Rare-earth permanent magnetic powder, bonded magnet containing thereof and device using the bonded magnet
A rare-earth permanent magnetic powder, a bonded magnet containing thereof and a device using the bonded magnet are provided of the present disclosure. The rare-earth permanent magnetic powder comprises: 70 vol % to 99 vol % of a hard magnetic phase and 1 vol % to 30 vol % of a soft magnetic phase, the hard magnetic phase has a TbCu 7 structure, and the grain size of the hard magnetic phase is 5 nm to 100 nm; the soft magnetic phase is a Fe phase having a bcc structure, the average grain size of the soft magnetic phase is 1 nm to 30 nm, and the standard deviation of the grain size is below 0.5σ.
1. A preparation method for rare-earth permanent magnetic powder, the preparation method comprises:
generating a sheet-shaped alloy powder by feeding molten raw materials onto a rotating roller and rapidly quenching the raw materials;
obtaining the rare-earth permanent magnetic powder by thermally treating the sheet-shaped alloy powder, and performing nitriding treatment or carbonizing treatment on the thermally treated alloy powder: wherein the step of generating a sheet-shaped alloy powder through the rapid quenching treatment comprises a two-step cooling comprising:
spraying the molten raw materials onto a rotating roller with a temperature from the melting points of the raw materials to 900° C., primarily cooling the molten raw materials to 880° to 920° at a cooling speed of 5×10 5 ° C./s to 80×10 5 ° C./s, and
secondarily cooling the molten raw materials to 280° C. to 320° C. at a cooling speed of 0.5° C./s to 3° C./s,
and wherein during the thermal treatment process, the sheet-shaped alloy powder is heated to 600-900 degrees centigrade at a heating speed of 10° C./s to 20° C./s and then thermally treated for 10 to 150 minutes.
2. A rare-earth permanent magnetic powder prepared by the method of claim 1 , wherein the rare-earth permanent magnetic powder comprises: 70 vol % to 99 vol % of a hard magnetic phase and 1 vol % to 30 vol % of a soft magnetic phase; wherein the hard magnetic phase is a TbCu 7 structure, and the grain size of the hard magnetic phase is 5 nm to 100 nm; and wherein the soft magnetic phase is a Fe phase having a bcc structure, the average grain size of the soft magnetic phase is 1 nm to 30 nm, and the standard deviation of the grain size of the soft magnetic phase is below 0.3α.
3. The rare-earth permanent magnetic powder according to claim 2 , wherein grain size distribution of the hard magnetic phase is within a range of 5 nm to 80 nm.
4. The rare-earth permanent magnetic powder according to claim 2 , wherein a volume of the soft magnetic phase accounts for 3 vol % to 30 vol % of a volume of the rare-earth permanent magnetic powder.
5. The rare-earth permanent magnetic powder according to claim 2 , wherein the average grain size of the soft magnetic phase is 1 nm to 20 nm.
6. The rare-earth permanent magnetic powder according to claim 2 , wherein the rare-earth permanent magnetic powder consists of R-T-M-A, wherein R is Sm or the combination of Sm with other rare-earth elements, T is Fe or the combination of Fe with Co, M is at least one of Ti, V, Cr, Zr, Nb, Mo, Ta, W, Si and Hf, A is N and/or C, and optionally, in the rare-earth permanent magnetic powder, the content of the R is 5 at. % to 12 at. %, that of the A is 10 at. % to 20 at. %, that of the M is 0 at. % to 10 at. %, and the balance is T.
7. The rare-earth permanent magnetic powder according to claim 2 , wherein in the rare-earth permanent magnetic powder, the content of the R is 5 at. % to 10 at. %.
8. The rare-earth permanent magnetic powder according to claim 2 , wherein in the R, the atomic content of Sm is 80 at. % to 100 at. %.
9. The rare-earth permanent magnetic powder according to claim 2 , wherein the T is the combination of Fe with Co, and the atomic content of Co is 0 at. % to 30 at. % in the T.
10. The rare-earth permanent magnetic powder according to claim 2 , wherein the thickness of the permanent magnetic powder is 5 pm to 50 pm.
11. The rare-earth permanent magnetic powder according to claim 3 , wherein the grain size distribution of the hard magnetic phase is within the range of 5 nm to 50 nm.
12. The rare-earth permanent magnetic powder according to claim 4 , wherein the volume of the soft magnetic phase accounts for 5 vol % to 15 vol % of the volume of the rare-earth permanent magnetic powder.
13. A bonded magnet, wherein the bonded magnet is prepared by bonding the rare-earth permanent magnetic powder of claim 2 with a bonding agent.
14. A device, wherein the device having the bonded magnet of claim 13 .