Hot-corrosion resistance and phase stability of Yb2O3–Gd2O3–Y2O3 costabilized zirconia-based thermal barrier coatings against Na2SO4 + V2O5 molten salts

• Published in: Surface & coatings technology 2020-10, Vol.400, p.126197, Article 126197
• Main Authors: Song, Dowon, Song, Taeseup, Paik, Ungyu, Lyu, Guanlin, Kim, Junseong, Yang, SeungCheol, Jung, Yeon-Gil
• Format: Article
• Language: English
• Subjects: Corrosion; Corrosion mechanisms; Corrosion resistance; Destabilization; Electronic structure; Gadolinium oxides; High temperature; Hot corrosion; Lewis acid; Molten salts; Phase stability; Rare-earth element; Reaction mechanism; Sodium sulfate; Thermal barrier coatings; Thermal barrier coatings (TBC); Vanadium pentoxide; Yttrium oxide; Zirconium dioxide
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2020.126197

The hot corrosion behavior of plasma-sprayed Yb2O3-Gd2O3-Y2O3 co-doped ZrO2 (YGYZ) coating against Na2SO4 + V2O5 molten salts was investigated and its detailed hot corrosion mechanism was suggested. The chemical reactivity order between the stabilizers was proposed based on the electronic structure and Lewis acid-base mechanism. After hot corrosion, the YGYZ coating exhibited the maintenance of tetragonality ratio and relatively lower extent of destabilization less than 40% of conventional yttria-stabilized ZrO2 coating. These great chemical and phase stabilities imply that YGYZ is promising candidate for high-temperature thermal barrier material. •Hot corrosion behavior of Yb2O3-Gd2O3-Y2O3 co-doped zirconia (YGYZ) was investigated.•YGYZ exhibit great chemical and phase stability, proved by the higher tetragonality and low extent of degradation.•The chemical reactivity order is proposed with the illustration of electronic structure and Lewis acid-base mechanism.