Abstract
This work focuses on different series of nanoparticles prepared by Haberland type of gas aggregation cluster source in various configurations. This preparation process includes no unsafety chemicals in contrast to chemical ways of preparation, is possibly scalable and by changing of deposition parameters it is easy to tune the properties of prepared nanoparticles.
First type of studied nanoparticles were heterogeneous metal/polymer nanoparticles Ag@HMDSO. Prepared samples differ in amount of HMDSO added to the gas mixture (2.5 %, 7 % and 9 %).
The properties of nanoparticles were investigated by combination of the small angle x-ray scattering, x-ray diffraction and electron microscopy. The difference in HMDSO content leads to changes in Ag core size and in thickness of the polymeric shell as well.
Silver nanoparticles prepared without HMDSO have the mean diameter around 40 nm. Increase of the HMDSO amount in the deposition chamber has the consequence in reduction of the nanoparticles size.
The mean diameter of nanoparticles created with 9% of the HMDSO decreases to about 5 nm. Lattice parameters, size of crystallites, microstrain and stacking faults density were determined from XRD powder pattern.
Second type of investigated nanoparticles were metal/metal nanoparticles Ni@Ti. The deposition chamber includes two magnetrons.
Measured samples vary in magnetron current in the planar magnetron with titanium target while deposition parameters for Ni nanoparticles are kept constant. The properties of prepared core@shell nanoparticles were investigated by XPS, small angle x-ray scattering and electron microscopy.
Pure Ni nanoparticles consist of nickel core of mean diameter about 27 nm and 6 nm thick oxide shell. Ni@Ti nanoparticles are formed when the second magnetron is operated.
With increasing current through the magnetron with Ti target, surprisingly, the thickness of the shell stays the same. The increase of the size of nanoparticles is due to the increase of the core diameter.
Third investigated series consists of metal/polymer Fe@CH nanoparticles. Iron nanoparticles prepared by magnetron sputtering were modified by additional argon plasma discharge in the deposition chamber and the samples in the series differ in plasma power supply.
The nanoparticles size decreases with increasing power but the change of the shell thickness is not linear with the deposition parameters. The SAXS results corresponds well with the TEM investigation.
The XRD measurements revealed the change of the nanoparticles phase composition after the plasma discharge treatment from pure iron to iron carbide.