Research On Structure Evolution And Properties Of SmCo And SmCo/feCo Alloy By Mechanicalalloying

The 21 st century, in this environment of energy conservation and environmental protection, demands for high-performance rare earth permanent magnet material which can work stably at high temperatures are more urgent. Nano-composite permanent material include SmCo with high HA, high Tc and Fe/Co with high Ms is expected to develop into a new generation of high-temperature magnetic materials. SmCo has many forms of compounds, and the magnetic corresponding different phases can be very different, in nano-composites, the addition of Fe/Co soft phase make it even more complex, therefore, it’s important to figure out the influence of Fe/Co on the crystallization process of hard magnetic phase for the preparation of a high-performance nano-composite SmCo-based alloy.In this article, amorphous precursor was prepared by high energy ball milling,combined with X-ray diffraction(XRD), differential scanning calorimetry(DSC) and vibrating sample magnetometer(VSM) to further analyze the influence of Fe/Co on the phase transition rules of SmCo during the subsequent heat treatment process.Comparative analysis of the precipitation process of SmCo-based amorphous precursor during heat treatment process with and without Fe/Co, and the results show that, Fe/Co did greatly contributed to the SmCo alloy amorphization, after annealing, the fraction of 1:7 phase was significantly increased, and the performance of the magnet was improved.During the SmCo alloy mechanical milling process, it was extremely difficult to obtain Sm Co amorphous phase. During the annealing process, for single-phase Sm Co5, the precipitation as follows: amorphous crystallized 1:7 phase, finally 1:7 phase converted to1:5 phase, Hci reached the maximum value at 500 ?C, over 13.8 kOe; and for Sm(Co, Cu,Fe, Zr)7.39 phase, the transformation rule is: amorphous phase successively crystallized1:7 phase and 1:5 phase,(BH)max is 8.7 MGOe obtained at 450 ?C.When Fe/Co participated in SmCo alloy mechanical milling process, they did greatly contributed to the Sm Co alloy amorphization, for SmCo5/FeCo, the amorphous only crystallized 1:7 phase,(BH)max is 10.6 MGOe obtained at 750 ?C; for Sm(Co, Cu, Fe,Zr)7.39/FeCo, the phase transformation rule is: amorphous first precipitated 1:5 phase,followed by the precipitation of 1:7 phase, then 1:5 phase transform to 1:7 phase,(BH)max is 6.8 MGOe obtained at 650 ?C.