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Monodisperse Spherical Heteroparticles Nano-powders of "Core-Shell" TypeDetails
Institute for Single Crystals of NAS of Ukraine by means of "soft chemistry" methods has developed a technology that allows creating a wide range of nanomaterials from the solutions using controlled processes of phase formation (colloidal synthesis, sol-gel method, synthesis in microemulsions at the temperatures of up to 90-95 °C).
The technology is environmentally friendly, allows to obtain nanoparticles of different chemical compounds (metals, alloys, oxides, chalcogenides, etc.) and with high reliability to control their composition, structure and geometric characteristics. The advantage of this technology is the possibility of obtaining of the nanopowders with controlled composition, size and shape of particles with a low degree of agglomeration.
The main stages of the technological process are: amorphous precipitate precursor obtaining by the method of the chemical co-precipitation from aqueous solutions, its drying and crystallization in low-temperature annealing at temperatures up to 1000 ÷ 1100 °C. The developed technology allows to obtain monodimensional particles already at the stage of the amorphous precursor formation or by traditional methods – to obtain the polydisperse amorphous sediment and, if necessary, to separate from it the fraction with a narrow particle distribution on sizes by the methods of ultracentrifugation and/or sedimentation.
The technology for obtaining low-agglomerated nanopowders from the particles of the different morphology (monodimensional spherical and combined particles with "core/shell” structure, isometric particles with low dispersion on sizes) was settled and it is based on:
• Lu2O3, (Lu1-XEuX)2O3, Y2O3, (Y1-XNdX)2O3 rare-earth oxides;
• Y3Al5O12, (Y1-X)3NdXAl5O12 refractory oxides;
• the particles with "SiO2 core/Lu2O3, (Lu1-XEuX)2O3 shell” structure;
• the particles with "SiO2 core/ZnO, PbS, Au, Pt, Pd shell” structure.
The stable sols of Au, Pt, Pd noble metals have been obtained. The methods of stabilization of the nanocrystals of this metal for prevention of their agglomeration in the forming of mono-and multilayers on different substrates.
Traditional and perspective fields of nanoparticles and nanopowders applications:
• raw materials for chemical industry, glass and glassceramics production, abrasive wear-resistant materials;
• structure-forming additives for metals and alloys hardening;
• components for obtaining of superhard, high temperature, wear-resistant, homogeneous and inert ceramics;
• raw materials for obtaining of optical ceramics (laser, scintillation, luminescence);
• photonics, plasmonics, sensorics, catalysis, and medicine.