Ce替代Y对Y_(1-x)Ce_xFe_2(x=0,0.15,0.25和0.50)合金吸氢性能的影响  

Hydrogen Absorption Property of Y_(1-x)Ce_xFe_2(x=0,0.15,0.25 and 0.50) Alloys with Ce Substitution for Y

作　　者：杨康 蒋利军[1] 苑慧萍[1] 辛恭标 万琦[1] 赵旭山[1] 

机构地区：[1]北京有色金属研究总院能源材料与技术研究所,北京100088

出　　处：《稀有金属》2017年第11期1202-1207,共6页Chinese Journal of Rare Metals

基　　金：工业和信息化部风力发电用高容量稀土储能材料及装置开发-续建项目(52203)资助

摘　　要：利用磁悬浮感应熔炼法制备了Y_(1-x)Ce_xFe_2(x=0,0.15,0.25,和0.50)合金,通过X射线衍射分析(XRD)、扫描电镜(SEM)、电子探针(EPMA)和定容法等测试方法,研究了Ce替代Y对Y_(1-x)Ce_xFe_2合金吸氢性能的影响。研究表明,Y_(1-x)Ce_xFe_2合金为多相结构,主相为MgCu_2型结构的YFe_2相,同时还含有Pu Ni3型结构的YFe_3第二相,且Ce元素有效替代了合金中的Y元素;当x≦0.25时,随着Ce替代量的增加,合金中YFe_3相增多,且合金的吸氢动力学性能和吸放氢循环稳定性得以改善,初始吸氢平衡时间t0.9由48 s降低至12 s,经7次吸放氢循环后,稳定吸氢容量由0.409%升高至0.598%(质量分数),吸氢容量衰减率由79%降低至55%,但合金初始吸氢容量有所下降;这主要归因于YFe_3相较之于YFe_2相结构更加稳定,但其吸氢容量更低;当x=0.50时,合金的吸氢容量及吸放氢循环稳定性均同步下降,此时合金中的YFe2相增多,合金吸氢后歧化反应加剧。因此,在Y_(1-x)Ce_xFe_2中,Ce对Y的替代量以小于0.50为宜。The Y1-xCexFe2 alloys were prepared by induction levitation melting method. The effect of Ce substitution for Y on hydro- gen absorption properties of the alloys was investigated by X-ray diffraction （ XRD ）, scanning electron microscope （ SEM ）, electron probe microanalysis （EPMA） and Sievert＇s method. The results revealed that Y1-xCexFe2 alloys had a multi-phase structure. The major phase was YFe2 and second phase was YFe3. In addition, Y element was substituted by Ce element efficiently in the alloys. When x ≤ 0. 25, the content of YF% phase increased with the increase of Ce substitution for Y. The hydrogen absorption kinetics and cycle stability of the alloys were improved with the increase of Ce content due to more stable structure of YFe3 than that of YFe2. The initial hydrogen absorption equilibrium time t09 decreased from 48 to 12 s. After 7 absorption and desorption cycles, the stable hydrogen absorption capacity increased from 0. 409% to 0. 598% （mass fraction）, and the hydrogen absorption capacity decay rate decreased from 79% to 55%. However, the hydrogen absorption capacity of the alloys decreased owing to much lower hydrogen storage capacity of YFe3. When x = 0.50, both the hydrogen absorption capacity and the cycle stability declined. Meantime, the content of YFe2 phase increased significantly which intensified disproportionation after hydrogenation. Hence, the substitution of Ce for Y should be less than 0. 50.

关 键 词：储氢合金 YFe2相 吸氢动力学性能 YFe3 循环稳定性 

分 类 号：TG139.7[一般工业技术—材料科学与工程]