Fe-Ni-B非晶纳米粒子不同处理后表面组成和结构的研究

Study on Surface Composition and Structure of Fe-Ni-B Amorphous Nanometer Particles by Different Processes

对Fe-Ni-B非晶纳米粒子表面施加了单宁酸和重铬酸钾处理后,采用X射线光电子能谱和透射电子显微镜等技术对处理后粒子的表面组成和结构进行了分析。结果表明,单宁酸和重铬酸钾处理均可以提高Fe-Ni-B非晶纳米粒子的饱和磁化强度,且后者的提高幅度远大于前者。原因在于两种处理均使粒子的表面状态发生了有利于增强饱和磁化强度的变化,在表面形成了复合型氧化物NiFe_2O_4;而重铬酸钾处理还在粒子表面形成了致密的Cr_2O_3层,阻挡了氧原子从表面向体内的扩散,减少了粒子的氧化态数量,从而使其饱和磁化强度得以大大提高。

The surface composition and structure of the Fe-Ni-B amorphous nanometer particles processed by means of potassium dichromate and tannic acid have been investigated using the techniques of XPS and TEM etc. The saturation magnetization of the processed particles is higher than that of the unprocessed. This may be attributed to the formation of an complex oxide NiFe_2O_4 on the surface, especially the formation of a dense layer of oxide Cr_2O_3 after the treatment by potassium dichromate. Perhaps, it is the oxides that retard the diffusion of oxygen from the surface into the bulk, reduce the content of oxide, and increase the saturation magnetization of the Fe-Ni-B amorphous nanometer particles greatly.