SmCo (2:17-type) magnets with high contents of Fe and light rare earths

Abstract

The magnetic properties of SmCo (2:17-type) magnets with high contents of Fe (v=Fe/3d≳0.34) and/or light rare earths (up to 0.4) were investigated. For magnets with compositions of Sm(FevCobalZr0.02Cu0.06{Ga}x)7.72, v=0.35, x=0–0.06, both iHc and (BH)max can be improved significantly by Ga doping, from 1.0 kOe and 5.4 MG Oe for x=0 to 6.4 kOe and 15.4 MG Oe for x=0.06. For magnets with compositions of Sm0.8Pr0.2(FevCobalZr0.02Cu0.06)7.67, v=0.30–0.31, iHc can be increased strikingly by a special heat treatment, from 2.5 to over 20 kOe for v=0.30 and from 0.5 to 15.5 kOe for v=0.31. Examining magnets with compositions of Sm0.59Pr0.41(Co0.68Fe0.20Cu0.10Zr0.02)z (z=6.68–7.75) shows two stages of the magnetization reversal process in the range of 5.5 to 9.5 kOe and 16 to 19 kOe. Observed (BH)max ranged from 17 to 22.5 MG Oe.