Synthesis of yttrium aluminium garnet by the citrate gel process

We describe the synthesis of polycrystalline yttrium aluminium garnet (YAG) by the citrate gel process. The conditions for obtaining the pure phase have been determined and the YAG powders were characterized by X-ray diffraction, IR spectroscopy and transmission electron microscopy. YAG powders were obtained at significantly lower temperatures than by other conventional techniques. Moreover, the particle size of the powders prepared through this process is in the range 20-70 nm, depending on the thermal treatment. The lattice parameter of the YAG powders was also determined and we observed that the lattice parameter depends on the particle size. An explanation for this behaviour is provided.