Multistep active screen plasma co-alloying the treatment of metallic bipolar plates

ABSTRACT

Active screen plasma (ASP) surface treatments have been widely utilized to improve surface performances of stainless steel in various applications. In our previous research, active screen plasma nitriding (ASPN) and active screen plasma co-alloying processes have been successfully employed to modify 316L stainless steel for the application of proton exchange membrane (PEM) fuel cell bipolar plates. In this study, a multistep active screen plasma co-alloying surface treatment with niobium and nitrogen was proposed to produce a tailored layer structure on the surface of 316L stainless steel. By tailoring the applied bias of step, single-layer and duplex-layer structures can be formed on the surface of 316L stainless steel. Performance tests showed that the sample with a duplex-layer structure exhibited improved interfacial contact conductivity and higher corrosion potential than the sample with a single-layer structure, indicating the feasibility of this multistep active screen plasma co-alloying surface treatment for PEM fuel cell bipolar plate application.

KEYWORDS:

• Active screen plasma treatment
• surface alloying
• 316L stainless steel
• PEM fuel cell
• bipolar plate
• interfacial contact resistance
• corrosion resistance

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China (grant number 51905269), Engineering and Physical Sciences Research Council (grant number EP/J018252/1); Fundamental Research Funds for the Central Universities (grant number 3082018NS2018038); Natural Science Foundation of Jiangsu (grant number BK20170787); the Open Fund of Key Laboratory of Materials Preparation and Protection for Harsh Environment (grant number 56XCA18159-4); Science Challenge Project (grant numbers TZ2018006-0301-02 and TZ2018006-0303-03); Young Scientists Fund (grant number 51905269). Professor Hanshan Dong and Dr Xiaoying Li would like to acknowledge the financial support from Engineering and Physical Sciences Research Council, UK (grant number EP/J018252/1).