颗粒尺寸对Mg-3Ni-2MnO_2储氢复合粉体放氢过程相转变行为影响

The effect of particle size on phase transformation behaviors of Mg-3Ni-2MnO_2 hydrogen storage materials during dehydrogenation process

利用充氢反应球磨技术制备了不同球磨时间的氢化态Mg-3Ni-2MnO2复合粉体材料,并对其放氢动力学性能进行了测试,进而利用J-M-A方程分析了放氢过程相转变行为特征。研究结果表明:反应球磨时间对氢化态Mg-3Ni-2MnO2复合粉体颗粒尺寸有影响;颗粒尺寸影响储氢复合粉体材料放氢相转变动力学性能。不同颗粒尺寸的储氢材料放氢相转变过程均经历三个阶段,每个阶段对应不同的相转变分数区间。颗粒尺寸不同,则完成其相转变过程的主要阶段不同。

The hydrided Mg-3Ni-2MnO2 powder materials were prepared through the reactive ball milling under some hydrogen pressure,and its dehydrogenation kinetics properties were measured by the self-made apparatus too,further,the character of phase transformation behaviors was analyzed according to the Johnson-Mahl-Avrami equation.The results show that the reactive ball-milling time has the effect on the particle size of hydrided Mg-3Ni-2MnO2,and the particle size has strongly effect on the dehydrogenation kinetics of Mg-3Ni-2MnO2 hydrogen storage materials too. The dehydrogenation process of all the hydrogen storage materials with various particle size can be divided into 3 stages,and each stage corresponds to different range of phase transformation fraction. The main stage to finish phase transformation is different for different particle size.