Preparation and Characterization of Forsterite (Mg2SiO4) Xerogels

Mg2SiO4 gels were prepared from alkoxide precursors, and the formation of the forsterite crystal phase was studied after heat treatments up to 1200°C. Prehydrolyzed TEOS in solution with 2-methoxyethanol was mixed with Mg(OEt)2, and the solution was hydrolyzed using excess water. The resultant gels were dried at 100°C to form xerogels which were subsequently powdered. These powders were characterized using thermal analysis (DTA and TGA), surface area analysis (BET), X-ray diffraction (XRD) and transmission electron microscopy (TEM).DTA and XRD indicated that forsterite crystallized at 770°C, and by 1000°C the powders were predominantly crystalline. BET gave powder surface areas between 400 and 550 m2 g–1. TEM revealed angular particles with sizes between 0.2 and 2 m. The low temperature of crystallization of forsterite indicates a high degree of intimate mixing between the precursor alkoxides, although XRD indicated some degree of inhomogeneity.