Mechanically activated self-propagated high-temperature synthesis of nanometer-structured MgB2

Nanometer-sized MgB2 was prepared via a two-step modification of the mechanically activated self-propagated high-temperature synthesis. The experimental conditions and some structural and phase characteristics of the synthesized product are reported. It is shown that a single-phase material can be prepared after 2 h of intense mechanical treatment of the starting magnesium and boron powders and a synthesis induced at a current-pulse density of 30 A cm−2. The average size of MgB2 particles synthesized in this way is 70-80 nm. It is also shown that using the same reagents and the “classic” high-temperature interaction at 850 °C with a protective atmosphere of pure Ar, mean particle size of the MgB2 obtained is 50 μm.