CRYSTALLIZATION OF YTTRIUM-ALUMINUM-GARNET (YAG) FROM A GEL OBTAINED BY A GLYCOTHERMAL METHOD

The crystallization of yttrium aluminum garnet (YAG) was investigated for the gelatinous product obtained by the reaction of yttrium acetate with aluminum isopropoxide in ethylene glycol at 280-degrees-C under spontaneous vapor pressure of the glycol (glycothermal method). Crystallization of YAG started at 880-degrees-C and completed at 1000-degrees-C. During these temperatures, a small amount of YA1O3 (hexagonal), was also detected. The crystallization temperature was as low as the reported temperatures for the products prepared by the alkoxide processes (Refs. 5 and 6). Therefore, glycothermal method provides a new route to prepare a gel for the preparation of mixed oxides.