磷化处理对软磁铁粉性能影响

Effect of Phosphate Processing on the Properties of Soft Magnetic Iron Powder

为提高软磁复合材料磁学和力学性能,采用还原纯铁粉为原料,利用磷化处理工艺制备绝缘软磁粉末,并用粉末冶金法制备磷化的软磁复合材料。研究了磷化程度对软磁复合材料的致密度、电阻率、粉末的显微结构和磁学性能等影响。研究表明,磷化浓度的提高可快速提高软磁复合材料的电阻率,但同时也降低了软磁复合材料的致密度、最大饱和感应强度和磁导率。当磷化浓度为0.005时,软磁复合材料的相对密度最大,为89.74%,磁学性能最好,饱和磁感应强度为1.442T,磁导率为375H/m。体视显微镜、SEM和EDS分析表明,经磷化处理的铁粉其表面被铁的磷酸盐绝缘层均匀完整地包覆,绝缘层的厚度随磷化浓度提高而升高。

In order to improve the magnetic and mechanical properties of soft magnetic composites, phosphate process- ing was used to prepare an insulation layer on the surface of pure iron powders. Abulk soft magnetic composite was pre- pared by means of powder metallurgy processing. The effects of phosphate concentration on the density, resistivity, micro- structure and magnetic properties were studied. The experimental results show that with the increase of phosphate concen- tration, the resistivity of the soft magnetic composites increases rapidly, but the density, maximum saturation induction in- tensity and magnetic permeability decrease. When the phosphate concentration is 0. 005, the best combination of the rela- tive density of 89. 74% and the magnetic properties is obtained. The maximum saturation induction intensity is 1. 442 T and the magnetic permeability is 375 H/m. Stereoscopic microscope, SEM and EDS analysis show that after phosphate processing, the surface of the iron powder is coated completely and uniformly by an iron phosphate insulating layer. The thickness of the insulating layer increases with the increase of phosphate concentration.