Chemical compatibility between lithium-based oxide ceramics and stainless steels

The compatibility behavior of Li-based oxide ceramics with stainless steels has been investigated between 500 and 800°C for annealing times of 125 and 500 h. The materials examined include Li ₂O, LiAlO ₂, Li ₂SiO ₃, Li ₄SiO ₄ and Li ₂ZrO ₃ on one side and one martensitic-ferritic and two austenitic steels on the other side. The breeder materials contained various amounts of H ₂O or NiO as initial contamination. Below 0.2 mol% H ₂O per 1 mol Li ₂O no chemical interaction took place between the oxide ceramics and the cladding materials. At higher H ₂O contents, Li ₂O caused the strongest cladding attack followed by Li ₄ SiO ₄, Li ₂SiO ₃, LiAlO ₂ and Li ₂ZrO ₃. The extent of reaction of the stainless steels investigated is comparable up to 700°C. The presence or formation of LiOH is not necessary for the chemical interactions, however, a sufficiently high oxygen potential is needed in the system to oxidize the cladding. The resulting cladding oxides then can interact with the breeder materials.