Thermal Resistance and the Kinetics of Hydrogen Desorption from Hydrides of the Mg–Al–Ni–Ti Mechanical Alloy

• Published in: Materials science (New York, N.Y.) N.Y.), 2016, Vol.51 (4), p.457-464
• Main Authors: Dobrovol’s’kyi, V. D., Ershova, O. H., Solonin, Yu. M.
• Format: Article
• Language: English
• Subjects: Alloys; Aluminum; Characterization and Evaluation of Materials; Chemistry and Materials Science; Decomposition; Desorption; Equilibrium; Fluorides; Heat transfer; Hydrides; Hydrogen; Hydrogen storage; Hydrogenation; Intermetallic compounds; Kinetics; Magnesium; Materials Science; Mechanical alloying; Nickel; Solid Mechanics; Solid solutions; Spectrum analysis; Structural Materials; Thermal resistance; Titanium
• ISSN: 1068-820X; 1573-885X
• DOI: 10.1007/s11003-016-9862-z

With the aim to decrease temperature and improve the kinetics of decomposition of the MgH 2 stoichiometric hydride, we study the possibility of its complex alloying with 3 at.% Al + 3 at.% Ni + 7 at.% Ti performed with the help of mechanochemical synthesis. It is shown that, as a result of the addition of Al, Ni, and Ti to magnesium, the thermal resistance of the MgH 2 hydride phase of the mechanical alloy obtained by the reactive mechanical alloying decreases and, hence, the temperature of the onset of hydrogen desorption decreases from 320°C (for MgH 2 without Al, Ni, and Ti) to 280°C. We do not detect any decrease in the equilibrium temperature of the onset of hydrogen desorption under its constant pressure of 1 bar in a reactor, which may serve as an indication of the loss of thermodynamic stability of MgH 2 as a result of mechanical alloying. It is shown that the kinetics of hydrogen desorption of the MgH 2 phase of the mechanical alloy is mainly improved by alloying with Ni and Ti, whereas the contribution of Al is negligible.