Corrosion behavior of dispersion-strengthened ferritic Fe-13Cr-2Mo steel in lead melt

Abstract

The corrosion behavior of dispersion-strengthened ferritic steel in oxygencontaining lead melt is investigated at 550 and 650°C. It is determined that duplex magnetite scale is formed on the steel surface at 550°C and oxygen concentration of about 10 -3 wt.% in the lead melt. The scale grows symmetrically with regard to the initial steel-melt interface toward the liquid metal and matrix. The outer oxide layer consists of Fe 3 O 4 , the upper part of which contains plumboferrites, while the inner oxide is Cr-rich spinel Fe 1+x Cr 2-x O 4 . As the scale grows, the imperfection of the duplex oxide increases. The oxidation intensifies as interaction temperature increases to 650°C. The scale loses its protective properties and becomes penetrable for lead. With decreasing oxygen concentration in the lead melt (10 -5 wt.%), the scale growth becomes slower while the corrosion resistance of steel increases.

Corrosion behaviour of oxide dispersion strengthened iron‐chromium steels in liquid lead at 973 K

“…Several authors have confirmed the formation of multiphase non‐protective scales occurring under the conditions of C O ≥ 10 −3 wt% O, which indicates intensive oxidation. Roy et al have studied the oxidation behaviour of austenitic steels in LBE and, according to their study, the experimental conditions used in the present work corresponds to so called “mixed domain” corrosion.…”

“…The oxidation/corrosion behaviour of 9Cr‐ODS, 12Cr‐ODS, 13Cr‐ODS and 14Cr‐ODS steels in a lead bath under stagnant conditions, for temperatures lower than 923 K and for different oxygen contents has been investigated recently. The formation of Fe‐Cr spinel type oxides on the tested steel samples has been observed to be independent of Cr content, but the oxide scales morphologies and their thickness are strongly dependent on the operating temperature and oxygen content …”

“…Although the compatibility of conventional austenitic and ferritic‐martensitic steels with liquid lead or its alloys has been widely studied the literature regarding the interactions of ODS steels with HLM is quite scarce and mainly focused on steels with 8–9 wt% Cr for temperatures lower than 923 K and for the oxygen contents ranging from 10 −8 to 10 −3 wt% O . The literature data on the corrosion behaviour of ODS steels with nominally 8 ÷ 13 wt% Cr, tested in HLM with a dissolved oxygen concentration ranging from 10 −6 to 10 −3 wt%, indicate the formation of a double oxide layer constituted by a spinel in the inner part and magnetite in the external part, whose stability depends on the oxygen content in the liquid metal. The oxidation/corrosion behaviour of 9Cr‐ODS, 12Cr‐ODS, 13Cr‐ODS and 14Cr‐ODS steels in a lead bath under stagnant conditions, for temperatures lower than 923 K and for different oxygen contents has been investigated recently.…”

“…The formation of Fe-Cr spinel type oxides on the tested steel samples has been observed to be independent of Cr content, [44,45] but the oxide scales morphologies and their thickness are strongly dependent on the operating temperature and oxygen content. [36,43] The effect of Cr content on corrosion resistance has been investigated through the corrosion tests performed on different steels under a flowing Pb-Bi eutectic (LBE) at T = 823 K for 1000 h [46] or longer (up to 10 000 h), [39] indicating the formation of a stable Cr rich oxide film on the high Cr steels, i.e. with Cr content ranging from 10 to 18 wt% .…”

Precipitation-hardened ferritic steels for fast neutron reactors

“…The corrosion behavior of precipitation-hardened steel Kh13M2 + 2.2% TiO 2 in lead melts was examined at 550 and 650°C, the oxygen content of lead being 10 -3 wt.% (maximum saturation of lead with oxygen) and 10 -5 wt.% (maximum oxygen content in lead in a hybrid-type nuclear installation) [15]. With the maximum oxygen content and temperature 550°C, the corrosion rate is not high (90 µm/h), and free lead penetrates neither into the scale nor the steel matrix.…”