KINETIC-STUDY OF THE HYDROGEN ABSORPTION IN THE ZR(ALXFE1-X)2 SYSTEM

The hydriding kinetic behavior of Zr(AlxFe1-x)2, 0.5 less-than-or-equa l-to x less-than-or-equal-to 0.75, specimens was examined at pressures up to 70 atm and temperatures up to 573 K. Quantitative information w as obtained only for Zr(Al0.5Fe0.5)2 and partly for Zr(Al0.6Fe0.4)2. T he results were interpreted in terms of a constant velocity movement o f the hydride-metal boundary. A significant increase of the hydrogenat ion activation energy was found for Zr(Al0.5Fe0.5)2 and Zr(Al0.6Fe0.4) 2 with respect to the previously investigated Zr(Al0.2Fe0.8)2. This wa s manifested by a corresponding two order magnitude decrease of the hy dride propagation velocities at room temperature. We regard the variat ion in hydriding kinetics, stability and hydrogen capacity across the Zr(AlxFe1-x)2-H2 system as an indication of a possible kinetic effect on the hydrogen absorption in the Al-rich compounds.