In lead-bismuth fast reactors (LFRs), ferritic/martensitic (F/M) steels, known as main structural materials, face severe corrosion at high-temperature liquid lead-bismuth eutectic (LBE). In this study, FeCrAl coatings with varying Al contents (4.9-14.1 wt.%) were deposited on F/M steel by using magnetron sputtering. The results indicate that FeCrAl coating with low Al content (4.9 wt.%) exhibits severe corrosion characteristics, forming porous and non-protective oxide scales similar to the substrate, which leads to significant LBE penetration and coating degradation. In contrast, the coating with high Al content (14.1 wt.%) demonstrates excellent protection, attributed to the synergistic formation of extremely dense, continuous inner Al 2 O 3 barrier layer and compact Fe-Cr-Al spinel layers with different crystal types (columnar crystals and equiaxed nanocrystals). This multilayered oxide architecture effectively inhibits inward oxygen diffusion and outward cation migration, providing good corrosion resistance in LBE environments at 550 °C.
Li et al. (Sun,) studied this question.