Influence of hydrogen on the corrosion behavior of stainless steels in lithium

Corrosion behavior of several stainless steels in lithium and lithium with 0.05%H has been examined. Corrosion tests were performed under static conditions at 600 and 700 C in the austenitic stainless steel of the type AISI 304 containers. Intensive formation of sigma-phase of the composition Fe50Cr43Mo3Ni4 on the surface of austenitic stainless steels of the type AISI 316 at 700 degrees C for 1000 h was established as a result of isothermal mass transfer. Addition of 0.05%H in the form of LiH to lithium resulted in an increase in the quantity of the a-phase. After corrosion tests of ferritic/martensitic steel in lithium at 700 degrees C for 1000 h the formation of the gamma-phase was observed. In Li + 0.05%H besides the gamma-phase was also formed the a-phase. The features of decarburization of investigated stainless steels were examined using the direct method of activation autoradiography on carbon. Addition of 0.05%H in lithium significantly decreased the carbon content in the decarburization zone of austenitic stainless steel Fe-18Cr-15Ni-0.15C-0.23B without a noticeable change in the thickness of the decarburization zone. Decarburization of ferritic/martensitic stainless steel was less than of austenitic stainless steel using the same corrosion tests. 2007 Elsevier B.V. All rights reserved.