INVESTIGATION OF THE CORE - SHELL TYPE CARBON MAGNETIC NANO –PARTICLES GEORGIAN TECHNICAL UNIVERSITY Department of engineering physics Giorgi Kukhalashvili Giorgi Kukhalashvili
The process set up is a closed-loop system which consists of the horizontal pipe furnace (1) to provide the given temperature distribution in the active section of the reactor (2). A plate-shape iron or cobalt catalyst (3) was placed in this section. The circulation circuit of the reactants with the reactor consists of the compressor (4) connected in series, the oxygen pump with the partial oxygen pressure gage (5), the ethanol container (6) and the valve (7) for releasing (or collecting) the excess hydrogen.
SEM images of granular nanoparticle fraction of magnetic carbon nanopowder doped with iron atom clusters synthesized at 700 O C: a)The image taken in K α radiation of iron and carbon atoms at the same time; b)The SEM image in K α radiation of carbon atoms only. Fig. 2
SEM images of another fraction of magnetic carbon nanopowder doped with iron atom clusters are shown on the Figure 3 a and b, where it is evident that the given fraction consists of nanotubes with the diameters ≤200nm and the lengths of ~1µm. Fig.3
Fig.4 SEM image of a) Ground iron plate surface before interaction with the ethanol pyrolysis prodacts. b)The same surface after synthesis of the doped carbon nanopowder at 1200 ˚ C and subsequent shaking off them. c) The area with the “corroded” surface of substrate at high magnification. d) The image of the shaken off, from the same surface, nanopowder particle in the free-poured state.
A sketch of hydrogen distribution in substrate surface and subsurface region at low hydrogen concentrations: (1)-the surface acts as H-trap with its surface and (2)-sub-surface sites; Defects also change the local concentration of hydrogen: (3)-grain boundries solve hydrogen differently compared to the matrix, beside the conventional H-solubility in the lattice matrix- (4); Also a cylindrical H-segregation volume is expected at the edge dislocations-(5) Fig.5
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