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本文通过对水热产物AlOOH的形貌及晶粒度测试,了解了由提高水热温度和延长水热时间导致的颗粒形态的变异以及多种形貌共生的现象。运用临界成核理论及颗粒成长理论给予了合理的解释。此外还结合晶体成长阶段性理论,阐述了第Ⅰ类聚集和第Ⅱ类聚集生长的机理。揭示了水热过程中产物形貌发生变异和多种形貌混杂的深层原因,得出了水热过程中普遍存在两类聚集生长方式的结论。其中,第Ⅰ类聚集容易导致颗粒大小的不均,而第Ⅱ类聚集生长则容易诱导定向生长。

A hydrothermal intermediate product,AlOOH,was used as the study object to investigate the influences of hydrothermal temperature and time on the hydrothermal product through testing the grain size and shape of the product.The critical nucleation theory and grain growth theory were applied to explain the reason of grain shape reversion caused by improving the hydrothermal temperature and prolonging the hydrothermal time.It discloses two kinds of aggregative growth modes which are induced under the condition of improving the hydrothermal temperature,prolonging the hydrothermal time and increasing the supersaturation state of the precursor through combining the crystal growth stage theory.It also expounds the fundamental reasons of the class Ⅰ and Ⅱ of the aggregative growth,wherein the class Ⅰ of the aggregative growth refers to the superposition of Al3＋ aggregates on the surfaces of other grains,wherein part of AlOOH grains are dissolved in the hydrothermal solution to form the Al3＋ aggregates due to the increase of supersaturation degree.The nature of generating the aggregative growth of the classⅡ 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.