Synthesis Of Ferromagnetic Nanoparticles Research Articles

In situ and post-synthesis polymer stabilization of ferromagnetic nanoparticles synthesized by a membrane or conventional reactor

Membrane reactors have been proven to be effective in producing nanoparticles with reduced polydispersity indices. Recently, our group has incorporated this technology into the synthesis of ferromagnetic nanoparticles. In the initial phase, we conducted post-synthesis stabilization experiments to assess the performance of various polymeric agents. Polyacrylic acid (PAA) was chosen because of its notable affinity for the functional groups on the nanoparticle surface. Subsequently, in situ stabilization experiments were conducted using a membrane reactor, with variations in PAA addition flow rates ranging from 0.33 to 1.5 mL/min and maturation times in an ultrasonic bath ranging from 0.5 to 2 h. The samples were characterized in terms of their hydrodynamic diameter, polydispersity, and Z-potential. Notably, the smallest particle size was achieved at the intermediate point with a PAA flow rate of 0.66 mL/min. However, the influence of maturation time did not follow a predictable pattern; the most favorable characteristics, based on the analyzed variables, were observed at 1.5 and 2 h.

Synthesis of ferromagnetic nanoparticles with a core/shell structure by a self-propagating combustion method

Ferromagnetic nanoparticles with a core/shell structure were fabricated by a self-propagating combustion method and subsequent hydrogen reduction process. Before the reduction process, synthesized particles were Fe oxide phases. Transmission electron micrographs confirmed that the nanoparticles were composed of α-Fe core and Fe–Al oxide shell after the reduction process. The saturation magnetization of the nanoparticles was measured about 180 emu/g and the permeability kept constant value of about 1.8 up to 10 GHz without any noticeable loss. These microstructural and magnetic analyses showed that the oxide phase changed into α-Fe and then Al atoms diffused out to the surface of the particles during the reduction process.