摘要
为了改善Mg2Ni型合金气态及电化学贮氢动力学性能,用La部分替代合金中的Mg,用快淬技术制备了Mg2-xLaxNi(x=0,0.2,0.4,0.6)合金,用XRD,SEM,HRTEM分析了铸态及快淬态合金的微观结构;用自动控制的Sieverts设备测试了合金的气态贮氢动力学性能,用程控电池测试仪测试了合金的电化学贮氢动力学。结果发现,快淬无La合金具有典型的纳米晶结构,而快淬含La合金显示了以非晶相为主的结构,表明La替代Mg提高Mg2Ni型合金的非晶形成能力。La替代Mg明显地改变Mg2Ni型合金的相组成。当La替代量x=0.4时,合金的主相改变为(La,Mg)Ni3+LaMg3。合金的气态及电化学吸放氢动力学对La含量及快淬工艺敏感,La替代使合金的吸氢动力学降低,但适量的La替代可以明显改善合金的放氢动力学及高倍率放电能力。适当的快淬处理可以提高合金的气态及电化学贮氢动力学,但获得最佳贮氢动力学的快淬工艺与合金的成分密切相关。
In order to improve the gaseous and electrochemical hydrogen storage kinetics of the Mg2Ni-type alloys,Mg in the alloy was partially substituted by element La,and melt-spinning technology was used for the preparation of the Mg2-xLaxNi（x = 0,0.2,0.4,0.6） alloys.The structures of the as-cast and spun alloys were characterized by XRD,SEM and HRTEM.The gaseous hydrogen storage kinetics of the alloys was measured using an automatically controlled Sieverts apparatus.The electrochemical hydrogen storage kinetics of the alloys was tested by an automatic galvanostatic system.The results showed that the as-spun La-free alloy held a typical nanocrystalline structure,whereas the as-spun alloys substituted by La exhibited an evident amorphous structure,meaning the substitution of La for Mg facilitates the glass formation of the Mg2Ni-type alloy.Furthermore,the substitution of La for Mg visibly changed the phase composition of the alloys.The major phase of the alloy was transferred to the（La,Mg）Ni3＋LaMg3 phases by increasing La content to 0.4.The gaseous and electrochemical hydrogen storage kinetics of the alloys was dependent on both the amount of La substitution and the rapid quenching technology.The substitution of La for Mg caused a decrease in the hydrogen absorption kinetics of the alloy,but it significantly ameliorated the hydrogen desorption kinetics and the high rate discharge ability of the alloy.A proper melt spinning process could significantly ameliorate the gaseous and electrochemical hydrogen storage kinetics of the alloy,whereas the melt spinning technology,by which the optimal hydrogen storage kinetics of the alloy could be yielded,was associated with the chemical composition of the alloy.
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2012年第1期67-73,共7页
Chinese Journal of Rare Metals
基金
国家自然科学基金项目(50871050和50961001)
内蒙古自治区自然基金重大项目(2010ZD05)资助
关键词
MG2NI型合金
快淬
La替代Mg
贮氢动力学
Mg2Ni-type alloy
melt spinning
substituting Mg with La
hydrogen storage kinetics
