Abstract:

Mg₂Ni-x%LaMg₂Ni（x=0，10，20 and 30） composites were prepared by mechanical ball milling，the effect of LaMg₂Ni content on phase composition，microstructure and hydrogen storage properties of Mg₂Ni matrix composites was studied.The results showed that Mg₂Ni alloy without LaMg₂Ni addition was mainly composed of Mg₂NiH₄ and Mg₂NiH_0.3 after full hydrogenation，while Mg₂Ni matrix composites with LaMg₂Ni addition were mainly composed of Mg₂NiH₄ and LaH₃.After full dehydrogenation，Mg₂NiH₄ and Mg₂NiH_0.3 were transformed into Mg₂Ni，while LaH₃ phase still existed.White bright LaH₃ particles were dispersed in the Mg₂Ni matrix composites added with LaMg₂Ni.When x=20，the distribution of white bright fine particles was the most uniform，and the content of La in the matrix of Mg₂Ni matrix composites increased gradually with the increase of LaMg₂Ni content.The maximum hydrogen absorption capacity of Mg₂Ni matrix composites with different LaMg₂Ni content was in the order of x=0，x=10，x=20，x=30，and the maximum hydrogen evolution capacity was in the order of x=20，x=10，x=30，x=0.It was that after adding LaMg₂Ni the hydrogen storage performance of Mg₂Ni matrix composites was improved.When x=20，Mg₂Ni matrix composites had the highest maximum hydrogen evolution capacity，which was mainly related to the existence of dispersed LaH₃ phase in Mg₂Ni matrix composites and the diffusion of La element to the matrix，which helped to improve the hydrogen storage performance.

Key words: LaMg₂Ni, Mg₂Ni matrix composites, LaH₃, micro morphology, hydrogen storage performance