Corrosion resistance of ceramic candidates for tritium permeation barriers exposed to molten lithium

Abstract

For the design of liquid lithium first wall in future fusion reactor, chemical compatibility between the tritium permeation barrier (TPB) and liquid lithium should be studied preferentially. The redox reaction is studied from the perspective of thermodynamics at different temperature, which indicates that metallic nitrides and rare earth oxides are predictable to provide higher stability in lithium corrosion situation. Then static compatibilities of Al2O3, AlN, SiC and Er2O3 ceramics with liquid lithium are tested. The surface analysis of TPB and lithium droplets shows that Al2O3 ceramic could react with molten Li, though it is considered as the preferred candidate of TPB for its easy fabrication, low cost, and self-repair ability. However, the other three ceramics did not show any reduction product peak, indicating the high stability with liquid lithium. These results provide meaningful compatibility with liquid Li and valuable reference in engineering design of structural and TPB materials for future fusion device.