還元拡散法により製造されたSm-(Fe, Mn)-N磁石粉末

概要

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We have produced Sm2(Fe, Mn)17Nx coarse powders by a reduction and diffusion (R/D) method and investigated the characteristics. The Sm2(Fe, Mn)17 mother alloy powder made by the R/D method showed rounded shape and sharp particle size distribution, and was consisting of almost only Th2Zn17-type phase with minor α-Fe. For the nitrided Sm2(Fe, Mn)17N3 compound, the Mn addition increased the lattice constants of the Th2Zn17 structure and decreased both Curie temperature and magnetization of the compound. The nitrogen content of Sm2(Fe,Mn)17Nx coarse powder increased with increasing coercive force and decreasing magnetization. The nitrogenation of x>5 resulted in high corecive force more than 900 kA/m. The highest magnetic properties of Sm2(Fe0.95Mn0.05)17Nx coarse powder is Br=1.10 T, HcJ=720 kA/m and (BH)max=193 kJ/m3 at x=4.2. The Sm2(Fe0.95Mn0.05)17Nx magnet powder indicated good thermal stability. The deterioration of coercive force of Sm2(Fe0.95Mn0.05)17N4.5 powder after exposure at 160 °C for 160 h was as small as those of MQP-O and Sm2Co17 powders. The coercive force of an Sm2(Fe0.95Mn0.05)17Nx injection molded magnet with PPS was almost the same as the powder used. The time dependence of irreversible flux loss at 180 °C was similar to that of Sm2Co17 bonded magnets.
社団法人電気学会の論文
2004-10-01