Synthesis of Tb4O7 nanopowders by the carbonate-precipitation method for Tb3Al5O12 magneto-optical ceramics

Tb 4 O 7 nanopowders were synthesized by the precipitation method using ammonium hydrogen carbonate (AHC) as the precipitant. The influence of calcination temperature on the properties of Tb 4 O 7 powders was investigated by FTIR, XRD and FESEM. It is found that 1000 °C is the optimum calcination temperature for Tb 4 O 7 powders used for fabrication of Tb 3 Al 5 O 12 (TAG) transparent ceramics, and the average particle size of the 1000 °C-calcined powder is about 150 nm. Using the 800 to 1100 °C-calcined Tb 4 O 7 powders as raw materials, TAG transparent ceramics were fabricated by vacuum sintering at 1700 °C for 20 h. The sample sintered from 1000 °C-calcined Tb 4 O 7 powders shows the best transparency, and its in-line transmittance is above 55% in the 500–1480 nm region, reaching 58.3% at the wavelength of 633 nm. The microstructures and the magneto-optical properties of the TAG ceramics sintered from 800 to 1100 °C-calcined Tb 4 O 7 powders were also studied.