Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1625026 | Journal of Alloys and Compounds | 2008 | 5 Pages |
Abstract
The effect of NiCo2O4 additives on the hydrogen absorption-desorption characteristics of 85Â wt% Mg-15Â wt% NiCo2O4 and 95Â wt% Mg-5Â wt% NiCo2O4 composites prepared by mechanical alloying in an inert atmosphere was investigated. The absorption of hydrogen was measured at temperatures of 573, 473, 423 and 373Â K and pressures of 1, 0.4 and 0.2Â MPa while the desorption studies proceeded at 573Â K under a pressure of 0.15Â MPa. The addition of NiCo2O4 was found to exercise a positive effect on the hydriding kinetics of pure magnesium, the absorption capacity remaining high at temperatures below 573Â K and pressures lower than 1Â MPa. A three-fold decrease of the additive content (from 15 to 5Â wt%) did not deteriorate the hydriding kinetics of the composite. After 85 absorption-desorption cycles the composite 95Â wt% Mg-5Â wt% NiCo2O4 showed no drastic drop in absorption capacity. The favourable absorption-desorption characteristics found for the composites investigated were supposed, on the basis of XPS data, to be due to the catalytic effect of the nickel and cobalt species obtained during hydriding of NiCo2O4 on the sample surface.
Keywords
Related Topics
Physical Sciences and Engineering
Materials Science
Metals and Alloys
Authors
Ts. Mandzhukova, M. Khrussanova, E. Grigorova, P. Stefanov, M. Khristov, P. Peshev,