Growth and Exfoliation Behavior of the Oxide Scale on 316L and T91 in Flowing Liquid Lead–Bismuth Eutectic at 480 °C

Abstract

Corrosion tests of the 316L and T91 steels were performed in flowing lead–bismuth eutectic (LBE) with a flowing velocity of 0.3 m/s at 480 °C up to 3000 h. The microstructure and growth kinetics of the oxide scale and metal dissolution for both steels were experimentally determined. The results showed that a thin Fe–Cr spinel layer is formed on the 316L surface, while the oxide scale on the T91 surface consists of magnetite, Fe–Cr spinel and internal oxidation zone. At the first 1500 h, the growth of the oxide layer follows a linear law and a parabolic law for the 316L and T91, respectively. With the increase in exposure time, the oxide scale on both steels partly spalls and subsequently continues to grow in situ. Compared with the T91, although the oxide scale on the 316L surface is thinner, more steel constituents dissolve into the LBE.