Influence of Cr content on hot corrosion and a special tube sealing test of single crystal nickel base superalloy

Abstract An investigation of hot corrosion was carried out on three single crystal Ni-based superalloys with different Cr contents pre-coated with salt at 900 ℃. Cr can change the hot corrosion performance of alloys by changing the composition of the oxide layer during the hot corrosion process in the open system. At the same time, a "satellite" shaped distribution of internal oxides and sulphides was found. Further, the tube sealing experiment was used to verify the phenomenon occurred inside alloys and in low oxygen condition. A reaction between matrix and molten salt was proposed based on thermodynamics and microscopic observation.