Role of lanthanum in microstructure evolution and enhanced magnetic properties of cerium‐containing sintered magnets

Abstract

In this study, lanthanum was applied to strip cast CeÀ FeÀ B alloy to improve its phase composition and microstructure. The results reveal that lanthanum doping can significantly enhance the proportion of 2 : 14 : 1 phase and improve the microstructure of CeÀ FeÀ B alloy. Besides, the influence of the starting alloys structure on the microstructure and magnetic properties of final multi-phases cerium-containing magnets was also systematically investigated. Compared to the multiphases magnet without lanthanum addition, a pronounced coercivity increment could be distinguished in lanthanum-doping multi-phases magnet, which could be attributed to the finer grain size together with ideal grain boundary. In this work, the superior performance of H cj = 701.28 kA/m B r = 1.30 T, and (BH) max = 313.70 kJ/m 3 were obtained by blending NdÀ FeÀ B alloy with (La 0.35 Ce 0.65)-FeÀ B alloy to meet 25.0 wt.% lanthanum-cerium utilization content, suggesting that the possibility to develop high abundant rare earth permanent magnetic materials.

Nd2Fe14B permanent magnets substituted with non-critical light rare earth elements (Ce, La): A review

“…Combined with the MMP process, the La/Ce co-substitution has also been found to improve the mechanical properties of magnets [15], due to the better ductility of the REFe2 phase, as well as the corrosion behavior [100], owing to the role of REFe2 precipitates that limit the penetration of electrolyte along GBs. As mentioned before, the co-substitution (Ce,La) allows tailoring the amount of REFe2 phase which could be excessive when Ce-rich alloys are used in MMP [101], [98], [102], [103]. Wei et al compared MMP magnets made with Ce (Ce/RE = 25%) and with Ce/La ([Ce,La]/RE = 25%) and showed that the La limits the REFe2 amount, meaning more T1 phase and better remanence (BHmax = 39.5 MGOe vs 37.8…”