Enhanced hydrogen storage kinetics of nanocrystalline and amorphous Mg_2N-type alloy by substituting Ni with Co  

Co替代Ni改善纳米晶和非晶Mg_2Ni型合金的贮氢动力学(英文)

作　　者：张羊换[1,2] 宋春红[1,2] 任慧平[2] 李志刚[1,2] 胡锋[1,2] 赵栋梁[1] 

机构地区：[1]钢铁研究总院功能材料研究所,北京100081 [2]内蒙古科技大学国家重点实验室培育基地,包头014010

出　　处：《Transactions of Nonferrous Metals Society of China》2011年第9期2002-2009,共8页中国有色金属学报（英文版）

基　　金：Projects(50871050,50961009)supported by the National Natural Science Foundation of China;Projects(2010ZD05,2011ZD10)supported by Natural Science Foundation of Inner Mongolia,China;Project(NJzy08071)supported by High Education Science Research Project of Inner Mongolia,China

摘　　要：In order to improve the hydrogen storage kinetics of the Mg2Ni-type alloys, Ni in the alloy was partially substituted with element Co. The Mg2Ni-type Mg2Ni1-xCox （x=0, 0.1, 0.2, 0.3, 0.4） alloys were fabricated by melt-spinning technique. The structures of the as-spun alloys were characterized by XRD and TEM. The gaseous and electrochemical hydrogen storage kinetics of the alloys was measured. The results show that the substitution of Co for Ni notably enhances the glass forming ability of the Mg2Ni-type alloy. The amorphization degree of the alloys visibly increases with rising of Co content. Furthermore, the substitution of Co for Ni significantly improves the hydrogen storage kinetics of the alloys. With an increase in the amount of Co substitution from 0 to 0.4, the hydrogen absorption saturation ratio of the as-spun （15 m/s） alloy increases from 81.2% to 84.9%, the hydrogen desorption ratio from 17.60% to 64.79%, the hydrogen diffusion coefficient increases from 1.07×10-11 to 2.79×10-11 cm2/s and the limiting current density increases from 46.7 to 191.7 mA/g, respectively.为了改善Mg2Ni型合金的贮氢动力学性能,用Co部分替代合金中的Ni,用快淬技术制备了Mg2Ni1?xCox(x=0,0.1,0.2,0.3,0.4)贮氢合金。用XRD、HRTEM表征了快淬态合金的微观结构,用自动控制的Sieverts设备测试了合金的吸放氢动力学性能,用程控电池测试仪测定了合金薄带的电化学贮氢动力学。结果表明:Co替代Ni提高了Mg2Ni型合金的非晶形成能力,合金的非晶化程度随着Co含量的增加而增加。此外,Co替代Ni显著地改善了合金的贮氢动力学,当Co含量从0增加到0.4时,快淬态(15m/s)合金在5min内的吸氢饱和率从81.2%增加到84.9%,20min的放氢率从17.60%增加到64.79%,氢扩散系数从1.07×10-11cm2/s增加到2.79×10?11cm2/s,极限电流密度从46.7mA/g增加到191.7mA/g。

关 键 词：Mg2Ni-type alloy substituting Ni with Co melt spinning hydrogen storage kinetics 

分 类 号：TG139.7[一般工业技术—材料科学与工程]