Characterization of liquid lithium corrosion for fusion reactor materials

As fusion devices push to become more compact, economical, and high performance, one potentially enabling technology is liquid lithium-based plasma-facing components (LL-PFCs). In our work, a new experimental setup was created to investigate the corrosion of seven fusion-relevant materials at 300 °C for 2000 h (≈3 months). A suite of surface, chemical, and imaging diagnostics were performed to determine the compatibility of the materials with liquid lithium. The seven materials were: tungsten, molybdenum, 304 stainless steel, 316 stainless steel, Inconel 625, silver-plated 316 stainless steel, and aluminum bronze. These materials can be roughly split into three categories: 1) refractory metals traditionally used as solid PFCs, 2) structural materials used for supports, and 3) bolt materials used for securing structures. Each material was submerged in a liquid-lithium filled canister and analyzed with a suite of chemical and imaging techniques. After investigation, it was determined that all the refractory and structural materials had a corrosion resistance of <1.0 µm/yr which will likely be an acceptable rate for future devices. However, both the silver-plated 316 stainless steel and aluminum bronze showed significant degradation over the course of the testing.