Low-Temperature Fabrication of Plate-like α-Al₂O₃ with Less NH₄F Additive

Abstract

Fluorinated compounds are effective mineralization agents for the fabrication of plate-like α-Al2O3. However, in the preparation of plate-like α-Al2O3, it is still an extremely challenging task to reduce the content of fluoride while ensuring a low synthesis temperature. Herein, oxalic acid and NH4F are proposed for the first time as additives in the preparation of plate-like α-Al2O3. The results showed that plate-like α-Al2O3 can be synthesized at a low temperature of 850 °C with the synergistic effect of oxalic acid and 1 wt.% NH4F. Additionally, the synergistic effect of oxalic acid and NH4F not only can reduce the conversion temperature of α-Al2O3 but also can change the phase transition sequence.

Keywords

• plate-like α-Al₂O₃
• low temperature
• oxalic acid
• NH₄F
• synergistic effect