Effects of substituting Cu for Sn on the microstructure and hydrogen absorption properties of Co-free AB5 alloys

Abstract

The effects of substituting Cu for Sn on the microstructure, hydrogen storage capacity of La0.7Mg0.3Al0.3Mn0.4Sn0.5 xCuxNi3.8 alloys (where X ¼ 0.0, 0.1, 0.2, 0.3, and 0.5) alloys were investigated with X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and pressure-composition isotherms (PCIs). The alloys were mainly composed of three phases: LaNi5, MgNi2, and LaNiSn. However, the La0.7Mg0.3Al0.3Mn0.4Cu0.5Ni3.8 alloy (X ¼ 0.5) exhibited a (La, Mg)Ni3 phase when studied with SEM. The PCI tests showed that increasing the Cu content increases the maximum hydrogen storage capacity.