Research on Hydriding Reaction Kinetics Mechanism of Mg_2-xNd_xNi (x = 0-0.3) Alloys

Abstract:

Mg2-xNdxNi (x=0.1, 0.2, 0.3) alloys, along with Mg2Ni for comparison, were prepared by vacuum induction melting, The influent of content of Nd on the microstructure and hydrogen storage performance were studied, the hydrogenation mechanism of Mg2-xNdxNi alloys was explored. The results showed that: the hydriding-dehydriding kinetics performance of Mg2Ni were improved by adding Nd, but the hydrogen storage capacity of alloys decreased. Mg2Ni, Nd2Ni7, NdMg12, Nd5Mg41 and other minor phases were observed in Mg-Nd-Ni alloys. Mg-Nd-Ni alloys had favorable kinetics performance. Compared with Mg2Ni alloy, the desorption rate and desorption ratio decreased with the increase of the amount of Nd, the hydriding-dehydriding kinetics performance Mg1.9Nd0.1Ni was the best. The hydrogenation mechanism of Mg2-xNdxNi alloy was nucleation and grown up mechanism controlled by diffusion ([-ln(1-ξ)]n=kt), the nucleation and grown up process was decided by the diffusion of hydrogen atom in alloy. Hydrogenation rate increased with the increase of hydrogen pressure and adding Nd, it was because the diffusive rate of hydrogen atom in alloy increased. According to the analysis of kinetics mechanism, methods to improve kinetics performance was put forward by reducing the diffusion path of hydrogen atom in alloy.

• Periodical: Advanced Materials Research (Volumes 512-515)
• Pages: 2250-2256
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.512-515.2250
• Online since: May 2012
• Authors: Qi Wan, Ping Li, Li Qun Cui, Wei Na Zhang, Yun Long Li, Xuan Hui Qu
• Keywords: Kinetics Performance, Mg Based Hydrogen Storage Alloy, Pct Curve, Vacuum Induction Melting

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