The study of hydrogen sorption properties of Mg_(17)Al_(12)La_(0.45)

摘要

Mg_(17)Al_(12) and rare earth improved Mg_(17)Al_(12)La_(0.45) alloys were prepared by resistance melting method. The hydrogen sorption properties of the alloys with and without ball-milling process were investigated with the help of PCT measurements. The phase compositions of the experimental alloys were determined through powder X-Ray diffraction. It is found that the introduction of La and the high energy ball-milling technique could remarkably improve the hydrogen sorption capability of Mg_(17)Al_(12)- For Mg_(17)Al_(12)La_(0.45) alloy, the hydrogen absorption starts at 473K and the hydridying rate increases at each temperature (573K, 523K, 473K) after high energy ball-milling process. The hydrogen desorption capacity of this alloy is 4wt% at 573K. XRD shows that there are two phases Mg_(17)Al_(12) and Al_2La_(0.15)Mg_(0.85) after melting and Al_2La_(0.15)Mg_(0.85) phase always exists during hydrogen sorption cycles of Mg_(17)Al_(12)La_(0.45).