ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Optimization of the calcination temperature for the solvent-deficient synthesis of nanocrystalline gamma-alumina

Toni Ivas, Milica Balaban, Vedrana Dosen, Jin Miyawaki, Kazuki Ito, Dragoljub Vrankovic, Gordana Ostojic, and Sasa Zeljkovic

Empa Materials Science and Technology, Dubendorf, Switzerland

E-mail: toni.ivas@empa.ch

Abstract: Nano-sized alumina is prepared using a cost-effective solvent-free method with aluminum nitrate and ammonium bicarbonate precursors. Combined investigations by thermal analysis (TG/DTA), X-ray diffraction (XRD), specific surface area (BET), scanning electronic microscopy (SEM), infrared emission spectroscopy (FTIR), dynamic light scattering (DLS) and dilatometry were used to examine the effects of calcination temperature on the formation of Al₂O₃. XRD analysis shows that the γ-Al₂O₃ phase forms already at 300 °C and slowly continues to form with increasing temperature indicating a diffusion-controlled reaction as shown by FTIR. The size of the γ-Al₂O₃ nanocrystalline, as determined by XRD, is between 1.5 and 1.9 nm and slowly increased with the reaction temperature. DLS results revealed that a particle size of γ-Al₂O₃ dispersed in water grows with increasing reaction temperature due to nanocrystalline particle aggregation, which was additionally confirmed by SEM. The densification behavior of the boehmite and γ-Al₂O₃ phases was investigated using dilatometry.

Keywords: Al₂O₃ ; Solvent-free method ; Phase transformation ; Densification 

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-018-0637-x

Chemical Papers 73 (4) 901–907 (2019)