The effect of duplex Surface mechanical attrition and nitriding treatment on corrosion resistance of stainless steel 316L

Nana Li,Ning Wang

doi:10.1038/s41598-018-26844-0

Abstract

Surface mechanical attrition treatment (SMAT) fabricates a nanostructured layer on the surface of 316L that possesses excellent mechanical properties. In this paper a duplex process combining SMAT with nitriding was performed, then the microstructure, hardness and corrosion properties of the treated materials were investigated by using X-ray diffraction (XRD), transmission electron microscopy (TEM), hardness tests, potentiodynamic polarization measurements, X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS). The results showed that this duplex surface treatment can effectively increase the hardness and corrosion resistance of the treated surface both at room temperature and in the simulated steam generator (SG) condition at high temperature and high pressure.

Highlights

The selection of Ni-based alloys and austenitic stainless steels for core internals of steam generator in nuclear power plants (NPPs)[1] is driven by the need for good corrosion resistance and mechanical characteristics
This phase usually forms at low nitriding temperatures, because the solubility limit of nitrogen in austenitic structure was exceeded with increasing of temperature[26]
The explanation for the difference between the γN peaks positions and intensities for the samples without and with Surface mechanical attrition treatment (SMAT) may be given as the following

Summary

Introduction

The selection of Ni-based alloys and austenitic stainless steels for core internals of steam generator in nuclear power plants (NPPs)[1] is driven by the need for good corrosion resistance and mechanical characteristics. The results suggest that the SMAT process leads to the diminution of corrosion resistance of 316L at room temperature, as the nanocrystalline materials, owing to a high surface energy and defects density, may accelerate corrosion process.

Results

Conclusion