Influence of Surface Strain on Passive Film Formation of Duplex Stainless Steel and Its Degradation in Corrosive Environment

Abstract A new duplex 25Cr-3Ni-7Mn-0.66 N alloy was prepared in a vacuum arc re-melting furnace and characterized by metallographic and EPMA methods. Its corrosion behavior was investigated by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and a Mott-Schottky (M-S) analysis in artificial seawater at room temperature and compared with those of super and normal commercial duplex stainless steel (SDSS and DSS). No significant difference in the open circuit potentials and pitting potentials was observed. Its passive film current density lies between those of SDSS and DSS. This was confirmed by EIS analysis. A pit attack was observed on the δ-phase for all duplex samples, because the PREN16 of the δ-phase was lower than that of the γ-phase. From the Mott-Schottky analysis, the passive films were found to be composed of bi-layer structures, a p-type semiconductor inner layer, and a n-type semiconductor outer layer. The degree of defect as well as the effect of nitrogen in passive film layer are discussed with respect to the point defect model.

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Short Crack Initiation during Low-Cycle Fatigue in SAF 2507 Duplex Stainless Steel

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.345-346.343 ◽

2007 ◽

Vol 345-346 ◽

pp. 343-346 ◽

Cited By ~ 5

Author(s):

M.C. Marinelli ◽

Suzanne Degallaix ◽

I. Alvarez-Armas

Keyword(s):

Stainless Steel ◽

Duplex Stainless Steel ◽

Room Temperature ◽

Low Cycle Fatigue ◽

Fatigue Cracks ◽

Surface Strain ◽

The Other ◽

Cycle Fatigue ◽

Cyclic Tests ◽

Characteristic Microstructure

In this work, the formation of fatigue cracks is considered as a nucleation process due to the development of a characteristic microstructure formed just beneath the specimen surface. Strain controlled cyclic tests were carried out at room temperature at total strain ranges εt = 0.8 and 1.2% in flat specimens of SAF 2507 Duplex Stainless Steel (DSS). The results show that for this DSS, at εt = 0.8%, the correlation between phases (Kurdjumov-Sacks crystallographic relation) plays an important role in the formation of microcracks. On the other hand, at εt = 1.2%, microcracks initiate in the ferritic phase and the K-S relation does not seem to affect the formation of the cracks.

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Lateral variation of the native passive film on super duplex stainless steel resolved by synchrotron hard X-ray photoelectron emission microscopy

Corrosion Science ◽

10.1016/j.corsci.2020.108841 ◽

2020 ◽

Vol 174 ◽

pp. 108841 ◽

Cited By ~ 2

Author(s):

M. Långberg ◽

F. Zhang ◽

E. Grånäs ◽

C. Örnek ◽

J. Cheng ◽

...

Keyword(s):

Stainless Steel ◽

Duplex Stainless Steel ◽

Passive Film ◽

Super Duplex Stainless Steel ◽

Lateral Variation ◽

Photoelectron Emission ◽

X Ray ◽

Emission Microscopy ◽

Photoelectron Emission Microscopy

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Effect of hydrogen on semiconductor properties and pitting initiation of 2205 duplex stainless steel passivation film

Anti-Corrosion Methods and Materials ◽

10.1108/acmm-11-2019-2220 ◽

2020 ◽

Vol 67 (3) ◽

pp. 313-320 ◽

Cited By ~ 1

Author(s):

Chuanbo Zheng ◽

Jiayan Huang ◽

Gua Yi

Keyword(s):

Stainless Steel ◽

Duplex Stainless Steel ◽

Passive Film ◽

Corrosion Behavior ◽

Current Density ◽

Anodic Polarization ◽

Content Type ◽

2205 Duplex Stainless Steel ◽

Passivation Film ◽

Semiconductor Properties

Purpose This paper aims to study the effect of current density of hydrogen charging on the semiconductor properties and pitting initiation of 2205 duplex stainless steel (DSS) passivation film. Design/methodology/approach In this work, the 2205 DSS is pre-hydrogenated and passivated. Then, the passivation film is tested by electrochemical impedance method, Mott–Schottky curve method and dynamic potential scanning method. The influences of hydrogen on the properties of the passivation film and the corrosion behavior of the matrix were studied by analyzing the curves obtained in the electrochemical test. The surface of the passivation film after pre-hydrogenation and anodic polarization was observed by using the ultra-depth three-dimensional microscopy and the scanning electron microscope. The integrity, density and corrosion morphology of the passivation film were studied and discussed. Findings With the increase of the hydrogen current density, the growth of the passivation film is hindered, the concentrations of donor and acceptor in the film are increased, the conductivity of the passivation film increases. In the anodic polarization, the dimensional passive current density increases with the increase of the hydrogen current density, and the pitting potential is reversed, the more likely the sample is pitting. In general, hydrogen hinders the formation of the passive film on duplex stainless steel, which increases the concentration of point defects in the passive film. Finally, the passive film is easy to crack and pitting. Originality/value The performance of passive film is an important condition to influence the corrosion behavior of stainless steel. However, little research has been done on the effects of hydrogen on the electrochemistry and pitting sensitivity of 2205 DSS passivation films. The effect of hydrogen on semiconductor properties and pitting initiation of 2205 DSS passivation film is needed to be investigated.

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