The results of investigation and analysis of electro-exploded aluminum nanopowders, whose surface were passivated with the following substances: liquids - nitrocellulose (NC), oleic acid (C17H33COOH) and stearic acid (C17H35COOH), suspended in kerosene and ethanol, fluoropolymer; solids - boron and nickel; gases - N-2, CO2 and air (for a comparison) are discussed. The surface protection for the aluminum nanopowders by coatings of different chemical origins leads to the some advantages of the powders properties for an application in energetic systems, e.g. solid propellants and "green" propellants (Al-H2O). Aluminum nanopowders with a protected surface showed the increased stability to oxidation in air during the storage period and higher reactivity by heating. The TEM-visual diagram of the formation and stabilization of the coatings on the particles has been proposed on the basis of experimental results. The kinetics of the interaction of aluminum nanopowders with air has been discussed. The recommendations concerning an efficiency of the protective "non-Al2O3" layers on aluminum nanoparticles were proposed. (C) 2007 Elsevier B.V. All rights reserved.