Microstructure, mechanical properties and lead-bismuth eutectic corrosion behavior of FeCrAlTiNb high-entropy alloy coatings

The FeCrAlTiNb high-entropy alloy coatings are fabricated by magnetron sputtering method to prevent the lead-bismuth eutectic (LBE) corrosion of structural components used in lead-cooled fast reactors, and their microstructure, mechanical properties and LBE corrosion behavior are investigated systematically. The coatings exhibit significantly improved hardness, creep and wear resistance compared with ferritic/martensitic (F/M) steel. Moreover, the coatings show promising LBE corrosion resistance with parabolic oxidation rate constant 3–5 orders of magnitude lower than other candidate steels, which is ascribed to their intrinsic amorphous structure and the formation of protective FeCr2O4/Cr2O3 double-layer. Finally, the growth of oxide scale is discussed in detail.