Ni纳米粉体的氧化特性和磁性研究

Study on oxidization resistance and magnetic behavior of Ni nanopowders

在CH4+H2+Ar的混合气氛下,用电弧放电法蒸发纯Ni制备了Ni纳米粉体,并对粉体进行了分析。结果表明,在CH4+H2+Ar的混合气氛下制备的粉体形貌接近类球形,平均粒度20nm,粒子具有核壳结构,核为Ni,壳为3 nm左右的碳膜。在CH4+H2+Ar气氛下制备的粉体抗氧化性比在H2+Ar气氛下制备的强,饱和磁化强度比在纯CH4气氛下制备的大。

Ni nanopowders were prepared by arc discharge evaporating pure Ni in CH4 ＋ H2 ＋ Ar atmosphere. The structure, morphology, surface layer and oxidation resistance as well as magnetic behavior of the particles were studied by X-ray diffraction（XRD）, high-resolution transmission electron microscopy（HRTEM） ,X-ray photoelectron spectroscopy（XPS）, chemical analysis, gas analysis and thermogravimetry analysis as well as vibrating sample magnetometer. The results show that the nanoparticles with mean particle sizes of 20nm form in a core-shell structure, which the core is Ni and the shell is carbon layer with 3nm thickness. The carbon layer prevents the particles from a further oxidation in air. The oxidization resistance of the samples prepared in CH4 ＋ H2 ＋ Ar atmosphere is better than the samples prepared in H2 ＋ Ar atmosphere, and the magnetization of the former is higher than the samples prepared in CH4 atmosphere.