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用快淬工艺制备了Mg2Ni型合金,其名义成分为Mg2Ni1-xCox(x=0,0.1,0.2,0.3,0.4)。以XRD、SEM、TEM分析了铸态及快淬合金的结构。用程控模拟电池测试仪测试了合金的电化学贮氢动力学。用电位跃迁法计算了氢在合金中的扩散系数。用电化学工作站测试了合金的电化学交流阻抗谱(EIS)和Tafel极化曲线。结果表明,快淬态无Co合金具有典型的纳米晶结构,而Co含量为0.4的快淬态合金具有纳米晶/非晶结构,表明Co替代Ni可以提高Mg2Ni型合金的非晶形成能力,且快淬态合金的非晶化程度随Co替代量的增加而增加。Co替代Ni显著地提高了合金电化学贮氢动力学。当Co含量从0增加到0.4时,淬速为25m/s的快淬态合金的高倍率放电能力(HRD)从65.3%增加到75.3%,氢扩撒系数(D)从2.22cm2/s增加到3.34cm2/s,极限电流密度(IL)从247.8mA/g增加到712.4mA/g。
The Mg2Ni-type alloy was prepared by a rapid quenching process. Its nominal composition is Mg2Ni1-xCox (x = 0,0.1,0.2,0.3,0.4). The structure of as-cast and quenched alloy was analyzed by XRD, SEM and TEM. The electrochemical hydrogen storage kinetics of the alloy was tested with a programmed analog battery tester. The potential diffusion method was used to calculate the diffusion coefficient of hydrogen in the alloy. The electrochemical electrochemical impedance spectroscopy (EIS) and Tafel polarization curves of the alloys were tested with an electrochemical workstation. The results show that the quenched non-Co alloy has a typical nanocrystalline structure, whereas the quenched alloy with a Co content of 0.4 has a nanocrystalline / amorphous structure, indicating that Co substitution for Ni can improve the amorphous formation ability of the Mg2Ni-type alloy, and The degree of amorphization of quenched alloy increases with the substitution of Co. The substitution of Co for Ni significantly improves the electrochemical hydrogen storage kinetics of the alloy. When the content of Co increases from 0 to 0.4, the high-rate discharge capacity (HRD) increases from 65.3% to 75.3% and the hydrogen diffusion coefficient (D) increases from 2.22cm2 / s to 25m / s To 3.34 cm2 / s, limiting current density (IL) increased from 247.8 mA / g to 712.4 mA / g.