2003 Volume 28 Issue 1 Pages 54-60
New magnesium-based intermetallic compounds including group 14 elements, such as Mg2 and Mg2Sn, which combine with hydrogen covalently were synthesized by mechanical alloying, and the hydrogenation characteristics of the compounds were investigated. From the Sievert’s measurement method, it was found that the mechanically alloyed Mg2 absorbs and desorbs hydrogen reversibly at moderate temperature, though the hydrogen content was not so large. The amounts of absorbed and desorbed hydrogen were enhanced by addition of nickel to Mg2. The best performance was obtained at the composition of Mg2Ge0.8Ni0.2. The analogous tendency was observed on the mechanically alloyed Mg2Sn, but this compound was inferior to Mg2 in the performance of hydrogenation properties. The pressure–composition isotherms for Mg2Ge–H and/or Mg2Ge0.8Ni0.2–H systems were obtained electrochemically at 303 K. The amounts of hydrogen released from the compounds were found to be 0.50 and 0.86 wt% for Mg2 and Mg2Ge0.8Ni0.2, respectively. The amount of desorbed hydrogen was larger for Mg2Ge0.8Ni0.2 than for Mg2Ge. This result was coincident with that from the Sievert’s measurement. The existence of hydrogen in the alloys obtained was also confirmed by neutron radiography.
