Corrosion of steels in molten gallium (Ga), tin (Sn) and tin lithium alloy (Sn–20Li)

Abstract

The compatibility of steels in liquid gallium (Ga), tin (Sn) and tin lithium alloy (Sn–20Li) was investigated by means of static corrosion tests. The corrosion tests were performed for reduced activation ferritic martensitic steel JLF-1 (JOYO-HEAT, Fe–9Cr–2W–0.1C) and austenitic steel SUS316 (Fe–18Cr–12Ni–2Mo). The test temperature was 873K, and the exposure time was 250 and 750h. The corrosion of these steels in liquid Ga, Sn and Sn–20Li alloy was commonly caused by the formation of a reaction layer and the dissolution of the steel elements into the melts. The reaction layer formed in liquid Ga was identified as Fe3Ga from the results of metallurgical analysis and the phase diagram. The growth rate of the reaction layer on the JLF-1 steel showed a parabolic rate law, and this trend indicated that the corrosion could be controlled by the diffusion process through the layer. The reaction layer formed in liquid Sn and Sn–20Li was identified as FeSn. The growth rate had a linear function with exposure time. The corrosion in Sn and Sn–20Li could be controlled by the interface reaction on the layer. The growth rate of the layer formed in liquid Sn and Sn–20Li was much slower than that in liquid Ga. The weight change of the JLF-1 specimen immersed in Sn–20Li for 750h was measured after the removal of the adherent Sn–20Li in a Li pool. The weight loss was 1.42×103g/m3, and this value was 1500 times larger than that tested in liquid lead lithium alloy (Pb–17Li) at the same conditions in the previous studies.