快淬对Mg_(24)Ni_(10)Cu_2和(Mg_(24)Ni_(10)Cu_2)_(85)La_(15)合金吸放氢动力学的影响

Effects of rapid quenching process on hydrogen storage kinetics of Mg_(24)Ni_(10)Cu_2 and (Mg_(24)Ni_(10)Cu_2)_(85)La_(15) alloys

用快淬工艺制备了La-Mg-Ni-Cu系Mg_2Ni型Mg_(24)Ni_(10)Cu_2和(Mg_(24)Ni_(10)Cu_2)_(85)La_(15)合金,用XRD及HRTEM分析了铸态及快淬态合金的结构;用全自动Sieverts设备测试了合金的气态吸放氢动力学;用差热分析仪测试了不同加热速率下合金的放氢DSC曲线,并用Kissinger方程计算了合金放氢激活能。结果表明:不含La的铸态合金具有Mg_2Ni单相结构,添加La的合金除含有Mg_2Ni相外,还含有第二相La_2Mg_(17)和LaMg_3相。快淬态合金具有纳米晶、非晶结构。La的加入显著地提高了合金在真空快淬过程中的非晶形成能力。真空快淬后合金的气态吸放氢动力学得到明显改善,这主要归因于纳米晶结构的形成和合金激活能的降低。

The Mg24Ni10Cu2and（Mg24Ni10Cu2）85La15 alloys,which belong to La-Mg-Ni-Cu system Mg2Ni type alloys,were prepared by rapid quenching process.The structures of the as-cast and quenched alloys were analyzed by XRD and HRTEM.The gaseous hydriding and dehydriding kinetics of alloys were tested by a fully automatic Sieverts equipment.Hydrogen desorption DSC curves of alloys were tested in different heating rates by a differential thermal analyzer and the activation energy of alloys was calculated by using the equation of Kissinger.The results showed that La-free alloys only possess Mg2Ni phase,however,La-containing alloys possess biphasic structures with a major phase Mg2Ni and a secondary phase including La2Mg17 and LaMg3phase.The quenched alloys have nanocrystalline and amorphous structure.Adding La expedites the formation of the glass in rapid quenching process.The treatment of rapid quenching can improve the gaseous hydriding and dehydriding kinetics,which mainly attributed to the formation of nanocrystalline structure and the reduction of activation energy.