The Effect of Powder Particle Size on Magnetic and Mechanical Properties of 2:17-Type SmCo-Based High-Temperature Permanent Magnets

Aiming at the demand for improving the mechanical properties of 2:17-type SmCo-based high-temperature permanent magnets, this study achieved the refinement of alloy powder particle size by adjusting the process parameters of jet milling, without altering the chemical composition of the magnet and the existing preparation process system. Consequently, 2:17-type SmCo-based high-temperature permanent magnets with synergistically enhanced flexural strength and comprehensive magnetic properties were successfully fabricated. The results demonstrate that slightly refining the alloy powder particle size of 2:17-type SmCo-based high-temperature permanent magnets from 5.16 to 4.62 μm can increase the magnet’s flexural strength by more than 20%. Specifically, the l//c (c-axis along the magnet length) orientation direction exhibits the most significant improvement, reaching 32.56%. Microscopic analysis reveals that powder particle refinement induces grain refinement in the magnet, which provides a structural basis for the enhancement of flexural strength. Magnetic property test results indicate that with the reduction of alloy powder particle size, the remanence and maximum energy product of the magnet remain stable at 300 K while the coercivity is significantly enhanced. At 723 K, the remanence and maximum energy product of the magnet show a gradual upward trend, and the coercivity decreases slightly.