摘要：
为了改善Mg2Ni型合金的气态贮氢动力学性能,在合金中添加少量La,并用快淬工艺制备La-Mg-Ni-Cu系Mg2Ni型(Mg24Ni10Cu2)100?xLax(x=0,5,10,15,20)(摩尔分数,x%)合金.采用XRD、SEM及HRTEM分析铸态及快淬态合金的微观结构;采用全自动Sieverts测试仪测试合金的气态吸放氢动力学;采用差热分析仪测试不同加热速率下合金的放氢DSC曲线,并用Kissinger方程计算合金的放氢激活能.建立动力学与La含量及淬速的关系.结果表明:添加La不改变合金的主相Mg 2 Ni相,但导致第二相La 2 Mg 17和LaMg 3相出现,第二相的量随La含量的增加而增加.添加La和快淬有助于合金形成纳米晶?非晶结构,降低放氢激活能,从而改善放氢动力学.当La含量x从0增加到20时,铸态合金的放氢激活能dekE从73.18 kJ/mol下降到60.41 kJ/mol,而30m/s的快淬态合金的dekE值从66.16 kJ/mol下降到50.50 kJ/mol.%In order to improve the gaseous hydrogen storage kinetics of Mg2Ni type alloys, a small quantity of La was added to alloys, and the La-Mg-Ni-Cu system Mg2Ni type (Mg24Ni10Cu2)100?xLax (x=0, 5, 10, 15, 20) (mole fraction, x %) alloys were prepared by rapid quenching. The structures of the as-cast and quenched alloys were analyzed by XRD, SEM and HRTEM. The gaseous hydrogen absorption and desorption kinetics of alloys were tested by a fully automatic Sieverts equipment. Hydrogen desorption DSC curves of alloys were tested at different heating rates by a differential thermal analyzer, and the activation energy of alloys was calculated by using the equation of Kissinger. The relationship between the kinetics and La content and quenching rate was established. The results show that adding La doesn't change the Mg2Ni major phase, however, leads to the formation of the second phases including La2Mg17 and LaMg3phases. The phase abundance of the second phases increases with increasing the La content. Increasing La content and quenching rate are helpful to form the nanocrystalline and amorphous structure, and reducing the hydrogen desorption activate energy, thus improving the hydrogen desorption kinetics for Mg2Ni type alloys. The hydrogen desorption activation energy reduces from 73.18 kJ/mol to 60.41 kJ/mol and 66.16 kJ/mol to 50.50 kJ/mol for the as-cast alloy and as-spun alloy (30 m/s), respectively.
