熔体快淬对Mm(NiCoMnAl)_5B_x贮氢合金电化学性能的影响

The effects of rapid quenching on the electrochemical characteristics of Mm(NiCoMnAl)_5B_xhydrogen storage alloys

为了改善低钴AB5型贮氢合金的电化学性能,对低钴AB5型贮氢合金Mm(NiCoMnAl)5Bx(x =0～0.4)进行快淬处理。用XRD和SEM分析了铸态及快淬态合金的相结构及微观组织形貌。研究了快淬工艺参数对低钴AB5型贮氢合金的电化学性能及微观结构的影响。结果表明,快淬态合金具有良好的活化性能,通过2～5次循环可以完全活化。在一定的淬速范围内,快淬处理可以提高合金的放电容量,但淬速超过某一临界值时,快淬合金的容量低于铸态合金,这一临界淬速随合金的成分不同而变化。合金的循环寿命随淬速的增加而单调增加。

In order to modify the electrochemical characteristics of low-Co AB5-type hydrogen storage alloy, the low-Co AB5-type Mm(NiCoMnAl)5Bx(x =0～0.4)hydrogen storage alloys were treated by using rapid quenching technique. The phase structure and microstructure morphologies of the as-cast and quenched alloys were analysed and observed by XRD and SEM. The effects of rapid quenching technique parameters on the electrochemical properties and microstructures of the low-Co AB5-type hydrogen storage alloys were investigated in detail. The obtained results showed that the as-quenched alloys have excellent activation performance and can be activated through 2 to 5 charge-discharge cycles. Rapid quenching treatment could enhanced the discharge capacity of the alloys in certain quenching rate range. The discharge capacity of as-quenched alloy was lower than that of the as-cast alloy when quenching rate is higher than a certain critical value. The critical quenching rate was changeable with different compositions of the alloys. The cycle life of the alloys monotonously increased with the increase of quenching rate.