High-abundant rare earth La/Ce substituted Nd2Fe14C based permanent magnet materials prepared by mechanochemical method
To balance the utilization of rare-earth resources and reduce the preparation cost, the La and Ce substituted Nd 2 Fe 14 C hard magnetic alloys were prepared by a facile mechanochemical method for the first time. A two-step process is typically employed: 1) Decomposition of hydrocarbon and disproportionation of (Nd 1-x RE x ) 2.5 Fe 14 B 0.08 (RE=La or Ce, x=0–0.3) alloys during high-energy ball milling, Nd+Nd 2 Fe 17 +n-hexane→NdH 2+δ +α-Fe+Fe 7 C 3 ; 2) (Nd, RE) 2 Fe 14 C hard magnetic powders were obtained via the vacuum annealing at 800 °C for 2 min. The phase relation, magnetic properties and microstructural evolution of (Nd, RE) 2 Fe 14 B 0.08 C 0.92 (named Nd-RE-Fe-C-based) alloys were systematically investigated. Substitution of La for x=0.1 Nd in the Nd-RE-Fe-C-based alloy increase the coercivity from 15.6 kOe to 18.6 kOe without reducing the remanence. First-principles calculation was performed to study the mechanism of magnetic properties La and Ce substituted samples. The results showed that La tends to be expelled from 2:14:1 phase to form more minor phases which act as the domain wall pinning center, increasing the coercivity. However, Ce prefers to enter the 2:14:1 phase, diminishing the permanent magnetic properties due to the poor intrinsic magnetic properties. This paper provides a novel viewpoint for the effective utilization of high abundant rare earth and the investigation of low cost Nd 2 Fe 14 C permanent magnet materials.
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