Microwave-flash combustion synthesis of yttria nanopowders

Single phase yttria nanopowders for transparent ceramics were successfully prepared by using a novel approach called microwave-flash combustion technique. This technique involves the reaction of yttrium nitrate and urea in microwave oven for few minutes. The as-prepared precursor powder was later calcined at 1100°C for 4h to form cubic crystalline yttria nanopowders. The as-prepared and calcined powders were analysed by such methods as thermogravimetry, Brunauer-Emmett-Teller surface area measurement, X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The results confirmed that the yttria powder synthesized by microwave-flash combustion was homogeneous and the particles size was in the range of 50-120 nm for calcined powders.