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Fe 3 O 4 is an important project, information materials, has a wealth of potential applications and a wide range of application areas. The the nano Fe 3 the O 4 has many unique properties different from its bulk, but nano Fe 3 the O 4 performance largely depends on the preparation method, and therefore improve Fe 3 O 4 preparation, not only has an important theoretical significance, but also expand the Fe 3 O 4 application prospects. Traditional liquid phase precipitation the prepared Fe 3 O 4 improved by the introduction of ultrasound in the course of the experiment as strengthen the means to study, to explore different ultrasound under the experimental conditions , of prepared nano Fe 3 O 4 , morphology, size, size distribution, and electromagnetic properties such studied. Calculated and experimental exploration, we use the following parameters to the experimental study: (1) ultrasound - 25kHz, 40kHz, 59kHz; (2) temperature - 40 ° C, 50 ° C, 60 ° C; (3) ion ratio - Fe2 : Fe3 = 1.1:2; (4) precipitating agent - NaOH, ammonia; (5) Surface active agents - polyvinyl-pyrrolidone (PVP), polyethylene glycol (PEG), sodium dodecylbenzene sulfonate ( SDBS). The subject of research, exploration, discovery obtained under ultrasound fortified nano Fe 3 O 4 , have the following characteristics: (1) morphology was nearly spherical particle size narrow segment (mainly 15 2 0 nm); smallest particle size, (2) lower ultrasonic frequency (25kHz) narrowest segment; (3) the magnetization characteristic was nearly superparamagnetic saturation magnetization was significantly higher than the case when not ultrasound; (4) gradually increased with the increase of the ultrasonic frequency saturation magnetization; (5) ultrasound is conducive to the increase nano Fe 3 O < / sub> crystalline; (6) surfactants help reduce Fe 3 O 4 particle size, but not significantly; surfactants on the preparation of nano Fe 3 O 4 the Ferrite performance had no significant effect; (7) the temperature of the reaction system (lower temperature) the impact is not large. Ultrasound fortified the nano Fe obtained 3 O 4 with the above characteristics, mainly attributed to acoustic cavitation effect of ultrasound (high-temperature, high-pressure micro-bubble point), this The effect provides extraordinary physical and chemical environment, completely broke the original room temperature in the course of the reaction, the reaction characteristics and pressure showed a tiny local severe changes characteristics. In addition, the complex and volatile reaction acoustic cavitation conditions, caused by a series of changes, and ultimately makes Fe 3 O 4 morphology of spherical, crystalline improve thereby affecting Fe 3 O 4 electromagnetic properties.
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