摘要
利用真空感应熔炼和退火方法制备了LaMg8.40Ni2.34合金.采用X射线衍射(XRD)分析、扫描电镜(SEM)和压力-组成-温度(PCT)测试仪测试了合金的相组成、微观形貌和储氢性能.LaMg8.40Ni2.34合金由La2Mg17、LaMg2Ni和Mg2Ni组成,且在第一次吸放氢循环中就可以完全活化.在558K下的可逆储氢量为3.01%(质量分数),合金的PCT曲线表现出双吸氢平台,分别对应着形成的MgH2和Mg2NiH4.但是放氢曲线却只有一个平台出现,这是由MgH2和Mg2NiH4之间的协同脱氢作用产生的.LaMg8.40Ni2.34合金在吸放氢时的活化能分别为(52.4±0.4)和(59.2±0.1)kJ·mol-1,均低于Mg2Ni合金.与纯Mg和Mg2Ni合金相比,LaMg8.40Ni2.34合金具有良好的活化性能、较高的储氢性能和优良的动力学性能.
The LaMg8.40Ni2.34 alloy was prepared by vacuum induction melting and subsequent heating treatment.The phase structure,morphology,and hydrogen storage properties were studied by X-ray diffraction(XRD),scanning electron microscopy(SEM),and pressure-composition-temperature(PCT) measurements.The LaMg8.40Ni2.34 alloy was composed of La2Mg17,LaMg2Ni,and Mg2Ni phases.The alloy can be activated in the first hydriding/dehydriding process.Its reversible hydrogen storage capacity was 3.01%(mass fraction) at 558 K.PCT curves showed two hydriding plateaus corresponding to the formation of MgH2 and Mg2NiH4 and only one dehydriding plateau,which is due to the synergetic effect of hydrogen desorption between MgH2 and Mg2NiH4.The activation energy values of LaMg8.40Ni2.34 alloy were(52.4±0.4) and(59.2±0.1) kJ·mol-1 for the hydriding and dehydriding processes,respectively,and these were lower than that of the Mg2Ni alloy.The LaMg8.40Ni2.34 alloy exhibited good activation behavior,hydrogen adsorption and desorption reversibility,and kinetic properties.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
2011年第2期403-407,共5页
Acta Physico-Chimica Sinica
基金
supported by the National High-Tech Research and Development Program of China(863)(2007AA05Z117)
National NaturalScience Foundation of China(50971112,51001043)
China Postdoctoral Science Foundation(20100470990)
Natural Science Foundation ofHebei Province,China (E2010001170)~~