Corrosion behavior of pressureless sintered SiC in molten LiF-NaF-KF salt: Role of metallic impurities in the salt

The corrosion of pressureless sintered silicon carbide (SiC) in molten LiF-NaF-KF (FLiNaK) salts at 700 ℃ was investigated. Results indicate that the impurities in the molten FLiNaK salt play an important role in the corrosion of SiC. The pressureless sintered SiC occurred local corrosion along the grain boundaries and the intersections of grains in the FLiNaK salt with more metallic impurities. The corrosion results in the formation of carbon, Fe 3 Si, and the dissolvable Si-containing products. The reaction between SiC and metallic impurities in the salt drives the corrosion of SiC by enhancing the outward diffusion of element Si. • The corrosion of pressureless sintered SiC in molten LiF-NaF-KF (FLiNaK) salt was investigated. • Metallic impurities in molten FLiNaK salt drive the corrosion of SiC. • Reactions between SiC and metallic impurities in molten FLiNaK salt drive the outward diffusion of element Si in SiC. • More impurities in molten FLiNaK salt increase the diffusion coefficient of element Si in SiC.