High performance Nd-Fe-B permanent magnets without critical elements

•Magnetic properties of Ce and Co co-doped Nd-Fe-B based alloys are investigated.•Substitution of Ce and Co results in the synergistic effect between Co and Ce3.44+.•Significant Nd can be replaced by Ce by maintaining good magnetic properties.•Substitution of Ce and Co in Nd2Fe14B increases both TC and the (BH)max.•Magnetic properties of V, Cr, Mn, and Ni doped Nd-Fe-Co-B alloys investigated.

Scanning electron microscopy, and magnetization measurements reveal that as cast (Nd1−xCex)2Fe14B alloys contain significant amounts of α-Fe that can be dramatically reduced by annealing the alloys at 1000 °C for 3 days. The room temperature intrinsic coercivity, Hci, of (Nd0.8Ce0.2)2.2Fe14B melt spun ribbons was found to be 11 kOe, which is ∼32–∼10% higher in comparison to that of Nd2Fe14B (Hci = 8.3 kOe), and (Nd0.8Ce0.2)2.0Fe14B (Hci = 10 kOe), respectively. The substitution of Co for Fe in (Nd0.8Ce0.2)2Fe14−zCozB significantly increases both TC and the maximum energy product, (BH)max. Our study shows that both Co-containing and Co-free Ce-substituted Nd2Fe14B alloys have excellent magnetic properties at room temperature and above. The experimental results also demonstrate the potential of Nd-Ce-Fe-TM-B based alloys as alternative to expensive Dy-containing high performance rare earth magnets.