Synthesis of nanocomposites based oN superhard ceramic nanoPOWdERS, S.Gierlotka, B.Palosz, E.Grzanka, A.Swiderska, S.Stelmakh, G. Kalisz, High Pressure Research Center UNIPRESS, Warsaw, Poland Preparation of bulk solid nanocrystalline specimens from powders is a challenge. The investigated process of preparation of nanocomposites involves infiltrating of compacted nano-powders of diamond and SiC by molten metals (Zn, Al, Au) and semiconductors (Si, Ge, GaAs, CdTe). The processes were performed in the pressure range 2-8 GPa. Melting temperatures depend on the pressure and the process temperatures were chosen accordingly. Upon melting the pressure forces liquids into the pores of the underlying nano-powder-compact and after crystallization a composite material is obtained. Under pressure the pores between the grains in the compacted nano-powder are of the nano-size and the nano-grains of either metal or semiconductor grow. The primary interest in the nano-composites is the investigations of the properties of the guest (infiltrating) nanocrystalline phase, which constitutes roughly 30 vol% of the composite. The ceramic host material (the matrix) can be either the main active component of the composite, or it is neutral with respect to specific properties of the guest nano-phase: electrical and/or optical properties of metals and semiconductors. Super-hard diamond-SiC nano-composites show properties better than sintered diamond polycrystals.
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