Arc ion plated Cr/CrN/Cr multilayers on 316L stainless steel as bipolar plates for polymer electrolyte membrane fuel cells

• Published in: Journal of power sources 2011-03, Vol.196 (6), p.3249-3254
• Main Authors: Zhang, Min, Wu, Bo, Lin, Guoqiang, Shao, Zhigang, Hou, Ming, Yi, Baolian
• Format: Article
• Language: English
• Subjects: Adhesive strength; Applied sciences; Arc ion plating; Austenitic stainless steels; Chromium; Chromium nitride; Coating; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Electrochemistry corrosion; Energy; Energy. Thermal use of fuels; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Fuel cells; Heat resistant steels; Interfacial contact resistance; Multilayer; Multilayers; Plates; Stainless steel bipolar plate; Stainless steels
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2010.11.154

▶ The design and synthesis by arc ion plating of sandwich-like Cr/CrN/Cr multilayers with high adhesion strength and enhanced microhardness. ▶ The application of multilayers on stainless steel 316L (SS316L) as bipolar plates to improve their performances in PEMFC operating conditions. ▶ Compared with the bare SS316L, the coated samples exhibit lower interfacial contact resistance (one order of magnitude lower) and better anticorrosion performance. Arc ion plating (AIP) is applied to coat sandwich-like Cr/CrN/Cr multilayers on stainless steel 316L (SS316L) as bipolar plates for polymer electrolyte membrane fuel cell (PEMFC). Phase structure, hardness, adhesion property, interfacial contact resistance (ICR) between bipolar plates and carbon papers, and electrochemical corrosion property in the simulated PEMFC conditions are investigated. Cr phase with crystal plane of (110), (211), (322), and CrN phase with (321) are observed in the multilayer. The coating is found smooth, continuous and dense in cross-sectional observation by SEM, and the sandwiched structure of the coating is also confirmed by EDX results. Scratch tests show that the multilayer exhibits strong adhesion strength with steel substrate, which is beneficial to prevent layers from peeling off mechanically. After the coating treatment, the performance of the bipolar plate is greatly improved. Knoop hardness of the bipolar plates increases from 324HK to 692HK. The ICR decreases by one order of magnitude; furthermore, the corrosion resistance was also enhanced. Our analysis indicates that the improvement is attributed to high adhesion force of the smooth and dense coating and the synergistic function of Cr/CrN/Cr multilayer structure.