Investigation on hot corrosion behaviour of Aluminum Rare Earth coating in mixed sulphate at 1050 °C

Highlights: • The hot corrosion behaviour at more than 1000 °C of the BC of TBC was investigated. • The Al-R.E. coating was chosen as an object due to its good representativeness. • It was showed that the corrosion resistance in mixed sulphate at 1050 °C is poor. • Molten salt at more than 1000 °C has stronger dissolution capacity to oxide scale. • Molten salt at more than 1000 °C will chemically attack the coating surface. - Abstract: In this paper, hot corrosion behaviour of the Aluminum Rare Earth coating in mixed sulphate at 1050 °C was investigated. Results demonstrated that during the first 20 h of hot corrosion, it was difficult to form a protective oxide scale on the coating surface, and the antioxidant element Al was consumed significantly. Meanwhile, it took more than 50 h to reach to the steady-state oxidation which lasted only for 10 h. It is clearly demonstrated that, the molten salt at temperature more than 1000 °C, not only acts as hot corrosion media, but also will chemically attack the coating surface.