Facile preparation and characterization of α-aluminum oxide particles by ultrasonic spray pyrolysis

• High-purity α-Al₂O₃ particles were prepared from aluminum precursor by ultrasonic spray pyrolysis . • The alumina particles are uniform and spherical with an average size of 800 to 1000 nm. • α-Al₂O₃ powder achieved 99.9 and 99.8 % purity after calcination at 1473 K. • High-purity alumina shows potential in the production of electronic materials, catalysts, and high-tech industries. The microscopic morphology and purity of alumina are crucial factors in determination of its practical applications in high-tech industries such as ceramics, bioceramics, catalyst carriers, and others. In the present paper, α-Al 2 O 3 particles were produced by ultrasonic spray pyrolysis employing the Al(NO 3 ) 3 ·6H 2 O and AlCl 3 ·6H 2 O precursors. The results of microscopic examinations, mapping investigation, and X-ray diffraction (XRD) patterns revealed that alumina formed separated hollow spherical particles with an averaging 0.8 -1.0 µm in size. The sizes of the experimentally acquired alumina particles were contrasted with the theoretically calculated values. The optimal parameters for alumina production such as the precursor concentration and the phase transition temperature were determined to be 1.0 M and 1223 K, respectively. Fourier transform infrared spectroscopy (FT-IR) confirmed that the γ- phase was converted to the α-Al 2 O 3 phase. In addition, energy dispersive X-ray (EDX) and X-ray fluorescence (XRF) measurements were utilized to determine the chemical composition of the alumina powder samples, which revealed that the produced α-Al 2 O 3 had purities of 99.9 and 99.8 %, respectively, at a sintering temperature of 1473 K. These results provide significant insights for industrial applications in the aforementioned sectors.