Evolution of hot corrosion resistance of YSZ and Gd_2Zr_2O_7 thermal barrier coatings in Na_2SO_4+V_2O_5 at 1050℃

摘要

This paper compares the hot corrosion performance of yttria stabilized zirconia (YSZ) andrnGd_2Zr_2O_7 coatings in the presence of molten mixture of Na_2SO_4+V_2O_5 at 1050℃. These YSZrnand rare earth zirconate coatings were prepared by air plasma spray (APS). Chemical interactionrnis found to be the major corrosive mechanism for the deterioration of these coatings.rnCharacterizations using X-ray diffraction (XRD) and scanning electron microscope (SEM)rnindicate that in the case of YSZ, the reaction between NaVO_3 and Y_2O_3 produces YVO_4 andrnleads to the transformation of tetragonal ZrO_2 to mon℃linic ZrO_2. Molten salt is also found tornreact with Gd_2Zr_2O_7 to form GdVO_4. Comparing to YSZ, under a high temperature of 1050 ℃,rnGd_2Zr_2O_7 is more stable, both thermally and chemically, than YSZ, and exhibits a better hotrncorrosion resistance.