RETM5 and RE2TM17 (RE=rare earth, TM=transition metal) permanent magnets are discussed in this review. The scientific and technological considerations which have guided their development are described. Along with a discussion of the various research efforts reported in the literature, they help establish the framework within which most of the work can be integrated and understood. In regard to the RETM5 alloys, the review limits itself to the technologically significant SmCo5 materials; others are discussed minimally, and only to the extent that they contributed to overall magnet development efforts. Likewise, from among the fabrication technologies, the review is limited to those processes which have been demonstrated as capable of producing magnets in bulk useful form. Areas covered in this review include phase diagrams, crystal structures, magnetocrystalline anisotropy, coercivity mechanisms, fabrication technologies, processing‐microstructure‐property interrelationships, and thermal effects related to...

RETM5 and RE2TM17 permanent magnets development

RETM5and RE2TM17permanent magnets development

Continuing the papers on alloys of Sc, Ti, V, Cr, Mn and Fe we review in the present paper, on the basis of the model developed by Miedema and co-workers, experimental and predicted enthalpies of formation of ordered binary intermetallic compounds of Co with arbitrary metal partners. The enthalpy effects are also reviewed for liquid Co alloys. The predicted values agree quite satisfactorily with the available experimental data for binary systems of Co with a transition metal. In the binary systems where Co is alloyed with a non-transition metal larger differences are sometimes observed. Since Co with other transition metals may often form solid solutions the enthalpy of forming solid solutions is dealt with in a concise way distinguishing between magnetic and non-magnetic matrix metals.

Enthalpies of formation of liquid and solid binary alloys based on 3d metals: IV. Alloys of cobalt

https://hal.archives-ouvertes.fr/hal-02394632/document

Exploits, advances and challenges benefiting beyond Li-ion battery technologies

Elaboration and characterization of magnesium-substituted La5Ni19 hydride forming alloys as active materials for negative electrode in Ni-MH battery

The crystal structure of R5Co19

http://journals.iucr.org/b/issues/1974/04/00/a10963/a10963.pdf

A contribution to the Sm–Co phase diagram

The tentative equilibrium phase diagrams of the binary CeCo and LaCo systems on the Co-rich side are given. Two isothermal sections of the ternary CeLaCo system (one at 850°C and the other at 1000°C) on the Co-rich side have been determined. The intermetallic compounds CeCo5 and Ce2Co17 are found to be congruently melting, contrary to the existing literature, and to possess a large homogeneity region. The extent of La solubility in CeCo5 over the whole homogeneity range has been studied. It is shown that the structure of the hyper-stoichiometric ★ AB5 compounds (A = rare earths, B = 3d transition metals) is different from that of the CaCu5 type with nearly the same lattice constants. How the formation of these hyper-stoichiometric RCo5 intermetallic compounds can lead to a drastic drop in the magnitude of the coercive fields of permanent magnets based on them is discussed.

Intermetallic compounds in the cobalt-rich part of the R-cobalt systems (R = Ce, La, CeLa)

An alloy having the composition SmCo5 has so far been considered to be a single phase compound with the CaZn5-type structure. It is shown by X-ray analysis and other methods that this material is actually always obtained as a composite of two phases, one having the CaZn5-structure and the other being a variant of that structure with doubled lattice constants.

Crystal structure of SmCo5

The crystal structure of the high-temperature phase of the intermetallic compound Sm2Co17 has been reported to be isotypic with the Th2Ni17 structure. In the present work it is shown that the structure of this phase, in fact, is of the CaZn5-type with the lattice constants a = 4.8561 7 A and c = 4.0813 3 A .

Y. Khan

Papers

The crystal structure of R5Co19

A contribution to the Sm–Co phase diagram

Intermetallic compounds in the cobalt-rich part of the R-cobalt systems (R = Ce, La, CeLa)

Crystal structure of SmCo5

Crystal structure of Sm2Co17