Corrosion behavior of dispersion-strengthened ferritic Fe-13Cr-2Mo steel in lead melt

The corrosion behavior of dispersion-strengthened ferritic Fe-13Cr-2Mo (TiO 2 ) steel in oxygen-containing lead melt is investigated at 550 and 650°C. It is determined that duplex magnetite scale is formed on the steel surface at 550°C and oxygen concentration of about 10 −3 wt.% in the lead melt. The scale grows symmetrically with regard to the initial steel-melt interface toward the liquid metal and matrix. The outer oxide layer consists of Fe 3 O 4 , the upper part of which contains plumboferrites, while the inner oxide is Cr-rich spinel Fe 1+x Cr 2−x O 4 . As the scale grows, the imperfection of the duplex oxide increases. The oxidation intensifies as interaction temperature increases to 650°C. The scale loses its protective properties and becomes penetrable for lead. With decreasing oxygen concentration in the lead melt (10 −5 wt.%), the scale growth becomes slower while the corrosion resistance of steel increases.