Compatibility studies of metallic materials with lithium-based oxides

Abstract The compatibility of Li 2 O, Li 4 SiO 4 and Li 2 SiO 3 with the cladding materials AISI 316, 1.4914, Hastelloy X and Inconel 625 was investigated at 800–1000°C for annealing times up to 1000 h. A controlled oxygen reactivity was established by adding 1 mol% NiO per mole Li 2 O to the Li-based oxides. In addition, some compatibility tests were performed at 600–900°C on Be, which is of interest as a neutron multiplier material, with Li 2 SiO 3 as well as AISI 316. Li 2 O accounted for the strongest cladding attack, followed by Li 4 SiO 4 and Li 2 SiO 3 . In the absence of NiO, Li 2 SiO 3 caused no chemical interactions at all. With respect to the cladding materials, there was no considerable difference in the reaction rates of AISI 316, Hastelloy X and Inconel 625. However, the steel 1.4914 was clearly more heavily attacked at and above 800°C. The compatibility of Be with Li 2 SiO 3 or AISI 316 seems to be tolerable up to about 650°C. At higher temperatures a liquid Li suicide phase is formed which results in strong local attack and penetration into Li 2 SiO 3 .