Synthesis of Tb3Al5O12 nano powders via nitrate decomposition and self-seeding

Terbium aluminum garnet (Tb 3 Al 5 O 12 , TAG) is a useful magneto-optical ceramic material and requires high-quality powders to improve sintering, microstructural control and the properties. The synthesis of TAG nano powders is challenging due to high temperatures (e.g., >1200 °C) required for phase formation, which causes particle coarsening and agglomerations. Here we tackled the problem by a self-seeding method and efficiently lowered the synthesis temperature of phase-pure TAG nano powders. The seeds were prepared by nitrate salt decomposition at 1200 °C, deagglomeration and selection, which produces TAG nano powders with 55 nm average particle size. When the same methodology was repeated using 55 nm seeds, we found 900 °C heat treatment was able to produce phase-pure TAG nano powders with 24 nm average particle size. The synthesized TAG nano powders have exceptional sinterability and can be sintered to full density at 1200 °C for 1 h while offering a fine average grain size of 117 nm. Our results could be useful to future development of TAG ceramics with tailored microstructure and improved mechano-magneto-optical properties.