Hydrogen sorption properties of Mg-20wt. %Fe23Y8 composite prepared by reactive mechanical alloying

Mg-20wt. % Fe23Y8 composite was successfully prepared by reactive mechanical alloying (RMA). X-ray diffraction (XRD) measurement shows that the main phases of composite are MgH2 and Mg2FeH6. The composite exhibits excellent hydrogen abs/desorption properties and can absorb 4.36wt. % and 5.72wt. % hydrogen at 473 and 573 K in 10 min under 3.0 MPa hydrogen pressure, respectively. The composite can desorb 5.27wt. % hydrogen at 573 K in 30 min under 0.02 MPa hydrogen pressure. Compared with the pure MgH2, the hydrogen desorption temperature of Mg-20wt. % Fe23Y8 composite is decreased about 40 °C. It is supposed that both the catalyst effect of Fe-Y distributed in Mg substrate and the crystal defects play the main role in improving hydrogen sorption properties of Mg-20wt. % Fe23Y8 composite.