Effect of Ni content on the electrical and corrosion properties of CrNiN coating in simulated proton exchange membrane fuel cell

• Published in: International journal of hydrogen energy Vol. 42; no. 2; pp. 1142 - 1153
• Main Authors: Jin, Jie, Zheng, Dacai, Han, Suiwu, Ma, Junjie, Zhu, Zhengxu
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 12.01.2017
• Subjects: Contact angle; Corrosion resistance; CrNiN coating; Electrochemical test; PEMFC; Corrosion resistance; Electrochemical test; PEMFC; Contact angle; CrNiN coating
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2016.11.007

In this paper, CrNiN coatings with various Ni content are deposited on 304ss bipolar plates by closed field unbalanced magnetron sputter ion plating from CrNi alloy targets. Simulative working environment of proton exchange membrane fuel cell (PEMFC) is applied to test the electrical and corrosion properties of uncoated 304ss and CrNiN-coated samples. The influence of Ni content on microstructure, phase structure, contact angle with water and electrochemical performance is investigated. Results show that all the coated samples significantly enhanced the corrosion resistance of the 304ss, and the CrN-coated 304ss sample without Ni has the best corrosion resistance of 153.8 and −141.9 mV in the simulated anodic and cathodic environments, respectively. Electrochemical impedance spectroscopy (EIS) studies reveal that the resistance of CrN coating is higher than that of other coated samples and 304ss in the cathodic environment. Furthermore, Interfacial contact resistance (ICR) studies revealed that CrN coating has a superior ICR of 11 mΩ cm2 at a compaction force of 160 N cm−2. In addition, the contact angle of the CrNiN coatings with water is approximately 114°, which is beneficial for water management in PEMFC. Analysis result indicates that the enhanced performance of the coated 304ss bipolar plates is related to the high film density determined by closed field unbalanced magnetron sputter ion plating, and the synergistic function of the CrNiN layered structure. •CrNiN coatings deposited by closed field unbalanced magnetron sputter ion plating.•Effect of Ni content on the performance of CrNiN coating is studied.•CrNiN coatings improve electrochemical behavior and hydrophobic characteristic of 304ss.•ICR of CrN-coated 304ss is significantly lower than for bare substrates.•CrN-coated 304ss sample without Ni behave better corrosion resistance than CrNiN coating.