Phase structure and hydrogen storage properties of REMg_(8.35)Ni_(2.18)Al_(0.21) (RE=La, Ce, Pr, and

• 作 者: 刘岩青 韩树民 扈琳 刘宝忠 赵鑫 贾彦虹
• 机 构: College of Environmental and Chemical Engineering, Yanshan University,State Key Laboratory of Metast
• 出 处: Journal of Rare Earths
• 发表日期: 2013年08期
• 关键词: hydride annealing Al Ce Ni Pr RE=La and Nd transformed desorption

REMg 8.35Ni2.18Al0.21 (RE=La, Ce, Pr, and Nd) alloys were prepared by induction melting and following annealing. X-ray diffraction (XRD) and scanning electron microscopy (SEM) results showed that the alloys were composed of Mg2Ni, (La, Pr, Nd)Mg2Ni, (La, Ce)2Mg17 , (Ce, Pr, Nd)Mg12 and Ce2Ni7 phases. The above phases were disproportioned into Mg2NiH4 , MgH2 and REH x (x=2.51 or 3) phases in hydriding. CeH2.51 phase transformed into CeH2.29 phase in dehydriding, whereas LaH3 , PrH3 and NdH3 phases remained unchanged. The PrMg8.41Ni2.14Al0.20 alloy had the fastest hydriding kinetics and the highest dehydriding plateau pressure while the CeMg8.35Ni2.18Al0.21 alloy presented the best hydriding/dehydriding reversibility. The onset hydrogen desorption temperature of the CeMg8.35Ni2.18Al0.21 hydride decreased remarkably owing to the phase transformation between the CeH2.51 and the CeH2.29 .

REMg 8.35Ni2.18Al0.21 (RE = La, Ce, Pr, and Nd) alloys were prepared by induction melting and following annealing. X-ray diffraction (XRD) and scanning electron microscopy (La, Pr, Nd) Mg2Ni, (La, Ce) 2Mg17, (Ce, Pr, Nd) Mg12 and Ce2Ni7 phases. The above phases were disproportioned into Mg2NiH4, MgH2 and REH x (x = 2.51 or 3) phases in hydriding. CeH2.51 phase transformed into CeH2.29 phase in dehydriding, while LaH3, PrH3 and NdH3 phases remained unchanged. The PrMg8.41Ni2.14Al0.20 alloy had the fastest hydriding kinetics and the highest dehydriding plateau pressure while the CeMg8 .35Ni2.18Al0.21 alloy presented the best hydriding / dehydriding reversibility. The onset hydrogen desorption temperature of the CeMg8.35Ni2.18Al0.21 hydride decreased remarkably owing to the phase transformation between the CeH2.51 and the CeH2.29.