SmCobased

SmCo-based magnets refer to a family of permanent magnets composed primarily of samarium and cobalt, often with small additions of iron, copper, and zirconium to optimize performance. The most common structural families are SmCo5 and Sm2Co17, with modern variants achieving improved coercivity through alloying and diffusion treatments.

Two main crystal structures dominate SmCo-based magnets. SmCo5 magnets have a simpler 1:5 ratio, while Sm2Co17 magnets have a 2:17 ratio and generally offer higher energy density and coercivity. Additions such as iron, copper, and zirconium are used to tailor magnetic properties and thermal stability. These magnets are anisotropic, allowing their magnetization to be oriented during processing for maximum performance.

Key properties include a high magnetic energy product, excellent resistance to demagnetization, and exceptional high-temperature performance. Typical energy products range around 20–32 MGOe, and usable operating temperatures can reach approximately 250–350°C depending on grade. SmCo magnets also exhibit good corrosion resistance relative to some other rare-earth magnets, though protective coatings are still common in aggressive environments.

Manufacturing commonly involves powder metallurgy and sintering, with additional steps to induce anisotropy, such as hot pressing or diffusion treatments. The resulting magnets are relatively brittle and require careful handling, but they offer strong performance in demanding conditions.

Applications span aerospace, military, automotive, and industrial sectors, particularly where high temperature tolerance and reliable performance under demagnetization pressures are essential. Although more expensive and heavier than NdFeB magnets, SmCo-based magnets remain favored for extreme environments and long-term stability.