Effects of Fe, Cu, and Zr Substitutions on Microstructure of SmCo/Fe(Co) Nanocomposite Magnets

The substitution of alloy elements is an effective method to tailor the phase composition and microstructure of nanocomposite magnets. Here, a good microstructure, i.e., high soft phase content (~28.5 wt.%), small soft phase grain size (~10 nm), and uniform distribution of soft magnetic phase grains, was successfully realized in a SmCo/Fe(Co) nanocomposite magnet through the simultaneous substitution of Fe, Cu, and Zr alloy elements. The influences of alloy element substitutions on phase composition and microstructure of SmCo nanocomposite magnets have been studied. The substitution of Fe element increases the content of soft magnetic phase. The substitution of Cu element promotes the crystallization degree of hard magnetic phase at low temperature. The substitution of Zr element reduces the grain size of the soft magnetic phase Fe(Co). The simultaneous substitution of the three elements stabilizes the existence of SmCo3 phase, which greatly improves the $H_{\mathrm {c}}$ of the sample. The optimized magnetic energy product was obtained at 580 °C when the contents of the Fe, Cu, and Zr were 14, 4, and 3 wt.%, respectively.