Synthesis and characterization of metal nanoparticles produced by sonoelectrochemistry

This work is about the production of metal nanopowders by pulsed sonoelectrochemical technique, optimized at University of Padova. Nanoparticles made of FeCo and FeCr alloy were synthesized at different bath's temperature, in order to study and evaluate the influence of this parameter on process efficiency and nanoparticles' features. Produced material was characterized by X-EDS to determine chemical composition of powders, X-ray diffraction in order to investigate crystalline structure and measure the mean grain size, and finally by transmission electron microscopy to perform a morphological study. Process efficiency was found to be strongly influenced by temperature, as shown in Fig.2 and 4;, in fact it tended to decrease while bath's temperature raised, because of redissolution phenomena which took place; in both two studied alloys a preferential deposition of iron was observed, due to the lower iron reduction overpotential. Chemical composition of nanopowders was affected by pH value of the electrolyte. Structural characterization stated that FeCo and FeCr nanoparticles showed a bcc structure and a mean grain size for FeCo nanopowders below 30nm, that depended on synthesis temperature and decrease with T until 5nm as shown in table 3. TEM characterization in Fig. 8 and 11 showed that nanoparticles exhibited the same mean dimensions like ones found from data elaboration of XRD analyses; this led to conclude that nanopowders are monocrystalline.