Corrosion behavior of Al–O coating in oxygen-saturated lead-bismuth eutectic at 550 °C

The amorphous Al–O coating with a thickness of approximately 6 μm was prepared on 316 L stainless steel using multi-arc ion plating technology to investigate the corrosion resistance of the coating in static lead–bismuth eutectic at 550 °C. The corrosion time ranged from 100 to 1000 h. The samples were characterized using different instruments, and the results showed that the Al–O coating had poor wettability and could effectively protect the substrate material from lead–bismuth corrosion in a static lead–bismuth eutectic. However, during the long-term high-temperature corrosion process, the coating changes from an amorphous phase to a polycrystalline doped structure, resulting in pores on the coating. Further, elemental interdiffusion was identified between the substrate and coating, indicating risk of coating failure.