Coating of plasma-processed nanosized powders

The homogeneous Si3N4/SiC nanocomposites with sintering additives of alumina and yttria have been prepared by plasma technique and combining plasma technique with chemical deposition of oxides. The powders have been characterized by XRD, TEM, Photon Correlation Spectroscopy and electrokinetic titration method. Both preparation routes allow us to produce coated particles with bimodal particle size distribution and average particle size in the range of 40–70 nm, but their surface characteristics and phase composition are different. The surface characteristics of Si3N4/SiC and Si3N4/SiC–Al2O3–Y2O3 nanocomposites prepared by plasma technique are similar to pure Si3N4 nanoparticles. The chemical deposition of oxides on the Si3N4/SiC nanoparticles leads to surface characteristics similar to pure alumina. The influence of the peculiarities of the prepared nanocomposites on their processing have been proved by hot pressing.