Corrosion-resistant characteristics of nitrided Ni-free stainless steel for bipolar plate of polymer electrolyte fuel cell. (2nd March 2017)

• Record Type: Journal Article
• Authors: Yu, Yang; Shironita, Sayoko; Mizukami, Takaaki; Nakatsuyama, Kunio; Souma, Kenichi; Umeda, Minoru
• Is Part Of: International journal of hydrogen energy. Volume 42:Number 9(2017)
• Page Start: 6303
• Page End: 6309
• Publication Date: 2017-03-02
• Subjects: Ni-free stainless steel -- Bipolar plate -- Nitriding surface treatment -- Corrosion resistance -- Mechanism -- Polymer electrolyte fuel cell; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2017.01.211
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: In this study, the effect of a high temperature nitriding treatment on the characteristics of the Ni-free stainless steel (SUS445) used as the metallic bipolar plate of a polymer electrolyte fuel cell (PEFC) was investigated. The phase structure, composition, electrical conductivity and electrochemical corrosion resistance of the stainless steel after the nitriding treatment (SUS445-N) were analyzed. The supersaturated nitrogen phase γN, nitrides CrN and Cr2 N in the nitride layer with a good electrical conductivity were observed and confirmed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The corrosion resistance of the nitrided SUS445-N stainless steel was significantly improved due to the formation of the chromium-containing nitrides. The conducted fuel cell durability test revealed that when using the nitrided SUS445-N stainless steel as the bipolar plate, the fuel cell voltage performance was almost the same as that using the graphite carbon as the bipolar plate for 2500 h. Highlights: We conducted a nitriding treatment to modify the Ni-free SUS445 stainless steel. The nitride layer mainly consists of expanded austenite γN and Cr-N phases. The Cr-N offers an excellent corrosion resistance to the SUS445 stainless steel. The durability of nitrided steel is as good as graphite carbon for bipolar plates.