硼对稀土系AB5型贮氢合金电化学容量及循环寿命的影响

为了提高低钴AB5型贮氢合金的电化学循环稳定性，在MmNi3．8Co0.4Mn0.6Al0．2贮氢合金中加微量的硼．用真空快淬工艺制备了稀土系低钴AB5型MmNi3．8Co0．4Mn0．6Al0．2Bx(x=0，0．1，0．2，0．3，0．4)贮氢合金，分析测试了铸态及快淬态合金的电化学性能及微观结构，研究了硼对铸态及快淬态合金电化学容量及循环寿命的影响．结果表明，硼使铸态及快淬态MmNi3.8Co0.4Mn0．6Al0．2贮氢合金的电化学容量不同程度地降低，但使电化学循环稳定性大幅度提高．硼对电化学性能的影响主要是促进非晶相的形成．

Effect of boron on the discharge capacity and cycle life of rare-earth-based AB5-type hydrogen storage alloy

In order to modify the discharge capacity and cycle stability of low-Co AB_5-type hydrogen storage alloy,a trace amount of boron was added in MmNi_(3.8)Co_(0.4)Mn_(0.6)Al_(0.2)hydrogen storage alloy.The rare-earth-based low-Co AB_5-type MmNi_(3.8)Co_(0.4)Mn_(0.6)Al_(0.2)B_x(x=0,0.1,0.2,0.3,0.4) hydrogen storage alloys were prepared by cast and rapid quenching.The microstructure and electrochemical performance of the as-cast and quenched alloys were analyzed and measured.The effect of boron additive on the discharge capacity and cycle life of the as-cast and quenched alloys were investigated comprehensively.The experimental results show that the addition of boron significantly lowered the discharge capacity and dramatically enhanced the cycle life of as-cast and quenched MmNi_(3.8)Co_(0.4)Mn_(0.6)Al_(0.2) hydrogen storage alloy.The main reason of boron producing obvious influences on the electrochemical properties of low-Co AB_5-type hydrogen storage alloy is that boron strongly promotes the formation of amorphous phase.