Investigation on the physical and electrochemical properties of typical Ni-based alloys used for the bipolar plates of proton exchange membrane fuel cells
Jiacheng Zhong, Beirui Hou, Wenmin Zhang, Zhansheng Guo, Chunwang Zhao
Abstract
The phase, mechanical properties, corrosion resistance, hydrophobicity, and interface contact resistance of three typical Ni-based alloys (Hastelloy B, Hastelloy C-276, and Monel 400) and 304 stainless steels were experimentally studied to evaluate their service performances as bipolar plate materials of proton exchange membrane fuel cells. All four alloys exhibit single-phase face-centered cubic structure, high strength, good ductility, and high hardness. Hastelloy C-276 has the best ductility with an uniform elongation of 72.5% and highest hardness of 363.7 HV. Hastelloy B has the highest ultimate tensile strength of 913.6 MPa. The hydrophobicity of all four alloys is not good, although Monel 400 has the highest water contact angle of 84.2°. Hastelloy B, Hastelloy C-276, and 304 stainless steel exhibit unsatisfying corrosion resistance in a simulated acidic work environment of proton exchange membrane fuel cell (0.5 M H 2 SO 4 +2 ppm HF, 80 °C, H 2 ) and high interface contact resistance. By contrast, Monel 400 demonstrates excellent corrosion resistance with a corrosion current density of 5.9 × 10 −7 A cm −2 and a low interface contact resistance of 7.2 mΩ cm 2 at 140 N/cm 2 . In terms of comprehensive performance, Monel 400 is the best uncoated material for the bipolar plates of proton exchange membrane fuel cells among typical Ni-based alloys.