论文部分内容阅读
通过对MgH_2+x%Ni(x=0,2,4,8,20,30)样品高能球磨不同时间,研究球磨时间及镍含量对MgH_2/Ni体系放氢性能的影响。对合金在球磨过程中的结构变化、组织演变及放氢动力学进行了系统研究。结果表明,当放氢温度高于380°C时,MgH_2的放氢动力学与晶粒尺寸、颗粒尺寸及合金中的缺陷数量无关,随着球磨时间增加,镍在MgH_2表面分布更加均匀,放氢动力学性能越好。体系放氢后会生成Mg_2Ni,从而降低复合体系在循环过程中的储氢性能。在MgH_2放氢过程中,镍不仅有助于氢原子的重组,还可以帮助镁的形核长大。
The effects of ball milling time and nickel content on the hydrogen evolution performance of MgH_2 / Ni system were studied by high energy ball milling of MgH_2 + x% Ni (x = 0, 2, 4, 8, 20, 30) The structural changes, microstructure evolution and hydrogen evolution kinetics of the alloy during ball milling were studied systematically. The results show that when the temperature is higher than 380 ° C, the hydrogen evolution kinetics of MgH_2 has nothing to do with the grain size, particle size and the number of defects in the alloy. With the increase of ball milling time, the distribution of nickel on MgH_2 surface is more uniform, Hydrogen kinetics better. The system will generate Mg_2Ni after the hydrogen is released, so as to reduce the hydrogen storage capacity of the composite system during the cycle. During the hydrogenation of MgH_2, nickel not only contributes to the recombination of hydrogen atoms, but also helps the nucleation and growth of magnesium.