Low-Density Forsterite (Mg2SiO4) Powders Prepared from Modified Alkoxides

2MgO-SiO₂ low-density powders have been prepared from alkoxide precursors modified with acetic anhydride. The resultant solutions did not gel, but formed precipitates. These consisted of an organic magnesium compound and amorphous silica. Tapping densities comparable with those of forsterite aerogels were obtained, with the density increasing as the precursor solution concentration increased. Crystalline forsterite formed around 790°C. Higher initial solution concentrations led to greater amounts of MgO in the powders after heating to 1000°C. Transmission electron microscopy showed primary particles between 20 and 30 nm which formed loose fractal agglomerates. By altering the preparation conditions, powders with morphologies more like aerogels than xerogels could be produced.