【摘要】 研究了Co和Cu取代Ni以及磁热处理对La0.67Mg0.33Ni3-xMx(M=Co,Cu)(x=0,0.5)合金吸放氢反应热力学和动力学性能的影响。结果表明,Ni被Co和Cu元素部分替代后,合金的吸放氢量增大,放氢温度降低,吸放氢特征时间(tc)减小,吸放氢过程中的扩散活化能降低。磁热处理明显地提高了3种铸态合金的吸氢量,增大了吸放氢平台宽度,改善了合金的吸放氢动力学性能,其中磁热处理对La0.67Mg0.33Ni2.5Co0.5合金改性效果最好,吸放氢量分别为1.40%和1.32%(质量分数,下同),放氢峰所对应的温度为77.8℃,吸放氢特征时间"tc"为91.4和379.3s,吸放氢扩散活化能分别为16.3和23.3kJ/mol。更多还原

【Abstract】 The effects of the substitution of Co and Cu for Ni and magnetic-heat treatment on the thermodynamics and kinetics properties of hydriding/dehydriding reaction for La0.67Mg0.33Ni3-xMx (M=Co,Cu)(x=0,0.5) hydrogen storage alloys were studied. Results show that after the partial substitution of Co and Cu for Ni, the hydrogen absorption/desorption capacity of the alloys is increased, and the temperature of endothermic peak, characteristic time (tc) of hydriding/dehydriding reaction and the activation energy are decreased. The magnetic-heat treatment improves performances of La-Mg-Ni type alloys, including hydrogen absorption capacity, the hydriding/dehydriding platform width and the hydriding/dehydriding kinetics. The thermodynamic and kinetic property of magnetic-heated La0.67Mg0.33Ni2.5Co0.5 alloy is excellent. It can absorb 1.40 wt% H and desorb 1.32wt% H. Its DSC measurement shows endothermic peak of 77.8 oC. The characteristic time (tc) of hydriding/dehydriding reaction is 91.4 and 379.3 s. The hydriding/dehydriding activation energy is calculated to be 16.3 and 23.3 kJ/mol by the Chou model.更多还原