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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。
The effects of Co and Cu substitution Ni and magnetocaloricum on the thermodynamic and kinetic properties of La0.67Mg0.33Ni3-xMx (M = Co, Cu) (x = 0,0.5) The results show that when Ni is partially replaced by Co and Cu, the amount of hydrogen absorption and desorption increases, the temperature of hydrogen desorption decreases, the time of hydrogen absorption and desorption (tc) decreases, and the activation energy of diffusion and desorption decreases. Magneto-thermal treatment obviously increased the amount of hydrogen absorption of the three as-cast alloys, increased the width of the hydrogen absorption-desorption platform and improved the kinetics of hydrogen absorption-desorption. The magnetic heat treatment of La0.67Mg0.33Ni2.5Co0.5 alloy The results showed that the best hydrogen absorption and desorption capacities were 1.40% and 1.32% (mass fraction, respectively), the corresponding peak temperature was 77.8 ℃ and the characteristic time of hydrogen absorption and desorption was 91.4 and 379.3, respectively. s, the activation energy of hydrogen absorption and desorption are respectively 16.3 and 23.3 kJ / mol.