Influence of Al2O3·XH2O Crystallinities on the Morphology of AlOOH Whiskers

Abstract

γ-AlOOH whisker is one of the most popular precursors for the formation of Al2O3 whisker. In this paper, a facile hydrothermal method was developed to prepare γ-AlOOH whiskers, using hydrated alumina with different crystallinity as the hydrothermal precursors. Amorphous hydrated alumina precursors were prepared by mixing HCl and NaAlO2 at room temperature, while crystalline hydrated alumina precursors were produced by precipitation of NaAlO2 solution. γ-AlOOH whiskers with a length of 800-1500 nm and a diameter of 20-40 nm were formed by hydrothermal treatment (220 ℃, 8.0 h) of the mixing of two kinds of precursors. The experimental results indicated that the different dissolving rates of hydrated alumina precursors were one of the main reasons for the formation of γ-AlOOH whiskers with high aspect ratio.

Keywords

• γ-alooh whiskers
• crystallinity of precursors
• hydrothermal technology