The Mechanism Analysis on the Two Types of 'Coalescence Growth' of Nano-AlOOH under Hydrothermal Conditions

摘要

AlOOH, as a product from hydrothermal experiments, is the subject investigated in this paper. By analyzing the morphological character of AlOOH, the paper reveals two types of coalescence during the growth of crystal, and points out that the reason for coalescence growth type I during hydrothermal process is that the Al3+ aggregates from the dissolution of some of the AlOOH particles in hydrothermal solution overlap the surface of other particles. And the nature of coalescence growth type II is that multiple AlOOH particles shape into particles with special morphology of growth through bondings between certain structurally compatible crystal boundaries, the experiments also concludes that the probability of coalescence growth type II is related not only to the supersaturation of the precursor, but to the acid-base environment (pH) and high temperature conditions.