Novel PrNd-Lean Ce-Based R₂Fe₁₄B Permanent Magnets With High Performance

In this article, the phase compositions, microstructures, and magnetic properties of PrNd-free Ce-Fe-B-based sintered magnets with the nominal composition of (Ce
_0.78
Y
_0.17
La
_0.05
)
_16.28
Fe
_bal.
B
_7.44
M
_1.94
(at.%: M = Co, Al, Cu, and Nb) have been investigated. It shows that a lamellar crystalline structure is formed in the Ce-Fe-B-based strip casting (SC) alloy. The Y-substituted Ce-Fe-B-based SC alloy is mainly composed of R
₂
Fe
₁₄
B and RFe
₂
phases. It suggests that Y substitution is helpful for depressing the α-Fe phase generated in the SC alloy. The island-like intermediate phases exist in the RFe
₂
region, which are probably caused by the incomplete peritectic reaction during alloy solidification. The Curie temperature T
_c
of the Y-substituted Ce-Fe-B-based alloy is about 463 K, which is higher than that of the Ce
₂
Fe
₁₄
B compound (T
_c
= 424 K). For the experimental Ce-Fe-B-based sintered magnet without PrNd addition, the remanence B
_r
of 8.31 kG, the coercivity H
_cj
of 0.92 kOe, and the maximum energy product (BH)
_max
of 5.30 MGOe have been obtained. A good combination of coercivity H
_cj
(= 5.57 kOe) and maximum energy product (BH)
_max
(= 20.17 MGOe) has been achieved in the Ce-Fe-B-based blended magnet with PrNd/ΣRE = 25% prepared using a binary main phase (BMP) method. The heterogeneous elemental distributions and microstructure characteristics of the BMP magnet are also analyzed.