Preparation of SiO2 / Ni core-shell structured nanoparticles and their magnetic properties
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摘要: 以硅酸钠为主要原料, 通过液相沉淀法在纳米镍粉表面包覆了一层SiO2 。应用XRD、FTIR、TEM、TGA、DSC 和VSM 对复合粉体的结构、形貌和磁性能进行了研究。结果表明, SiO2 以非晶态的形式包覆在纳米镍粒子表面, 形成了核壳结构, 降低了纳米粉体的团聚现象。TGA 和DSC 结果表明, SiO2 的包覆提高了纳米粉体的抗氧化性。磁性分析结果表明, 粉体包覆前由于表面氧化层(NiO) 的存在, 粉体的磁滞回线偏移; 包覆后的粉体由于SiO2的存在, 饱和磁化强度降低, 矫顽力升高。
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关键词:
- SiO2 / Ni 纳米粒子 /
- 表面包覆 /
- 抗氧化性 /
- 磁性能
Abstract: Magnetic Ni nanoparticles coated with silica were successfully synthesized via the liquid deposition methodusing Na2SiO3 as the main raw material , and their st ructures and properties were studied by X-ray diff raction(XRD) , Fourier t ransform inf rared spect rometer ( FTIR) , t ransmission elect ron microscopy ( TEM) , thermogravimet ric analysis ( TGA) , differential scanning calorimet ry (DSC) and vibrating sample magnetometer (VSM) . XRD ,FTIR and TEM result s show that there is noncrystal silica on the surface of Ni nanoparticles and it prevents the nanoparticles f rom agglomerating. The oxidation resistance of SiO2 / Ni nanoparticles is improved because of the protection of the silica coating. Magnetic properties show that Ni and SiO2 / Ni are ferromagnetic materials. The hysteresisloop of Ni has an excursion because of the anti-ferromagnetic NiO. The silica coating reduces the saturation magnetization and improves the coercivity.-
Key words:
- Ni/ SiO2 nanoparticles /
- surface coating /
- oxidation resistance /
- magnetic properties
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