Results of investigation and chemical analysis of electro-exploded metal nanopowders passivated and/or coated with the non-inert reagents and air (for a comparison) are discussed. Surface protection of aluminum nanopowders by coatings of different origin results in significant advantages in the energetic properties of the powders. Aluminum nanopowders with a protecting surface show increased stability to oxidation in nitrogen, air and in water during storage period. On the basis of experimental results, diagram of the formation and stabilization of the coatings on particles has been proposed. Kinetics of interaction of aluminum nanopowders with nitrogen, air and water has been discussed. Recommendations concerning efficiency of non-inert reagent passivation are proposed on a basis of comprehensive analysis of the experimental data.