Corrosion behavior of CMAS coupling NaVO3 salt for plasma-sprayed Al2O3/YSZ thermal barrier coatings

Cost-effective of 20 wt.% Al2O3-7YSZ TBCs were designed and achieved desirable corrosion resistance against CMAS and CMAS + NaVO3 salt (abbreviated as CN). NaVO3 additions decreased the melting point, viscosity and improved the wettability of CMAS deposits, thereby promoting globular zirconia formation and interior infiltration in the TBCs. Furthermore, compared to conventional 7YSZ TBCs, the Al2O3 addition effectively mitigated CMAS- and CN-induced corrosion by limiting the initial melt spreading and subsequent infiltration. This was because Al2O3 dissolution into the CMAS/CN melt modified its thermophysical properties, inducing crystallization and dense layering of the anorthite interfacial reaction product.