X-ray characterization of structural defects in electroexplosive nanopowders

摘要

X-ray structure investigations of nanosized aluminum and copper powders prepared with a transient plasma process by wire electrical explosion (WEE) have been carried out. To compare structural characteristics, powders produced by conventional routes have also been investigated. Calculations of lattice parameter values in different plane (hkl) directions were done using experimental data. Visible deviations of lattice parameter values for nanosized powders, in comparison with JCPDS references and powders prepared through conventional pathways, have been found out. To determine the influence of the dimensional factor on microdeformations, all specimens were divided into sub-micronic and nanometric fractions by the sedimentation in cold absolute alcohol. According to X-ray structure analysis, the increase of lattice parameter is more considerable in the submicronic fraction of electroex-plosive powder than that of nanometric fraction. The conclusion was made that severe conditions of electroexplosive powders fabrication, as well as different cooling rates of particles, can play an essential role in the deformation of their crystal lattice. In addition, we may conclude that the deformation of the crystal lattice corresponds to an energy excess stored in these nano-sized powders prepared with the wire electrical explosion technology.