In situ TEM study of Nd-rich phase in NdFeB magnet

Abstract

Hot stage in transmission electron microscope has been used to study the structure and stability of Nd-rich phase in NdFeB magnet. The present observation shows that the so-called complex cubic phase is in fact the prototype of Mn 2 O 3 (space group Ia 3) with lattice parameter of a ¼ 1:08 nm: The Nd-rich phase with P 3m1 structure (h-Nd 2 O 3 ) was first observed to be transformed from the BCC phase after in situ heating over 400 1C. The orientation relationship between these two structures satisfies as follows: (0 0 0 1) HCP //(2 0 0) BCC , ð10 1 0Þ HCP ==ð0 2 0Þ BCC ; ½ 1 2 1 0 HCP ==½0 0 1 BCC : It is argued that the h-Nd 2 O 3 was arising from the oxidation of the BCC Nd-rich phase rather than from Nd 2 Fe l4 B matrix phase as suggested in the literature. r

Nanoanalytical TEM Studies and Micromagnetic Modelling of Nd-Fe-B Magnets

“…The c-Nd 2 O 3 phase, which has a cubic crystal structure (a = 1.108 nm, Ia ͞ 3 (no.206)) [10], is mostly found in grain boundary junctions (GBj) and is colored red in Figure 1 Figure 1 (a-2). These phases were also reported by Fidler [12], Fidler et al [13], Tang et al [14], Lemarchand et al [15], Wang and Li [16] and Hrkac et al [17]. The RE-rich GBj phase of sample (b), which is colored in green, is a mixture of the Nd 2 O 3 and NdCu phase.…”

Application of a Dy3Co0.6Cu0.4Hx Addition for Controlling the Microstructure and Magnetic Properties of Sintered Nd-Fe-B Magnets

“…Phase 3 (Figure 5a) corresponded to the oxide phases. In accordance with the literature data [19,20], they may be based on NdO, Nd2O3, or NdO2. The presence of a phase based on Fe-Nb in triple junctions (TJ) was observed (Phase 4, Figure 5b).…”

Microstructure analysis of Nd‐Fe‐B sintered magnets improved by Tb‐metal vapour sorption

“…Recently space group I a3 (No. 206) with a = 1.1 nm have been reported (Shinba et al, 2005;Wang & Li, 2005). Detailed structure analysis is underway.…”