Hydrothermal synthesis and morphology control of boehmite

The effect of synthesis conditions on the size and morphology of boehmite particles in the sol produced by hydrothermal processing has been investigated. Transmission electron microscopy, X-ray diffraction and Laser particle size analysis were used to characterise the synthesized boehmite. Results show that the initial hydrothermal solution pH has a significant effect on the particle size and morphology. As the pH changes from low (acid) to high (alkaline), the morphology changes from a "needle-like" one to a "platelet" one. Under the conditions investigated here, the synthesis temperature and time in comparison have little apparent effect on the particle size. However, the precursor concentration, while having little noticeable effect on the elementary particle size, does result in extensive agglomeration when it is very high.