Lead-bismuth eutectic (LBE) corrosion behavior of AlTiN coatings at 550 and 600 °C

High performance LBE corrosion-resistant- materials have great potential for application in the future 4th generation nuclear reactor. In this paper, LBE corrosion behavior of AlTiN coating was carefully evaluated at typical working temperatures of nuclear reactor. The coating was synthesized by cathodic arc ion plating on 316L stainless steel (SS) substrates and subjected to LBE corrosion at 550 and 600 degrees C for 500 h. We used SEM, AFM, EDS, XRD and Raman to carefully characterize the microstructure evolutions of the coating. The results show that the coating could effectively enhance the LBE corrosion resistance of the SS at both 550 and 600 degrees C. The excellent corrosion resistance performance could be attributed to the in-situ formation of a dense oxide layer on the coating surface, which mainly consists of TiO2 (Anatase and Rutile) and gamma-Al2O3 phases with slow growth rate and stable structure. In addition, the dense oxide layer of the coating exhibits a lower wettability to liquid LBE metal because of the nano-scale surface morphology, which further enhance the corrosion resistance. While for bare SS substrate, porous oxide was formed after LBE corrosion. These results suggested that AlTiN coating is a promising material for improving the LBE corrosion-resistant performance of the component used in the future nuclear reactor. (C) 2020 Elsevier B.V. All rights reserved.