Effects of silicon carbide on the corrosion of metallic materials in molten LiF-NaF-KF salt

Highlights: • The compatibility between SiC and alloys in molten fluoride salt is a critical issue for molten salt reactors. • Effects of SiC on the corrosion of metallic materials in molten LiF-NaF-KF (FLiNaK) salt were investigated. • SiC in molten FLiNaK salt can induce the corrosion of metallic materials. • Corrosion products of SiC can react with Ni, Fe, and Cr to form silicides. • The continuous formation of silicides promotes the corrosion of metallic materials in FLiNaK salt. - Abstract: The effects of silicon carbide (SiC) on the corrosion behavior of metallic materials in molten LiF-NaF-KF (FLiNaK) salt were investigated. Results reveal that the corrosion products of SiC in molten FLiNaK salt can react with nickel-based alloy GH3535, Ni metal, 316L stainless steel, and Cr metal to form Ni₃₁Si₁₂, Ni₃Si, CrFe₈Si, and Cr₃Si, respectively. The formation of silicide enhances the corrosion of GH3535 alloy in molten FLiNaK salt. The depletion of Cr along grain boundaries in alloys can promote the diffusion of silicon into the alloys and increase the corrosion depth.