磁场热处理温度对Nd0.75Mg0.25(Ni0.8Co0.2)3.8储氢合金倍率性能的影响

Effects of Magnetic Annealing Temperature on Rate Properties of Nd0.75Mg0.25(Ni0.8Co0.2)3.8 Hydrogen Storage Alloys

摘要:

在不同温度下对Nd0.75Mg0.25(Ni0.8Co0.2)3.8储氢合金进行磁场热处理，分别对合金的电化学性能、磁性能、合金的相组成及点阵参数进行测试和计算。结果表明：合金在磁场热处理前后的相组成没有发生明显变化，主相均为Ce2Ni7型(Nd,Mg)2(Ni,Co)7相和CaCu5型NdNi5相。磁场热处理使Ce2Ni7型磁性相的易磁化轴沿c轴取向，且晶格参数c增大，氢质子在四面体间隙中迁移的势能减小，合金的倍率性能大幅提高。温度越高，磁场热处理对合金的倍率性能改善越明显

Abstract:

Magnetic annealing were carried out for Nd0.75Mg0.25(Ni0.8Co0.2)3.8 hydrogen storage alloys at different temperatures. The electrochemical properties, magnetic properties, phase composition and lattice parameters of alloys were systematically investigated. The results show that magnetic annealing has little influence on phase composition of alloys, which includes Ce2Ni7 type (Nd,Mg)2(Ni,Co)7 phase and CaCu5 type NdNi5 phase. Magnetic annealing results in the orientation of easy magnetization axis along c axis. As the annealing temperature increases, the lattice parameter c is increased, which coincides with the extension of tetrahedral interstitials along c axis. Additionally, the obstacle of transportation for hydrogen proton decreases and the rate properties are improved with the annealing temperature increasing