Characterization of aluminum powders: II. Aluminum nanopowders passivated by non-inert coatings

Results of DTA-TG investigation and chemical analysis of electro-exploded aluminum nanopowders, passivated and/or coated with the non-inert reagents: nitrocellulose (NC), oleic acid (C₁₇H₃₃COOH) and stearic acid (C₁₇H₃₅COOH), which were suspended in kerosene and ethanol, amorphous boron, nickel, fluoropolymer, ethanol and air (for 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 the experimental results, a diagram of the formation and stabilization of the coatings is proposed. The kinetics of the interaction of aluminum nanopowders with nitrogen, air and water is discussed. Recommendations concerning the efficiency of non-inert reagent passivation are proposed on the basis of comprehensive analysis of the experimental data.