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用快淬技术制备了Mg2Ni型贮氢合金,合金的名义成分为Mg20-xLaxNi10(x=0,2,4,6)。用XRD、SEM、HRTEM分析了合金的微观结构。发现不含La的快淬合金中没有非晶相,但含La快淬合金中显示以非晶相为主。当La含量x≤2时,铸态合金的主相为Mg2Ni相,但随着La含量的进一步增加,铸态合金的主相改变为(La,Mg)Ni3+LaMg3相。应用Sieverts设备研究了铸态及快淬态合金的吸放氢量及动力学,结果表明,x=2的合金吸放氢量及动力学随淬速的增加而增加,但对于x=6的合金,结果是相反的。电化学测试结果表明,x=2合金的放电容量随淬速的增加而增加,而对于x=6合金,结果也是相反的。快淬显著地提高了x=2,6合金的循环稳定性。
The Mg2Ni-type hydrogen storage alloy was prepared by quenching technology. The nominal composition of the alloy is Mg20-xLaxNi10 (x = 0, 2, 4, 6). The microstructure of the alloy was analyzed by XRD, SEM and HRTEM. It is found that there is no amorphous phase in the La-free quenched alloy, but the La-containing rapidly quenched alloy is mainly amorphous. When La content is less than or equal to 2, the main phase of as-cast alloy is Mg2Ni phase, but the main phase of as-cast alloy changes to (La, Mg) Ni3 + LaMg3 phase with further increase of La content. The hydrogen absorption and desorption capacities and kinetics of as-cast and quenched alloys were investigated using Sieverts apparatus. The results show that the hydrogen absorption and desorption capacity and kinetics of the alloy with x = 2 increase with increasing quenching rate. However, for x = 6 Alloy, the result is the opposite. The results of electrochemical tests show that the discharge capacity of x = 2 alloy increases with the increase of quenching rate, but the opposite is true for x = 6 alloy. Quenching significantly improves the cycle stability of the x = 2,6 alloy.