Development of bonded (La,Ce,Y)-Fe-B permanent magnets with higher performance/cost ratio than Nd-Fe-B and (Nd,La,Ce)-Fe-B magnets

Aiming at developing cost-effective bonded permanent magnets, the microstructure, magnetic properties, thermal stability, corrosion resistance, and mechanical properties of bonded (La,Ce,Y)-Fe-B magnet were investigated and compared with Nd-Fe-B and (Nd,La,Ce)-Fe-B magnets. Only RE2Fe14B and Ce(La) grain boundary phases were found in the melt-spun (La,Ce,Y)-Fe-B alloy with a composition of [(Ce0.7La0.3)(0.8)Y-0.2](17)Fe(7)8B(6), and no paramagnetic CeFe2 phase was detected, which is beneficial to hard magnetic properties. Bonded (La,Ce,Y)-Fe-B magnet exhibits a combination of magnetic properties with intrinsic coercivity Hcj = 330 kA/m, remanence Jr = 0.40 T, and maximum energy product (BH)max = 21.7 kJ/m(3), compared to Hcj = 519 kA/m, Jr = 0.52 T, and (BH)max = 43.8 kJ/m(3) for (Nd,La,Ce)-Fe-B magnet and Hcj = 751 kA/m, Jr = 0.66 T, and (BH)max = 75.3 kJ/m3 for Nd-Fe-B magnet. Despite its relatively low hard magnetic properties, (La,Ce,Y)-Fe-B magnet exhibits the highest performance/cost ratio. In the temperature range of 300-400 K, (La,Ce,Y)-Fe-B magnet shows better thermal stability than Nd-containing magnets, demonstrated by the high temperature coefficient of coercivity (-0.181%/K). The corrosion processed of bonded magnets are studied, and (La,Ce,Y)-Fe-B magnet exhibits better corrosion resistance than other magnets. The mechanical properties of various bonded magnets were also investigated and the highest compressive strength was obtained in (La,Ce,Y)-Fe-B magnet, possibly due to its higher density and the less brittleness of (La,Ce,Y)-Fe-B alloy. This work is beneficial to accelerating the industrialization of high abundance RE magnets.

Automated summary

This study investigates and compares the microstructure, magnetic properties, thermal stability, corrosion resistance, and mechanical properties of bonded (La,Ce,Y)-Fe-B magnet with Nd-Fe-B and (Nd,La,Ce)-Fe-B magnets. The results show that bonded (La,Ce,Y)-Fe-B magnet exhibits a combination of magnetic properties with lower coercivity but higher performance-to-cost ratio compared to other magnets. It also demonstrates better thermal stability and corrosion resistance. The study suggests that bonded (La,Ce,Y)-Fe-B magnet has great potential for industrial applications.