The chemical and physical mechanisms for the formation of passivation coatings on active metal nanoparticles were studied in this work. The passivation processes involved in the formation of coatings on nanoparticles were analyzed by SEM, TEM, XRD, EDS, DTA-TG and chemical analysis. Inorganic passivation coatings for aluminum nanopowders were more effective in terms of thermal stability than organic ones. The stability of organic passivation coatings to further oxidation did not depend on the type of coating, but instead depended on the particle size of the passivated powders. A new advanced approach involving a metal nanopowder passivation technique has been applied.