Zhang Yang-Huan, Li Bao-Wei, Ren Hui-Ping, Li Xia, Qi Yan, Zhao Dong-Liang
Elected State Key Laboratory, Inner Mongolia University of Science and Technology, Baotou 014010, China.
Department of Functional Material Research, Central Iron and Steel Research Institute, Beijing 100081, China.
Materials (Basel). 2011 Jan 18;4(1):274-287. doi: 10.3390/ma4010274.
Mg₂Ni-type Mg₂NiCo (x = 0, 0.1, 0.2, 0.3, 0.4) alloys were fabricated by melt spinning technique. The structures of the as-spun alloys were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The hydrogen absorption and desorption kinetics of the alloys were measured by an automatically controlled Sieverts apparatus. The electrochemical hydrogen storage kinetics of the as-spun alloys was tested by an automatic galvanostatic system. The results show that the as-spun (x = 0.1) alloy exhibits a typical nanocrystalline structure, while the as-spun (x = 0.4) alloy displays a nanocrystalline and amorphous structure, confirming that the substitution of Co for Ni notably intensifies the glass forming ability of the Mg₂Ni-type alloy. The melt spinning treatment notably improves the hydriding and dehydriding kinetics as well as the high rate discharge ability (HRD) of the alloys. With an increase in the spinning rate from 0 (as-cast is defined as spinning rate of 0 m/s) to 30 m/s, the hydrogen absorption saturation ratio () of the (x = 0.4) alloy increases from 77.1 to 93.5%, the hydrogen desorption ratio () from 54.5 to 70.2%, the hydrogen diffusion coefficient (D) from 0.75 × 10 to 3.88 × 10 cm²/s and the limiting current density I from 150.9 to 887.4 mA/g.
采用熔体快淬技术制备了Mg₂Ni型Mg₂NiCo（x = 0、0.1、0.2、0.3、0.4）合金。通过X射线衍射（XRD）和透射电子显微镜（TEM）对快淬态合金的结构进行了表征。采用自动控制的Sieverts装置测量了合金的吸氢和脱氢动力学。通过自动恒电流系统测试了快淬态合金的电化学储氢动力学。结果表明，快淬态（x = 0.1）合金呈现典型的纳米晶结构，而快淬态（x = 0.4）合金呈现纳米晶和非晶结构，证实Co取代Ni显著增强了Mg₂Ni型合金的玻璃形成能力。熔体快淬处理显著改善了合金的吸氢和脱氢动力学以及高倍率放电能力（HRD）。随着纺丝速率从0（铸态定义为纺丝速率0 m/s）增加到30 m/s，（x = 0.4）合金的吸氢饱和率（）从77.1%增加到93.5%，脱氢率（）从54.5%增加到70.2%，氢扩散系数（D）从0.75×10增加到3.88×10 cm²/s，极限电流密度I从150.9增加到887.4 mA/g。
