The phase formation of the (Nd0.70Pr0.30−xCex)2.28Fe13.58B1.14 (x = 0.10, 0.15, and 0.20; hereafter defined as Pr20Ce10, Pr15Ce15 and Pr10Ce20, respectively) and (Nd0.60Pr0.40−yCey)2.28Fe13.58B1.14 (y = 0.10, 0.20, and 0.30; hereafter defined as Pr30Ce10, Pr20Ce20 and Pr10Ce30, respectively) alloys that were prepared via the arc-melting method was investigated experimentally. The x-ray diffraction results revealed that all alloys annealed at 1173 K for 360 h consisted of a (NdPrCe)2Fe14B main phase with a tetragonal Nd2Fe14B-typed structure (space group P42/mnm) and an α-Fe minor phase, except for the Pr10Ce30 alloy, which contained an additional CeFe2 phase. The magnetic properties of the (Nd0.70Pr0.30−xCex)2.28Fe13.58B1.14 and (Nd0.60Pr0.40−yCey)2.28Fe13.58B1.14 ribbons that were prepared by melt spinning were examined. The remanence (Br) and maximum magnetic energy product ((BH)max) of the (Nd0.70Pr0.30−xCex)2.28Fe13.58B1.14 ribbons increased first and then decreased, whereas the coercivity (Hcj) of the ribbons increased with an increase in Ce content. The Br and (BH)max of the (Nd0.60Pr0.60−yCey)2.28Fe13.58B1.14 ribbons increased, whereas the Hcj of the ribbons decreased gradually with an increase in Ce content. This changed behavior of magnetic properties is attributed to the variation of volume fraction of the α-Fe phase and different phase formations in the melt-spun ribbons. The Curie temperatures (Tc) of all ribbons decreased slightly with Ce substitution, which results from the lower Curie temperatures of Pr2Fe14B and Ce2Fe14B. The Pr10Ce30 ribbon with a higher Ce content exhibited optimal magnetic properties (Br = 9.71 kGs, Hcj = 13.09 kOe, (BH)max = 18.78 MGOe), which indicates that suitable magnetic properties of the Nd–Pr–Ce–Fe–B melt-spun ribbons can be achieved by alloy-composition and phase-formation design.

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As a rapid solidification technology, strip casting (SC) technology is one of importance method in the production of Nd2Fe14B-based rare-earth permanent magnets. (Nd1-2xPrxYx)2.28Fe13.58B1.14 (x=0.05, 0.10, 0.15, 0.20) alloys prepared by arc melting method under an argon atmosphere were annealed at 1173 K for 360 hrs and then were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Differential Scanning Calorimetry (DSC). Magnetic properties of the ribbons prepared by melt-spinning method with high cooling rate were measured by Physical Property Measurement System (PPMS). The XRD and SEM results showed that the annealed (Nd1-2xPrxYx)2.28Fe13.58B1.14 (x=0.10, 0.15, 0.20) alloys had a single phase with tetragonal Nd2Fe14B-tpyed structure, while the annealed (Nd0.90Pr0.05Y0.05)2.28Fe13.58B1.14 alloy contained Nd2Fe14B phase and α-Fe secondary phase. On the other hand, the coercivities (Hcj) of (Nd1-2xPrxYx)2.28Fe13.58B1.14 (x=0.05, 0.10, 0.15, 0.20) melt-spun alloys were about 13.42 kOe, 13.49 kOe, 7.97 kOe and 8.36 kOe, respectively, while the remanences (Br) of the alloys were 7.52 kGs, 7.48 kGs, 9.14 kGs and 7.48 kGs, respectively. In addition, The Curie temperature (Tc) of the annealed (Nd1-2xPrxYx)2.28Fe13.58B1.14 (x=0.05, 0.10, 0.15, 0.20) alloys were determined to be 573 K, 574 K, 579 K and 580 K, respectively.

In this work, the microstructure, crystal structure and magnetic properties of (Nd0.7Pr0.15RE0.15)2.28Fe13.58B1.14 (RE=La, Ce, Y) alloys prepared by arc-melting were investigated experimentally. The experimental results show that all alloys annealed at 1173 K for 360 hrs contain the isotropic Nd2Fe14B structure phase. The coercivities (Hc) of (Nd0.7Pr0.15RE0.15)2.28Fe13.58B1.14 (RE=La, Ce, Y) melt-spun ribbons are 12.3 kOe, 13.2 kOe, 8.5 kOe, and the Curie temperatures (Tc) of annealed (Nd0.7Pr0.15RE0.15)2.28Fe13.58B1.14 (RE=La, Ce, Y) alloys are 569 K, 552 K and 576 K, respectively. Meanwhile, the remanences (Br) of (Nd0.7Pr0.15RE0.15)2.28Fe13.58B1.14 (RE=La, Ce, Y) melt-spun ribbons are about 67 emu/g, 74 emu/g and 72 emu/g, respectively. It was indicated that the coercivity, remanence and Curie temperatures of (Nd0.7Pr0.15RE0.15)2.28Fe13.58B1.14 alloys are dependent on light rare earth elements.