Enhanced Magnetic Properties and Thermal Stability of Nd2Fe14B/SmCo5 Composite Permanent Magnets Prepared by Spark Plasma Sintering

Nanocomposite Nd
₂
Fe
₁₄
B/SmCo
₅
permanent magnets with different weight ratios have been prepared by spark plasma sintering mixtures of homemade amorphous SmCo
₅
powders and commercially available Nd
₂
Fe
₁₄
B powders. The magnetic properties of the nanocomposite magnets are sensitive to the ratio of the two hard phases. The peak (BH)max value of 14.4 MGOe is obtained at the SmCo
₅
/Nd
₂
Fe
₁₄
B ratio of 4:1, which is ~50% higher than that of the single-phase SmCo
₅
magnet prepared under the same preparation conditions. Hysteresis loop of the nanocomposite magnet shows the characteristics of single-phase magnet due to strong exchange coupling between the two phase grains. At high temperatures, the nanocomposite magnets exhibit greatly improved thermal stability compared with the single-phase Nd
₂
Fe
₁₄
B magnet.