The purpose of this study was to investigate the chemically induced interface migration (CIIM) and the chemically induced recrystallization (CIR) in the alumina system. The experimental observation of CIIM and CIR were obtained by observing the microstructural evolution during the heat treatment and analyzing the concentration of $Fe_2O_3$ in the swept region by the migrating grain boundary.
When sintered $Al_2O_3-(7wt%)Fe_2O_3$ specimens with a normal grain boundary structure were heat-treated in air atmosphere at 1600°C, the grain boundaries often migrated away from their centers of curvature, producing wiggling grain boundaries. The microprobe analysis of $Fe_2O_3$ showed that the concentration of $Fe_2O_3$ in the swept region by the migrating grain boundaries is lower than in the other region. The observed CIIM was induced by the loss of $Fe_2O_3$ because of its high vapor pressure.
When sintered alumina specimen with a normal grain boundary structure were heat-treated with $Fe_2O_3$ powders at 1600°C, the grain boundaries often migrated away from their centers of curvature, sometimes producing undulating grain boundaries. The microprobe analysis of $Fe_2O_3$ showed that the concentration of $Fe_2O_3$ in the swept region is higher than in the other region. Recrystallization also occurred in the surface of specimen near $Fe_2O_3$ powders. The observed grain boundary migration and recrystallization were induced by the gain of $Fe_2O_3$.
