Aim and Background: Generally, reduction of the particle size in the nanoscale particles increases the surface to volume ratio and the impact of the behavior of the material surface atoms compared to the behavior of the mass of atoms. The most important effect of the surface increase is the extreme reactivity of nanomaterials due to high concentration of the surface atoms or molecules in comparison with the mass of the surface atoms or molecules which causes the nanoparticles agglomeration or cluster. To prevent the reactions, a stabilizer should be used to protect particles against abrasion and corrosion.

Materials and Methods: This process is performed using Tetra-Ethyl-Ortho-Silicate. The obtained nanoparticles were characterized by Scanning electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) and Vibrating Sample Magnetometer (VSM).

Results: According to the analysis carried out, particles measured 40 nm were obtained and silica-coated magnetite nanoparticles were well synthesized. In addition, the nanoparticles magnetic saturation decrease significantly after coating and reduce ability to absorb nanoparticles in magnetic separation process well as.

Conclusion: In this article, coating iron oxide magnetic nanoparticles with very thin layer of the silica coating is investigated. According to this method, after stabilization of iron oxide magnetic nanoparticles with silica, in addition to stabilizing the magnetic nanoparticles, magnetic properties of nanoparticles are not decreased.