Hydriding/dehydriding behaviors of La2Mg17-10 wt.%Ni composite prepared by mechanical milling |
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Authors: | LIU Jing LI Qian |
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Affiliation: | 1. School of Materials and Architectural Engineering, Guizhou Normal University, Guiyang 550001, China; 2. Shanghai Key Laboratory of Modern Metallurgy & Materials processing, Shanghai University, Shanghai 200072, China) |
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Abstract: | The structure and hydriding/dehydriding behaviors of La2Mg17-10 wt.%Ni composite prepared by mechanical milling were investigated. Compared with the un-milled sample, the as-milled alloys were ready to be activated and the kinetics of hydrogen absorption was relatively fast even at environmental temperature. The composite milled for 10 h absorbed 3.16 wt.% hydrogen within 100 s at 290 K. The kinetic mechanisms of hydriding/dehydriding reactions were analyzed by using a new model. The results showed that hydrogenation processes for all composites were controlled by hydrogen diffusion and the minimum activation energy was 15.3 kJ/mol H2 for the composite milled for 10 h. Mechanical milling changed the dehydriding reaction rate-controlling step from surface penetration to diffusion and reduced the activation energy from 204.6 to 87.4 kJ/mol H2. The optimum milled duration was 5 h for desorption in our trials. |
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Keywords: | hydrogen storage La2Mg17-10 wt% Ni mechanical milling kinetics rare earths |
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