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研究纳米尺寸磁性颗粒常温液相合成化学及其颗粒外层氧化稳定性控制工艺和机理。以二价和三价混合铁盐和硫化钠(Na_2S)为原料,氨水为沉淀剂,用化学沉积的方法制备了稳定的四氧化三铁(Fe_3O_4)纳米颗粒,并通过XRD、TEM和振动磁强计对磁性颗粒进行了表征。结果表明,所合成的纳米Fe_3O_4颗粒纯度高、抗氧化性能好,颗粒形状为近圆形的多边形,粒径10~15nm。干燥过程不影响颗粒的纯度和粒度。在对颗粒进行了有机表面改性后,颗粒表面为亲油性。磁性检测结果显示,作分散用的表面活性剂会影响颗粒的磁学性能,样品S2的磁化强度达到21.67A/m,剩余磁化强度达到1.43A/m,保磁力达到17.00Gs。提出了单颗粒表面多层微观结构功能性和稳定性控制机理模型,对氧化防止和防团聚本质问题进行了分析。
The technology and mechanism of nanosized magnetic particles in room-temperature liquid-phase synthesis chemistry and particle outer layer oxidation stability were studied. The ferric oxide (Fe 3 O 4) nanoparticles were prepared by chemical deposition using divalent and trivalent mixed iron salts and sodium sulfide (Na 2 S) as raw materials and ammonia as the precipitating agent. XRD, TEM and vibrating magnetic Strong meter magnetic particles were characterized. The results show that the synthesized nano-Fe 3 O 4 particles have high purity, good oxidation resistance, and the shape of the particles is a nearly circular polygon with a particle size of 10-15 nm. The drying process does not affect the purity and particle size of the particles. After the organic surface modification of the particles, the surface of the particles is lipophilic. The results of magnetic measurements show that the surfactant used for dispersion affects the magnetic properties of the particles. The sample S2 has a magnetization of 21.67 A / m, a remanent magnetization of 1.43 A / m and a coercive force of 17.00 Gs. The functional and stability control mechanism model of multi-layer microstructure on single particle surface was proposed, and the nature of oxidation prevention and anti-agglomeration was analyzed.