Effect of surface roughness on contact resistance and electrochemical corrosion behavior of 446 stainless steel in simulated anode environments for proton exchange membrane fuel cell

• Published in: Journal of solid state electrochemistry Vol. 28; no. 9; pp. 3087 - 3098
• Main Authors: Xu, Ronghai, Jin, Xinyu, Bi, Hongyun, Zhang, Zhixia, Li, Moucheng
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 2024; Springer Nature B.V
• Subjects: Analytical Chemistry; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Condensed Matter Physics; Contact resistance; Corrosion; Corrosion cell; Corrosion effects; Corrosion environments; Corrosion potential; Corrosion products; Corrosion resistance; Corrosion resistant steels; Corrosion tests; Electrochemical corrosion; Electrochemical impedance spectroscopy; Electrochemistry; Electrode polarization; Energy Storage; Fuel cells; Galvanic corrosion; Grit; Original Paper; Physical Chemistry; Proton exchange membrane fuel cells; Protons; Stainless steel; Stainless steels; Sulfuric acid; Surface roughness; Surface roughness effects; Surface roughness; Bipolar plate; Corrosion; Interfacial contact resistance; 446 stainless steel
• ISSN: 1432-8488; 1433-0768
• DOI: 10.1007/s10008-024-05864-z

The effect of surface roughness on the interfacial contact resistance (ICR) and the corrosion behavior of 446 stainless steel in simulated anode environments for proton exchange membrane fuel cell (PEMFC) (i.e., 0.5 mol L
−1
H
2
SO
4
 + 2 ppm F
−
and 5 × 10
−4
mol L
−1
H
2
SO
4
 + 0.1 ppm F
−
bubbled with hydrogen gas at 80 °C) was investigated by means of atomic force microscopy, potentiodynamic polarization, electrochemical impedance spectroscopy and ICR test. The surface roughness (
R
a
) produced by mechanical grinding increases noticeably with the decrease of sandpaper grit size from 1000# to 240#. 446 stainless steel shows the active state under free corrosion conditions in the two test solutions and the passive state at the typical anode working potential of PEMFC after the activation-passivation transition. The corrosion resistance decreases with the increase of roughness in both solutions. The corrosion product films formed in the solution with lower acidity are more protective, leading to the appearance of the diffusion process. The enlargement of surface roughness results in the gradual reduction of ICR, but the acceleration of active and passive dissolutions.