The solubility limit of SiO2 in α-alumina at 1600 °C

The solubility limit of Si in α-alumina was measured using wavelength-dispersive spectroscopy on a scanning electron microscope. Samples were doped with Si such that the equilibrated material would contain two phases: mullite (3Al2O3·2SiO2) and alumina saturated with Si. Thus the amount of Si measured in the alumina grains represents the solubility limit. Measurements were conducted on water-quenched and furnace-cooled samples. For the quenched samples the Si solubility limit in Al2O3 was found to be 188 ± 7 ppm at 1600 °C.