Formation mechanism of MgO hollow nanospheres via calcination of C-MgO composite produced by electric arc spraying

Spherical MgO nanoparticles were obtained using the method of electric arc spraying of the Mg-C composite electrode, followed by calcination in air. The composition and morphology of nanostructures, formed at spraying, were studied; kinetics of changes in the elemental composition of the carbon-magnesium composite was investigated at annealing in the range of up to 900 °C. It is shown that during arc spraying, core-shell nanoparticles are formed with a carbon core and shell enriched with magnesium nanoparticles, which are oxidized to MgO at contact with the atmosphere. When carbon-magnesium composites are annealed, carbon burns out; the morphology of magnesium oxide nanoparticles is a 250-nm sphere of magnesium crystals of 20–30 nm in size.