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Oxidation behavior of T91 steel in flowing oxygen‐containing lead‐bismuth eutectic at 500 °C
Author(s) -
Tian S. J.,
Jiang Z. Z.,
Luo L.
Publication year - 2016
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/maco.201609075
Subject(s) - spinel , eutectic system , magnetite , oxide , materials science , oxygen , kinetics , metallurgy , bismuth , chemical engineering , chemistry , alloy , organic chemistry , engineering , physics , quantum mechanics
T91 is considered as a possible structural material for lead‐bismuth eutectic (LBE) cooled reactors. However, one of the main issues is the compatibility of T91 with LBE. In this work, the corrosion tests of T91 were performed in flowing (1 m/s) oxygen‐controlled LBE (1–3 × 10 −6 wt% O) at 500 °C for up to 5000 h. The results show that a three‐layer oxide scale forms at the interface of T91 and LBE, consisting of Fe 3 O 4 (magnetite), Fe‐Cr spinel and an internal oxidation zone (IOZ). The growth kinetics of the oxide scale follows a parabolic dependence ( Δ x 2 = k p t ). The rate constants ( k p ) of Fe 3 O 4 , Fe‐Cr spinel, and IOZ are 0.052, 0.040, and 0.0057 μm 2 /h, respectively. In addition, the growth model of the oxide scale is established under consideration of the exfoliation process. This model clarifies the growth direction of each oxide layer and the transformation of Fe‐Cr spinel to magnetite.