Microstructure and Magnetic Properties of SmCo-Based Nanocrystalline Magnets Doped With Cr3C2

The effect of wheel speed as well as an additive Cr₃C₂ on the structure, crystalline texture, and magnetic properties of SmCo-based nanocrystalline magnets has been investigated. A low wheel speed of melt spinning of SmCo_4.8(Cr₃C₂)_0.2 promotes the formation of the Crand C-contained SmCo₇ main phase with a (0001) out-of-plane texture, an average grain size of 38-60 nm, and a smooth M-H loop with sound rectangularity. On the other hand, for SmCo_4.8(Cr₃C₂)_0.2 alloys, Hci significantly enhances from 28.1 to 36.6 kOe and Mr increases from 23.2 to 28.0 emu/g with an increasing wheel speed from 30 to 50 m/s. A high wheel speed of 50 m/s in SmCo_4.8(Cr₃C₂)_0.2 contributes to the formation of dendrite SmCo₅ grains with the short axis of about 20-50 nm and the long axis ranging from 100 nanometers to about 1 micrometer. An obviously preferential orientation along the (0001) direction in SmCo₅ grains is observed, which could be confirmed by the transmission electron microscope analysis and anisotropic magnetic behavior. The addition of Cr₃C₂ gives a hint toward the direction of texturing in SmCo-based magnets melt spun at high wheel speeds.