Study On Fe-Ferrite Based High Performance Soft Magnetic Materials By Powder Metallurgy

Experiments were carried out by combining powder metallurgy method and the idea of high purity atomized iron powder particles coated with an electrically insulated layer, through traditional powder metallurgy and mechanical alloying powder metallurgy. Fe-Ferrite based soft magnetic samples were prepared with several different components without any precious metals. Ballistic method was used in magnetic testing and the deficiency of open test was discussed. For the mechanical alloying powder metallurgy method, by studying the X-ray diffraction powder diffraction pattern for different milling times, it is found that factors like suitable ball mill machine, ratio and speed selection are conducive to the formation of amorphous structure. It is not easy to obtain high-density compact by using fine powder as starting materials through cold pressing. Moreover, the sintering temperature should be reduced due to high internal stress and surface energy. As for the traditional powder metallurgy method, high density compacts were obtained by proper powder pretreatment. It reaches 96.7 % and 97.5% of the theoretical density, after compaction and sintering, respectivley. By testing the magnetic properties of different samples, it is shown that the most excellent magnetic properties sample is obtained with Ferrite 0.6 wt.% and P 0.45 wt.%. For example, Bs reaches 1.61 T, the coercive force is less than 2 Oe, and the magnetic permeability close to 4000. Moreover, by comparing the tests, it is found that reduced iron powder with low purity and irregularly shaped is unsuitable for the starting materials of as high-performance soft magnetic materials.