Development of Flexible Rare Earth–Fe–B Rubber Magnets toward Efficient Utilization of Ce, La, and Y Elements

Abstract

The microstructure, magnetic properties, corrosion and aging resistance, and mechanical properties of Nd–Fe–B, (Nd, La, Ce)–Fe–B, and (Ce, La, Y)–Fe–B rubber magnets have been investigated. For Nd–Fe–B magnets, increasing particle size and filling ratio of magnetic particles not only improves the overall magnetic properties but also increases the tensile strength. Using the Nd26.4Fe67.6Co5B powder with particle size of 75–106 μm and filling ratio of 90%, the optimum magnetic properties with the coercivity Hcj = 738.2 kA m−1, remanence Jr = 0.51 T, and maximum energy product (BH)max = 43.5 kJ m−3 are obtained. The magnet also exhibits an enhanced tensile strength of 4.52 MPa owing to its compact and uniform microstructure. In addition, the magnetic properties of Hcj = 518 kA m−1, Jr = 0.34 T, and (BH)max = 20.6 kJ m−3 are obtained in the partial high‐abundance (Nd, La, Ce)–Fe–B rubber magnet, which is superior to some of commercial Nd–Fe–B rubber magnets. For full high‐abundance (Ce, La, Y)–Fe–B magnet, these values are 320 kA m−1, 0.27 T, and 10.5 kJ m−3, respectively. Despite its lower magnetic properties than Nd‐based rubber magnets, (Ce, La, Y)–Fe–B rubber magnet exhibits a competitive advantage over the Nd‐containing magnets in terms of corrosion resistance and aging resistance performance. Moreover, (Ce, La, Y)–Fe–B magnet shows a tensile strength of 7.86 MPa, which is nearly 74.2% and 56.8% higher than the Nd–Fe–B and (Nd, La, Ce)–Fe–B rubber magnets. The present results indicate that the Ce, La, and Y elements can be reasonably selected to manufacture flexible rare earths–Fe–B rubber magnets with a high performance/cost ratio and good performance stability.