D.M. Liu

Phase Component and Microstructure of laser-sintered Mg-Ni Alloys

The Mg-Ni hydrogen storage alloys were prepared using the laser sintering technology. The effects of laser sintering power on the phase component and the weight loss of Mg element for the Mg-Ni alloys were investigated. The samples P1, P2 and P3 consisted of five phases: Mg2Ni, MgNi2, Mg, Ni and MgO. The weight loss of Mg element remarkably increased at 1200 W. The addition of extra Mg significantly promoted the reaction between Mg and Ni. Mg2Ni, MgNi2, and a small amount of Ni and MgO phases were present in the samples PM (pestle milling) and BM (bail milling). The sample PM has a homogeneous microstructure, and the contents of Mg2Ni and MgNi2 were approximately consistent with those of the Mg-Ni alloy under the equilibrium conditions. The maximum hydrogen storage capacity of the sample BM was 1.72 wt.% and the sample can be activated easily at 573 K (only 3 activation cycles).

The superior desorption properties of MgCl2-added ammonia borane compared to MgF2-added systems—the unexpected role of MgCl2 interacting with [NH3] units

An uncommon dehydrogenation mechanism for metal chloride-added ammonia borane (NH3BH3, AB) systems revealed that MgCl2 interacts with the [NH3] units in AB, analogous to the amine complex of Mg(NH3)xCl2, thus not only resulting in a remarkable decrease in the hydrogen desorption temperature but also effectively suppressing undesirable volatile by-products, particularly ammonia gas.