The corrosion behavior of structural materials in liquid lead alloys like Pb-17Li as a liquid tritium
breeder for future Fusion Reactors and Pb-55Bi (LBE) as an envisaged spallation target and/or coolant
for Accelerator Driven Systems (ADS) and lead-cooled Gen IV reactors is a key issue in the roadmap
for developing of new energy systems within the next decades. Ferritic-martensitic steels of the 8-10
wt.-% Cr type are considered as structural materials for the use in liquid Pb-17Li at temperatures up to
550°C. Due to the specific physical chemistry of Pb-17Li, dissolution corrosion is the major corrosion
mechanism of iron-based alloys. No oxide formation on steel surfaces can occur due to the very low
oxygen potential. Therefore, coatings could/must be applied to minimize corrosion effects at medium
(500°C) and higher operational temperatures (650°C) of advanced fusion blanket concepts. Ferriticmartensitic
and austenitic CrNi-steels are considered as potential structural materials for ADS and Gen
IV reactor applications. Nevertheless, the high nickel solubility in LBE limits the use of unprotected
austenitic steels to temperatures of about 550°C. Because of the much higher oxygen potential in LBE,
a totally different strategy of minimizing corrosion must be adopted. By using active oxygen control, a
desired oxygen activity will be adjusted in the liquid metal via gas phase equilibrium which enables the
controlled formation of oxide layers on the steel surfaces. These in-situ formed oxides can act as
corrosion barriers and make the use of high-nickel alloys possible, even at temperatures of around
600°C.