A homogeneous co-precipitation method to synthesize highly sinterability YAG powders for transparent ceramics

Abstract

A homogeneous co-precipitation method was developed to synthesize well dispersed yttrium aluminum garnet (YAG, Y3Al5O12) powders. This method ensures the co-precipitation of Y3+ and Al3+, solving the problem of differential precipitation of Y3+ and Al3+ in the conventional homogeneous precipitation method. Furthermore, the pH value can be controlled to be a plateau (around 5.2) during the titration process due to the continuous decomposition of the heated urea which can compensate for the pH reduction when adding the mother salts, which is beneficial to the narrow size distribution of the precipitates. Pure YAG nanopowders can be obtained at 900°C without the formation of impurity phases such as YAM (Y4Al2O9) or YAP (YAlO3). The resultant YAG powders are well dispersed and have excellent sinterability that can be sintered into transparent ceramics at 1700°C by vacuum sintering.