Pitting and Repassivation Behavior of 316L Austenitic Stainless Steel under Different Potentials

FAN Xue-hua, YU Yong, ZHANG Zi-ru, FENG Zhe, CHEN Li-juan, DONG Lei, ZHANG Lei

Surface Technology ›› 2020, Vol. 49 ›› Issue (7) : 287-293.

PDF(4454 KB)
PDF(4454 KB)
Surface Technology ›› 2020, Vol. 49 ›› Issue (7) : 287-293. DOI: 10.16490/j.cnki.issn.1001-3660.2020.07.036
Surface Failure and Protection

Pitting and Repassivation Behavior of 316L Austenitic Stainless Steel under Different Potentials

  • FAN Xue-hua1, YU Yong1, CHEN Li-juan1, DONG Lei1, ZHANG Zi-ru2, FENG Zhe2, ZHANG Lei2
Author information +
History +

Abstract

The work aims to investigate the effect of applied potentials on the pitting and repassivation behavior of 316L austenitic stainless steel. Cyclic polarization, potentiostatic polarization and electrochemical impedance spectroscopy tests were selected to study the effect of series potential and mixed potential on pitting sensitivity of 316L austenitic stainless steel. In addition, SEM and XPS were used to observe the pitting morphology and analyze the elemental concentration of passivation film. At 60 ℃, the passive region of 316L austenitic stainless steel in saturated CO2 and 10 g/L NaCl test solution was -0.394~0.168 V, but when the potential was between -0.100~0.168 V, there was a certain current fluctuation, namely metastable pitting zone. The current density of 316L stainless steel in passive region was very small, slightly increasing with the increase of potential and the pit was not observed on the sample surface after polarization. However, the current density of 316L austenitic stainless steel in metastable pitting region was high and obvious pitting appeared on the samples. In the mixed polarization with potential from 0.1 V to -0.1 V, the current density droped sharply and eventually stabilized at a lower current value. Meanwhile, the results of XPS showed that the Cr and Mo concentration increased with the potential transition, but the Fe element was selectively dissolved in this condition. Cr and Mo are corrosion resistance elements, and the existence of the oxides or hydroxides can promote the local repair of passivation film. Therefore, the surface of 316L stainless steel presents repassivation behavior, the stability of the passivation film is enhanced and the corrosion resistance is improved with the transition to low potential.

Key words

austenitic stainless steel; polarization; EIS; pitting corrosion; repassivation

Cite this article

Download Citations
FAN Xue-hua, YU Yong, ZHANG Zi-ru, FENG Zhe, CHEN Li-juan, DONG Lei, ZHANG Lei. Pitting and Repassivation Behavior of 316L Austenitic Stainless Steel under Different Potentials[J]. Surface Technology. 2020, 49(7): 287-293

Funding

Supported by China Petroleum Engineering Co., Ltd Scientific Research and Technological Development Support Program (CPECC2018KJ04)
PDF(4454 KB)

Accesses

Citation

Detail

Sections
Recommended

/