A semi-empirical methodology to predict hydrogen permeability in amorphous alloy membranes

A semi-empirical methodology for prediction of hydrogen permeability in metallic amorphous alloys is proposed by combining a thermodynamic calculation and a molecular dynamics simulation. A CALPHAD-type thermodynamic calculation technique is used to calculate hydrogen solubility and thermodynamic factor for hydrogen diffusivity, and a molecular dynamics simulation based on a second nearest-neighbor modified embedded-atom method (2NN MEAM) interatomic potential is used to predict concentration-independent (tracer) diffusivity. The approach is applied to a prediction of hydrogen permeability in amorphous Cu50Zr50 and Cu65Zr35 alloys for which experimental data is available. The predicted permeability is in good agreement with experimental data, successfully reproducing the overall trend for the effect of alloy composition, which enables an alloy design of amorphous or crystalline metal hydrogen purification membranes.