This project on nanocrystalline materials has three primary objectives. First, the spark erosion technique for producing nanoparticles of a very wide range of materials will be investigated and optimized for maximum yield of the desired particle sizes and compositions. Second, a variety of nanoparticle systems representing superconducting, magnetic and structural properties will be extensively characterized. Third, the consolidation of the nanoparticles into macroscopic samples retaining the unusual properties of the precursors, utilizing dynamic extrusion and shock consolidation as well as conventional processing methods, will be implemented. Using liquid dielectics, the spark erosion technique has been shown to yield high purity particles of metals, alloys, oxides, carbides, and semiconductors in sizes from nanometers to micrometers at significant production rates. Sparks erosion may be carried out also in ultrapure gases. This approach increases the performance of this method in the synthesis, treatment and subsequent handling of nanoparticles. The characterization of various types of nanoparticles produced will involve diffraction (x-ray, electron, neutron), high resolution TEM, surface analysis, as well as methods particularly suited to specific systems such as optical and Mossbauer spectroscopy, transport measurements and magnetic properties. Research is planned to demonstrate and extend the capabilities of the spark erosion method to produce economically significant quantities of various types of nanoparticles, as well as to investigate some of the unique properties of these systems in particulate and consolidated form.
