Y添加对球磨态Mg_2Ni型合金结构与性能的影响

The effect of Y addition on the structure and properties of the milled Mg_2Ni type alloys

采用中频感应炉冶炼出x分别等于0,0. 5,1. 0,1. 5,2. 0的5种加Y的Mg_(24-x)Y_xNi_(10)Cu_2储氢合金,并将各合金质量分数为100%Ni球磨40 h,制备出球磨态复合储氢材料,研究了Y含量对球磨态合金结构及储氢性能的影响. XRD,SEM及TEM分析结果表明:球磨态合金已具有非晶纳米晶结构,但复合的Ni和添加Y生成的YMgNi_4相仍然保留有晶体结构.电化学性能测试表明:Y的添加减小了合金的储氢容量,相比x=0时,x=2时的最大放电容量下降了26. 78%,但却明显改善了合金的循环稳定性.动力学的结果表明:Y的添加对合金的高倍率性能影响较小,在以900,1 200和1 500 m A·g-1大电流放电时,x=2性能略好,对极限电流密度的影响也较小,但却提高了材料的电化学交流阻抗.

Five kinds of Mg 24-x Y x Ni 10 Cu 2 hydrogen storage alloys with Y addition were prepared by medium frequency induction furnace smelting, among which, x equal to 0, 0.5, 1.0, 1.5 and 2.0 ,respectively. Ball-milled composite hydrogen storage materials were prepared by compounding each alloy with 100% Ni(mass fraction) and milling them for 40 hours. The effect of Y content on the structure and hydrogen storage properties of the ball-milled alloy was studied. XRD, SEM and TEM results show that the ball-milled alloy has amorphous nanocrystalline structure, but the composite Ni and YMgNi 4 phases formed by adding Y still retains crystal structure. The electrochemical performance tests show that the addition of Y reduces the hydrogen storage capacity of the alloy, and the maximum discharge capacity at x=2 decreases by 26.78% compared with that at x=0 , but it improves the cyclic stability of the alloy significantly. Dynamics results show that the addition of Y has little effect on the high rate performance of the alloy. The performance of x=2 is slightly better when discharged at high current of 900, 1 200 and 1 500 mA·g^-1 , but the effect on the limiting current density is small. However, it increases the electrochemical AC impedance of the material.