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从相变驱动力、成核功、成核速率和晶体生长速率等四个方面探讨了一步法合成纳米氧化锌的结晶动力学问题。理论分析与试验结果相比较表明,影响纳米氧化锌晶粒形成与生长的因素主要是反应温度、反应物起始浓度和过饱和比。纳米氧化锌合成过程中,既有均匀成核,又有非均匀成核。加快成核速率的途径有升高成核时的温度、增大成核时反应物浓度和增大过饱和比。而晶体的生长也受合成条件的影响,温度升高及过饱和比增大均会遏制晶体的生长,从而获得粒度细小且分布窄的纳米氧化锌粉体。
The crystallization kinetics of nano zinc oxide synthesized by one-step method was discussed from the aspects of driving force, nucleation work, nucleation rate and crystal growth rate. The theoretical analysis and experimental results show that the main factors affecting the formation and growth of nano-ZnO are the reaction temperature, the initial concentration of reactants and the supersaturation ratio. In the process of nano-ZnO synthesis, both uniform nucleation and non-uniform nucleation. The way to speed up the nucleation rate is to raise the temperature during nucleation, increase the reactant concentration during nucleation and increase the supersaturation ratio. The crystal growth is also affected by the synthesis conditions, the temperature increases and supersaturation ratio will curb the growth of crystals, resulting in small size and narrow distribution of nano-zinc oxide powder.