Selective leaching of nickel and chromium from Type 316 austenitic steel in oxygen-containing lead–bismuth eutectic (LBE)

• Selective leaching of Ni and Cr was assessed both qualitatively and quantitatively.
• Austenite dissolves completely in the LBE, but iron re-deposits as ferrite.
• Steel consumption apparently follows linear kinetics, at least initially.
• Oxidation of steel elements occurs outside the developing depletion zone.
• Oxidation impacts mass transport away from the depletion zone/steel interface.

Selective leaching of nickel and chromium is a corrosion mode of austenitic steels that typically occurs during exposure to a liquid metal at elevated temperature. In lead–bismuth eutectic (LBE), selective leaching is observed even if oxygen is added in order to form protective oxides on the steel surface. The main characteristic is the development of a depletion zone consisting of ferrite that is penetrated by the liquid metal. For the experimental conditions investigated, a mechanism including non-selective dissolution of austenite followed by deposition of ferrite is proposed. Oxygen dissolved in the LBE influences the concentration gradients above the depletion zone.