Europium-driven Alloy 709 corrosion in static FLiNaK molten salt at 700 °C

The effect of europium-driven corrosion behavior of Alloy 709 in FLiNaK molten salt was investigated by static immersion tests at 700 degrees C. It was found that the corrosion of Alloy 709 increased after the addition of EuF3, even though the standard reduction potential of Eu(III)/Eu(II) was negative than those of Fe(II)/Fe, Ni(II)/Ni and Cr (II)/Cr. The presence of Eu(III) led to deeper corrosion attack layers and more pits on the steel surface in comparison with corrosion in blank FLiNaK. However, the addition of Eu(III) seemed to have a role in reducing surface cracking that was explored in corrosion by blank FLiNaK, which depended on Eu(III) concentration.