Crystallization behavior of the eutectic glass in the C12A7–CaYAlO4 system

Crystallization behavior during annealing of eutectic glass in the C12A7–CaYAlO4 system was investigated by SEM, STEM, XRD, and TG–DTA. At 900 °C, phase separation of Y-poor and Y-rich phases appeared without crystallization. The phase separation might lead bulk crystallization of C12A7 by subsequent crystallization. At 950 °C, crystallization of unknown metastable phase was observed together with C12A7 crystallization. Above 1000 °C, crystallization of CaYAlO4 and C12A7 was observed. Crystallization behavior was schematically explained and bulk crystallization of C12A7 was explained by the phase separation.