化学计量比对钇-镍基储氢合金结构和储氢性能的影响  

Phase Structure and Hydrogen Storage Properties of Yttrium-Nickel-Based Alloys with Different Stoichiometric Ratio

作　　者：侯振宇 苑慧萍 刘彧儒 沈浩 李志念 蒋利军 Hou Zhenyu;Yuan Huiping;Liu Yuru;Shen Hao;Li Zhinian;Jiang Lijun(National Engineering Research Center of Nonferrous Metals Materials and Products for New Energy,GRINM Group Co.,Ltd.,100088,China;GRIMAT Engineering Institute Co.,Ltd.,101407,China;General Research Institute for Nonferrous Metals,Beijing 100088,China)

机构地区：[1]中国有研科技集团有限公司国家有色金属新能源材料与制品工程技术研究中心,北京100088 [2]有研工程技术研究院有限公司,北京101407 [3]北京有色金属研究总院,北京100088

出　　处：《稀有金属》2024年第12期1671-1680,共10页Chinese Journal of Rare Metals

基　　金：国家重点研发计划项目(2021YFB3502200)资助。

摘　　要：采用磁悬浮感应熔炼和分步退火的方法制备了YNi_(x)(x=1.9,2.1,2.3,2.5)合金,通过X射线衍射(XRD)、电子显微探针(EPMA)和Sieverts方法研究了化学计量比x对合金相结构和储氢性能的影响。结果表明,随着x从1.9增加至2.5,合金中YNi相消失,Y_(0.95)Ni_(2)相含量逐渐减小,YNi_(3)相出现,且含量逐渐增加,当x=2.5时,YNi_(3)相含量达到92.85%。储氢性能测试结果表明,随着化学计量比x的增加,合金前4周储氢容量衰减率逐渐减小,稳定吸氢容量逐渐增加,YNi_(2.5)合金在循环后容量不发生衰减,具有最大的稳定吸氢容量,为1.716%。吸放氢前后结构变化研究表明,YNi_(x)(x=1.9,2.1,2.3,2.5)合金容量衰减主要来源于Y_(0.95)Ni_(2)相的歧化,而YNi_(3)相结构在吸放氢后不发生改变。化学计量比x的增大能够显著改善钇-镍基合金的吸放氢容量和可逆储氢容量。Hydrogen is an ideal secondary energy source,with high energy density,zero carbon emission,and a wide range of sources.Efficient and safe hydrogen storage materials are one of the keys to enabling hydrogen energy applications.Rare earth-based hydrogen storage alloys have the advantages of high volumetric hydrogen storage density,superior kinetic,and moderate temperature for hydrogen absorption and desorption.Due to the structural limitations,the actual hydrogen storage capacity of the commercialized AB_(5)type alloy is close to the theoretical hydrogen storage capacity of 1.4%.The hydrogen storage capacity of rare earth alloys should be further improved to meet practical application needs.In recent years,rare earth AB_(2)type hydrogen storage alloys with large theoretical hydrogen storage capacity(>2.0%)are a class of promising hydrogen storage materials.However,the structures of rare earth AB_(2)alloys are prone to occur hydrogen-induced amorphization and disproportionation after hydrogen absorption and desorption.Compared with other rare earth AB_(2)alloys,YNi_(2)alloy has a smaller relative molecular mass and a smaller atomic radius ratio(R_(A)/R_(B)),but YNi_(2)alloy can only form crystalline Y_(0.95)Ni_(2)H_(2.6)(1.27%).Hydrogen-induced amorphization can occur when more hydrogen atoms are absorbed,and adjusting the stoichiometric ratio of alloys is a common method to improve the hydrogen storage properties of the rare earth hydrogen storage alloys.By this method,the unit cell volume of the alloys will change due to the change of the atomic ratio and a second phase may also be formed,which can improve the hydrogen storage capacity and plateau characteristics of the alloys.At present,the effect of stoichiometric ratio on the structure and hydrogen storage performance of the yttrium-nickel-based alloys has not been investigated.In this study,YNi_(x)(x=1.9,2.1,2.3,2.5)alloys were prepared by magnetic induction melting under Ar atmosphere from high purity metals Y(99.5%)and Ni(99.9%).After melting,the alloys were

关 键 词：钇-镍基合金 化学计量比 储氢性能 相结构 

分 类 号：TG139.7[一般工业技术—材料科学与工程]