Nano Fe <sub> 3 </ Sub> O <sub> 4 </ Sub> Grain Hydrothermal Preparation And Impact Study Of The Factors

Fe3O4 nanocrystal is valuable in industrial applications, in the process, the precise control of the purity, the grain size as well as its distribution are key factors. Here we report that Fe3O4 nanocrystal was prepared by hydrothermal technique, and the effects of hydrothermal conditions, the pH value of the starting solution, the processing temperature and the processing time, on the purity and the grain size of Fe3O4 were studied systematically. Some results were achieved.1. The choice of the pH value of the starting solution is decisive for obtaining high-purity Fe3O4 nanocrystal, 11 is the best pH value for synthesizing high-purity Fe3O4 nanocrystal.2. The processing temperature is important to control the purity and the grain size of as-synthesized Fe3O4 nanocrystal. The highly purified Fe3O4 nanocrystal could only be obtained at a temperature higher than 150℃, and based on which, the raise of the temperature would result in an increment of the grain size of Fe3O4 nanocrystal.3. The processing time is also important to control the purity and the grain size of as-synthesized Fe3O4 nanocrystal. At various temperature permitted, the minimum time needed to obtain high-purity Fe3O4 nanocrystal was different. The higher the processing temperature adopted, the shorter the minimum time is needed; the lower the processing temperature adopted, the longer the minimum time is needed. Furthermore, longer processing time would lead to an increment of the grain size of Fe3O4 nanocrystal.These researches make it possible to control the purity and the grain size of Fe3O4 nanocrystal effectively through changing the synthesizing conditions, and might have set up a credible foundation for practical applications of the material.