Na2SO4 and V2O5 molten salts corrosion resistance of plasma-sprayed nanostructured ceria and yttria co-stabilized zirconia thermal barrier coatings

The hot corrosion behavior of plasma-sprayed ceria yttria co-stabilized zirconia (CYSZ) nanostructured coatings (with the chemical composition of ZrO2-2.5 wt%Y2O3-25 wt%CeO2) was studied in the presence of 45 wt% Na2SO4+ 55 wt%V2O5 as the corrosive molten salts, for 6, 12, 18, 30, 72, 156, and 300 h at 1000 degrees C. As the hot corrosion products, YVO4, CeVO4 and Ce0.75O2Zr0.25 crystals were formed by leaching Y2O3 and CeO2 from CYSZ due to the reaction between the corrosive salts and (Y2O3, CeO2) stabilizers of zirconia. The CYSZ nanostructured coating showed remarkable resistance to degradation throughout the hot corrosion test, irrespective of an additional reaction with the corrosive salts. A mechanism was suggested based on the prohibition of the further diffusion of molten salts into the deeper layers of the coating, via diffusional resistance in the nanoporous media. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.