中文摘要：

采用选择氧化法首次制备具有核壳结构的NiSi/SiO2纳米颗粒。通过SEM,TEM,EDX,XRD和VSM等测试手段对材料进行表征。结果表明,用上述方法制备得到的NiSi/SiO2纳米颗粒直径在40～200 nm之间,SiO2壳层厚度约为20 nm。基于选择氧化、结晶和热力学理论对SiO2壳层结构的形成机理进行了阐释。制备得到的NiSi/SiO2纳米颗粒在室温下显示出超顺磁性。

英文摘要：

NiSi /SiO2core-shell nanoparticles were firstly synthesized by DC arc-discharge approach and annealing process.The products were characterized by SEM,TEM,EDX,XRD and VSM.The results show that as-prepared NiSi /SiO2core-shell nanoparticles have the diameter bettween 40-200 nm and the thickness of the SiO2 shell is about 20 nm.The growth mechanism of SiO2 shell was also explained based on the preferential oxidation,crystallographic and thermodynamic theory.The as-prepared NiSi /SiO2core-shell nanoparticles exhibit superparamagnetism at room temperature.