纳米三氧化二铝在水热条件下的聚集生长模式研究

Research of Aggregated Growth Mode of Heterogenic Nano AIOOH under Hydrothermal Condition

通过对产物形貌及晶粒度测试，掌握水热温度、水热时间对水热产物影响的基本规律，运用临界成核理论及颗粒成长理论解释提高水热温度、延长水热时间导致的颗粒形态逆转的原因，结合晶体成长阶段性理论，揭示了提高水热温度或延长水热时间以及增大前躯体过饱和状态条件下诱发的两类聚集生长方式，阐述了第Ⅰ类聚集和第Ⅱ类聚集生长的根本原因，其中第Ⅰ类聚集生长是因为过饱和度的增大使得部分AlOOH颗粒在水热溶液中溶解形成的Al^3＋聚集体在另一些颗粒表面的叠合，而发生第Ⅱ类聚集生长的本质是由于pH酸碱环境使得多个AlOOH颗粒通过某些结构相容晶界间的键联而形成的具有特殊生长形态的颗粒。

The influence of hydrothermal temperature and hydrothermal time on the hydrothermal product was investigated by testing the shape and grain size.The reason of grain shape reversion caused by improving the hydrothermal temperature and prolonging the hydrothermal time were explained by critical nucleation theory and grain growth theory. Two kinds of aggregated growth modes, which are induced under the condition of improving the hydrothermal temperature, prolonging the hydrothermal time and increasing the hypersaturated state of the precursor,were detailed through combining the crystal growth stage theory. The fundamental reasons of the class Ⅰ and Ⅱ of the aggregated growth were discussed,where the class Ⅰ of the aggregated growth refers to the superposition of Al^3＋ aggregates on the surface of another grains,and a part of AlOOH grains are dissolved in the hydrothermal solution to form the Al^3＋ aggregates due to the increase of supersaturation degree. The nature of generating the aggregated growth of the class Ⅱ is that grains with special growth state are formed by a plurality of AlOOH grains through bond linkage of the compatible grain boundaries of certain structures in the pH acid and alkali processes.