Origin of darkening in 8 wt% yttria-zirconia plasma-sprayed thermal barrier coatings

Journal Article · Fri Feb 01 00:00:00 EST 1991 · Journal of the American Ceramic Society; (United States)

DOI:https://doi.org/10.1111/j.1151-2916.1991.tb06891.x· OSTI ID:5057383

Ingo, G M ^[1]

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1. Inst. di Teoria e Struttura Elettronica del CNR, CP 10, 00016 Monterotondo Stazione, Roma (IT)

This paper reports on the origins of darkening of 8 wt% Y{sub 2}O{sub 3}-ZrO{sub 2} air plasma-sprayed (APS) and low-pressure plasma-sprayed (LPPS) thermal barrier coatings (TBC) studied using x-ray photoelectron spectroscopy. The change of valence states of zirconium, due to the reduction of ZrO{sub 2} to Zr{sub 2}O{sub 3}, was responsible for darkening of TBC. Quantification of Zr{sup 3+} oxide was related both to the black color of TBC and to the spraying technologies and parameters. Furthermore, impurity (Fe, Al, Si, and Na) segregation and exsolution phenomena were monitored as a function of the air thermal treatment (up to 1473 K) and it was demonstrated not to be the origin of darkening.

• OSTI ID: 5057383
• Journal Information: Journal of the American Ceramic Society; (United States), Vol. 74:2; ISSN 0002-7820
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
YTTRIUM OXIDES
COLOR
PHYSICAL PROPERTIES
ZIRCONIUM OXIDES
PLASMA ARC SPRAYING
SPRAY COATING
THERMAL BARRIERS
VALENCE
X-RAY SPECTROSCOPY
CHALCOGENIDES
DEPOSITION
OPTICAL PROPERTIES
ORGANOLEPTIC PROPERTIES
OXIDES
OXYGEN COMPOUNDS
SPECTROSCOPY
SURFACE COATING
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
ZIRCONIUM COMPOUNDS
360204* - Ceramics
Cermets
& Refractories- Physical Properties