Catalytic effect of melt-spun Ni3FeMn alloy on hydrogen desorption properties of nanocrystalline MgH2 synthesized by mechanical alloying

• The hydrogen desorption properties of MgH2-5 at% Ni3FeMn composite is studied.
• The catalyst was prepared in the two forms of as-cast and melt-spun ribbon.
• Addition of catalyst decreased the desorption temperature from 319 °C to 290 °C.
• Significant catalytic effect was observed after milling of composite for 30 h.

To improve hydrogen desorption properties of magnesium hydride, a composite material with composition of MgH2-5 at% Ni3FeMn has been prepared by co-milling MgH2 powder with Ni3FeMn alloy either in the form of as-cast (sample A) or melt-spun ribbon (sample B). The study has shown that the addition of Ni3FeMn alloy to magnesium hydride can yield a finer particle size after mechanical alloying (MA). As a consequence, the desorption temperature of mechanically activated MgH2 for 30 h has decreased from 319 °C to 307 °C for sample A and to 290 °C for sample B. Furthermore, some favorable effects of Ni3FeMn alloy on hydrogen desorption kinetics have been observed. Further improvement in the hydrogen desorption of melt-spun containing composite can be related to higher hardness value of the melt-spun powder compared to the as-cast alloy, and probably a more homogeneous distribution of the alloyed elements.