Effect of the Ce Content on the Magnetic Properties and Microstructure of CeCo5-based Sintered Bulk Magnets

Abstract

CeCo5-based magnets have recently attracted much attention due to their moderate magnetic performance and low cost. Nevertheless, there have been few studies on the effects of Ce content on the magnetic properties and microstructures of CeCo5-based magnets. In response to this, the magnetic properties of sintered bulk magnets with nominal compositions of Ce(Co0.73Cu0.135Fe0.135) z (z = 4.95, 5.15, 5.35, and 5.55), prepared by the conventional powder metallurgy method, were investigated here. Based on experimental findings, it was shown that Ce(Co0.73Cu0.135Fe0.135)5.15 sintered bulk magnets had comprehensive magnetic properties—maximum energy product of 80 kJ m− 3 (10 MGOe) and intrinsic coercivity (H cj) of 452 kA m− 1 (5.69 kOe)—superior to those previously reported by us. For z = 5.35 and 5.55, due to the presence of the minor Ce2Co17 phase (which has a Curie temperature (T c ) < 20 °C), magnets had low H cj values. Based on x-ray diffraction and scanning electron microscopy observations, it was suggested that the volume fraction of the 1:5 matrix phase was the main factor determining the H cj of CeCo5-based sintered bulk magnets obtained with different Ce contents. Furthermore, the importance of the dispersion characteristics of the Ce2O3 phase within the matrix was emphasized. Uniform dispersion of the Ce2O3 phase can significantly improve the overall magnetic performance of CeCo5-based magnets.