Síntese de pós de alumina por meio de um método Pechini modificado com adição de sementes em diferentes atmosferas de calcinação

Abstract

Alumina is a largely studied material due to its excellent refractory characteristics and mechanical properties. The a-phase, the most stable one, has a formation temperature of about 1200 °C. Due to this high temperature, many researchers have been trying to decrease this temperature by addition of seeds of a-phase in chemical processes of synthesis. This work had the purpose to synthesize powders of a-alumina by the Pechini method with seeding and to compare calcination under air and with a O2 flow, thus verifying its influence on the characteristics of the obtained powders. The powders were characterized by X-ray diffraction, infrared spectroscopy and scanning electron microscopy. The results were compared with those of the same powders calcined under air. The seeding favored a decrease in the temperature of phase transformation to a-phase, since it is identified in the powders calcined at 1000 °C. The presence of oxygen in the calcination atmosphere also led to the formation of the a-phase at 900 °C, temperature lower than those of the powders calcined under air.