Permanent magnet materials with high energy product of (BH)max = 30 MGOe at 450°C are needed for advanced Air Force power and weapon systems, which represents a 150% improvement in magnetic performance. Owing to the degree of difficulty this objective is unlikely achievable if using any existing permanent magnets, such as conventional high temperature SmCo5, Sm2Co17, or nanocomposite Sm2Co17/Fe-Co because of various technical problems. New R2Co17 compounds have been identified and will be used in the proposed STTR Phase II project to synthesize novel high temperature and high energy product permanent magnet materials. These compounds have high Curie temperatures of 910 - 930°C. Their saturation magnetization values are 12.1 - 14.0 kG. Studies in Phase I project have demonstrated that high magnetocrystalline anisotropy can be developed in these compounds. By using these compounds coupled with composition and processing adjustments and optimization, it is anticipated that new high temperature and high energy product permanent magnets that meet the Air Force requirement can be developed by further R&D.
Keywords: High Temperature, High Energy Product, Permanent Magnets, Thermal Stability, Nd-Fe-B, Sm-Co