Results of the comprehensive characterisation of electro-exploded aluminum nanopowders, passivated with the non-inert reagents: oleic acid (C17H33COOH) and stearie acid (C17H35COOH), Which were suspended in kerosene and ethanol, amorphous boron, nickel, fluoropolymer and Al2O3 (for a comparison), are discussed. Aluminum nanopowders with a protecting surface show increased stability towards oxidation in air and in water during the storage period. On the basis of the experimental results, a diagram of the formation and stabilization of the coatings is proposed. (C) 2006 Elsevier B.V. All rights reserved.