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目的：研究经Fe( NO3)3处理后γ-Fe2 O3/Ni2 O3复合纳米微粒稳定分散在磁性液体中的机理。方法使用共沉淀法制备FeOOH/Ni(OH)2前躯体,经FeCl2溶液处理后得到以γ-Fe2O3为核心,Ni2O3在外层,FeCl3·6H2 O在最外层的核-壳结构γ-Fe2 O3/Ni2 O3复合纳米微粒。用硝酸铁溶液对其进一步处理,使微粒表面性质稳定以适合配制离子型磁性液体。使用振动样品磁强计、透射电子显微镜、X射线衍射仪、X射线光电子能谱仪对硝酸铁处理后复合纳米微粒的磁性、形态、晶体结构、化学组成及结构进行分析。结果经硝酸铁处理后,微粒的磁性减弱,粒径略微变大,约为11 nm,但位于微粒核心的主要成分γ-Fe2O3保持不变,且在微粒表面包裹了一层Fe(NO3)3·9H2O抗腐蚀层。结论经Fe(NO3)3处理后微粒表面包裹的抗腐蚀层及配制磁性液体时微粒表面吸附同种H+或OH-形成的静电斥力,使微粒在磁性液体中稳定分散。

Objective To investigate the mechanism ofγ-Fe2 O3/Ni2 O3 composite nanoparticle stably dispersed in the ferrofluids after Fe( NO3 ) 3 treatment. Methods The FeOOH/Ni( OH) 2 precursor was prepared by coprecipitation, and was then treated with the FeCl2 solution to obtain composite nanoparticles containingγ-Fe2 O3 core, Ni2 O3 external shell and FeCl3 ·6H2 O outermost lay-er. The nanoparticles were then treated with Fe( NO3 ) 3 to obtain modified particles with stable surface properties for the preparation of ionic ferrofluids. The magneticity, morphology, crystal structure, chemical composition and structure of the composite nanoparti-cles after Fe( NO3 ) 3 treatment were analyzed by VSM, TEM, XRD, EDX and XPS. Results The particles after treatment were slightly larger ( about 11 nm) , but the major componentγ-Fe2 O3 located in the core of particles remained unchanged. And the sur-face of the particles was covered with a Fe(NO3)3·9H2O corrosion-resistant layer. Conclusion The corrosion-resistant layer cov-ering the particles after Fe( NO3 ) 3 treatment and the electrostatic repulsion formed by the same species H+ or OH- adsorbed onto the surface of the particles during the preparation of magnetic liquid made the particles stably dispersed in the ferrofluids.