Effect of La on the crystalline and electrochemical properties of Ti-Zr-Ni melt-spun alloys

Ti45Zr30Ni25 and Ti45Zr30Ni25La alloys were prepared by melt-spinning, and the phase structure and electrochemical performances of the melt-spun alloys were investigated. The results showed that the Ti45Zr30Ni25 alloy was composed of the quasicrystalline phase, amorphous phase and Laves phase. The Ti45Zr30Ni25La alloy contained quasicrystalline and amorphous phases. The maximum discharge capacity was 111 mAh/g for the Ti45Zr30Ni25 alloy electrode, and 124 mAh/g for the Ti45Zr30Ni25La alloy electrode. The Ti45Zr30Ni25La alloy electrode exhibited a better high-rate dischargeability and cycling stability than the Ti45Zr30Ni25 alloy electrode. The improvement of electrochemical properties was mainly ascribed to the increase in the amorphous phase due to the addition of La.

Ti_(38)Zr_(45)Ni_(17)准晶合金的储氢性能及其V合金化

研究了三元Ti_(38)Zr_(45)Ni_(17)准晶合金及其V合金化后的四元合金(Ti_(0.38)Zr_(0.45)Ni_(0.17))_(100-x)V_x(x=5%、10%、30%、40%、60%(原子分数))的吸放氢性能。准晶成分设计思想源自于团簇线方法,即在Ti-Zr-Ni三元合金体系中利用两条团簇线的交点确定最佳准晶成分Ti_(38)Zr_(45)Ni_(17)。利用铜模吸铸快冷工艺制备直径为3mm的合金棒。吸放氢测试结果表明,Ti_(38)Zr_(45)Ni_(17)准晶在303K首次吸氢量为0.9%(质量分数),在573K时合金首次吸氢量可达2.38%(质量分数),合金吸氢过程快速完成,并放出大量的热,可将吸氢前的粉末样品烧结成块体凝聚物。吸氢后准晶结构消失,完全转化为氢化物结构。添加5%～30%(原子分数)的V进行合金化时可提高合金在573K下的首次吸氢量,最大为2.96%(质量分数),具有固溶体结构的(Ti_(0.38) Zr_(0.45)Ni_(0.17))_(40)V_(60)合金在室温下首次吸氢量为3.2% (质量分数)。由于准晶及其V合金化的合金在吸放氢之后均形成了稳定的氢化物,导致其放氢非常困难。