铸态La_(1-x)Sm_xMg_(3.6)Co_(0.4)(x=0～0.4)合金的贮氢性能（英文）  

Hydrogen Storage Properties of as-Cast La_(1-x)Sm_xMgNi_(3.6)Co_(0.4)(x=0～0.4) Alloys

作　　者：翟亭亭[1,2] 杨泰[1] 袁泽明[1] 许胜[1] 张羊换[1] 

机构地区：[1]钢铁研究总院,北京100081 [2]东北大学,辽宁沈阳110819

出　　处：《稀有金属材料与工程》2016年第8期1938-1942,共5页Rare Metal Materials and Engineering

基　　金：National Natural Science Foundations of China(51161015,51371094);Natural Science Foundation of Inner Mongolia,China(2011ZD10)

摘　　要：采用真空感应熔炼方法制备了La_(1-x)Sm_xMgNi_(3.6)Co_(0.4)(x=0~0.4)合金,并系统研究了Sm替代La对合金相结构、形貌、以及贮氢性能的影响。利用XRD和SEM分析了合金的相结构。结果表明,合金包含LaMgNi_4和LaNi_5两相;La_(1-x)Sm_xMgNi_(3.6)Co_(0.4)(x=0~0.4)系列合金在348 K,3 MPa下的气态吸氢量(质量分数,%)随着Sm添加呈现逐渐降低的趋势,分别为1.859、1.707、1.585、1.578、1.471;合金的P-C-T曲线显示LaMgNi_4相在吸放氢时有平坦的平台压,同时通过在323,348,373 K下对合金P-C-T曲线的研究表明,La_(1-x)Sm_xMgNi_(3.6)Co_(0.4)(x=0~0.4)合金中LaMgNi_4相在吸氢过程中的焓变在x=0时为-40.37 kJ/mol,随着Sm替代量增加到x=0.4,焓变降到了-26.99 kJ/mol。而熵变也从x=0时的-101.9 J·(mol/K)^(-1)。降到了x=0.4时的-77.56 J·(mol/K)^(-1);La_(1-x)Sm_xMgNi_(3.6)Co_(0.4)(x=0~0.4)合金的电化学合金测试表明,最大放电容量随着Sm替代量的增加从347 mAh/g降到了270.5 mAh/g,但是合金的循环稳定性随着Sm替代的增加得到了很大的提高。La_（1-x）Sm_xMgNi_（3.6）Co_（0.4）（x=0~0.4） alloys were prepared by a vacuum intermediate frequency induction furnace with a high purity helium gas as the protective atmosphere.The effects of partially substituting Sm for La on the phase structure,morphology and hydrogen storage properties of the alloys were investigated.The detections of XRD and SEM reveal that the as-cast alloys contain two phases,LaMgNi_4 and LaNi_5.The hydrogen storage capacity（wt%） of the alloys decreases with increasing Sm content,namely 1.859,1.707,1.585,1.578 and 1.471,corresponding the variation of x from 0 to 0.4.The P-C-T curves of the alloys show flat plateaus corresponding to the absorption/desorption pressure plateaus of the LaMgNi_4 hydride.Meanwhile,the enthalpy change（ΔH） and entropy change（ΔS） of the LaMgNi_4 hydrides for hydriding decrease from- 40.37 kJ/mol（x=0） to- 26.99 kJ/mol（x=0.4）and from-101.9 J·（mol/K）^（-1）（x=0） to-77.56 J·（mol/K）^（-1）（x=0.4）,respectively.The electrochemical measurement displays that the maximum discharge capacity of the alloy electrodes declines from 347 mAh/g to 270.5 mAh/g,which is similar to the trend of the gaseous hydrogen absorption capacity.On the contrary,the cycle stability of the as-cast alloys obviously improves with the Sm content increasing,which can be attributed to the facilitated corrosion resistance by Sm substituting.

关 键 词：La-Mg-Ni系合金 贮氢性能 焓变 熵变 电化学性能 

分 类 号：TG139.7[一般工业技术—材料科学与工程]