Many investigations on the dissolution of AlzO3 into silicate melts have been made and focused on the dissolution kinetics and reaction products. The formation of CaO.6A1203 (CA6) during the dissolution of A1203 into Ca-Al-silicate melts was observed by Oishi et al. and Bates. Sandhage and Yurek, on the other hand, observed an
MgA1204 spinel layer at the dissolving sapphire
interface in Ca-Mg-Al-silicate melts and characterized
the~ formation of the Mg-spinel. These
previous investigations demonstrate that the dissolution
reaction of A1203 into silicate melts depends on
the melt composition and dissolution temperature
and time.