氧化物晶体的成核机理与晶粒粒度

从微观动力学角度研究了晶粒的成核机理，认为晶粒的成核机理主要包括生长基元的形成，生长基元之间的氧桥合作用和Ｏ桥转变为ＯＨ桥。并从核核速度角度分析了影响晶粒粒度的主要原因，揭示了影响晶粒粒度的内部原因为生长基元的生成能、晶体的晶格能，由此总结出不同结构类型的氧化物粉体的晶粒粒度的相对大小，即具有ＣａＦ２或ＴｉＯ２结构的氧化物粉体的晶粒粒度比具有α－Ａｌ２Ｏ３结构的氧化的晶粒粒度小，具有α－Ａｌ２Ｏ３

Nucleating Mechanism of Oxide Crystal and Its Particle Size

The nucleating mechanism of crystallite was investigated from the microcosmic kinetics. It was proposed that the idealized nucleation mechanism consists of the formation of growth unit, the oxolation reaction, and the transform of O bridge into OH bridge. The main factors affecting the particle size of powders were analyzed from nucleating rate. It was concluded that the interior factors affecting the particle size of powders are the formation energy of growth unit and lattice energy of crystal. The relative particle size of various oxide powders as a function of structure type was summed up from this. The particle size of powders with the structure type of CaF2 or TiO2 is smaller than that of powders with the structure type of a-Al2O3; the particle size of powders with the structure type of a-Al2O3 is smaller than that of powders with the structure type of ZnO. According to above analysis, the difference in particle size of various oxide powders prepared by hydrothermal method, and the effect of the reaction medium and the reaction temperature on the particle size were reasonably explained.