Hot-Press Workability of Ni-based Glassy Alloys in Supercooled Liquid State and Production of the Glassy Alloy Separators for Proton Exchange Membrane Fuel Cell

Abstract

Optimum alloy compositions of the Ni-Nb-Cr-Mo-P-B, Ni-Cr-Nb-P-B and Ni-Cr-Mo-P-B glassy alloys were investigated for trail production of separator of fuel cell. Eventually the Ni₆₀Nb₂Cr₁₆Mo₂P₁₆B₄, Ni₆₅Cr₁₀Nb₅P₁₆B₄ and Ni₆₅Cr₁₀Mo₅P₁₆B₄ glassy alloys were chosen from the viewpoint of having a wide supercooled liquid region.
Then the groove formability of the compositionally optimized alloys in a supercooled liquid state was studied by hot-pressing with the dies having precise grooves. A precise groove forming can be achieved by hot-pressing the Ni₆₀Nb₂Cr₁₆Mo₂P₁₆B₄ and Ni₆₅Cr₁₀Mo₅P₁₆B₄ glassy alloys in a supercooled liquid state at T_g + 20 K. However, it was difficult to form the precise grooves in the Ni₆₅Cr₁₀Nb₅P₁₆B₄ glassy alloy.
Finally, we successfully demonstrated that it is possible to form the grooves by hot-pressing using viscous flow deformation in a supercooled liquid state and to produce metallic glassy separators for proton exchange membrane fuel cells (PEMFC).