Mehdizadeh Chellehbari Yasin, Gupta Abhay, Li Xianguo, Shahgaldi Samaneh
Hydrogen Research Institute, Université du Québec à Trois-Rivières, Trois-Rivières, QC G8Z 4M3, Canada.
Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo, ON N2L 3G1, Canada.
Molecules. 2024 Sep 12;29(18):4319. doi: 10.3390/molecules29184319.
Coated SS316L is a potential alternative to the graphite bipolar plates (BPPs) used in proton-exchange membrane fuel cells (PEMFCs) owing to their low manufacturing cost and machinability. Due to their susceptibility to corrosion and passivation, which increases PEMFC ohmic resistance, protective and conductive coatings on SS316L have been developed. However, coating adhesion is one of the challenges in the harsh acidic environment of PEMFCs, affecting the performance and durability of BPPs. This study compares mechanical polishing and the frequently adopted chemical etchants for SS316L: Adler's, V2A, and Carpenter's etchant with different etching durations and their impact on the wettability, adhesion, and corrosion resistance of a Nb-coated SS316L substrate. Contact angle measurements and laser microscopy revealed that all etching treatments increased the hydrophobicity and surface roughness of SS316L substrates. Ex situ potentiodynamic and potentiostatic polarization tests and interfacial contact resistance analysis revealed high corrosion resistance, interfacial conductivity, and adhesion of the Nb-coated SS316L substrate pretreated with V2A (7 min) and Adler's (3 min) etchant. Increased hydrophobicity (contact angle = 101°) and surface roughness (R = 74 nm) achieved using V2A etchant led to the lowest corrosion rate (3.3 µA.cm) and interfacial resistance (15.4 mΩ.cm). This study established pretreatment with V2A etchant (a solution of HNO, HCl, and DI water (1:9:23 mole ratio)) as a promising approach for improving the longevity, electrochemical stability, and efficiency of the coated SS316L BPPs for PEMFC application.
涂层SS316L因其制造成本低和可加工性，是质子交换膜燃料电池（PEMFC）中使用的石墨双极板（BPP）的一种潜在替代品。由于SS316L易受腐蚀和钝化影响，会增加PEMFC的欧姆电阻，因此已开发出SS316L上的保护和导电涂层。然而，在PEMFC的苛刻酸性环境中，涂层附着力是一个挑战，会影响BPP的性能和耐久性。本研究比较了SS316L的机械抛光和常用化学蚀刻剂：不同蚀刻时间的阿德勒蚀刻剂、V2A蚀刻剂和卡彭特蚀刻剂，以及它们对Nb涂层SS316L基材的润湿性、附着力和耐腐蚀性的影响。接触角测量和激光显微镜显示，所有蚀刻处理均增加了SS316L基材的疏水性和表面粗糙度。异位动电位和恒电位极化测试以及界面接触电阻分析表明，用V2A（7分钟）和阿德勒蚀刻剂（3分钟）预处理的Nb涂层SS316L基材具有高耐腐蚀性、界面导电性和附着力。使用V2A蚀刻剂实现的疏水性增加（接触角 = 101°）和表面粗糙度增加（R = 74 nm）导致最低腐蚀速率（3.3 µA.cm）和界面电阻（15.4 mΩ.cm）。本研究确定用V2A蚀刻剂（HNO、HCl和去离子水的溶液（摩尔比1:9:23））预处理是提高用于PEMFC应用的涂层SS316L BPP的寿命、电化学稳定性和效率的一种有前景的方法。
