FORMATION OF YAG FROM COPRECIPITATED YTTRIUM ALUMINUM HYDROXIDES

Thermal decomposition of the amorphous coprecipitate of yttrium and al uminium hydroxides farming yttrium aluminium garnet has been investiga ted employing thermal analyses, X-ray diffraction and IR spectroscopy. On heating, the coprecipitate progressively loses water forming a sta ble but highly disordered hydroxy garnet which crystallizes at similar to 1180 K and decomposes to YAG at similar to 1290 K. Nucleation of t he crystalline phase appears to begin at similar to 800 K.