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.