**4. Conclusions**

Hot corrosion behavior of BaLa2Ti3O10 thermal barrier oxide in V2O5 and Na2SO4 + V2O5 molten salts at 900 ◦C were investigated. After 4 h corrosion tests, a reaction layer formed on the sample surface, the phase constitution and structure of which depend on the type of the molten salt. In V2O5 molten salt, the layer consisted of LaVO4, TiO2 and Ba3V4O13, with a dense structure and having a thickness of 8–10 μm. While in Na2SO4 + V2O5 molten salt, it contained LaVO4, TiO2 and BaSO4, mainly exhibiting a porous structure, which could be attributed to the participation of SO3 gas during the formation process of the reaction layer. At the bottom of the porous layer, there existed a dense, thin band, consisting of Ba3V4O13, LaVO4 and TiO2. Beneath the dense layer or the band, no molten salt trace existed in the samples, indicating that further infiltration of the molten salts has been arrested. Based on this study, it could be concluded that though BaLa2Ti3O10 ceramic as TBC candidate has good resistance in both salts, it shows better resistance to V2O5salt corrosion.

**Author Contributions:** Conceptualization, J.Z.; Methodology, H.L. and J.C.; Validation, H.L. and J.Z.; Formal Analysis, H.L. and J.Z.; Investigation, H.L.; Data Curation, H.L.; Writing—Original Draft Preparation, H.L.; Writing—Review and Editing, J.C. and J.Z.; Supervision, J.Z.

**Funding:** This research was funded by National Key Research and Development Program (No. 2017YFB1102800), National Natural Science Foundation of China (Nos. 11722219, 11432011, 11620101002).

**Conflicts of Interest:** The authors declare no conflict of interest.
