Corrosion of thermal barrier coatings by vanadium and sulfur compounds

Degradation of plasma-sprayed yttria-stabilized zirconia coatings via ingress of vanadium oxide

“…For example, substantial chemical attack occurs when vanadiumcontaining melts contact YSZ. This attack can remove the affected layer of the coating, or simply replace the original tetragonal zirconia phase with the less desirable reaction products 7,8 like YVO 4 and a m-ZrO 2 . 9 Even if the infiltrant does not react extensively with the coating, its presence in the near-surface layer can cause failure in the coating.…”

Hot-corrosion behaviors of overlay-clad yttria-stabilized zirconia coatings in contact with vanadate–sulfate salts

“…at the temperature of 600-1000 • C. [7][8][9][10][11] Interconnected pores and microcrack networks in the plasma-sprayed YSZ coatings reduce thermal conductivity and also affect mechanical properties of the coatings. However, these pores and microcracks inevitably provide infiltration paths for molten salts to attack the coatings.…”

Investigation of reactions between vanadium oxide and plasma-sprayed yttria-stabilized zirconia coatings

“…[14][15][16][17][18] Further complicating the analysis is that Na 2 SO 4 is often combined with V 2 O 5 to produce the corrosive species, and this combination is less reactive with the coating. [13][14][15][16] Published accounts of reactions above ∼750 • C describe yttria, which is basic with respect to the acidic V 2 O 5 , being sequestered or leached from the t -ZrO 2 by the corrosive agent to form YVO 4 . [5][6][7] According to these reports, removal of the yttria stabilizer from the zirconia leaves unstabilized zirconia (i.e.…”