Exploring the Application Potential of FexAl/Al2O3 Coatings for Lead-Cooled Fast Reactors

FexAl/Al2O3 (x ≈ 3, 2, 1, 0.5) coatings are prepared on steel to investigate their potential for application in lead-cooled fast reactors through mechanical tests and corrosion tests. The results show that the increase of Al content in the transition layer changes its structure (ordered transition from α - Fe to B2), which enhances the hardness, brittleness, and wear properties of the coating, but decreases the bonding of the coating to the substrate (tough-brittle transition). In addition, FexAl/Al2O3 coatings have excellent resistance to lead-bismuth eutectic. The Al content in the transition layer has an almost negligible effect on the lead-bismuth eutectic corrosion properties but increases the segregation of the Al element in the substrate. The segregations are mainly hexagonal and cubic AlN, and their generation mechanisms are elucidated in detail.