Structural, morphological, and electrochemical properties of AB(5) hydrogen storage alloy by mechanical alloying

Mechanical alloying (MA) is one of the most promising methods in the development of intermetallic alloys and their scientific research. In this paper, elemental powder mixtures of Ca, Ni, and Mn of nominal composition CaNi5-xMnx (with x = 0.3, 0.5, and 1) were elaborated by MA technique during different milling times (2-60 h). Structural, morphological, and electrochemical changes were investigated by X-ray diffraction (XRD), scanning electron microscopy, and Ec-Lab galvanostat, respectively. The XRD test indicated that each alloy has Ni and CaNi3 or CaNi5 phases. In addition, the particle size of the ground powders is decreased with increasing milling time. Furthermore, all alloys have a very high activation capacity, whereby the activation capacity can be fully realized during the first cycle. The results showed that the most significant value of discharge capacity for all alloys was 40 h.