Productions of ultra-fine powders and their use in high energetic compositions

Fine and ultra-fine powders are actively studied in pyrotechnics, explosives and propellants. The important questions are how to produce a powder with specified characteristics and how to use the powder produced. This paper presents an approach to the powder production by the exploding wire method. The influence of initial conditions on the properties of powders is discussed. The basic factors are as follows: the level and the uniformity of the energy, dissipated in the exploding wire metal; the density and the chemical activity of the surrounding gas; the initial radius of wire. Electron Microscopes (Transmission and Scanning) and the Surface BET Method have been used for analyses. The production of ultra-fine powders based on such metals as Al, W, Zr, Cu, Fe, Ag, Co, In, Pt has been investigated. Different surrounding passive gases (nitrogen, argon, xenon, and helium) were used for producing powders of pure metals. Samples were studied by chemical methods. X-ray Diffraction and Electron Diffraction methods were used for the determination of the phase compositions. Characterization included also Differential Scanning Calorimetry and Thermogravimetry in air with a heating rate of 100 K/min. In summary, it was shown that the exploding wire method allows to produce ultra-fine powders of various metals. The results obtained can be applied directly to the production of powders with specified characteristics.