Crystallization kinetics and characterization of nanosized Nd:YAG by a modified sol–gel combustion process

Abstract

Nanosized neodymium doped yttrium aluminum garnet (Nd:YAG) powders have been synthesized by a modified sol–gel combustion method by using nitrate salts as starting materials. Phase evolution, morphology, and microstructure of the synthesized powders were investigated. Solvent plays an important role in the phase formation of the precursor. Crystallized Nd:YAG powders can be directly obtained at as low as 800°C without the formation of any intermediate phase. The crystallization kinetics of amorphous YAG precursor was studied by variable heating rate of DTA. The activation energy for crystallization of the YAG by modified sol–gel combustion is 361.7kJmol−1, which is much lower than 480.6kJmol−1 determined from that by general sol–gel combustion. The as-prepared powders are well crystallized and soft aggregated with average crystalline size about 60nm at 1200°C. Good luminescent property is observed in the Nd:YAG nanopowders and the emission intensity increased with increasing the calcination temperatures.