Nano-Cr2N dominated films with high conductivity and strong corrosion resistance for Ti bipolar plates

• Published in: Materials & design 2022-12, Vol.224, p.111305, Article 111305
• Main Authors: Chen, Li, Liu, Ruixuan, Zhang, Bin, Lv, Jianxiang, Zhang, Junyan
• Format: Article
• Language: English
• Subjects: Bipolar Plate; Conductivity; Corrosion Resistance; CrN Films; Fuel Cells; HiPIMS
• ISSN: 0264-1275; 1873-4197
• DOI: 10.1016/j.matdes.2022.111305

[Display omitted] •CrN films prepared by HiPIMS exhibit good interface conductivity. The lowest interface contact resistance can reach 6.14 mΩ·cm2 at 1.4 MPa.•The high energy density during magnetron sputtering is beneficial to inhibition the growth of columnar structure and formation Cr2N films with high metallicity and stability.•The corrosion current density of all CrN films prepared by HiPIMS is less than 1 µA·cm−2, and the lowest value can reach 0.086 µA·cm−2.•The space network structure of amorphous wrapped Cr2N nanoclusters inhibited corrosion solution invading into Ti substrates, which greatly improves the corrosion resistance of CrN films. Films for bipolar plates deposited from PVD are always restricted by narrow parameters’ widow, which restrict the robust quality of high conductivity and anticorrosion due to the fluctuation of deposition plasma naturally. In this study, CrN films with high conductivity and strong corrosion resistance was deposited on Ti plates by high power impulse magnetron sputtering in wider Ar/N2 ratios. The results show that the CrN film prepared by this method effectively inhibits the columnar structure and forms a dense structure of amorphous wrapped nano Cr2N clusters, providing good protection for Ti plate. Meanwhile, First-principal calculations shown Cr2N has stronger metallicity than CrN, resulting in lower ICR. This work has opened up a new way for the large-scale preparation of metal bipolar plate films.