Formation process of GdAlO 3 -Al 2 O 3 eutectic-like microstructure from amorphous phase

Abstract

Several eutectic-like microstructures were prepared from amorphous phases in the authors’ previous works. In this research, the formation process of the microstructure from amorphous phase was investigated for GdAlO₃-Al₂O₃ eutectic system. Amorphous films were prepared by rapid quenching of melt having the eutectic composition. The films were heated at temperatures between 1000 and 1600°C for 30 min to form eutectic phases (GdAlO₃ and Al₂O₃). The films were also heated at 1500°C for various periods between 0·5 and 30 min. GdAlO₃ and Al₂O₃ crystal phases formed from the amorphous phases were identified by XRD. Both components began to crystallise and grow from the amorphous phase separately at different temperatures. This formation process was different from that of the ordinary eutectic microstructure. The microstructures formed from the amorphous phases at sufficiently high temperatures were similar to the ordinary eutectic microstructures.