A. Israel et I. Jacob, KINETICS AND THERMODYNAMICS OF HYDROGEN ABSORPTION IN THE ZR(AL0.1FE0.9)(2) INTERMETALLIC COMPOUND, Journal of alloys and compounds, 260(1-2), 1997, pp. 131-134
Thermodynamic and kinetic characteristics of hydrogen absorption in Zr
(Al0.1Fe0.9)(2) were investigated at pressures up to 80 atm of H-2 and
temperatures between 248 K and 270 K. The heat and entropy of formati
on of the Zr(Al0.1Fe0.9)(2) hydride are estimated to be -24.7 kJ/(mole
H-2) and -120 J/(Kmole H-2), respectively. Small, well-defined sampl
es were utilized for the kinetic research. The experimental kinetic da
ta fit a shrinking core (sc) model, in accord with a visual examinatio
n of partly hydrided samples. The pressure dependence of the rate cons
tants indicates an interface-controlled phase transition as the hydrid
e formation rate-determining step. The activation energy for the hydri
ding process is estimated from Arrhenius plots of the reaction rates t
o be 0.30 eV/H atom. The kinetic data are discussed in view of similar
results for additional intermetallic compounds. (C) 1997 Elsevier Sci
ence S.A.