SINTESIS OF METALLIC NANOPOWDERS BY CHEMICAL VAPOR CONDENSATION (CVC) PROCESS

sintesis of metallic nanopowders by chemical vapor condensation (CVC) process

Fe based nanoparticles

encapsulated by Fe₃O₄ oxide shells

Description

We have studied the production of metal-based nanoparticles by CVC process and capacity of this method for getting powders with different chemical and granulometric composition of particles.

Generally, the full scheme of CVC equipment can be described as follow. The carrier gas (inert or reactive) is feed through a heated bubbling unit containing a liquid or solid precursor, which can be evaporated without decomposition at comparatively low temperature. The flow of carrier gas entraining a precursor vapour passed thought the heated tubular furnace to a cooled chamber. This instrumented for the collecting of powder and passivation process to the stabilization as-prepared particles.

The most popular precursors, which could be used in this method, are metal-organic compounds, such as the carbonyls of metal, acetilacetonate compounds of metal, or other compounds with the high vaporization tension. It could be for example nickel, Ni (acac)₂, and cooper, Cu (acac)₂ acetilacetonates, iron Fe(CO)₅, tungsten W(CO)₆ or cobalt Co₂(CO)₇carbonils, etc.

Research chemical and phase composition Fe-based nanoparticles sustain availability the even surface shells consisted of magnetite Fe₃O₄, with defined thickness and composition.

The production particles shows range of goodness, specific physical and mechanical characteristics. And could be use for working in air atmosphere.

Advantages

In the chemical routes, chemical homogeneity is achieved and the particles size can be reduced in nanoscale regime in wide diapason quite exactly.

Process is very flexible, and allows additions of independent evaporation units with different precursors. It is very kindly for production of alloyed nanoparticles.

The important advantage of this method is a mass production of nanoparticles and relatively high capacity of process. It is quite suitable for realization not only for laboratory, but also for industrial application.

We synthesized various kids of metallic nanoparticles (Fe, Ni, Co, W) encapsulated by oxides, carbides or pure carbon. Also alloyed and composite particles based on those components have been produced. The average size of particles can be various from 6-100 nm and the shape can be different.

The mechanism of forming nanoparticles and the influence of experimental parameters on size distribution, structure and chemical compound oxide- and carbon- coated nanoparticles were evaluated.