快淬工艺对La-Mg-Ni系贮氢合金微观结构及电化学性能的影响

Effects of Rapid Quenching on Microstructure and Electrochemical Performances of La-Mg-Ni System Hydrogen Storage Alloys

摘要:

用铸造及快淬工艺制备了La-Mg-Ni系（PuNi3型）贮氢合金La2Mg（Ni0．85Co0.15）9Bx（x=0，0．1，0．2），分析测试了铸态及快淬态合金的微观结构与电化学性能，研究了硼及快淬工艺对合金微观结构及电化学性能的影响。结果表明，铸态合金具有多相结构，主相包括（La，Mg）Ni3相（PuNi3型）和LaNi5相，残余相为一定量的LaNi2相和微量的Ni2B相，经快淬处理后Ni2B相消失，并且其它相的相对量随淬速的变化而变化。不含硼合金的容量随淬速的增加而单调减小，含硼合金的容量随淬速变化有一个极大值。合金的循环寿命随淬速的增加而增加，铸态及快淬态合金均有优良的活化性能。

Abstract:

The La-Mg-Ni system(PnNi3-type)electrode alloys La2Mg(Ni0.85Co0.15)9Bx(x = 0,0.1,0.2)were prepared by casting and rapid quenching.The microstructures and electrochemical performances of the as-cast and quenched alloys were determined and measured.The effects of boron content and quenching rate on the microstructures and electrochemical properties of the alloys were investigated in detail.The results show that the as-cast and quenched alloys are composed of the(La,Mg)Ni3 phase(PuNi3-type structure),the LaNi5 phase and the LaNi2 phase.A trace of the Ni2B phase exists in the as-cast alloys containing boron,and after the as-cast alloys are quenched,the Ni2B phase in the alloys nearly disappears.The relative amount of each phase in the alloys depends on the composition of the alloys and the quenching rate.The capacity of the alloys without boron monotonously decreases with the increase of the quenching rate,but for the alloys containing boron,the capacities have a maximum value with the variety of the quenching rate.The cycle lives of the as-quenched alloys increase with the increase of the quenching rate.The activation performances of the as-cast and quenched alloys are excellent.