Hydriding behavior of Mg-Al and leached Mg-Al compounds prepared by high-energy ball-milling

摘要: The structure and hydrogen absorption properties of Mg:Al alloys prepared by high-energy ball milling were studied over the whole compositional range. These materials in their as-milled Al-leached forms. latter are obtained from former leaching out Al a 1 N NaOH solution. various was determined X-ray diffraction. material hydrided state also some cases. In state, hcp Mg(Al) with small proportion Mg17Al12 fcc Al(Mg) formed at (90:10) (20:80) compositions, respectively. At intermediate (58:42) (37:63) intermetallic Mg3Al2 phases formed, Following leaching, content varies 10.4 77.0 to 3.0 51.0 at.%, both cases, noticeable change XRD pattern confirms that bulk dissolution has been achieved. There is two-fold increase specific surface area following Al. case Al, if any, does not lead discernable modification material. measured capacity as milled decreases content, H/M=1.74 for pure un-milled Mg, 1.38 (90:10), then 1.05 (75:25). each case, there further 10–15% decline after leaching. (58:42), which basically only contains nanocrystalline phase, hydriding leads formation MgH2 This reaction totally reversible recovered upon de-hydriding. an kinetics desorption