Effects of Rapid Quenching on Structure and Hydrogen Storage Characteristics of Mg20Ni10-xMnx (x=0-4) Alloys

摘要:

为了改善Mg2Ni型合金的贮氢性能，用Mn部分替代合金中的Ni，并采用快淬工艺制备Mg20Ni10-xMnx (x=0, 1, 2, 3, 4)合金。用XRD和HRTEM分析了铸态及快淬合金的微观结构，用自动控制Sieverts设备测试合金的吸放氢动力学，并采用程控电池测试仪测试合金的电化学性能。结果表明，当淬速为20 m/s时，快淬(x=4)合金中出现非晶相，且非晶化程度随淬速的增加而增加。合金的吸放氢量及动力学性能随淬速的增加而增加。此外，快淬显著地改善了合金的电化学性能，包括放电容量及含Mn合金的循环稳定性

Abstract:

In order to improve the hydrogen storage characteristics of the Mg2Ni-type alloys, Ni in the alloy was partially substituted by Mn. Rapid quenching technology was used to prepare the Mg20Ni10-xMnx (x=0, 1, 2, 3, 4) hydrogen storage alloys. The microstructures of the as-cast and quenched alloys were characterized by XRD and HRTEM. The hydriding and dehydriding kinetics of the alloys were measured by an automatically controlled Sieverts apparatus. The electrochemical performances were tested by an automatic galvanostatic system. The results show that, as the quenching rate reaches to 20 m/s, an amorphous phase can be detected in the (x=4) alloy, and the amorphization degree of the alloy visibly increases with the growing of the quenching rate. The rapid quenching improves the hydrogen absorption and desorption characteristics of the alloy dramatically. Additionally, it also enhances the electrochemical hydrogen storage performances greatly, including the discharge capacity and cycle stability of the alloys substituted by Mn