2011 Volume 52 Issue 4 Pages 610-613
The alloying effects of tungsten on the hydrogen solubility, the resistance to hydrogen embrittlement and the hydrogen permeability are investigated for Ta-based hydrogen permeable membranes. The hydrogen solubility is found to decrease by the addition of tungsten into tantalum or by increasing the temperature. It is also found that the mechanical properties (i.e., strength and ductility) for Ta-based alloy is better than that for Nb-based alloy in hydrogen atmosphere at high temperature. It is demonstrated that the Ta-5 mol%W alloy possesses excellent hydrogen permeability without showing any hydrogen embrittlement when used under appropriate permeation conditions. For example, the hydrogen flux for Ta-5 mol%W alloy measured at 773 K under the pressure condition of inlet/outlet = 0.15/0.01 MPa is about 5 times higher than that for Pd-27 mol%Ag alloy measured at the same testing condition.
