Early stages of liquid-metal corrosion on pre-oxidized surfaces of austenitic stainless steel 316L exposed to static Pb-Bi eutectic at 400 °C

Abstract

The effect of pre-oxidation in air at 300–500 °C on the initiation and development of liquid metal corrosion attack on 316L austenitic steel in static lead-bismuth eutectic (LBE) with ∼10−10 – 10−9 mass% dissolved oxygen at 400 °C for 1200 h is investigated. General dissolution with preferential attack along twin boundaries was observed on polished surfaces with native oxide films. Fe/Cr-based oxide films pre-formed in air at 300 and 400 °C protect surfaces against dissolution. Localized corrosion was observed on surfaces pre-oxidized at 500 °C. Thermal oxide degradation rate depends on its composition rather than thickness.