Study On Preparation Of Yttrium Aluminum Garnet Nanopowers

Yttrium Aluminum Garnet (YAG) polycrystalline ceramics has excellent optical, mechanical and thermal properties, it is expected to replace the YAG single crystal as a new generation of solid-state laser host material. The dispersion and sintering performance of YAG powder have a major impact on the final ceramics, so the powder technology and sintering technology is essential. In this thesis, YAG nanopowders were prepared both by direct calcination and solvothermal method.In the two methods, YAG precursors were both co-precipitated from a mixed solution of aluminum and yttrium nitrates using ammonia water and ammonium hydrogen carbonate as precipitants. In the direct calcination method, We studied the influence of the temperature at which preparing precursors, the precipitant and the dose of surfactant on the morphology and the temperature that caused YAG phase. We also studied the Influence of calcination temperature, calcination time and heating rate on the phase formation temperature of YAG In the end, We prepared the pure YAG phase at 1000℃by 2h.In the Solvothermal method, We made the following studies respectively, The influence of precursors prepared by different precipitating agents on the formation of YAG phase; The influence of reactor pressure, holding time and precursor prepared by different salts concentration on the YAG phase formation, size and morphology. The results showed that, We prepared YAG more easily with ammonia as the precipitant, and pure phase of YAG was prepared at 300℃by 6h.