During the electrical explosion of aluminum wires in argon and nitrogen, Al nanoparticles and Al/AlN composite nanopartides were synthesized. The as-prepared samples were characterized by transmission electron microscopy, energy dispersive X-ray microanalysis, X-ray diffraction and Brunauer-Emmett-Teller specific surface area measurements. The parameters of the electrical explosion of wires and the gas medium influenced the average size of the nanopartides and the content of aluminum nitride in the powder. A nanoparticle formation mechanism caused by the coagulation of the primary particles generated in the early stages of the electrical explosion of the wires has been proposed. (C) 2016 Elsevier B.V. All rights reserved.