高密度煤油基磁性液体的制备及其性能表征

采用化学共沉淀法，通过改变Fe₃O₄纳米颗粒的生长温度、包覆环境pH、清洗、分散方式等工艺参数进行对比试验，得出Fe₃O₄纳米颗粒在生长阶段、包覆阶段、分散阶段的最佳参数条件，优化以往的制备工艺，使油酸包覆的磁性颗粒在煤油中的分散稳定性得到提高。通过XRD、TEM、VSM等对样品进行表征，并使用旋转流变仪对所制煤油基磁性液体的流变性能进行分析。结果表明，改性后的Fe₃O₄纳米颗粒平均粒径约为14nm，呈现较为规则的球形，饱和磁化强度为60 (A·m²)·kg^-1，可制备出质量分数可达60%的高密度煤油基磁性液体，与普通磁液相比，以此制备工艺得的高密度煤油基磁性液体在饱和磁化强度、抗氧化性等方面皆有较大提升，拥有更高的应用价值。

Preparation and characterization of high density kerosene based magnetic fluid

Using the chemical coprecipitation method, the comparative experiments were carried out by changing the process parameters such as growth temperature, pH of coating environment, cleaning and dispersion mode of Fe3O4 nanoparticles. The best parameters and conditions of Fe3O4 nanoparticles in growth stage, coating stage and dispersion stage were summarized and the previous preparation process was optimized to improve the dispersion stability of oleic acid coated magnetic particles in kerosene. The samples were characterized by XRD, TEM and VSM and the rheological properties of the kerosene based magnetic fluid were analyzed by rotating rheometer. The results show that the average particle size of the modified Fe3O4 nanoparticles is about 14 nm, showing a regular sphere. The saturation magnetization of modified Fe3O4 nanoparticle is 60 emu/g and high-density kerosene based magnetic fluid with a mass fraction of 60% was prepared. Compared with ordinary magnetic fluid, the high-density kerosene based magnetic fluid obtained by this preparation process has a great improvement in saturation magnetization and oxidation resistance and has higher application value.