A combined experimental and first-principle study on the oxidation mechanism of super austenitic stainless steel S32654 at 900 °C

Abstract

A combined experimental and first-principle study on the oxidation mechanism of super austenitic stainless steel S32654 at 900 °C for a short time period ( Super austenitic stainless steels S32654 are primarily used in applications where increased pitting and crevice corrosion resistances are required, such as marine and offshore applications, seawater handling systems, nuclear power plant condenser tubes, waste incineration systems, and chemical-processing equipment [1][2][3] . Their extensive use is because of their superior corrosion resistance, enhanced mechanical property, formability, and weldability 4, 5 . However, the high Mo and Cr concentrates in S32654 steels may promote the segregation of the elements and formation of precipitated phases such as σ, χ, and Laves phase 3, 6-8 . Recently, many reported investigations on S32654 mainly focused on the hot deformation behaviour, precipitation behaviour, and corrosion resistance [9][10][11] .In recent years, many studies have examined the high-temperature oxidation mechanism of the lower-Mo-content stainless steels [12][13][14][15][16] . Yun et al. 13 examined the effect of Mo on the oxidation resistance of Fe-22Cr-0.5Mn ferritic stainless steel at 800 °C and confirmed that the lower Mo addition (<4 wt.%) effectively enhanced the oxidation stability at the initial oxidation stage up to 300 h. Buscail et al. 14 demonstrated that Mo could restrain the outward diffusion of Fe and decrease the growth rate of the oxide layer, which enhanced the oxidation stability of the AISI 316 L stainless steel at 900 °C. Mo contents below 3 wt.% in the ferritic stainless steel could reduce the absorption of O 2 , prevent the outward diffusion of the metal cations and inward diffusion of anions, and enhance the oxidation resistance 16 . Furthermore, alloys with high Mo contents sustain the heavy oxidation at high temperatures because of the formation of volatile MoO 3 species [17][18][19][20] investigated the effect of Mo on the oxidation behaviour of AISI 304 and discovered that Mo could accelerate the oxidation rate because the evaporation of volatile MoO 3 damaged the Cr 2 O 3 layer. However, for high-Mo-content austenitic stainless steels such as S32654 steels, the effect of Mo on the high-temperature oxidation behaviour is inadequate. Therefore, the investigation on the high-temperature oxidation behaviour of S32654 steels is useful.Moreover, our previous work 21 mainly investigated the oxidation behaviour of S32654 steels at 900 °C, 1000 °C, and 1200 °C in air. At 900 °C, the samples exhibit excellent oxidation resistance because the MnMoO 4 layer and

Investigating the Influence of Cr and Mo Additions to Commercial Ni-Based Alloys Exposed to Neutral and Acidic Chloride Solutions

“…9,[26][27][28] For Cr/Mo containing alloys, this is often attributed to the formation of a Mo-rich oxide layer over an inner Cr-rich barrier layer. 3,[29][30][31][32][33] These results confirm a role for Mo in protecting an alloy from degenerating to active corrosion, providing the Mo content is >13 wt.%. For Mo <13 wt.%, any Cr III barrier layer is dissolved and active corrosion can be achieved.…”

“…In neutral solutions (pH ∼ 7), oxides formed on Cr-containing alloys have been shown to be dominated by a Cr III -rich barrier layer and as a result, exhibit excellent corrosion resistance. 2,3 However, in acidic environments, the increased solubility of Cr III species can lead to the destruction of this passive layer. 4,5 Additions of Mo have been shown to increase the resistance to corrosion in acidic solutions.…”

“…Empirical relationships such as the pitting resistance equivalent number (PREN) 6 and the atomic percent factor (APF) 7,8 have been successfully used to describe the benefits Cr and Mo; but are limited in the mechanistic information they provide. While the relationship between alloyed Cr and Mo has been extensively studied, [9][10][11] ongoing research 3,[12][13][14][15][16] continues to provide new information.…”

Temperature-Dependent Selective Oxidation Behavior of Al2Au Alloy: Insights for Tailoring Au-Enhanced Oxide Layers

“…Alloying is a common strategy for obtaining protective oxide layers on surfaces by selectively oxidizing a specific component within the alloy. − The process of selective oxidation in alloys involves numerous physical and chemical phenomena such as atomic diffusion, oxidation reactions, and interface evolution, which are influenced by factors including alloy structure, composition, and oxidation conditions. − Establishing a comprehensive theoretical framework for selective oxidation presents a substantial challenge.…”

Improvement of high-temperature initial oxidation behavior of HR3C austenitic heat-resistant steel using silicon modification: experimental and first-principle study

“…A combination of experiment and theoretical research on the formation of the oxide layer in alloys has attracted a lot of attention. Recently, high temperature oxidation mechanisms of some alloys including the g-TiAl [24], FeCrAl [25], Ni-22Cr [26] and austenitic heat resistant steels [27] have been investigated based on first-principle density functional theory. However, the knowledge on how Si affects the structure of oxide scale is lacking; thus, more detailed analysis at the atomic scales is still required to understand the specific role of Si in the oxidation resistance.…”