Oxygen-driven de-alloying of Fe-14Cr-12Ni-10Mn-3Cu-2.5Al-1Nb austenitic steel at 500 °C in static Pb-Bi eutectic with concentration of dissolved oxygen alternating from ∼10-6 to 10-9 mass% for 10000 h

Research outputpeer-review

Abstract

A high-Mn austenitic steel Fe-14Cr-12Ni-10Mn-3Cu-2.5Al-1Nb was tested at 500 °C in static Pb-Bi eutectic for 10000 h. In the course of the test, oxygen concentration in liquid metal was cycled from ∼10-6 to ∼10-9 mass%, which provides oxidation and dissolution regimes, respectively. After 10000 h exposure steel showed formation of ferrite corrosion zone depleted in Mn, Ni, Cu, Cr, Fe and penetrated by Pb and Bi. Average depth of corrosion is 15±5 µm, while maximum corrosion depth locally reaches ∼35 µm. Dissolved Mn and Cr re-precipitated in the vicinity of steel surface in a form of stratified Mn-O/Cr-Mn-O oxide scale. Obtained results were compared to those of similar Al-alloyed austenitic steels with lower Mn content, which exhibited protective oxidation under same test conditions. The phenomenological mechanism of oxygen-driven de-alloying of steel in Pb-Bi[O] is discussed.

Original languageEnglish
Pages (from-to)1-11
Number of pages11
JournalCorrosion Communications
Volume17
DOIs
StatePublished - Mar 2025

ASJC Scopus subject areas

  • Metals and Alloys

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