Dual-tuning effects of In, Al, and Ti on the thermodynamics and kinetics of Mg85In5Al5Ti5 alloy synthesized by plasma milling

The dehydrogenation enthalpy change of MgH2 by reversibly forming an Mg0.95In0.05 solid solution offers a new method for tuning the thermodynamics of Mg-based alloys. In order to further lower the stability of MgH2, Al has been introduced into Mg(In) solid solution. At the same time, to solve the problem of sluggish kinetic properties of Mg-In solid-solution systems and to lower the dehydrogenation activation energy, Ti has also been added. It has been demonstrated that the Mg85In5Al5Ti5 alloy synthesized by plasma milling (P-milling) shows both enhanced dehydriding thermodynamics and kinetics. This technique could be used to synthesize Mg(In, Al) ternary solid solution incorporating the Ti catalyst in only one step, making it much more efficient than the two-step method. Compared with Mg-based solid solutions, the addition of Ti and in-situ synthesized MgF2 improved the kinetics and the introduction of In as well as Al imparted enhanced thermodynamics to the Mg85In5Al5Ti5 system. The dehydrogenation enthalpy change and activation energy were lowered to 65.2 kJ/(mol H2) and 125.2 kJ/mol, respectively, for the Mg85In5Al5Ti5 alloy.