Fusion Science and Technology / Volume 47 / Number 4 / May 2005 / Pages 851-855
Technical Paper / Fusion Energy - Fusion Materials
Current compatibility research in the U.S. focuses on two topics: dual- or multi-layer electrically-resistant Y2O3/vanadium coatings in a V-Li blanket concept and SiC composites with a Pb-Li coolant. The compatibility issue for multi-layer coatings includes the ceramic insulating layer and the metallic vanadium alloy layer. Characterization of Y2O3 coatings after exposure to Li shows significant changes in the microstructure. Initial static capsule results for V-4Cr-4Ti alloys in Li at 800°C showed unexpected small mass gains. Capsule tests of monolithic SiC in Pb-17Li showed no mass change and no wetting after 1000h at 800°C and only limited wetting after 1000h at 1100°C. Chemical analysis of the Pb-Li after the tests did not detect Si to the detectability limit of 30ppma (5wppm). In both liquid metal systems, loop tests with a representative temperature gradient are needed to truly determine compatibility limits.