Thermodynamic characterization of (Nb1 −xFex)1 −xCrx−H systems

Pressure-composition isotherms for hydrogen absorption and desorption are determined for (Nb1 −xFex)1 −xCrx alloys (x = 0.05, 0.07) over the temperature range 298–353 K. Pronounced hysteresis was observed at all temperatures. The average enthalpies ([H]/[M]= 0.2–0.7) for hydride formation are −14.9 and −145.4 kJ (mol H)−1 and for hydride decomposition are 33.6 and 33.4 kJ (mol H)−1 forx-values of 0.05 and 0.07, respectively.