Hydridic, thermodynamic and kinetic properties of Hf2Ni intermetallic phase

The intermetallic compound Hf2Ni was the subject of investigations by several methods. The relative stability was checked by calculating its enthalpy and cohesive properties, using the augmented plane wave plus local orbitals (APW + lo) method of ab initio calculations. The kinetics of hydrogen absorption in this compound was investigated in the temperature range from 573 to 823 K, under the constant hydrogen pressure of 1 bar. The obtained rate constants, k (s−1), and hydriding capacities (H/M) are as follows: 0.00038 (0.69), 0.00131 (0.95), 0.00246 (1.13) and 0.0042 (0.92) for temperatures 573, 673, 723 and 823 K, respectively. The changes in crystal structure and morphology caused by multiple hydriding/dehydriding cycles were followed by XRD and SEM.