The microstructure and magnetic characteristics of Sm(CobalFe0.1Cu0.09Zr0.03)7.24 high temperature permanent magnets

The temperature dependence of the coercivity of the Sm(CobalFe0.1Cu0.09Zr0.03)7.24 high temperature magnets prepared by a traditional powder metallurgical technology with different annealing processes was analyzed, as shown in Fig. 1. Fig. 1(a) shows three Hc(T) curves for 2μ0cKII/cJII  = 26.1 T, 2μ0cKI/cJI  = 1.25 T, εKA = 0.25 ± 0.05, εAJ = 1.8, Tccell = 1093 K, Tcwall = 920 ± 50 K and the critical exponent ξ = 0.365. Fig. 1(b) shows the temperature dependence of the type-A magnet with a higher Cu content in the cell wall and the superposition of all three analytical curves in Fig. 1(a). Fig. 1(c) shows three Hc(T) curves for 2μ0cKII/cJII  = 26.1 T, 2μ0cKI/cJI  = 1.25 T, εKA = 0.4 ± 0.1, εAJ = 1.8, Tccell = 1093 K, Tcwall = 940 ± 60 K and the critical exponent ξ = 0.365. Fig. 1(d) shows the temperature dependence of Hcj of the type-B magnet with a lower Cu content in cell wall phase and the superposition of all three analytical curves in Fig. 1(c).165