Improving H-sorption in MgH2 powders by addition of nanoparticles of transition metal fluoride catalysts and mechanical alloying

Mechanical alloying of nanograined MgH2 with addition of small amounts of FeF3 can produce, via a fluoride transfer reaction, a nanocomposite powder containing both the transition metal and fluorine as catalysts. The solid-state phase transformations and microstructural changes during milling and/or during heating were studied by X-ray diffraction during in-situ heating, transmission electron microscopy, differential scanning calorimetry and magnetization measurements. The fluoride transfer reaction occurs partially during milling and can be completed during the first heating cycle. An improved H-desorption behavior was observed in such nanocomposite powder in comparison with the best reported values for MgH2-based composites.