NTRS - NASA Technical Reports Server

Back to Results
Degradation of a two-layer thermal barrier coating under thermal cyclingA two-layer plasma-sprayed thermal barrier coating on a directionally solidified nickel-base eutectic alloy substrate was characterized prior to and after thermal cycling to 1095 C in an accelerated furnace test. The coating was comprised of an inner layer of Ni-16.4Cr-5.1Al-0.15Y (wt%) bond coat and an outer layer of ZrO2-7.9Y2O3 (wt%) thermal barrier. Characterization of the bond coat revealed that substantial amounts of yttrium and aluminum were oxidized during plasma-spraying in air. The oxidation of these elements reduced the protective capacity of the bond coat so that, on thermal exposure, severe degradation of the bond coat resulted and large amounts of nickel oxide formed. This nickel oxide was demonstrated to grow outward into the thermal barrier, which appears to have increased the stresses in the thermal barrier and contributed to its failure near the thermal barrier-bond coat interface.
Document ID
Document Type
Reprint (Version printed in journal)
Maier, R. D.
(Case Western Reserve University Cleveland, Ohio, United States)
Scheuermann, C. M.
(Case Western Reserve Univ. Cleveland, OH, United States)
Andrews, C. W.
(NASA Lewis Research Center Cleveland, Ohio, United States)
Date Acquired
August 11, 2013
Publication Date
May 1, 1981
Subject Category
Chemistry And Materials (General)
Report/Patent Number
Distribution Limits
No Preview Available