Investigation of a Tin-lithium Eutectic as a Liquid Plasma-facing Material

Heather Sandefur, University of Illinois at Urbana-Champaign

Sn-Li is a low melting-point eutectic that can withstand the projected heat load of a magnetic confinement fusion device. The bulk segregation of lithium has been observed when the liquid-phase material is exposed in a plasma environment. This surface segregation prevents the high-Z tin from entering the plasma and results in a lithium film that can act as a low-recycling wall. In addition, Sn-Li is less reactive than pure lithium, which can pose a number of safety threats during operation. While the eutectic is of considerable interest to the PMI community, little data has been collected on its surface chemistry in a plasma environment. In order to expand the existing body of knowledge in this area, samples of an 80/20 Sn-Li eutectic were analyzed in both the solid and liquid phases in order to assess the surface composition and degree of lithium segregation in the liquid phase. The eutectic's hydrogen retention and corrosive nature also were investigated.

Abstract Author(s): H. Sandefur, D. Ruzic, R. Kolasinski, D. Buchenauer