MgYNi合金的结构与快速吸氢动力学  

Structure and Fast Hydrogen Absorbing Kinetics of MgYNi Alloys

作　　者：李永治 翟亭亭 罗龙 赵增武 张羊换[1,2] 赵栋梁 Li Yongzhi;Zhai Tingting;Luo Long;Zhao Zengwu;Zhang Yanghuan;Zhao Dongliang(Department of Functional Material Research,Central Iron and Steel Research Institute,Beijing 100081,China;Key Laboratory of Integrated Exploitation of Bayan Obo Multi-Metal Resources,Inner Mongolia University of Science and Technology,Baotou 014010,China)

机构地区：[1]钢铁研究总院功能材料研究所,北京100081 [2]内蒙古科技大学内蒙古自治区白云鄂博矿多金属资源综合利用重点实验室,内蒙古包头014010

出　　处：《稀有金属》2019年第3期247-254,共8页Chinese Journal of Rare Metals

基　　金：国家自然科学基金项目(51761032);内蒙古自然科学基金项目(2018LH05010;2017BS0507);内蒙古科技大学科研仪器专项(2015KYYQ07)资助

摘　　要：采用真空悬浮熔炼法制备了Mg_(80)Ni_(20), Mg_(77)Y_3Ni_(20)和Mg_(73)Y_7Ni_(20) 3种镁基合金,研究了Y替代Mg对合金微观结构和吸氢动力学的影响,并对快速吸氢动力学数据进行了方程模拟。结果表明, Mg_(80)Ni_(20)合金主要由带状的Mg_2Ni和层状的Mg+Mg_2Ni共晶组织组成, Y的加入主要形成了分布在共晶基体里的Ni_3Y相,并造成带状的Mg_2Ni相的减少与消失,及Mg-Mg_2Ni共晶组织向针状组织的转变。吸氢后的合金中Ni_3Y相消失,与Mg和H反应,原位形成了Mg_2NiH_4和YH_2相。Y对Mg的替代显著改善了合金的吸氢动力学,尤其是较低温度下和快速吸氢性能。393 K下, Mg_(77)Y_3Ni_(20)能在180 s内吸氢2.35%(质量分数),是Mg_(80)Ni_(20)吸氢量的4倍多。Y的添加改善合金吸氢动力学的原因在于,原位形成的YH_2相增加了氢原子在合金中的扩散通道和晶面数量,缩短了氢原子的扩散时间。通过对现有吸氢动力学模型的比较分析,给出一种选取快速吸氢动力学临界时间节点的方法,并找出可以较好模拟Mg基合金快速吸氢动力学数据的方程。Mg-based Mg80Ni20,Mg77Y3Ni20,and Mg73Y7Ni20 alloys were prepared by vacuum induction levitation melting furnace.Effects of Y substitution on the structure and hydrogen absorbing kinetics of the alloys were investigated.The result showed that the Mg80Ni20 alloy was composed of lath-like Mg 2 Ni phase and lamellar eutectic Mg+Mg2Ni.Addition of Y into the alloys led to the decreasing and eventually vanished of Mg2Ni,and changing eutectic Mg+Mg2Ni into coarse acicular structure.Combined with Mg,Ni3Y,which were the main phase of Y in the alloys,translated into Mg2NiH4 and YH2 during hydrogenation process.Substitution of Mg with Y significantly improved the hydrogen absorbing kinetics,especially for lower operating temperature and fast absorbing processing.At 393 K,the hydrogen absorption capacity of the Mg73Y7Ni20 alloy within 180 s was 2.35%,which was 4 times than that of Mg80Ni20.The improvement of hydrogen absorption kinetics was owning to the formation of large number of phase interface caused by in situ formed YH2,which acted as an effect way for hydrogen diffusion and shortening the diffusion time of hydrogen atoms.A method of selecting critical time for the fast hydrogen absorbing process was provided,and a first order reaction equation was performed to simulate the data of fast hydrogen absorbing.

关 键 词：储氢 MgYNi合金 快速吸氢动力学 模拟方程 

分 类 号：TG139.7[一般工业技术—材料科学与工程]