Synthesis and characterization of silica-coated nanoparticles of magnetite

Magnetic nanoparticles coated with silica have been subjected of extensive,and, in many aspects, also intensive investigations because of their potentialapplication in different technological fields, particularly in biomedicine. This work was conceived and is being carried out in two main parts: (1) synthesis of the ferrimagnetic nanoparticles, specifically magnetite, and (2) coating these particles with tetraethyl orthosilicate (TEOS). The nanosized magnetite sample was preparedby the reduction–precipitation and the nanomagnetite particles were coated by the sol-gel method, based on the hydrolysis of tetraethyl orthosilicate (TEOS). The so obtained materials were characterized with powder X-ray diffraction (XRD), FTIR spectroscopy, saturation magnetization measurements, and 57Fe Mössbauer spectroscopy at room temperature.