Early stages of dissolution corrosion in 316L and DIN 1.4970 austenitic stainless steels with and without anticorrosion coatings in static liquid lead-bismuth eutectic (LBE) at 500$^\circ$C

TL;DR

This study investigates the early dissolution corrosion behavior of 316L and DIN 1.4970 stainless steels in liquid lead-bismuth eutectic at 500°C, evaluating the effects of microstructure and coatings for nuclear reactor applications.

Contribution

It provides new insights into the early-stage corrosion resistance of different stainless steels and assesses the effectiveness of various anticorrosion coatings in LBE environments.

Findings

Uncoated steels show varying resistance based on microstructure.

Certain coatings improve corrosion resistance in LBE.

Microstructural features influence dissolution rates.

Abstract

This work addresses the early stages ($\le$1000 h) of the dissolution corrosion behavior of 316L and DIN 1.4970 austenitic stainless steels in contact with oxygen-poor (C$_O$ < 10$^-$$^8$ mass%), static liquid lead-bismuth eutectic (LBE) at 500{\deg}C for 600-1000 h. The objective of this study was to determine the relative early-stage resistance of the uncoated steels to dissolution corrosion and to assess the protectiveness of select candidate coatings (Cr$_2$AlC, Al$_2$O$_3$, V$_2$Al$_x$C$_y$). The simultaneous exposure of steels with intended differences in microstructure and thermomechanical state showed the effects of steel grain size, density of annealing/deformation twins, and secondary precipitates on the steel dissolution corrosion behavior. The findings of this study provide recommendations on steel manufacturing with the aim of using the steels to construct Gen-IV lead-cooled fast reactors.