of 6 to 8 wt% YSZ plasma sprayed thermal barrier coatings, published in 1978. The impact of this discovery, arguably, continues in some form to this day. At one point, 7YSZ thermal barrier coatings were used in every new aircraft and ground power turbine engine produced worldwide. It is a tribute to its inventor, Dr. Stephan J. Stecura, NASA retiree.
Document ID
Document Type
Technical Memorandum (TM)
Smialek, James L.
(NASA Glenn Research Center Cleveland, OH, United States)
Miller, Robert A.
(Vantage Partners, LLC Cleveland, OH, United States)
Date Acquired
March 17, 2017
Publication Date
March 1, 2017
Subject Category
Nonmetallic Materials
Report/Patent Number
Funding Number(s)
WBS: WBS 109492.
Distribution Limits
Public Use Permitted.
turbine blades
thermal barrier coatings
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