储氢材料新合成方法的研究——置换-扩散法合成Mg_(2)Cu

目前,国外普遍采用高温熔炼法制备Mg_(2)Cu,这种方法的优点是工艺比较简单,缺点是产物表面性能较差,吸、放氢速度较慢,且使用前必须经过粉碎。 本文提出一种新的合成Mg_(2)Cu的方法,即置换-扩散法,其要点是:在适当的非水溶剂中,用金属镁置换溶液中化合态的铜,俟铜接镀在镁上,然后在适当的温度下扩散,形成金属互化物Mg_(2)Cu。所得Mg_(2)Cu在适当条件下可以较好地吸、放氢。

储氢材料新合成方法的研究(Ⅱ)——置换—扩散法合成Mg_(2)Ni

本文用置换-扩散法合成了储氢材料Mg_(2)Ni.它是在二甲基甲酰胺中,用金属镁锉屑去置换溶液中化合态的镍(NiCl_(2)),使镍接镀在镁上.然后在温度500—580℃、氩气氛下扩散2-3小时.所得的Mg_(2)Ni有较好的物理和化学性能,特别是氢化物分解温度有明显的降低.

Mg_(2)Ni_(0.75)Cu_(0.25)-Mg_(1.76)体系的合成及氢化过程的初步研究

Leilly、Rudmen和本研究组分别对Mg_(2)Ni-xMg,Mg_(2)Cu-xMg体系进行了研究,巳发现Mg_(2)Ni或Mg_(2)Cu的存在对镁的氢化,释氢过程有催化作用,并描述了二元合金Mg_(2)Ni,Mg_(2)Cu对Mg的吸、放氢过程的催化氢化、脱氢模型。但有关三元合金对纯镁的吸、放氢催化性能研究,至今未见报道。我们合成了在基质镁粒表面包覆Mg_(2)Ni_(0.75) Cu_(0.25)的新型材料,并研究此三元合金表面对所包覆的Mg核与H2之间反应的影响。

Structure and electrochemical performance of hydrogen storage alloy La_(0.7)Mg_(0.3)Ni_(2.875)Co_(0.525)Mn_(0.1)-boron composite

The structure and electrochemical characteristics of La_(0.7)Mg_(0.3)Ni_(2.875)Co_(0.525)Mn_(0.1)-boron composite was studied systematically.The AB_(3) type hydrogen storage alloys La_(0.7)Mg_(0.3)Ni_(2.875)Co_(0.525)Mn_(0.1) were successfully synthesized by means of inter-media alloy La_(2)Mg_(17).The alloys were composited with boron at different weight rate.From the XRD analyses,each alloy of this series is mainly composed of(La,Mg)Ni_(3) phase and the LaNi_(5) phase,and the phase abundance of each phase varies with the boron weight rate,moreover,after composition,the c and cell volumes of(La,Mg)Ni_(3) phase increase,and the LaNi_(5) phase keep the same,which indicate that the boron may enter(La,Mg)Ni_(3) phase.The electrochemical studies show that the maximum discharge capacity of the composites decreases,but the cycling life improved.And the high rate discharge ability and exchange impendence spectroscopy(EIS)of the AB_(3) alloys and its composite were also studied.