镁元素对A_5B_(19)型La_(0.8-x)Gd_(0.2)Mg_xNi_(3.3)Co_(0.3)Al_(0.1)(x=0～0.4)储氢合金微观结构和电化学性能的影响  

The effect of Mg on the microstructure and electrochemical properties of La_(0.8-x)Gd_(0.2)Mg_xNi_(3.3)Co_(0.3)Al_(0.1)(x=0-0.4) hydrogen storage alloys

作　　者：郭兴波[1] 罗永春[1,2] 高志杰[1] 张国庆[1] 康龙[1] 

机构地区：[1]兰州理工大学材料科学与工程学院,甘肃兰州730050 [2]兰州理工大学甘肃省有色金属新材料省部共建国家重点实验室,甘肃兰州730050

出　　处：《功能材料》2012年第18期2450-2455,共6页Journal of Functional Materials

基　　金：国家高技术研究发展计划(863计划)资助项目(2011AA03A408)

摘　　要：用高频感应熔炼法制备了稀土系La0.8-xGd0.2MgxNi3.3Co0.3Al0.1(x=0～0.4)储氢合金,并在氩气和1273K下对铸态合金进行退火处理,系统研究了用Mg部分替代La元素对合金微观组织和电化学性能的影响规律。合金相结构分析表明,合金组织主要由Pr5Co19型、PuNi3型、Ce2Ni7型和Ca-Cu5型相组成,随Mg含量增加,主相Pr5Co19型相含量先增加后减少,当x=0.15时达到最大值88.23%(质量分数)。电化学测试分析表明,随Mg含量的变化,合金电极最大放电容量和容量保持率均呈先增加后减小的规律,当x=0.15时,合金电极放电容量达到最大值377.9mAh/g,经100次充放电循环后其电极容量的保持率S100为90.2%,具有较好的电化学综合性能。La0.8-xGd0.2MgxNi3.3Co0.3Al0.1（x = 0-0.4） hydrogen storage alloys were prepared by induction melting followed by annealing treatment for 16 hours at 1273K under high purity argon atmosphere.The effect of Mg on the microstructure and electrochemical properties of La0.8-xGd0.2MgxNi3.3Co0.3Al0.1（x = 0-0.4） were investigated systematically by means of X-ray diffraction（XRD）,electron probe micro-analysis（EPMA） and electrochemical measurements.The results showed that all the annealed alloys mainly consisted of Pr5Co19-type,PuNi3-type,Ce2Ni7-type and CaCu5-type phase.The main phase of Pr5Co19-type abundance first increased and then decreased with increasing Mg contents,and the maximum main phase abundance reached 88.23wt% when x was 0.15.The equilibrium pressures of hydrogen absorption rose gradually and became flatter when x increased.The lowest plateau pressure of the alloys was about 0.02MPa and the hydrogen storage capacity was 1.334wt% when x was 0.15.The electrochemical measurements showed that all the alloys had a superior activation capability and the discharge capacity of the alloys first increased and then decreased with the increase of Mg contents.Among the alloys study,the La0.65Gd0.2Mg0.15Ni3.3Co0.3Al0.1 alloy（x=0.15）possessed the best electrochemical properties,the maximum discharge capacity of the alloy reached 377.9 mAh/g and the discharge capacity retention rate S100 reached 90.2% after 100 charge-discharge cycles.

关 键 词：A5B19型La-Mg-Ni系储氢合金 微观组织 储氢性能 电化学性能 

分 类 号：TG139.7[一般工业技术—材料科学与工程] TG146.4[金属学及工艺—合金]