Corrosion resistance in Pb-Bi alloy of 15-15Ti steel coated with Al2O3/SiC bilayer thin films by magnetron sputtering

Abstract

15-15Ti austenite stainless steel has better corrosive resistance compared with 316L steel, and it has better mechanical and processing properties than T91 steel. So 15-15Ti steel has been chosen as one of cladding materials for the lead-cooled fast reactor. The Al2O3/SiC bilayer thin films were prepared on 15-15Ti specimens by magnetron sputtering technology for further improving its corrosive resistance and radiation resistance. The structures and morphologies of the thin films were observed with XRD, FESEM and AFM. The results showed that the Al2O3/SiC bilayer films were crystalline after being annealed at 900°C. The root mean square roughness of the film was 3.73nm and the average particle diameter was 347nm. The corrosion experiment for 15-15Ti specimens with and without Al2O3/SiC bilayer films was carried out in the Pb-Bi alloy at 500°C for 500h. After the continuous corrosion experiment, there was no Fe3O4 oxidized layer on 15-15Ti specimen coated with Al2O3/SiC bilayer films compared with the uncoated 15-15Ti specimen. So the corrosion resistance of 15-15Ti specimen coated with Al2O3/SiC bilayer thin films in Pb-Bi alloy is obviously improved.