Improvement of Magnetic Properties of Mechanically Ground Sm2Fe17Nx Powders by Vacuum Heat Treatment

• Published in: Materials Transactions, JIM Vol. 38; no. 2; pp. 142 - 147
• Main Authors: Ito, Mikio, Majima, Kazuhiko, Katsuyama, Shigeru, Nagai, Hiroshi
• Format: Journal Article
• Language: English
• Published: Sendai The Japan Institute of Metals 1997; Japan Institute of Metals
• Subjects: Applied sciences; composition; Condensed matter: electronic structure, electrical, magnetic, and optical properties; crystallization; Domain effects, magnetization curves, and hysteresis; Exact sciences and technology; grain size; magnetic properties; Magnetic properties and materials; Magnetization curves, magnetization reversal, hysteresis, barkhausen and related effects; mechanical grinding; Metals. Metallurgy; nitrogenation; oxidation; Physics; rare-earth magnet; rectangularity; α-iron precipitation; Grain size; Metal powder; Crystallization; Grinding(comminution); Samarium alloy; Nitriding; Powder metallurgy; Vacuum treatment; Precipitation; Oxidation; Permanent magnet; Microstructure; Saturation magnetization; Iron base alloys; Magnetic properties
• ISSN: 0916-1821; 2432-471X
• DOI: 10.2320/matertrans1989.38.142

Sm2Fe17NX permanent magnetic powders have been prepared by mechanical grinding (MG) and subsequent heat treatments for crystallization and nitriding. Sm2.5Fe17 and Sm2.3Fe17 alloy powders have been used as a starting material. The oxygen content of the powders crystallized in vacuum is less than that of the powders crystallized in Ar atmosphere: it is less than 9000 ppm for Sm2.5Fe17 powders. Consequently, the precipitation of α-Fe, which deteriorates the rectangularity of their demagnetization curves, is suppressed. After MG for 72 ks and crystallization in vacuum the nitrided Sm2.3Fe17 powders close to stoichiometric Sm2Fe17, has no α-Fe precipitation. The saturation magnetization and remanence are larger than those of the nitrided Sm2.5Fe17 powders.