Abstract: Background: Recently, the molten salt reactor (MSR), a generation IV fission reactor candidate, has drawn much attention because of its intrinsic safety. However, the harsh service environment of the MSR, especially the corrosion environment, raises many challenges in terms of applying structural materials, such as intergranular cracking and embrittlement. MAX phases materials are promising structural materials that can be used in MSRs. However, the corrosion behaviour of these materials in molten LiF-NaF-KF (FLiNaK) is yet to be evaluated. Purpose: The present work is a preliminary investigation of the corrosion behaviour of MAX phase materials in molten fluoride salts and aims to understand the corrosion mechanism of MAX phases to enable their application in next generation MSR. Methods: We choose two common MAX phases: Ti3SiC2 and Ti3AlC2 as experiment subject. The corrosion tests were performed at 850 oC for 144 h in airtight graphite crucibles under an argon cover gas. Results & Conclusion: The corrosion of these two MAX phases in molten FLiNaK salt mainly showed as the corrosion of element A and then left us mostly cubic TiCx. The difference was that Ti3AlC2 lost Al entirely, however, the loss of Si in Ti3SiC2 occurred only 150 μm depth below the surface. The weight loss data showed that Ti3SiC2 had a much better corrosion resistance than Ti3AlC2.

Key words: MAX phases, Molten salts, Corrosion