Production of metallic glassy bipolar plates for PEM fuel cells by hot pressing in the supercooled liquid state

A screening test was conducted to optimize the alloy composition in the Ni60NbxCryMozP16B4 (x + y + z = 20 at%) alloy system in order to achieve a large supercooled liquid region, ΔTx, and a low crystallization temperature, Tx. From this study, the Ni60Nb2Cr16Mo2P16B4 glassy alloy was found to be the optimal alloy. The static and potentiodynamic corrosion behaviors of this glassy alloy were measured. Polarization measurements showed that the current density of the non-polished glassy alloy sample was smaller than that of a SUS316L sample. By contrast, the current density of the surface-polished glassy sample was slightly larger than that of the SUS316L sample in the voltage range of 0.2–0.7 V. The interfacial contact resistance of the Ni60Nb2Cr16Mo2P16B4 glassy alloy was smaller than that of the SUS316L alloy and it decreased with increasing compaction force. A bipolar plate was successfully produced by hot pressing the glassy alloy sheet in a supercooled liquid state. The I–V characteristics of a single cell with the glassy bipolar plates were measured.