The (SmZr)Co$_3$Phase in Sm(CoFeCuZr)$_rm z$Magnets

The evolution of phase constitution and microstructure in iron-rich 2:17-type Sm-Co magnets with high magnetic performance

“…Fe x Cu 0.08 Zr 0.03 ) 8.2 (x = 0.23, 0.26, and 0.28) as-cast alloys 21 . According to the chemical composition, the Zr-rich phase can be shortened in form of (SmZr) 1 (CoFeCu) 3 , which is in accord with the results of Campos 22 . Furthermore, it can be seen that the content of Zr in Zr-rich 1:3 phase increases with the increase of the Fe content, which indicates that the addition of Fe tends to promote the segregation of Zr in 1:3 phase.…”

Microstructural changes during the slow-cooling annealing of nanocrystalline SmCo 2:17 type magnets

“…6. The 1:3 phase has been described as Rhombohedral Sm 1 Zr 2 Co 9 , a stable phase in the ternarium Sm-Zr-Co, with structure derived from PuNi 3 [30][31][32], see Table 1. The X-ray spectra of the 820°C sample and 400°C sample are very similar, both with $7% of nanocrystalline Sm(CuCu) 5 phase (crystallite size $12 nm), 3% of 1:3 and all the rest 2:17R (crystallite size $50 nm provided best fitting in the Rietveld analysis).…”

Interacting Stoner–Wohlfarth behavior in hysteresis curves of Sm(CoFeCuZr)z magnets

“…This result can be attributed to the presence of grains of Zr-rich impurity phases [9], which are presumably softer and generate stray fields that could provoke magnetic reversal of the 2:17 nanograins. Microstructural analysis was carried out to determine the nature of these impurity phases [6,7,9]. The results obtained from scanning electron microscopy (SEM) [9] indicated the presence of several phases with the sum Sm+Zr ranging from 15 to 25 at%.…”

“…The results obtained from scanning electron microscopy (SEM) [9] indicated the presence of several phases with the sum Sm+Zr ranging from 15 to 25 at%. Rietveld analysis of X-ray diffraction (XRD) spectra [6,7] was then employed, and the results from both SEM and Rietveld XRD are summarized as follows.…”

“…The commercial alloys are, in fact, fiveelement alloys, with composition based on Sm 2 Co 17 phase with additions of Cu, Fe and Zr. The microstructure of the SmCo 2:17 magnets is nanocrystalline and has three main phases, all of them crystallographically coherent: the cell phase Sm 2 (Co,Fe) 17 , the cell boundary phase Sm(Co,Cu) 5 and the lamellar or platelet phase (ZrSm) 1 (CoFeCu) 3 with PuNi 3 structure [6,7] (also described as BeNb 3 structure [8])…”