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Sintering and Creep Behavior of Plasma-Sprayed Zirconia and Hafnia Based Thermal Barrier CoatingsThe sintering and creep of plasma-sprayed ceramic thermal barrier coatings under high temperature conditions are complex phenomena. Changes in thermomechanical and thermophysical properties and in the stress response of these coating systems as a result of the sintering and creep processes are detrimental to coating thermal fatigue resistance and performance. In this paper, the sintering characteristics of ZrO2-8wt%y2O3, ZrO2-25wt%CeO2-2.5wt%Y2O3, ZrO2-6w%NiO- 9wt%Y2O3, ZrO2-6wt%Sc2O3-2wt%y2O3 and HfO2-27wt%y2O3 coating materials were investigated using dilatometry. It was found that the HfO2-Y2O3 and baseline ZrO2-Y2O3 exhibited the best sintering resistance, while the NiO-doped ZrO2-Y2O3 showed the highest shrinkage strain rates during the tests. Higher shrinkage strain rates of the coating materials were also observed when the specimens were tested in Ar+5%H2 as compared to in air. This phenomenon was attributed to an enhanced metal cation interstitial diffusion mechanism under the reducing conditions. It is proposed that increased chemical stability of coating materials will improve the material sintering resistance.
Document ID
19980211578
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Zhu, Dongming (Ohio Aerospace Inst. Cleveland, OH United States)
Miller, Robert A. (NASA Lewis Research Center Cleveland, OH United States)
Date Acquired
September 6, 2013
Publication Date
July 1, 1998
Subject Category
Nonmetallic Materials
Report/Patent Number
E-11239
NAS 1.15:208406
NASA/TM-1998-208406
Meeting Information
Meeting: Metallurgical Coatings and Thin Films
Location: San Diego, CA
Country: United States
Start Date: April 27, 1998
End Date: May 1, 1998
Sponsors: American Vacuum Society
Funding Number(s)
PROJECT: RTOP 505-23-2U
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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