The corrosion behavior of AlO coatings exposed to lead-bismuth eutectic at 350 °C–650 °C

The service life of heat-resistant materials is crucial for safe operation in the nuclear industries. Usually, it is necessary to coat the surface of the materials with a heat-resistant coating. In this paper, XPS, EDS, XRD, SEM, and TEM characterization techniques were used to study the corrosion behavior of continuous high-power magnetron sputtered (C-HPMS) AlO x coatings with different oxygen contents exposed to lead-bismuth eutectic (LBE) at 350 °C to 650 °C for 2000 hours was investigated. Stable oxide γ-Al 2 O 3 and Al 2 PbO 4 were formed at 350 °C-550 °C, which will increase the hardness and Young's modulus of the coating, and the dense layer Al 2 PbO 4 and AlO x layer inhibited the outward diffusion of iron and the inward diffusion of O. At 650 °C, the internal Fe will be oxidized to Fe 3 O 4 , resulting in corrosion resistance failure. Therefore, the AlO x coating at the oxygen injection rate of 120 sccm (O/Al=1.5) is best, which can resist corrosion at T<550 °C. Finally, the corrosion mechanism of the AlO x coating in liquid LBE is discussed, providing a research idea for developing high-performance anti-corrosion coatings.