Preparation of monodispersed magnesia coated silica particles through a surface-induced precipitation method

Monodispersed magnesia coated silica particles were prepared by the surface-induced precipitation method, in which a sol type of magnesium precursor was deposited on the surface of spherical silica particles via electrostatic attraction route, and then calcined at 700 °C for 90 min. The magnesium precursor was synthesized by the sol–gel technique, which employs ethanol as a solvent. The resulting particles were characterized with field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), thermal (TG/DTA) analysis, Fourier transform infrared (FTIR), and X-ray photoelectron spectroscopy (XPS). The results show the formation of a well-crystallized magnesia layer on the surface of the core silica particles. The resultant coated particles exhibited the spherical shape without the formation of a hard aggregate in spite of the heat treatment. XPS and FTIR investigations also confirmed that the magnesia coating layer and core silica particle were connected through the Mg–O–Si chemical bonding at the interface.