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

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 degrees 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 mu m/a. At least the 550 degrees 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. (c) 2007 Elsevier B.V. All rights reserved.