Irradiation effects on microstructure, mechanical properties, and lead-bismuth eutectic corrosion resistance of alumina coating

A comprehensive evaluation including microstructure, mechanical properties, and lead-bismuth eutectic corrosion resistance of amorphous alumina coatings after different doses of Au2+ irradiation was done using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, nanoindentation, SRIM software, and eRDF Analyzer. The results showed that irradiation decreased the surface roughness and induced crystallization in the middle of the coating and at the interface. The middle crystallization might be dominated by electron energy loss, while the interface had to consider the influence of defects and doping. The regions that remain amorphous after irradiation also showed differences in topological bonding and nanovoid. The changes in topological bonding hardened the coating, while the nanovoids generated by atomic rearrangement weakened the mechanical properties. The irradiation deteriorated the lead-bismuth corrosion resistance of the coating due to the void formation and alumina phase transformation. In addition, enhanced temperature sensitivity at the interface was observed after irradiation.