【作者】 冯佃臣； 王西涛； 张羊换； 李鹏欣；

【Author】 Feng Dianchen;Wang Xitao;Zhang Yanghuan;LI Pengxin;State Key Laboratory for Advanced Metals and Materials,University of Science and Technology Beijing;School of Materials and Metallurgy,Inner Mongolia University of Science and Technology;Department of Functional Material Research,Central Iron and Steel Research Institute;

【机构】 北京科技大学新金属材料国家重点实验室； 内蒙古科技大学材料与冶金学院； 北京钢铁研究总院；

【摘要】 采用真空感应熔炼法制备了La_2-xSm_xMg₁₆Ni（x=0.1,0.2,0.3,0.4）储氢合金,用XRD分析了合金吸放氢前后的结构变化。用自动控制的Sievert设备测试了铸态合金在不同温度及压力下吸放氢动力学曲线,并用Arrhenius法估算了合金吸氢及放氢的活化能。研究结果表明,铸态合金的主相是La₂Mg₁₇并存在少量的SmNi和Sm₅Mg₄₁第二相,Sm部分替代La对合金的相组成没有影响。合金吸氢后形成的氢化物相为LaH₃和MgH₂。合金的吸氢量、吸氢和放氢动力学随Sm替代量的增加而增加,当Sm替代量从0.1增加到0.4时,最大吸氢量从4.67 wt.%增加到5.025 wt.%.在3MPa压力及49gK温度下,10 min的吸氢量分别为:4.342wt.%,4.488 wt.%,4.564 wt.%,4.787 wt.%,在真空及498K温度下,20 min的放氢量分别为4.342 wt.%,4.488 wt.%,4.564 wt.%,4.787 wt.%。Sm替代对合金吸放氢动力学性能的改善主要归因于Sm替代引起的活化能降低。随着合金中Sm的取代量增加,合金生成焓△H的绝对值及吸氢平台压先减小后增加。当x=0.3时,La_1.7Sm_0.3Mg₁₆Ni储氢合金的生成焓△H的绝对值最小,其生成焓△H为-6.38 KJ·mol^-1。更多还原

【Abstract】 Hydrogen storage alloys of La_2-xSm_xMg₁₆Ni（x =0.1,0.2,0.3,0.4） were prepared by induction melting furnace.The absorption/desorption hydrogen dynamics curves of the alloys were tested at different temperature under pressure of 3MPa.The activation energy values of the alloy for absorption/desorption hydrogen were counted by fitting absorption/desorption hydrogen dynamics curves.The alloy phase composition of the alloywere analyzed by X-ray diffraction（XRD） before and after hydrogen absorption.The results showed that main phase of the alloy was La2 Mgn after different amount of Sm partly replacing La,and the second phase were SmNi and Sm₅Mg₄₁.The phases of the alloy after hydrogen absorption were LaH₃ and MgH₂.The activation energy values of the alloy for absorption hydrogen was two to three times as much as that for desorption hydrogen,and Kinetics of gaseous hydrogen absorption performance is better than the hydrogen dynamics performance.At 498 K the hydrogen storage capacity of La1.6Sm0.4Mgl6 Ni alloy is 5.025 wt.%in 20 min,and the hydrogen absorption speed of the alloy is the fastest.At 633 K,the maximum desorption hydrogen storage capacity of Lal.6Srn0.4Mgl6 Ni alloy is 4.814 wt.%in 7.4 min.,With the increase of Sm replace content in alloy,the absolute value of alloy formation enthalpy AH and hydrogen absorption platform pressure decreases after increasing first.When x = 0.3,the absolute formation enthalpy A H of La1.7Sm0.3 Mg16 Ni alloys is the minimum,and its value is-6.38 KJ mol^-1.更多还原