Please use this identifier to cite or link to this item: http://hdl.handle.net/2440/123911
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Type: Journal article
Title: A reactive-sputter-deposited TiSiN nanocomposite coating for the protection of metallic bipolar plates in proton exchange membrane fuel cells
Author: Peng, S.
Xu, J.
Li, Z.
Jiang, S.
Munroe, P.
Xie, Z.
Lu, H.
Citation: Ceramics International, 2020; 46(3):2743-2757
Publisher: Elsevier
Issue Date: 2020
ISSN: 0272-8842
1873-3956
Statement of
Responsibility: 
Shuang Peng, Jiang Xu, Zhengyang Li, Shuyun Jiang, Paul Munroe, Zong-Han Xie, Hong Lu
Abstract: To meet the needs of corrosion resistance and electrically conductivity for metallic bipolar plates that are employed in proton exchange membrane fuel cells (PEMFCs), a TiSiN nanocomposite coating was fabricated on to a Ti–6Al–4V substrate using reactive sputter-deposition through the double cathode glow discharge plasma technique. The microstructure of the TiSiN coating comprised nanocrystallite TiN grains embedded in an amorphous Si₃N₄ matrix. Electrochemical measurements were employed to investigate the corrosion behavior of the TiSiN coating in the simulated operating environments of a PEMFC, specifically 0.5 M H₂SO₄ solution containing different HF concentrations (namely 2, 4 and 6 ppm) at 70 °C pumped with H₂ at the anode and air at the cathode. With increasing HF concentration, a higher corrosion current density and lower corrosion potential were observed from both the coating and the uncoated substrate, indicating that the addition of HF accelerated their corrosion rates under these conditions. Compared to the uncoated substrate, the TiSiN coating showed a markedly higher corrosion resistance at all HF concentrations. The passive film that formed on the TiSiN coating, with a resistance of the order of magnitude of ~10⁷ Ω cm, displayed good electrochemical stability and was less affected by changes in HF co²ncentration. For the TiSiN coating, the values of interfacial contact resistance (ICR) were 14.7 mΩ cm⁻² and 18.3 mΩ cm⁻², respectively, before and after 2.5 h potentiostatic polarization with 6 ppm HF under cathodic conditions under a compaction pressure of 140 N cm⁻². Both values are much lower than those for the bare substrate. Moreover, the TiSiN coating was shown to improve the hydrophobicity of Ti–6Al–4V that would help facilitate water management in the PEMFC operating environment. This coating, which exhibited excellent corrosion resistance, electro-conductivity and hydrophobicity, is therefore a promising material for protecting metallic bipolar plates from corrosive attack.
Keywords: Proton exchange membrane fuel cell (PEMFC); bipolar plate; titanium alloy; TiSiN coating; corrosion resistance
Rights: © 2019 Elsevier Ltd and Techna Group S.r.l. All rights reserved.
RMID: 1000001715
DOI: 10.1016/j.ceramint.2019.09.263
Grant ID: http://purl.org/au-research/grants/arc/DP150102417
Appears in Collections:Mechanical Engineering publications

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