Mg22 Y2Ni10 Cu2储氢合金的放氢性能  

Dehydrogenation properties of Mg22 Y2Ni10 Cu2 hydrogen storage alloy

作　　者：孙昊[1] 贾凯波 赵凤光[1] 张羊换[1] 任慧平[1] SUN Hao;JIA Kai-bo;ZHAO Feng-guang;ZHANG Yang-huan;REN Hui-ping(School of Materials and Metallurgy,Inner Mongolia University of Science and Technology,Baotou 014010,Inner Mongolia,China)

机构地区：[1]内蒙古科技大学材料与冶金学院,内蒙古包头014010

出　　处：《材料工程》2020年第9期100-106,共7页Journal of Materials Engineering

基　　金：国家自然科学基金项目(51471054);内蒙古自治区高校研究项目(NJZZ18142);内蒙古自治区自然科学基金项目(2018LH05003)。

摘　　要：采用中频感应炉冶炼了添加少量Y和Cu的Mg 2Ni型储氢合金,利用X射线衍射仪、扫描电子显微镜、能谱分析仪、透射电子显微镜对合金不同状态下的物相结构与显微组织进行测试,借助基于Sieverts法的吸放氢设备和差示扫描量热仪测试合金的放氢性能,研究合金在等温与连续加热条件下的放氢过程和放氢活化能,并讨论相应的放氢机制。结果表明:铸态合金呈片层状组织,其主相为Mg 2Ni,YMgNi 4,并含有少量Mg;在前6次放氢中,每次达到90%最大放氢量所用时间分别为446,418,360,354,342 s和336 s;对等温放氢曲线拟合的结果表明:合金脱氢过程是以随机成核和随后生长的机制完成;等温放氢时的活化能E a=67.6 kJ/mol,而连续升温时的放氢活化能E a=69.5 kJ/mol;同时发现,505 K和512 K为Mg 2NiH 4相的晶型转变点,且Mg 2NiH 4比MgH 2先行放氢。The Mg 2Ni-type hydrogen storage alloy with the addition of a little Y and Cu was prepared by medium frequency induction melting.The phase composition and microstructure were characterized by X-ray diffractometer,scanning electron microscope,energy dispersive spectrum analyzer and transmission electron microscope.Hydrogen desorption performances of the alloy were measured by hydrogen absorption/desorption equipment based on the Sieverts method and high pressure differential scanning calorimeter.The activation energy and corresponding mechanism of dehydrogenation under isothermal and continuous heating conditions were investigated.The results show that the as-cast alloy presents lamellar-shaped structures which are composed of Mg 2Ni and YMgNi 4 as the main phase and small amount of Mg.The alloy exhibits good activation properties in which the time taken to reach 90%of the maximum dehydrogenation content is 446,418,360,354,342 s and 336 s in the first six isothermal hydrogen desorption cycles respectively.The fitting results of the hydrogen desorption kinetics indicate that the dehydrogenation is governed by random nucleation and subsequent growth mechanism.The activation energy of the isothermal hydrogen desorption of the alloy is E a=67.6 kJ/mol.Comparatively,the activation energy of hydrogen evolution at continuous heating is E a=69.5 kJ/mol.At the same time,it is found that crystal transitions of Mg 2NiH 4 are identified to be triggered at 505 K and 512 K.Furthermore,dehydrogenation of Mg 2NiH 4 starts more easily than that of MgH 2.

关 键 词：Mg22 Y2 Ni10 Cu2储氢合金 放氢性能 活化能 随机成核 随后生长 

分 类 号：TG146.2[一般工业技术—材料科学与工程]