magnetron sputtering

Different from the vapor deposition diffusion method described above, magnetron sputtering separates the Dy deposition process from the diffusion process. It deposits Dy on the surface of the original magnet by physical sputtering, and then performs high temperature diffusion. Magnetron sputtering has the advantages of uniform film layer and obvious coercivity improvement effect.

Studies have shown that the coercive force of N35 sintered and tempered magnets is greatly improved after the sputtering Dy treatment, and the remanence is only reduced by 0.009T and 0.03T, which are increased by 708.44kA/m and 665.46, respectively. kA/m, the increases are as high as 73.5% and 64.8%, respectively, and the average mass fraction of Dy element in the magnets after Dy infiltration does not increase by more than 0.4%. In the magnet treated with Dy, Dy is enriched in the Nd-rich phase in a continuous band, which makes the Nd-rich phase more continuous and smooth. The improvement of the structure and morphology of the Nd-rich phase is one of the reasons for the increase in coercivity. The formed (Nd,Dy)2Fe14B epitaxial layer has a large magnetocrystalline anisotropy field, and the hardening of the grain epitaxial layer can better suppress reverse domain nucleation, which is also the main reason for the increase in coercivity.