Compatibility of surface-coated steels, refractory metals and ceramics to high temperature lead–bismuth eutectic

Compatibility of cladding material with lead–bismuth eutectic at temperature higher than 650 °C is one of the most crucial issues for feasibility of lead–bismuth-cooled fast reactors with cycle efficiency as high as 40%. In order to search for corrosion-resistant materials with lead–bismuth eutectic at temperature higher than 650 °C, surface-coated steels, some refractory metals and various ceramics were tested by means of stirred-type corrosion test. Lead–bismuth was heated up to 700 °C electrically in an alumina crucible, and oxygen concentration in the lead–bismuth was adequately controlled by injection of argon, steam and hydrogen gas mixture into the lead–bismuth. Specimens of aluminum–iron-alloy-surface-coated steels, refractory metals and ceramics including SiC/SiC composites were immersed in the stirred lead–bismuth for 1000 h. It was found that the surface-coated steels showed good compatibility with the lead–bismuth due to formation of a thin and stable protection layer on the surfaces. Tungsten and molybdenum exhibited high corrosion resistance. On the other hand, niobium is not a reliable material for the high temperature LBE. SiC and Ti3SiC2 also exhibited high corrosion resistance. On the other hand, the physical performance of the SiC/SiC composite must be improved especially by minimizing the porosity.