J. Mater. Sci. Technol. ›› 2019, Vol. 35 ›› Issue (11): 2630-2637.DOI: 10.1016/j.jmst.2019.07.031

• Orginal Article • Previous Articles     Next Articles

Enhancing the mechanical and anticorrosion properties of 316L stainless steel via a cathodic plasma electrolytic nitriding treatment with added PEG

Zhang Tianyia, Wu Junshenga*(), Jin Leib*(), Zhang Zhana, Rong Wanc, Zhang Boweia, Wang Yia, He Yedonga, Liu Weia, Li Xiaoganga   

  1. aCorrosion and Protection Center, Key Laboratory for Corrosion and Protection (MOE), University of Science and Technology Beijing, Beijing 100083, China
    bDepartment of Materials Application Research, China Aviation Manufacturing Technology Institute, Beijing 100024, China
    cNorthwest Institute for Non-Ferrous Metal Research, Xi’an 710016, China
  • Received:2019-04-23 Revised:2019-06-11 Accepted:2019-06-13 Online:2019-11-05 Published:2019-10-21
  • Contact: Wu Junsheng,Jin Lei
  • About author:

    1The authors equally contributed to this work.

Abstract:

A cathodic plasma electrolytic nitriding (CPEN) treatment with a urea aqueous solution was performed on 316L stainless steel to rapidly improve its surface properties in this work. Test results show that the PEG2000 macromolecules increased the nitriding energy via enhancing the ability to bond the produced gas film to the metal/electrolyte interface. The cross-sectional morphologies indicate that a thick nitrided layer was obtained when the urea concentration was 543 g l-1, corresponding to a Vickers hardness 450 HV0.1, which was 3.5 times larger than that of the substrate. The nitrided layer mainly contained expanded austenite (γN), oxides and iron nitrides (e.g., Fe3O4 and FeN0.076). In terms of its performance, coefficient of friction (COF) of the nitride layer decreased to nearly two-thirds that of the untreated layer, and the passivation current densities of the nitrided sample in a 3.5% NaCl solution decreased by an order of magnitude compared to that of the substrate. Therefore, the approach presented herein provides an attractive way to modify the effect of CPEN in a urea aqueous solution.

Key words: 316L stainless steel, Cathodic plasma electrolytic nitriding, Coefficient of friction, Polarization curves