A novel route for the synthesis of CaF2-coated SmCo5 flakes

CaF2-coated single-crystal and textured polycrystalline flakes have been synthesized by a solid surfactant-assisted high energy ball milling (HEBM), which is totally different from the traditional liquid surfactant-assisted HEBM. The results show that as-milled SmCo5 specimens were crystallographically anisotropic and coated very well with CaF2. Single-crystal SmCo5 flakes with a thickness of 150–700 nm were formed after HEBM for 2 h with 40 wt.% CaF2. After HEBM for 5 h, [0 0 1] textured poly-nanocrystalline SmCo5 flakes were mainly formed. The c-axes of most of the grains is perpendicular to the flake surface. The texture intensities reduced with either increasing the milling time or reducing the amount of CaF2.

► A novel solid inorganic surfactant, CaF2, did work to assist to fabricate SmCo5 flakes. ► Single-crystal and textured polycrystalline SmCo5 flakes were obtained by using solid surfactant. ► SmCo5 flakes coated with CaF2 layers have unique or new applications in high electrical resistivity magnets.