Controlled synthesis of nanopowders via electrical explosion of wires

Abstract

Fine and ultra-fine powders are actively studied in a broad and interdisciplinary area of nanotechnology. This paper presents the complex of well-grounded solutions for direct production of nanopowders 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 heating, the heating rate, the density and the chemical activity of surrounding gas, the initial radius of wire, the initial microstructure of wire metal. The 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. The X-ray Diffraction and the Electron Diffraction methods were used for determination of the phase compositions. Characterization included also the Differential Scanning Calorimetry and the Thermogravimetry in air. In summary, it was shown that exploding wire method allows producing ultra-fine powders of various metals. The results obtained can be applied directly to the production of powders with specify characteristics.