Corrosion behaviour of nanocrystallines 304 stainless steel in simulated secondary side environment

Abstract

Surface nanocrystallisation (SNC) was prepared on the top-surface layer of 304 stainless steel by ultrasonic surface rolling treatment (USRT). Meanwhile, martensite transformation also occurred during grain refinement, and the surface microhardness increased more than tripled after USRT. The corrosion resistance of nanocrystallines (NC) 304 stainless steel was notably better than that of untreated samples in simulated pressurised water reactor (PWR) secondary water by potentiodynamic polarisation curves, electrochemical impedance spectroscopy and Mott-Schottky curves. Meanwhile, the corrosion mechanism was discussed before and after USRT by X-ray photoelectron spectroscopy (XPS). The main reason is due to the formation of denser Cr(OH)₃ protective film and the reduction of the porous structure Fe₂O₃ content in the NC 304 stainless steel.

KEYWORDS:

• Nanocrystallisation
• steel
• corrosion
• USRT
• XRD
• SEM
• TEM
• XPS

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Jiang Liu http://orcid.org/0000-0002-7676-9006

Chunming Wang http://orcid.org/0000-0003-3564-8176

Additional information

Funding

This study is financially supported by the National Natural Science Foundation of China [grant numbers 518711145 and 51804138], the National Key Research and Development Program of China [grant number 2016YFB0301400], the Natural Science Foundation of Jiangxi Province [grant number 20161BAB206136 and GJJ180430].