Magnesium aluminate (MgAl2O4) spinel powders from water-based sols

Magnesium aluminate (MgAl2O4) spinel powders of irregular and spherical morphologies were obtained from the bi-component water-based sols following the sol-gel and sol-emulsion-gel methods, respectively. For the synthesis of the oxide microspheres, the surfactant concentration and viscosity of the sols were found to affect the characteristics of the derived microspheres. The gel and calcined powders were investigated by using thermogravimetry analysis, differential thermal analysis, X-ray diffraction (XRD), optical and scanning electron microscopy (SEM), Fourier transformed infrared spectroscopy, and particle size analysis. XRD results indicated crystallization of the only phase MgAl2O4 spinel from 200degrees to 1000degreesC. Formation of hollow microspheres with a single cavity was identified by SEM.