Influence of Ultrasonic Wave on Preparation of Nano Alumina Powder by Wet Chemical Method

alpha-Al2O3 powder was synthesized by a wet chemical reaction in the ultrasonic field. The effects of ultrasonication on the formation of their precursor and the nucleation and growth of the alumina powders were studied. The supersonic energy accelerated the nucleation of the precursor. The ultrasonication had large effects on the growth and agglomerating of the crystal nucleus. The precursor sized was 20 nm. The alpha-phase alumina powder derived from the precursor by aging for 8 h and calcining at 1150 degrees C for 20 min was highly crystallized of 10 nm in diameter. Moreover, the temperatures for the formation of alumina lowered with the increase of the ultrasonic frequency.