Complex Mg-based hydrides obtained by mechanosynthesis: Characterization and formation kinetics

Ternary Mg 2 TH y , as well as quaternary Mg 2 T 0.5 T 0.5 ′ H y , Mg-based hydrides with T , T ′ = Fe , Co , Ni were synthesized by reactive mechanical alloying in hydrogen atmosphere at 0.3 MPa. The reaction progress was followed from the H 2 absorption during milling until a steady state was reached, and different kinetic behaviors were found in each case. These regimes could be related to the presence or absence of hydrogen-free Mg 2 T intermetallic precursors in the respective phase diagrams. The steady state samples were characterized by X-ray diffraction and differential scanning calorimetry, and those systems including Fe were studied, in addition, with Mössbauer spectroscopy.