Comparison of corrosion behavior of bare and hot-dip coated EUROFER steel in flowing Pb–17Li

Abstract

In future fusion systems reduced activation ferritic–martensitic steels (RAFM) are considered as structural materials which are in contact with the cooling and breeding medium Pb–17Li. The most promising alloy to fit the requirements is the reference steel EUROFER 97. Due to the contact with Pb–17Li, the corrosion behavior will be of importance for the application, in addition to mechanical and neutronic properties. Corrosion testing of EUROFER 97 was performed at 480 and 550 °C at flow rates of 0.3 m/s. Both test series showed a homogeneous corrosion attack by dissolution mechanism, however, with a dramatic increase in rate from 90 to 700 μm/a. At least the 550 °C tests indicate that corrosion may cause a serious problem due to the high risk of blockage by precipitation. Thus corrosion resistant Al-coatings were developed and tested in Pb–17Li. The performed tests showed that the degree of protection depends strongly on properly reacted FeAl-scales.