Effect of hot deformation on texture and magnetic properties of Sm–Co and Pr–Co alloys

Advances in nanostructured permanent magnets research

“…Hot deformation of nanocrystalline RCo 5 (R = Pr, Sm), RCo 5 /Fe and RCo 5 /Co a alloys has also been reported [224][225][226][227][228][229][230]. Yue et al [225] observed texture formation in the nanocrystalline SmCo 5 alloys prepared by a very high degree deformation at 800-900 • C. It was reported that with increasing height reduction of the sample the c-axis crystallographic alignment improves while coercivity of the magnet increases first, and then decreases again with the increase in the height reduction.…”

“…Hot deformation is an effective way to induce texture in NdFeB single-phase magnets based on the minor Nd-rich liquid phase along the grain boundaries [207][208][209][210][211][212][213][214][215][216][217][218]. Recently, several attempts have been made for preparation of anisotropic nanocomposites magnets by hot deformation [219][220][221][222][223][224][225][226][227][228][229]. For example, Lee et al [222] reported the hot deformed bulk anisotropic composite Nd 13.5 Fe 80 Ga 0.5 B 6 /α-Fe and Nd 14 Fe 79.5 Ga 0.5 B 6 /Fe-Co magnets by blending a Nd-rich Nd-Fe-Ga-B powder with an α-Fe or Fe-Co powder followed by hot compaction at 600-700 • C and hot deformation at 850-950 • C. The composite Nd 13.5 Fe 80 Ga 0.5 B 6 /α-Fe and Nd 14 Fe 79.5 Ga 0.5 B 6 /Fe-Co magnets had microstructures consisting of a very large soft phase up to ∼50 µm; however, smooth demagnetization curves and (BH) max up to 50 MG Oe were reported.…”

“…Yue et al [225] observed texture formation in the nanocrystalline SmCo 5 alloys prepared by a very high degree deformation at 800-900 • C. It was reported that with increasing height reduction of the sample the c-axis crystallographic alignment improves while coercivity of the magnet increases first, and then decreases again with the increase in the height reduction. Gabay et al [226,227] investigated hot deformation induced texture and magnetic properties of Sm-Co and Pr-Co alloys prepared by high-energy ball milling. Recently, Liu et al [230] prepared bulk anisotropic SmCo 5 /α-Fe nanocomposite magnets via chemical coating of soft phase on hard phase followed by hot deformation.…”

Effect of Deformation Temperature on Crystal Texture Formation in Hot Deformed Nanocrystalline SmCo5Permanent Magnets

“…Hot deformation is one effective way to obtain a crystallographic texture and, thereby, magnetic anisotropy in nanocrystalline permanent magnets. Gabay et al [6] observed an enhanced (00l) diffraction peak corresponding to the SmCo 5 phase in hot deformed Sm 17 Co 83 magnets, indicating a certain degree of crystallographic texture. Yue et al [7] reported that significantly improved texture can be obtained in nanocrystalline SmCo 5 alloys subjected to die upsetting at a very high degree of deformation (more than 85% height reduction).…”

Hydrogenation, Disproportionation, Desorption, and Recombination in the Sm2Co17–x Fe x –H2 System (x =3.9 and 5.95). X-Ray Diffraction

“…The magnets produced from Nd-Fe-B alloys in this way reach a maximum energy product of 50 MGsOe [6], which is lower than the theoretical value. Methods of texturing samarium-cobalt magnets are being studied extensively [7,8], but no favorable results have been obtained so far [9,10].…”