Preparation of Gadolinium Gallium Garnet [Gd3Ga5O12] by Solid-State Reaction of the Oxides

We have prepared dense polycrystalline gadolinium gallium garnet (GGG) by solid-state reaction of the oxides. The oxides were prereacted at 1350°C, ground, pressed, and sintered at 1650°C, yielding 97% dense samples. Ga2O3 evaporated from the sample surface leaving Gd4Ga2O9 that could spall off the sample. For the short times needed to sinter samples, the bulk composition of the material remained essentially constant. The microhardness of the GGG was 11.8 ± 1.2 GN · m−2.