Mg-C 複合材料の創製とその水素吸蔵特性

抄録

  Mg-based alloys possess light-weight and high hydrogen absorption capacity, so they have been investigated extensively for several decades. Also, attention has recently been paid to graphite as a hydrogen absorber. In this study Mg-C composites were prepared by ball milling and their hydrogenation properties were investigated. Powders were first mixed with a 1:1 molar ratio of Mg (99.9% purity) to graphite (99.9% purity), and then milled using ZrO₂ balls in a ZrO₂ pot for 60 hours. This process was performed in a vibration ball mill at the speed of 345 rpm under an Ar gas atmosphere. The powders prepared in this way were handled in a glove box filled with an Ar gas. From the XRD patterns, it was found that the peak corresponding to the Mg phase shifted slightly to lower diffraction angles, indicating that the lattice spacing of the Mg phase was expanded by alloying partially with C in the powders. On the other hand, graphite peaks were rather broadened. An affinity for the powders with hydrogen was confirmed from the absorption experiment at the temperature of 453 K and the hydrogen pressure of 1.8 MPa. The total amount of absorbed hydrogen was estimated to be 3.5 mass% from the TDS measurement.