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采用微乳液法成功合成出以磁性铁氧体(NiFe_2O_4)为内核,以氧化硅(SiO_2)为壳层的纳米颗粒。NiFe_2O_4/SiO_2核壳结构纳米复合材料的形成过程是:将合成出的NiFe_2O_4纳米颗粒均匀分散正硅酸乙酯(TEOS)溶液中,然后对TEOS进行水解并在NiFe_2O_4纳米颗粒表面沉淀,将纳米颗粒分离出并进行后续热处理。通过XRD、IR、SEM、TEM等测试手段对纳米颗粒样品的显微组织结构进行了相应分析和观察。研究发现,纳米颗粒具有NiFe_2O_4/SiO_2核壳结构,其晶粒的平均直径大约为40 nm。采用振动样晶磁强计测试样品磁性能可发现纳米颗粒表现出典型的超顺磁性,其饱和磁化强度为12.97 emu·g~(-1)
Microemulsion method was used to synthesize nanoparticles with magnetic ferrite (NiFe_2O_4) as the core and silicon oxide (SiO_2) as the shell. The formation process of NiFe 2 O 4 / SiO 2 core-shell nanocomposites is that the synthesized NiFe 2 O 4 nanoparticles are homogeneously dispersed in TEOS solution, and then TEOS is hydrolyzed and precipitated on the surface of NiFe 2 O 4 nanoparticles. Separated and subjected to subsequent heat treatment. The microstructure of the nano-particles was analyzed and observed by XRD, IR, SEM and TEM. The study found that the nanoparticles with NiFe 2 O 4 / SiO 2 core-shell structure, the average grain diameter of about 40 nm. The magnetic properties of the sample were measured with a vibrating sample magnetometer to find that the nanoparticles exhibited typical superparamagnetism with a saturation magnetization of 12.97 emu · g -1