A Comparison Study of Hydrogen Storage Thermodynamics and Kinetics of YMg11Ni Alloy Prepared by Melt Spinning and Ball Milling

摘要

Melt spinning(MS)and ball milling(BM)were employed to fabricate YMg_(11)Ni alloy,and their structures and hydrogen storage performances were examined.The results reveal that the as-spun and as-milled alloys both exhibit the nanocrystalline and amorphous structure.The as-milled alloy shows a larger hydrogen absorption capacity as compared with the as-spun alloy.More than that,the as-milled alloy exhibits lower onset hydrogen desorption temperature than the as-spun one,which are 549.8 and 560.9 K,respectively.Additionally,the as-milled alloy shows a superior hydrogen desorption property to the as-spun one.On the basis of the time needed by desorbing hydrogen of 3 wt%H_2,for the asmilled alloy,it needs 1106,456,343,and 180 s corresponding to hydrogen desorption temperatures of 593,613,633,and653 K.However,for the as-spun alloy,the time needed is greater than 2928,842,356,and 197 s corresponding to the same temperatures.Hydrogen desorption activation energies of as-milled and as-spun alloys are 98.01 and 105.49 k J/mol,respectively,which is responsible for that the as-milled alloy possesses a much faster dehydriding rate.By means of the measurement of pressure–composition–temperature(P–C–T)curves,the dehydrogenation enthalpy change of the alloys prepared by MS(DH_(de)(MS))and BM(DH_(de)(BM))is 81.84 and 79.46 k J/mol,respectively,viz.DH_(de)(MS)[DH_(de)(BM).