Na2SO4 + V2O5 Corrosion Behavior of BaNd2Ti3O10 for Thermal Barrier Coating Applications

Abstract

BaNd2Ti3O10 has been considered as a promising thermal barrier coating (TBC) candidate material, which reveals many advantages over the widely used TBC material of yttria partially stabilized zirconia, such as lower thermal conductivity, better high-temperature capability, and higher resistance to environmental deposits corrosion. In this study, the hot corrosion behavior of BaNd2Ti3O10 in Na2SO4 + V2O5 molten salt at 900 °C and 1000 °C is investigated. Exposed to the salt for 4 h at 900 °C, BaNd2Ti3O10 pellets had an obvious reaction with the salt, forming corrosion products of NdVO4, TiO2, and BaSO4, and the reaction layer was ~30 μm, beneath which no salt trace could be found. Prolonging the corrosion time to 20 h, the type of the corrosion products had no change. At an elevated corrosion temperature of 1000 °C for 4 h, the corrosion products were still NdVO4, TiO2, and BaSO4, but NdVO4 revealed a significant growth, which fully covered the pellet surface. The mechanisms by which the corrosion reaction between BaNd2Ti3O10 and the molten salt occurred were discussed.

Hot-Corrosion Behavior of Gd2O3–Yb2O3 Co-Doped YSZ Thermal Barrier Coatings in the Presence of V2O5 Molten Salt

“…Previous studies have shown that YSZ coatings have poor resistance to V 2 O 5 corrosion due to the V 2 O 3 stabilizer's tendency to react with V 2 O 5 , leading to the depletion of Y and the decomposition of the desirable t phase. The formation of the m phase due to V 2 O 5 attack could result in large stress and cracks in the coatings, which is detrimental for the thermal cycling performance of the coatings [22,24,25,39]. Despite being susceptible to V 2 O 5 attack, the GdYb-YSZ coating exhibits a certain degree of hot-corrosion resistance, as confirmed by the presence of the t phase on the corroded surface even after 10 h of corrosion at 1000 • C. This suggests that the coating could retain its phase stability and may still display some resistance to hot corrosion.…”

“…Coatings 2023, 13, 886 2 of 10 YSZ TBCs undergo severe degradation when operated in corrosive environments [22][23][24][25][26][27][28]. Impurities, such as vanadium, condense on the coating surface and melt at temperatures exceeding 700 • C, followed by their penetration into the coating.…”