Evolution of hot corrosion resistance of YSZ, Gd 2Zr 2O 7, and Gd 2Zr 2O 7+YSZ composite thermal barrier coatings in Na 2SO 4+V 2O 5 at 1050°C

Document Type

Article

Publication Date

7-1-2012

Abstract

This paper compares the hot corrosion performance of yttria stabilized zirconia (YSZ), Gd 2Zr 2O 7, and YSZ+Gd 2Zr 2O 7 composite coatings in the presence of molten mixture of Na 2SO 4+V 2O 5 at 1050°C. These YSZ and rare earth zirconate coatings were prepared by atmospheric plasma spray (APS). Chemical interaction is found to be the major corrosive mechanism for the deterioration of these coatings. Characterizations using X-ray diffraction (XRD) and scanning electron microscope (SEM) indicate that in the case of YSZ, the reaction between NaVO 3 and Y 2O 3 produces YVO 4 and leads to the transformation of tetragonal ZrO 2 to monoclinic ZrO 2. For the Gd 2Zr 2O 7+YSZ composite coating, by the formation of GdVO 4, the amount of YVO 4 formed on the YSZ+Gd 2Zr 2O 7 composite coating is significantly reduced. Molten salt also reacts with Gd 2Zr 2O 7 to form GdVO 4. Under a temperature of 1050°C, Gd 2Zr 2O 7 based coatings are more stable, both thermally and chemically, than YSZ, and exhibit a better hot corrosion resistance. © 2012 Elsevier Ltd.

Publication Source (Journal or Book title)

Journal of the European Ceramic Society

First Page

1635

Last Page

1642

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